Abstract

Transverse myelitis (TM) is an inflammatory disorder of the spinal cord characterized by acute or subacute development of bilateral motor, sensory, and autonomic dysfunction attributable to focal spinal cord inflammation. Although historically associated with viral infections, systemic autoimmune disorders, demyelinating diseases, and idiopathic immune-mediated mechanisms, the emergence of SARS-CoV-2 has introduced a new context in which inflammatory spinal cord injury has been reported following both acute infection and, less commonly, after immunization. The COVID-19 pandemic has provided unprecedented insight into the complex interactions between viral infection, host immunity, vascular biology, and neuroinflammation.

Reported cases of COVID-19–associated transverse myelitis have occurred during acute infection, during the postinfectious period, and in the setting of multisystem inflammatory responses. Clinical presentations range from isolated sensory disturbances and weakness to severe paraplegia with bowel and bladder dysfunction. Magnetic resonance imaging (MRI) typically demonstrates longitudinally extensive or focal spinal cord lesions, while cerebrospinal fluid (CSF) analysis frequently reveals inflammatory abnormalities, including pleocytosis and elevated protein concentrations. However, considerable heterogeneity exists, suggesting that COVID-19–associated TM represents a spectrum of immunologic disorders rather than a single disease entity.

Current evidence supports several possible pathogenic pathways, including immune-mediated demyelination, molecular mimicry between viral antigens and neural proteins, dysregulated T-cell and B-cell activation, cytokine-driven inflammation, endothelial injury, complement activation, and disruption of the blood–spinal cord barrier. Direct invasion of spinal cord tissue by SARS-CoV-2 remains controversial, with limited pathological evidence supporting true viral neurotropism compared with indirect immune-mediated mechanisms.

Genetic susceptibility is likely to influence individual risk. Variations in human leukocyte antigen (HLA) genes, interferon signaling pathways, innate immune regulators, and autoimmune susceptibility loci may determine whether an individual mounts a protective antiviral response or develops pathological inflammation. Advances in genomics, single-cell immune profiling, and molecular biomarker discovery are beginning to clarify why rare individuals develop severe neurologic complications after SARS-CoV-2 exposure.

Treatment strategies remain based primarily on established approaches for inflammatory myelitis, including high-dose intravenous corticosteroids, plasma exchange, intravenous immunoglobulin, and targeted immunotherapy for refractory disease. Early recognition and aggressive treatment are associated with improved neurological recovery, although persistent sensory abnormalities, neuropathic pain, gait impairment, and autonomic dysfunction may occur.

Long-term outcome data remain limited but suggest that COVID-19–associated TM can follow diverse trajectories. Some patients experience substantial neurological recovery, whereas others develop chronic disability consistent with incomplete spinal cord injury. Future research integrating clinical phenotyping, immunology, genomics, and longitudinal follow-up will be essential to determine mechanisms, identify susceptible individuals, and develop precision therapies.

Introduction

The spinal cord represents one of the most biologically complex structures in the human nervous system, integrating descending motor pathways, ascending sensory systems, autonomic networks, and segmental reflex circuits. Injury to this highly organized structure can produce profound functional impairment, including paralysis, sensory loss, chronic neuropathic pain, and irreversible disturbances of bladder and bowel control. Among inflammatory disorders affecting the spinal cord, transverse myelitis occupies a unique position because it represents not a single disease but a clinical syndrome produced by multiple convergent biological mechanisms.

The classical definition of transverse myelitis describes an inflammatory lesion involving the spinal cord that produces bilateral neurological dysfunction attributable to spinal cord involvement, with evidence of inflammation demonstrated clinically, radiologically, or through cerebrospinal fluid analysis. The disorder may involve a short segment of the spinal cord or extend across multiple vertebral levels, producing the syndrome known as longitudinally extensive transverse myelitis (LETM). Historically, TM has been recognized following viral infections, vaccinations, autoimmune diseases, malignancies, and systemic inflammatory states.¹

Before the COVID-19 pandemic, transverse myelitis was considered a rare neurological condition, with estimated annual incidence rates ranging from approximately 1 to 8 cases per million persons depending on diagnostic criteria and population studied.² The rarity of the disorder creates substantial challenges in establishing causation when cases appear after a new biological exposure. A temporal relationship alone cannot determine whether an exposure caused the event, because rare neurological disorders occur spontaneously within any large population.

The emergence of SARS-CoV-2 fundamentally altered understanding of infection-associated neurological disease. Although initially characterized primarily as a respiratory pathogen, SARS-CoV-2 rapidly became recognized as a multisystem inflammatory virus capable of affecting the nervous system through immune activation, vascular injury, endothelial dysfunction, and systemic inflammatory pathways. Neurological manifestations reported during COVID-19 include encephalopathy, cerebrovascular disease, seizures, peripheral neuropathies, dysautonomia, anosmia, cognitive dysfunction, and inflammatory demyelinating disorders.³

Transverse myelitis emerged as one of the rare but biologically important neurological complications associated with SARS-CoV-2 infection. The earliest reports described patients developing rapidly progressive weakness, sensory abnormalities, and autonomic dysfunction during or shortly after COVID-19 illness. Some patients had evidence of spinal cord inflammation despite minimal respiratory disease, suggesting that neurological injury may occur through immune mechanisms rather than through the severity of pulmonary infection alone.⁴

Several observations support an immune-mediated model of COVID-associated TM. First, many patients develop neurological symptoms after the peak of viral replication, during a period when adaptive immune responses are activated. Second, CSF studies often reveal inflammatory patterns without detectable viral RNA. Third, many patients respond to immunomodulatory therapies such as corticosteroids and plasma exchange, consistent with an inflammatory rather than purely degenerative process.⁵

Nevertheless, the pathogenesis remains incompletely understood. SARS-CoV-2 possesses several biological properties capable of triggering immune dysregulation. Viral proteins may activate innate immune pathways through pattern-recognition receptors, stimulating production of interferons, interleukins, tumor necrosis factor, and chemokines. In susceptible individuals, these responses may become excessive, resulting in immune-mediated injury to neural tissue.⁶

The concept of molecular mimicry has received particular attention. In this model, structural similarities between viral proteins and host neural antigens may generate cross-reactive immune responses. Activated T cells or antibodies initially directed against SARS-CoV-2 antigens may inadvertently recognize components of myelin, oligodendrocytes, neurons, or vascular structures within the spinal cord. Similar mechanisms have been proposed in other postinfectious neurological disorders, including Guillain–Barré syndrome and acute disseminated encephalomyelitis.⁷

Another emerging mechanism involves vascular and endothelial dysfunction. SARS-CoV-2 infection can induce widespread endothelial activation, platelet abnormalities, complement activation, and microvascular inflammation. The spinal cord has a particularly vulnerable microvascular architecture, and disruption of spinal cord perfusion or the blood–spinal cord barrier may permit immune-cell infiltration and inflammatory injury.⁸

The genetic basis of susceptibility remains an important area of investigation. Most individuals infected with SARS-CoV-2 do not develop inflammatory neurological complications, suggesting that host factors strongly influence disease expression. Variants affecting antigen presentation, interferon signaling, immune regulation, and inflammatory pathways may determine whether immune responses remain protective or become pathogenic.⁹

The study of COVID-associated transverse myelitis therefore provides a broader window into neuroimmunology. It illustrates how a viral infection can act as a trigger for complex interactions between genetic predisposition, immune activation, vascular biology, and neural vulnerability. Understanding these mechanisms may improve not only management of COVID-associated TM but also treatment of other immune-mediated neurological diseases.

This review examines current evidence regarding COVID-19–associated transverse myelitis, integrating epidemiology, immunopathogenesis, genomics, physiology, neuropathology, diagnostic approaches, therapeutic strategies, and long-term outcomes. Particular emphasis is placed on distinguishing established evidence from evolving hypotheses and identifying areas where future research is needed.

Epidemiology

Determining the true incidence of COVID-19–associated transverse myelitis (TM) represents a significant epidemiological challenge. Transverse myelitis is itself a rare neurological syndrome, and the additional requirement of establishing a temporal or mechanistic relationship with SARS-CoV-2 infection introduces further complexity. Unlike common complications of COVID-19, such as respiratory failure, thromboembolic disease, or acute kidney injury, inflammatory spinal cord syndromes occur infrequently and are often identified through individual case reports, institutional series, and neurological surveillance systems.

Prior to the COVID-19 pandemic, population-based studies estimated the annual incidence of acute transverse myelitis to be approximately 1–8 cases per million persons per year, although estimates vary according to diagnostic criteria, geographic region, and ascertainment methodology.¹ In pediatric populations, incidence estimates are generally lower but may vary substantially because of differences in recognition and classification of acute inflammatory demyelinating syndromes.²

The appearance of TM following SARS-CoV-2 infection was first recognized during the early months of the pandemic. Published reports described patients developing neurological deficits during active infection or within several days to weeks after respiratory symptoms had resolved. These cases raised the possibility that SARS-CoV-2 could function as a trigger for inflammatory spinal cord injury, similar to other viral infections historically associated with postinfectious myelitis.

However, the rarity of reported cases makes precise risk estimation difficult. Large observational studies examining neurological complications after COVID-19 infection have identified increased risks of multiple neurological disorders, but transverse myelitis remains uncommon relative to other manifestations.³ The available evidence suggests that while SARS-CoV-2 infection may increase the probability of inflammatory neurological disease, the absolute risk of developing TM remains extremely low.

A critical methodological issue is distinguishing increased recognition from increased incidence. During the pandemic, clinicians were highly alert to neurological complications of COVID-19, potentially increasing reporting of rare events that may previously have been attributed to idiopathic causes. Conversely, some cases may have been missed because neurological symptoms occurred after mild or asymptomatic infection.

Temporal Relationship Between SARS-CoV-2 Infection and Transverse Myelitis

Reported cases of COVID-associated TM demonstrate three broad temporal patterns:

1. Acute COVID-19–Associated Myelitis

Some individuals develop spinal cord inflammation during active SARS-CoV-2 infection. These patients may present with respiratory symptoms, fever, systemic inflammation, and rapidly progressive neurological deficits.

The simultaneous presence of infection and neurological disease raises several possibilities:

direct viral-mediated injury,
systemic cytokine-driven inflammation,
endothelial injury,
immune activation occurring early in infection.

However, direct detection of SARS-CoV-2 within spinal cord tissue has been uncommon, and most cases do not demonstrate evidence of viral replication within the central nervous system.

2. Postinfectious Transverse Myelitis

The majority of reported cases appear to follow a postinfectious pattern, occurring days to weeks after recovery from acute COVID-19.

This timing resembles classic postviral autoimmune neurological disease. The immune system, after successfully responding to infection, may remain activated and generate inflammatory responses directed against host tissues.

Typical features include:

delayed neurological onset,
negative viral testing in cerebrospinal fluid,
inflammatory CSF findings,
spinal cord lesions on MRI,
response to immunotherapy.

This pattern supports an autoimmune mechanism rather than direct viral destruction.

3. Transverse Myelitis in the Context of Long COVID

A subset of patients with persistent post-COVID symptoms have reported sensory disturbances, weakness, autonomic dysfunction, neuropathic pain, and gait abnormalities. In some individuals, inflammatory spinal cord disease has been proposed as a contributor to long COVID neurological syndromes.

However, it is important to distinguish confirmed inflammatory myelitis from broader post-COVID neurological dysfunction. Many patients with long COVID have symptoms related to:

autonomic dysregulation,
small-fiber neuropathy,
immune activation,
metabolic abnormalities,
vascular dysfunction,
central nervous system inflammatory changes,

without evidence of structural spinal cord inflammation.

Clinical Phenotypes

COVID-associated TM does not present as a uniform disorder. Published cases demonstrate substantial variation in severity, anatomical localization, and recovery.

Motor Dysfunction

Weakness is among the most common presenting features. Depending on lesion location and severity, patients may experience:

lower-extremity weakness,
paraparesis,
quadriparesis,
spasticity,
impaired gait,
complete paralysis.

The neurological pattern reflects interruption of corticospinal pathways within the spinal cord.

Damage to descending motor tracts produces:

loss of voluntary movement,
increased muscle tone,
hyperreflexia,
pathologic reflexes.

Early in the disease process, however, patients may demonstrate flaccid weakness because of spinal shock, in which reflex activity temporarily decreases below the level of injury.

Sensory Dysfunction

Sensory abnormalities are highly characteristic of TM and often provide important diagnostic clues.

Patients may report:

numbness,
tingling,
burning pain,
altered temperature perception,
electrical sensations,
impaired proprioception.

A sensory level on neurological examination—the point below which sensation becomes impaired—is a key finding suggesting spinal cord localization.

Commonly reported sensory levels include:

cervical levels producing arm and leg involvement,
thoracic levels producing lower-body dysfunction,
conus or lower spinal involvement affecting sacral sensation.

Persistent sensory symptoms are among the most frequent long-term complications, even in patients with substantial motor recovery.

Autonomic Dysfunction

The spinal cord contains critical pathways controlling bladder, bowel, and sexual function. Consequently, autonomic impairment is common in moderate-to-severe cases.

Clinical manifestations include:

Urinary dysfunction

urinary retention,
incomplete bladder emptying,
urgency,
incontinence,
recurrent urinary infections.

Bowel dysfunction

constipation,
impaired bowel sensation,
fecal incontinence.

Sexual dysfunction

erectile dysfunction,
impaired genital sensation,
autonomic sexual dysfunction.

Autonomic recovery often occurs more slowly than motor recovery and may remain incomplete.

MRI Characteristics

Magnetic resonance imaging is central to diagnosis.

Typical findings include:

T2 hyperintense intramedullary lesions

These represent increased water content associated with:

inflammation,
edema,
demyelination,
tissue injury.

Longitudinally extensive lesions

Some COVID-associated cases demonstrate lesions extending over three or more vertebral segments.

These lesions raise consideration of:

neuromyelitis optica spectrum disorder,
MOG antibody-associated disease,
systemic autoimmune disease,
severe inflammatory activation.

Enhancement patterns

Gadolinium enhancement may indicate active inflammation and breakdown of the blood–spinal cord barrier.

Patterns include:

patchy enhancement,
peripheral enhancement,
longitudinal enhancement.

Evidence for Causality: Association Versus Coincidence

A central challenge in interpreting COVID-associated TM is determining whether SARS-CoV-2 caused the disease or whether cases represent coincidental occurrence.

The evaluation of causality requires consideration of:

Temporality
Did infection precede neurological disease?
Biological plausibility
Are there mechanisms by which SARS-CoV-2 could trigger myelitis?
Strength of association
Is the risk substantially higher than background incidence?
Consistency
Are findings reproducible across populations?
Specificity
Is the association unique compared with other infections?
Experimental evidence
Do immunological or pathological studies support causation?

Applying these criteria suggests that SARS-CoV-2 infection can plausibly trigger inflammatory myelitis in rare individuals. However, the absolute frequency remains very low, and the precise magnitude of increased risk remains uncertain.

Summary of Epidemiologic Findings

Current evidence indicates:

COVID-19 infection is associated with rare cases of transverse myelitis.
Most cases appear immune-mediated rather than caused by direct viral invasion.
The condition occurs most commonly during the postinfectious period.
Clinical severity ranges from sensory abnormalities to severe paralysis.
Recovery is variable and depends on lesion extent, early treatment, and underlying immune mechanisms.
Large-scale epidemiologic studies are still needed to quantify risk accurately.

Overview

The biological mechanisms responsible for COVID-19–associated transverse myelitis (TM) remain incompletely defined, but current evidence strongly favors a model in which immune-mediated injury, rather than direct viral destruction of spinal cord tissue, represents the dominant pathway. SARS-CoV-2 possesses multiple properties capable of initiating profound immunological activation, including stimulation of innate immune receptors, induction of inflammatory cytokines, endothelial injury, complement activation, and prolonged immune dysregulation.

The spinal cord is particularly vulnerable to immune-mediated injury because neurological function depends on highly organized networks of neurons, axons, oligodendrocytes, myelin sheaths, astrocytes, microglia, and vascular structures. Even limited inflammatory injury can disrupt conduction through major ascending and descending pathways, producing profound neurological deficits.

COVID-19–associated TM likely represents a convergence of several mechanisms:

Postinfectious autoimmunity
Molecular mimicry between viral and neural antigens
Aberrant T-cell activation
Autoantibody generation
Cytokine-mediated neuroinflammation
Complement-mediated injury
Microvascular and endothelial dysfunction
Disruption of the blood–spinal cord barrier
Genetic susceptibility influencing immune responses

These mechanisms are not mutually exclusive. A genetically susceptible individual may experience viral exposure, develop excessive innate immune activation, generate cross-reactive adaptive immunity, and subsequently sustain inflammatory spinal cord injury.

Direct Viral Neuroinvasion: A Controversial Mechanism

Early during the COVID-19 pandemic, concern arose that SARS-CoV-2 might directly invade the central nervous system (CNS) and infect neural tissue. Several observations supported this possibility:

neurological symptoms occurred during acute infection;
SARS-CoV-2 RNA was detected occasionally in cerebrospinal fluid (CSF);
the virus demonstrated neurotropic behavior in experimental models;
anosmia suggested involvement of neural pathways.

However, evidence for direct spinal cord infection remains limited.

In most reported cases of COVID-associated TM:

SARS-CoV-2 PCR in CSF has been negative;
inflammatory markers are present without detectable virus;
immune-directed therapies have produced improvement.

These findings suggest that the spinal cord is usually injured indirectly through immune mechanisms.

The difficulty in demonstrating viral invasion is partly related to the biology of SARS-CoV-2. Unlike viruses such as poliovirus or West Nile virus, which have established neuroinvasive patterns, SARS-CoV-2 appears to produce neurological injury predominantly through systemic inflammation, endothelial dysfunction, immune activation, and vascular mechanisms.

Molecular Mimicry and Autoimmune Cross-Reactivity

Conceptual Basis

Molecular mimicry occurs when microbial proteins contain molecular structures sufficiently similar to host proteins that immune responses generated against the pathogen cross-react with human tissues.

This mechanism has been proposed in:

Guillain–Barré syndrome,
rheumatic fever,
autoimmune encephalitis,
multiple sclerosis-like disorders.

In SARS-CoV-2 infection, antibodies and T cells directed against viral proteins may theoretically recognize:

myelin proteins,
oligodendrocyte components,
neuronal antigens,
vascular endothelial proteins.

The spike protein has received particular attention because it contains multiple immunogenic regions capable of stimulating strong antibody and T-cell responses.

Potential Neural Targets

Candidate targets include:

Myelin-associated proteins

Possible immune targets include:

myelin basic protein (MBP),
proteolipid protein (PLP),
myelin oligodendrocyte glycoprotein (MOG).

Damage to these structures can impair saltatory conduction and produce neurological deficits.

Oligodendrocytes

Oligodendrocytes maintain CNS myelin. Immune-mediated injury may result in:

demyelination,
conduction block,
axonal vulnerability.

Astrocytes

Astrocytes regulate:

blood–brain barrier integrity,
extracellular potassium balance,
inflammatory signaling.

Astrocytic injury may amplify spinal cord inflammation.

T-Cell–Mediated Neuroinflammation

Adaptive cellular immunity is central to inflammatory myelitis.

After SARS-CoV-2 exposure, antigen-presenting cells activate T lymphocytes through major histocompatibility complex (MHC) pathways.

Several T-cell populations may participate:

CD4+ Helper T Cells

CD4+ cells coordinate immune responses through cytokine production.

Important subsets include:

Th1 cells

Produce:

interferon-γ,
tumor necrosis factor-α.

These cytokines promote macrophage activation and inflammatory tissue injury.

Th17 cells

Produce:

interleukin-17,
interleukin-22.

Th17 responses have been implicated in autoimmune neurological diseases because they promote:

neutrophil recruitment,
endothelial activation,
blood–brain barrier disruption.

Regulatory T Cells

Regulatory T cells normally suppress excessive immunity.

Impaired regulatory function may permit uncontrolled inflammation.

Cytokine Dysregulation and the Inflammatory Cascade

Severe COVID-19 is characterized by abnormal cytokine signaling, sometimes referred to as a “cytokine storm.”

Although TM patients do not necessarily experience systemic cytokine storms, localized immune activation may occur within the nervous system.

Important cytokines include:

Interleukin-6 (IL-6)

IL-6 promotes:

immune-cell recruitment,
acute-phase responses,
differentiation of inflammatory T cells.

Elevated IL-6 has been associated with severe COVID-19 and neurological complications.

Tumor Necrosis Factor-α (TNF-α)

TNF-α contributes to:

oligodendrocyte injury,
myelin disruption,
endothelial inflammation.

TNF signaling has long been implicated in inflammatory demyelinating disease.

Interferon Signaling

Type I interferons (IFN-α and IFN-β) represent critical antiviral defenses.

However, abnormal timing or intensity of interferon responses may contribute to tissue injury.

Early interferon activation is protective, whereas delayed excessive activation may promote inflammation.

Blood–Spinal Cord Barrier Dysfunction

The blood–spinal cord barrier (BSCB) is essential for maintaining neural homeostasis.

It consists of:

endothelial cells,
tight junction proteins,
pericytes,
astrocytic end-feet,
extracellular matrix components.

Inflammation can disrupt this barrier, allowing:

lymphocyte infiltration,
antibody entry,
complement activation,
inflammatory mediator penetration.

SARS-CoV-2 infection promotes endothelial activation through:

inflammatory cytokines,
oxidative stress,
platelet activation,
complement deposition.

Loss of BSCB integrity provides a pathway through which systemic immune activation can become spinal cord injury.

Complement Activation

The complement system is an ancient component of innate immunity that recognizes pathogens and promotes immune defense.

However, excessive complement activation can damage host tissue.

Mechanisms include:

membrane attack complex formation,
endothelial injury,
inflammatory amplification,
recruitment of immune cells.

Studies of severe COVID-19 have demonstrated complement activation in vascular tissues.

Similar pathways may contribute to inflammatory spinal cord injury in susceptible individuals.

Autoantibodies and Humoral Immunity

B-cell activation following SARS-CoV-2 infection may produce antibodies directed against:

viral antigens,
host neural proteins,
vascular structures.

Potentially relevant antibodies include:

aquaporin-4 antibodies,
MOG antibodies,
nonspecific autoimmune antibodies.

Importantly, COVID-associated TM must be differentiated from established autoimmune disorders.

A patient developing TM after SARS-CoV-2 infection may actually have:

neuromyelitis optica spectrum disorder (NMOSD),
MOG antibody-associated disease,
multiple sclerosis,
systemic lupus-associated myelitis.

Therefore, comprehensive antibody testing is essential.

Microvascular Injury and Spinal Cord Ischemia

Another proposed mechanism involves vascular injury.

SARS-CoV-2 can produce:

endothelial inflammation,
abnormal coagulation,
platelet activation,
microthrombi formation.

The spinal cord has a vulnerable arterial supply, particularly in watershed regions.

Microvascular dysfunction may cause:

ischemic injury,
secondary inflammation,
impaired repair.

Some cases initially diagnosed as inflammatory TM may include a vascular component.

Integrated Pathogenic Model

A unified model of COVID-associated transverse myelitis can be summarized as follows:

Step 1: Viral exposure

↓

Step 2: Innate immune activation

Activation of macrophages, dendritic cells, interferons, and inflammatory pathways

↓

Step 3: Adaptive immune stimulation

Activation of T cells and B cells

↓

Step 4: Loss of immune tolerance

Molecular mimicry and autoimmune activation

↓

Step 5: Blood–spinal cord barrier disruption

Immune cells and antibodies enter CNS tissue

↓

Step 6: Spinal cord inflammation

Demyelination, axonal injury, edema, neuronal dysfunction

↓

Step 7: Clinical syndrome

Weakness, sensory loss, autonomic dysfunction

Conclusions

Current evidence suggests that COVID-19–associated transverse myelitis represents a rare but biologically plausible immune-mediated complication of SARS-CoV-2 infection. The dominant mechanisms appear to involve dysregulated host immunity rather than direct viral destruction of spinal cord tissue.

The disorder likely emerges from interaction between:

viral-triggered immune activation,
genetic susceptibility,
autoimmune cross-reactivity,
inflammatory cytokine signaling,
vascular dysfunction.

Understanding these pathways is essential because it may allow future development of targeted therapies aimed not only at suppressing inflammation but at correcting specific immune abnormalities responsible for neurological injury.

Genomics of Susceptibility in COVID-19–Associated Transverse Myelitis: HLA Biology, Interferon Networks, Autoimmune Predisposition, and Precision Neuroimmunology

Overview

One of the most fundamental unanswered questions in COVID-19–associated transverse myelitis (TM) is why only a very small proportion of individuals exposed to SARS-CoV-2 develop inflammatory spinal cord disease. Hundreds of millions of people worldwide have experienced SARS-CoV-2 infection, yet inflammatory myelitis remains exceedingly uncommon. This discrepancy strongly suggests that infection alone is insufficient to produce spinal cord injury and that additional factors—genetic susceptibility, immune regulation, environmental exposures, age, comorbid conditions, and stochastic immune events—shape individual risk.

Modern genomic research has demonstrated that severe infectious and autoimmune diseases are rarely determined by a single gene mutation. Rather, they arise from complex interactions among multiple genetic variants that influence:

antigen recognition,
interferon signaling,
inflammatory regulation,
complement activation,
lymphocyte development,
immune tolerance,
tissue repair.

COVID-19–associated TM therefore provides an opportunity to study a broader principle in medicine: the transition from a protective antiviral immune response to pathological autoimmunity.

At present, no single genetic variant has been proven to cause COVID-associated TM. However, several genomic pathways have biological plausibility based on knowledge from autoimmune neurological disease, inflammatory demyelination, and severe COVID-19.

Human Leukocyte Antigen (HLA) System and Antigen Presentation

Central Role of HLA Biology

The human leukocyte antigen (HLA) system represents the major genetic determinant of adaptive immune recognition.

Located on chromosome 6, HLA genes encode molecules responsible for presenting peptide fragments to T lymphocytes.

Two major pathways are relevant:

Class I HLA molecules

Including:

HLA-A
HLA-B
HLA-C

These present intracellular peptides to CD8+ cytotoxic T cells.

Class II HLA molecules

Including:

HLA-DR
HLA-DQ
HLA-DP

These present extracellular peptides to CD4+ helper T cells.

Because SARS-CoV-2 infection produces extensive viral protein exposure, HLA variation may influence:

which viral peptides are presented,
the strength of immune activation,
whether self-reactive lymphocytes escape suppression.

HLA and Autoimmune Neurological Disease

HLA associations have been identified in multiple neuroinflammatory disorders.

Examples include:

Multiple sclerosis

Strong associations exist with:

HLA-DRB1*15:01

This allele enhances presentation of myelin-derived peptides and increases susceptibility to CNS demyelination.

Neuromyelitis optica spectrum disorder

Associations include:

HLA-DPB1 variants,
HLA-DRB1 variants.

MOG antibody-associated disease

Specific HLA backgrounds appear to influence antibody generation against myelin oligodendrocyte glycoprotein.

These observations are relevant because some cases of COVID-associated TM may represent activation of previously silent autoimmune tendencies.

HLA and SARS-CoV-2 Immune Responses

Different HLA types bind SARS-CoV-2 peptides with different efficiency.

Some variants may produce:

stronger antiviral responses,
rapid viral clearance,
limited inflammation.

Others may promote:

prolonged antigen presentation,
excessive T-cell activation,
inflammatory cytokine production.

Computational studies have suggested that some HLA alleles may present SARS-CoV-2 peptides that share similarity with human proteins, potentially increasing the theoretical risk of molecular mimicry.

However, these findings remain hypothesis-generating and require confirmation in patients with documented inflammatory neurological disease.

Type I Interferon Pathway Genetics

Importance of Interferon Signaling

Type I interferons represent one of the earliest antiviral defense mechanisms.

The pathway includes:

viral recognition receptors,
interferon production,
interferon receptors,
downstream signaling molecules,
antiviral gene activation.

Important genes include:

IFNAR1
IFNAR2
STAT1
STAT2
IRF7
IRF9
TLR3

Interferon Defects and COVID-19 Neurological Disease

Research has demonstrated that some patients with severe COVID-19 possess inherited or acquired defects in type I interferon immunity.

These defects may produce:

inadequate early antiviral defense,
increased viral persistence,
excessive inflammatory compensation.

A defective interferon response may theoretically contribute to neurological complications through two opposing mechanisms:

Failure to rapidly control infection

leading to greater antigen exposure.

Delayed immune activation

leading to uncontrolled inflammatory responses.

STAT Pathway Regulation

Signal transducer and activator of transcription (STAT) proteins regulate cytokine responses.

Important pathways include:

JAK-STAT signaling,
interferon response genes,
inflammatory regulation.

Alterations in STAT signaling may influence:

antiviral immunity,
autoimmunity,
inflammatory tissue injury.

In the spinal cord, abnormal cytokine signaling may amplify activation of:

microglia,
astrocytes,
infiltrating lymphocytes.

Autoimmune Susceptibility Genes

Beyond HLA and interferon pathways, multiple genes influence autoimmune risk.

Important categories include:

Immune checkpoint regulation

Genes affecting immune tolerance include:

CTLA4
PTPN22
IL2RA

These pathways regulate whether activated immune cells are suppressed or allowed to persist.

Cytokine regulation genes

Variants affecting:

IL6 signaling,
TNF pathways,
IL17 pathways,

may influence inflammatory intensity.

Complement pathway genes

Complement activation is increasingly recognized as a component of COVID-associated inflammation.

Genes influencing complement regulation include:

C3
C4
CFH
CD46

Alterations could modify susceptibility to inflammatory vascular or neural injury.

Epigenetic Regulation

Genetic sequence alone does not determine immune behavior.

Epigenetic mechanisms modify gene expression through:

DNA methylation,
histone modification,
noncoding RNA regulation.

Viral infections can produce long-lasting epigenetic changes in immune cells.

Potential consequences include:

persistent inflammatory signaling,
altered immune memory,
abnormal cytokine responses.

This concept may be particularly relevant to long COVID, where persistent immune abnormalities have been observed months after infection.

MicroRNA Regulation

MicroRNAs are small RNA molecules that regulate gene expression after transcription.

SARS-CoV-2 infection alters expression of multiple microRNAs involved in:

interferon pathways,
inflammation,
apoptosis,
immune-cell differentiation.

Certain microRNA profiles may influence whether immune activation resolves or persists.

Potential future applications include:

diagnostic biomarkers,
predictors of neurological complications,
therapeutic targets.

Genomic Similarities Between COVID-19 TM and Other Demyelinating Disorders

A major research question is whether COVID-associated TM represents a new disease entity or whether SARS-CoV-2 triggers known autoimmune pathways.

Several similarities exist with established disorders:

Multiple Sclerosis

Shared mechanisms:

T-cell activation,
oligodendrocyte injury,
blood–brain barrier disruption.

Differences:

COVID-associated cases often have a monophasic course.

Neuromyelitis Optica Spectrum Disorder

Shared mechanisms:

severe spinal cord inflammation,
longitudinal lesions.

Differences:

aquaporin-4 antibodies are usually absent in postinfectious TM.

MOG Antibody Disease

Shared mechanisms:

immune targeting of myelin.

Differences:

MOG antibodies are not consistently detected.

The Concept of Genetic Thresholds

The most likely model is not a single susceptibility gene but a cumulative threshold effect.

An individual may possess:

moderately increased autoimmune susceptibility,
specific HLA characteristics,
altered interferon regulation,
environmental triggers.

Individually, each factor may be insufficient.

Together, they may create a biological environment where SARS-CoV-2 exposure triggers pathological inflammation.

A conceptual model:

Genetic predisposition

Viral immune activation

Environmental modifiers

Failure of immune regulation

Inflammatory spinal cord injury

Future Directions in Genomic Research

Future studies should incorporate:

Whole-genome sequencing

to identify rare variants.

Genome-wide association studies

to detect common susceptibility loci.

Single-cell RNA sequencing

to characterize immune-cell states.

Spatial transcriptomics

to determine where inflammatory pathways occur within nervous tissue.

Multi-omics approaches

Combining:

genomics,
transcriptomics,
proteomics,
metabolomics.

These approaches may eventually allow prediction of which patients are most vulnerable to neurological complications after infection.

Conclusions

The genomic basis of COVID-19–associated transverse myelitis remains an emerging field. Current evidence suggests that susceptibility is likely determined by a complex interaction among antigen presentation genes, interferon pathways, autoimmune risk variants, inflammatory regulators, and epigenetic modifications.

The rarity of the disorder despite widespread SARS-CoV-2 exposure strongly supports the existence of host susceptibility factors. Identifying these factors may ultimately transform management from reactive treatment to predictive, preventive neuroimmunology.

Physiology and Neurobiology of COVID-19–Associated Transverse Myelitis: Spinal Cord Pathways, Demyelination, Axonal Injury, Neurovascular Dysfunction, and Mechanisms of Recovery

Overview

Understanding the neurological consequences of COVID-19–associated transverse myelitis (TM) requires an appreciation of the highly specialized physiology of the spinal cord. The spinal cord is not merely a passive communication pathway between the brain and peripheral nervous system; it is an active computational structure responsible for integrating sensory information, coordinating movement, maintaining posture, regulating autonomic function, and supporting complex reflex networks.

Inflammatory injury associated with SARS-CoV-2 infection can disrupt this delicate organization through multiple mechanisms:

inflammatory demyelination,
oligodendrocyte dysfunction,
axonal injury,
neuronal stress,
astrocytic activation,
microglial-mediated inflammation,
vascular compromise,
disruption of synaptic networks.

The clinical manifestations of COVID-associated TM—weakness, sensory loss, neuropathic pain, gait impairment, bladder dysfunction, and autonomic abnormalities—reflect interruption of specific spinal cord pathways.

Functional Organization of the Spinal Cord

The spinal cord consists of:

Gray matter
White matter
Ascending sensory pathways
Descending motor pathways
Autonomic networks

The central gray matter contains neuronal cell bodies and interneurons, while the surrounding white matter contains heavily myelinated axons traveling between the brain and peripheral nervous system.

Inflammation can affect all components simultaneously.

The Major Motor Pathways

Corticospinal Tracts

The corticospinal tracts are the principal pathways controlling voluntary movement.

Origin:

motor cortex of the brain.

Course:

internal capsule,
brainstem,
medullary pyramids,
spinal cord.

Function:

precise control of limb movement,
fine motor coordination,
voluntary strength.

Inflammation affecting corticospinal fibers produces:

weakness,
spasticity,
hyperreflexia,
impaired coordination.

The severity depends on:

lesion location,
lesion length,
degree of axonal preservation.

The Major Sensory Pathways

Dorsal Column System

The dorsal columns transmit:

vibration,
fine touch,
proprioception,
position sense.

Damage produces:

impaired balance,
sensory ataxia,
difficulty walking,
impaired foot placement.

Many patients with spinal inflammatory disorders describe a sensation of “walking on foam” or uncertainty about foot position because proprioceptive information is disrupted.

Spinothalamic Tracts

The spinothalamic pathways transmit:

pain,
temperature,
crude touch.

Inflammatory injury can produce:

burning pain,
temperature abnormalities,
hypersensitivity,
numbness.

Neuropathic pain may persist even after inflammation resolves because damaged sensory pathways undergo abnormal electrical remodeling.

Why Transverse Myelitis Produces Bilateral Symptoms

The term “transverse” refers to involvement across the width of the spinal cord.

Unlike a peripheral nerve injury affecting a single nerve distribution, a transverse spinal cord lesion can interrupt multiple systems simultaneously.

A single inflammatory lesion may affect:

corticospinal tracts,
sensory pathways,
sympathetic pathways,
parasympathetic pathways.

This explains why patients may simultaneously experience:

leg weakness,
numbness,
urinary dysfunction,
sexual dysfunction,
abnormal pain sensations.

Demyelination: The Central Physiological Event

Normal Myelin Function

Myelin is produced in the central nervous system by oligodendrocytes.

Its functions include:

increasing conduction velocity,
insulating axons,
maintaining metabolic support.

Myelin allows saltatory conduction, where electrical impulses rapidly jump between nodes of Ranvier.

Consequences of Demyelination

When inflammation damages myelin:

Electrical conduction slows.
Signals become unreliable.
Axons become metabolically stressed.
Permanent injury may occur.

Clinical consequences include:

weakness,
sensory loss,
fatigue,
impaired coordination.

Early in disease, conduction failure may be reversible.

Later, axonal degeneration can produce permanent disability.

Oligodendrocyte Injury

Oligodendrocytes are particularly vulnerable during inflammatory attacks.

Potential mechanisms include:

cytokine toxicity,
oxidative stress,
complement activation,
immune-cell attack.

Important inflammatory mediators include:

TNF-α,
interferon-γ,
IL-17,
reactive oxygen species.

Loss of oligodendrocytes reduces remyelination capacity and may contribute to chronic neurological deficits.

Axonal Injury: The Determinant of Long-Term Disability

A central concept in inflammatory spinal cord disease is the difference between:

Reversible conduction block

and

Irreversible axonal destruction.

Patients with preserved axons may recover substantially after inflammation decreases.

Patients with extensive axonal loss may experience:

permanent weakness,
chronic sensory impairment,
incomplete neurological recovery.

MRI abnormalities do not always perfectly predict disability because functional outcome depends more on microscopic axonal integrity than lesion size alone.

Neuroinflammation and Microglial Activation

Microglia are the resident immune cells of the central nervous system.

Under normal conditions, they:

monitor tissue health,
remove debris,
support repair.

During inflammatory disease, microglia become activated and release:

cytokines,
chemokines,
reactive oxygen species.

Activated microglia can have dual roles:

Harmful effects

inflammation amplification,
oligodendrocyte injury,
synaptic dysfunction.

Protective effects

debris clearance,
tissue remodeling,
repair signaling.

The balance between these functions influences recovery.

Astrocyte Biology and Spinal Cord Inflammation

Astrocytes maintain:

ion balance,
neurotransmitter regulation,
blood–spinal cord barrier support.

During inflammatory injury, astrocytes undergo reactive transformation.

Reactive astrocytes may:

produce inflammatory molecules,
alter barrier function,
influence immune-cell trafficking.

However, astrocytes also contribute to repair by:

restoring homeostasis,
supporting surviving neurons,
promoting remyelination.

Blood–Spinal Cord Barrier Physiology

The blood–spinal cord barrier functions similarly to the blood–brain barrier but has unique regional vulnerabilities.

It depends on:

endothelial tight junctions,
pericytes,
astrocytic end-feet,
basement membrane structures.

Inflammatory disruption permits entry of:

lymphocytes,
macrophages,
antibodies,
complement proteins.

This transforms a localized immune response into direct spinal cord injury.

Neurovascular Dysfunction in COVID-19

SARS-CoV-2 infection has been associated with:

endothelial activation,
platelet abnormalities,
coagulation disturbances,
complement activation.

The spinal cord receives blood through:

anterior spinal artery,
paired posterior spinal arteries,
segmental radicular arteries.

Microvascular injury may contribute to:

inflammatory amplification,
tissue hypoxia,
impaired repair.

This mechanism may explain why some patients demonstrate mixed inflammatory and ischemic features.

Autonomic Physiology and COVID-Associated TM

The autonomic nervous system controls:

bladder,
bowel,
cardiovascular regulation,
sweating,
sexual function.

Spinal cord lesions can interrupt autonomic pathways.

Bladder Dysfunction

Damage to sacral pathways can produce:

urinary retention,
incomplete emptying,
urgency.

Chronic bladder dysfunction may lead to:

recurrent infections,
kidney complications,
reduced quality of life.

Cardiovascular Autonomic Dysfunction

Some COVID-associated neurological syndromes involve dysautonomia.

Potential mechanisms include:

autonomic pathway injury,
inflammatory effects on sympathetic regulation,
small-fiber involvement.

Mechanisms of Neurological Recovery

Recovery after TM depends on several biological processes:

Resolution of inflammation

Reduction of:

immune-cell infiltration,
cytokine signaling,
edema.

Remyelination

Surviving oligodendrocytes and precursor cells may restore myelin.

Factors influencing remyelination:

age,
lesion severity,
inflammatory environment.

Neural Plasticity

The nervous system can reorganize function through:

synaptic adaptation,
cortical remodeling,
recruitment of alternate pathways.

Rehabilitation promotes these processes.

Limitations of Recovery

Recovery may be incomplete because of:

axonal loss,
spinal cord scarring,
persistent inflammation,
maladaptive neural signaling.

Patients may continue to experience:

neuropathic pain,
sensory abnormalities,
gait difficulty,
fatigue.

Relationship to Long COVID Neurological Dysfunction

COVID-associated TM represents one extreme of a spectrum of post-infectious neurological effects.

Other long COVID neurological manifestations include:

cognitive dysfunction,
dysautonomia,
small-fiber neuropathy,
fatigue,
sensory disturbances.

Possible shared mechanisms include:

persistent immune activation,
endothelial dysfunction,
mitochondrial stress,
altered autonomic regulation.

However, structural inflammatory myelitis must be distinguished from functional neurological symptoms and non-inflammatory post-COVID syndromes.

Summary

The physiology of COVID-associated transverse myelitis reflects disruption of multiple interconnected spinal systems.

SARS-CoV-2–associated immune activation may produce:

inflammatory infiltration,
demyelination,
axonal injury,
vascular dysfunction,
autonomic pathway disruption.

Clinical outcomes depend largely on whether injury remains confined to reversible inflammatory dysfunction or progresses to permanent structural damage.

Understanding these physiological mechanisms provides the foundation for accurate diagnosis, rational therapy, and prediction of long-term outcomes.

Neuropathology of COVID-19–Associated Transverse Myelitis: Histological Features, Immune Infiltration, Demyelination, Complement Injury, and Biomarkers of Tissue Damage

Overview

The neuropathology of COVID-19–associated transverse myelitis (TM) remains one of the least completely characterized aspects of this emerging disorder. Unlike classical neurological diseases in which extensive autopsy series and biopsy studies have established pathological mechanisms, COVID-associated inflammatory spinal cord disease has been described primarily through clinical observations, magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) analysis, immunological studies, and limited pathological material.

Nevertheless, available evidence supports a model of immune-mediated spinal cord injury characterized by inflammatory infiltration, myelin disruption, vascular dysfunction, and variable degrees of axonal preservation or destruction.

The pathological spectrum appears to overlap with several established neuroinflammatory disorders, including:

acute transverse myelitis,
acute disseminated encephalomyelitis (ADEM),
neuromyelitis optica spectrum disorder (NMOSD),
myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD),
autoimmune demyelinating syndromes.

However, COVID-associated TM may contain unique features related to SARS-CoV-2–induced immune activation, endothelial dysfunction, and systemic inflammation.

Anatomical Localization of Injury

The pathological process in TM is typically centered within the spinal cord parenchyma.

Commonly affected regions include:

cervical spinal cord,
thoracic spinal cord,
cervicothoracic junction,
conus medullaris.

Lesions may involve:

central gray matter,
dorsal columns,
corticospinal tracts,
peripheral white matter.

The distribution depends on the underlying mechanism.

Gross Pathological Changes

Although direct pathological examination is rare, inflammatory spinal cord lesions generally demonstrate:

swelling of the spinal cord,
focal discoloration,
softening of affected tissue,
inflammatory infiltration.

MRI correlates include:

T2 hyperintensity,
spinal cord enlargement,
gadolinium enhancement.

These findings reflect increased tissue water content caused by:

inflammatory edema,
cellular infiltration,
vascular leakage.

Cellular Components of Inflammation

The inflammatory environment in TM consists of multiple immune-cell populations.

CD4+ T Lymphocytes

CD4+ helper T cells are among the most important regulators of autoimmune inflammation.

Subtypes include:

Th1 Cells

Associated with:

interferon-γ production,
macrophage activation,
tissue inflammation.

Th1 responses are strongly implicated in CNS inflammatory diseases.

Th17 Cells

Th17 cells produce:

interleukin-17,
interleukin-22.

They contribute to:

neutrophil recruitment,
endothelial activation,
blood–spinal cord barrier disruption.

Th17 biology is particularly relevant because similar pathways are implicated in multiple sclerosis and other autoimmune neurological disorders.

CD8+ Cytotoxic T Cells

CD8+ lymphocytes can directly injure cells displaying abnormal antigens.

Potential targets include:

infected cells,
stressed oligodendrocytes,
antigen-presenting neural cells.

Excessive CD8 activation may contribute to neuronal injury.

B Lymphocytes and Plasma Cells

B cells contribute through:

antibody production,
antigen presentation,
cytokine secretion.

Potential mechanisms include:

generation of pathogenic antibodies,
immune-complex formation,
complement activation.

The presence of B-cell activity has therapeutic implications because B-cell–targeted therapies such as rituximab are effective in several inflammatory neurological diseases.

Macrophages and Microglia

Macrophages entering the CNS and activated microglia perform both destructive and reparative functions.

They can:

Promote injury through:

phagocytosis of myelin,
cytokine release,
oxidative stress,
inflammatory amplification.

Promote repair through:

debris clearance,
growth factor production,
remodeling.

The balance between inflammatory and reparative macrophage states influences recovery.

Demyelination

Mechanism

Demyelination represents loss or injury of myelin surrounding CNS axons.

Pathological mechanisms include:

immune attack against myelin proteins,
complement-mediated oligodendrocyte injury,
inflammatory cytokine toxicity.

The consequences are:

slowed nerve conduction,
conduction block,
neurological deficits.

Patterns of Demyelination

Different inflammatory disorders demonstrate characteristic pathological patterns.

Pattern I: Macrophage-Mediated Demyelination

Features:

macrophage accumulation,
myelin debris,
relative axonal preservation.

Observed in some multiple sclerosis lesions.

Pattern II: Complement-Associated Demyelination

Features:

antibody deposition,
complement activation,
oligodendrocyte injury.

This mechanism resembles disorders such as NMOSD.

Pattern III: Oligodendrocyte Apoptosis

Features:

diffuse oligodendrocyte loss,
inflammatory injury,
impaired remyelination.

COVID-associated TM may involve overlapping patterns depending on individual immune responses.

Axonal Injury and Neurodegeneration

Although demyelination is central, axonal injury determines long-term disability.

Mechanisms include:

inflammatory toxicity,
mitochondrial dysfunction,
excitotoxicity,
ischemic stress.

Markers of axonal damage include:

Neurofilament Light Chain (NfL)

NfL is released into CSF and blood when axons are injured.

Elevated NfL is associated with:

multiple sclerosis activity,
neurodegeneration,
severe neurological injury.

Future studies may determine whether NfL predicts recovery after COVID-associated TM.

Astrocytic Pathology

Astrocytes regulate:

neuronal metabolism,
ion homeostasis,
barrier function.

During inflammatory injury, astrocytes become reactive.

Reactive astrocytes may:

release inflammatory mediators,
alter synaptic function,
influence immune-cell migration.

However, astrocytes also support recovery by:

restoring metabolic balance,
promoting repair,
maintaining surviving neurons.

Oligodendrocyte Vulnerability

Oligodendrocytes are among the most vulnerable cells during inflammatory spinal cord disease.

Reasons include:

high metabolic demand,
dependence on mitochondrial function,
sensitivity to oxidative stress.

Inflammatory injury can cause:

impaired myelin maintenance,
apoptosis,
reduced remyelination.

Age-related reduction in oligodendrocyte precursor activity may partially explain poorer recovery in older adults.

Complement-Mediated Injury

Complement activation has become increasingly recognized in COVID-19 pathology.

The complement cascade can produce:

C3 activation

↓

inflammatory amplification

↓

membrane attack complex formation

↓

cellular injury

Potential targets include:

endothelial cells,
oligodendrocytes,
neurons.

Complement activation may connect systemic COVID-19 inflammation with focal spinal cord injury.

Endothelial and Vascular Pathology

The spinal cord requires continuous oxygen delivery through a specialized vascular network.

COVID-related endothelial injury may produce:

vascular inflammation,
capillary leakage,
microthrombi,
impaired perfusion.

Histological changes described in severe COVID vascular disease include:

endothelial swelling,
inflammatory-cell attachment,
complement deposition.

These mechanisms may contribute to mixed inflammatory-vascular spinal cord injury.

Blood–Spinal Cord Barrier Breakdown

A central pathological event is disruption of the blood–spinal cord barrier.

Normally, this barrier prevents uncontrolled immune entry.

Inflammatory disruption allows:

T cells,
antibodies,
complement proteins,
cytokines.

MRI evidence of barrier disruption includes:

gadolinium enhancement.

CSF evidence includes:

elevated protein,
inflammatory cells,
immune activation markers.

Cerebrospinal Fluid Biomarkers

CSF analysis provides indirect evidence of pathology.

Common findings include:

Pleocytosis

Increased white blood cells:

lymphocyte predominance is common.

Elevated Protein

Reflects:

barrier disruption,
inflammation.

Oligoclonal Bands

These indicate intrathecal immunoglobulin production.

Their absence does not exclude inflammatory myelitis.

Emerging Biomarkers

Research is investigating additional biomarkers.

Cytokine Profiles

Potential markers:

IL-6,
IL-17,
TNF-α,
interferon-related molecules.

Glial Fibrillary Acidic Protein (GFAP)

GFAP reflects astrocytic injury.

Elevations may indicate:

CNS inflammation,
astrocyte damage.

Neurofilament Light Chain

Reflects axonal injury.

Potential applications:

predicting disability,
monitoring treatment response.

Relationship Between Pathology and Clinical Outcome

The degree of neurological recovery depends on several pathological variables.

Favorable factors

limited lesion length,
early treatment,
preserved axons,
rapid inflammation control.

Poor prognostic factors

extensive spinal lesions,
severe initial paralysis,
marked axonal injury,
delayed treatment,
persistent inflammation.

Integrated Pathological Model

A proposed sequence:

SARS-CoV-2 infection

↓

Innate immune activation

↓

Cytokine release and endothelial activation

↓

Blood–spinal cord barrier disruption

↓

Immune-cell infiltration

↓

Demyelination and axonal stress

↓

Neurological dysfunction

↓

Repair or permanent injury

Conclusions

The neuropathology of COVID-19–associated transverse myelitis is most consistent with an immune-mediated inflammatory disorder involving multiple interacting systems.

The dominant pathological processes appear to include:

T-cell and macrophage infiltration,
demyelination,
oligodendrocyte injury,
complement activation,
vascular dysfunction,
variable axonal destruction.

Future pathological studies using advanced technologies—including single-cell sequencing, spatial transcriptomics, and molecular imaging—will likely provide critical insights into why SARS-CoV-2 triggers spinal cord inflammation in rare individuals and how targeted therapies can prevent irreversible neurological injury.

Clinical Presentation, Diagnostic Evaluation, MRI Findings, Cerebrospinal Fluid Analysis, Differential Diagnosis, and Modern Diagnostic Algorithms for COVID-19–Associated Transverse Myelitis

Overview

The clinical diagnosis of COVID-19–associated transverse myelitis (TM) requires integration of neurological examination, spinal imaging, cerebrospinal fluid (CSF) analysis, immunological testing, and careful exclusion of alternative diagnoses. Because transverse myelitis is a syndrome rather than a single disease, clinicians must determine whether spinal cord inflammation represents:

a postinfectious immune-mediated disorder,
an autoimmune demyelinating disease,
vascular injury,
infection,
malignancy,
metabolic disease,
structural compression,
or another neurological process.

The diagnostic challenge is particularly important in patients with recent SARS-CoV-2 infection because many neurological symptoms reported after COVID-19—including weakness, fatigue, sensory disturbances, and autonomic dysfunction—may occur without objective evidence of spinal cord inflammation.

A diagnosis of COVID-associated TM should therefore require evidence of true spinal cord dysfunction, supported by objective findings such as:

a spinal cord sensory level,
upper motor neuron signs,
MRI abnormalities,
inflammatory CSF changes,
or compatible neurophysiological findings.

Clinical Presentation

Typical Onset

The onset of COVID-associated TM is generally:

acute (hours to days),
subacute (days to several weeks),
occasionally delayed after infection.

The temporal relationship with SARS-CoV-2 exposure varies.

Patients may develop symptoms:

during active COVID-19,
1–6 weeks after infection,
after apparent recovery.

This delayed onset supports a postinfectious immune mechanism in many cases.

Motor Symptoms

Motor dysfunction is one of the most common presenting features.

Patients may experience:

leg weakness,
difficulty walking,
falls,
limb heaviness,
impaired coordination,
paralysis.

The pattern depends on lesion location.

Cervical Spinal Cord Lesions

Lesions in the cervical cord may cause:

arm weakness,
hand dysfunction,
leg weakness,
respiratory compromise in severe cases.

Symptoms may resemble cervical spinal cord compression, requiring careful imaging evaluation.

Thoracic Spinal Cord Lesions

Thoracic involvement commonly produces:

bilateral leg weakness,
spastic gait,
sensory level on the trunk,
bladder dysfunction.

Conus Medullaris Lesions

Lower spinal involvement may produce:

urinary retention,
bowel dysfunction,
sexual dysfunction,
saddle sensory loss.

Sensory Manifestations

Sensory abnormalities are among the most diagnostically useful features.

Common complaints include:

numbness,
tingling,
burning sensations,
electrical sensations,
abnormal temperature perception,
hypersensitivity to touch.

Sensory Level

A sensory level is one of the most important findings suggesting spinal cord involvement.

It represents a horizontal boundary below which sensation is impaired.

Examples:

nipple-level sensory loss suggests approximately T4 involvement,
umbilical-level sensory loss suggests approximately T10 involvement.

The sensory level helps localize the lesion and distinguish spinal cord disease from peripheral neuropathy.

Neuropathic Pain

Pain is common and may persist after motor recovery.

Mechanisms include:

damaged sensory pathways,
abnormal neuronal firing,
central sensitization.

Patients often describe:

burning,
stabbing,
electric shock sensations.

Neuropathic pain may become a chronic disability independent of strength recovery.

Autonomic Dysfunction

Autonomic involvement is a major feature of clinically significant TM.

Urinary Dysfunction

Symptoms include:

urinary retention,
urgency,
frequency,
incomplete emptying,
incontinence.

Evaluation may require:

bladder scanning,
urodynamic studies,
renal monitoring.

Bowel Dysfunction

Possible manifestations:

constipation,
impaired sensation,
bowel incontinence.

Sexual Dysfunction

Spinal cord inflammation can impair:

erectile function,
genital sensation,
autonomic sexual responses.

Neurological Examination

A comprehensive examination should document:

Motor system

muscle strength,
tone,
spasticity,
reflexes.

Typical upper motor neuron findings:

hyperreflexia,
clonus,
Babinski sign.

Sensory system

Testing should include:

light touch,
pinprick,
temperature,
vibration,
proprioception.

Coordination and gait

Assessment includes:

balance,
tandem walking,
lower extremity coordination.

Autonomic assessment

Includes:

bladder symptoms,
bowel function,
sexual function.

Diagnostic Criteria

The Transverse Myelitis Consortium Working Group proposed diagnostic criteria requiring:

Clinical evidence of spinal cord dysfunction

Including:

bilateral motor, sensory, or autonomic abnormalities.

Clearly defined sensory level

Supporting spinal localization.

Exclusion of compression

Structural causes must be ruled out.

Evidence of inflammation

Demonstrated by:

CSF pleocytosis,
elevated CSF immunoglobulin,
MRI enhancement.

Magnetic Resonance Imaging

MRI is the cornerstone of diagnosis.

Recommended imaging:

cervical spine MRI,
thoracic spine MRI,
contrast-enhanced sequences.

Typical MRI Findings

T2 Hyperintense Intramedullary Lesions

The most common abnormality.

Represents:

edema,
inflammation,
demyelination.

Longitudinally Extensive Transverse Myelitis (LETM)

Defined as lesions extending:

three or more vertebral segments.

LETM is associated with:

NMOSD,
MOG antibody disease,
severe inflammatory activation.

Enhancement Patterns

Contrast enhancement suggests active inflammation.

Patterns include:

Patchy enhancement

Often seen in inflammatory lesions.

Ring-like enhancement

May indicate active demyelination.

Central enhancement

May reflect gray matter involvement.

MRI Differentiation From Other Conditions

Spinal Cord Compression

Examples:

cervical spondylotic myelopathy,
epidural abscess,
tumor,
hematoma.

Features:

external compression,
canal narrowing,
displaced cord.

Spinal Cord Infarction

Features:

sudden onset,
vascular distribution,
diffusion abnormalities.

Multiple Sclerosis

Typical features:

shorter lesions,
characteristic brain lesions,
oligoclonal bands.

NMOSD

Important testing:

aquaporin-4 antibody.

Features:

LETM,
severe attacks,
optic neuritis.

MOG Antibody Disease

Testing:

serum MOG-IgG.

Features:

optic neuritis,
myelitis,
ADEM-like syndromes.

Cerebrospinal Fluid Analysis

Lumbar puncture provides important diagnostic information.

Cell Count

COVID-associated TM often demonstrates:

mild-to-moderate lymphocytic pleocytosis.

Findings may include:

increased white blood cells,
inflammatory profile.

Protein Concentration

Elevated CSF protein reflects:

blood–spinal cord barrier disruption,
inflammation.

Oligoclonal Bands

Oligoclonal bands indicate intrathecal immunoglobulin production.

Interpretation:

positive results suggest chronic immune activation,
absence does not exclude TM.

Infectious Evaluation

Because infection itself can cause myelitis, evaluation should consider:

SARS-CoV-2 testing,
herpes simplex virus,
varicella-zoster virus,
Epstein–Barr virus,
cytomegalovirus,
HIV,
syphilis,
tuberculosis where appropriate.

Autoimmune Testing

Recommended evaluation includes:

Aquaporin-4 antibody

Identifies NMOSD.

MOG antibody

Identifies MOG-associated disease.

Autoimmune screening

May include:

ANA,
ENA panel,
antiphospholipid antibodies,
inflammatory markers.

Neurophysiological Testing

Electrophysiology may help when diagnosis is uncertain.

Useful tests include:

Somatosensory evoked potentials (SSEP)

Assess sensory pathway conduction.

Motor evoked potentials (MEP)

Assess corticospinal pathway integrity.

Electromyography (EMG)

Helps distinguish:

spinal cord disease,
peripheral neuropathy,
nerve root disorders.

Differential Diagnosis

A careful differential diagnosis is essential.

Structural Disorders

Including:

cervical spondylotic myelopathy,
spinal stenosis,
tumors,
abscesses.

Vascular Disorders

Including:

spinal cord infarction,
arteriovenous malformations.

Demyelinating Diseases

Including:

multiple sclerosis,
NMOSD,
MOGAD.

Infectious Myelitis

Including:

HSV,
VZV,
HIV,
tuberculosis.

Metabolic Disorders

Including:

vitamin B12 deficiency,
copper deficiency,
nitrous oxide toxicity.

Diagnostic Algorithm

A practical approach:

Step 1: Confirm spinal cord localization

↓

Neurological examination:

sensory level,
reflex changes,
weakness pattern.

↓

Step 2: Emergency MRI

Exclude:

compression,
infarction,
tumor.

↓

Step 3: CSF analysis

Assess:

inflammation,
infection,
immune activation.

↓

Step 4: Autoimmune testing

Evaluate:

AQP4-IgG,
MOG-IgG,
systemic autoimmune markers.

↓

Step 5: Determine relationship to SARS-CoV-2

Assess:

timing,
infection severity,
alternative explanations.

Prognostic Factors at Diagnosis

Factors associated with poorer outcomes include:

severe initial weakness,
extensive MRI lesions,
delayed treatment,
significant sphincter dysfunction,
evidence of axonal injury.

Factors associated with better recovery include:

early recognition,
early immunotherapy,
preserved motor function,
limited lesion burden.

Conclusions

Diagnosis of COVID-associated transverse myelitis requires rigorous neurological assessment and objective evidence of spinal cord inflammation. The presence of SARS-CoV-2 infection alone does not establish causation; rather, diagnosis depends on demonstrating a compatible inflammatory myelopathy while excluding alternative causes.

Modern diagnostic approaches combining MRI, CSF analysis, immunological testing, and emerging biomarkers are allowing clinicians to distinguish COVID-triggered inflammatory myelitis from other neurological disorders and to guide appropriate treatment.

Therapeutic Strategies for COVID-19–Associated Transverse Myelitis: Acute Immunotherapy, Plasma Exchange, Intravenous Immunoglobulin, Targeted Immunomodulation, Rehabilitation, and Emerging Precision Treatments

Overview

Treatment of COVID-19–associated transverse myelitis (TM) is based primarily on therapeutic principles developed for inflammatory demyelinating diseases of the spinal cord. Because randomized controlled trials specifically addressing SARS-CoV-2–associated myelitis are not yet available, current management relies on:

established evidence from idiopathic transverse myelitis,
multiple sclerosis-associated myelitis,
neuromyelitis optica spectrum disorder (NMOSD),
myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD),
autoimmune encephalomyelitis,
accumulated experience from reported COVID-associated cases.

The fundamental therapeutic objectives are:

Rapid suppression of inflammation
Prevention of irreversible axonal injury
Restoration of neurological function
Management of chronic complications
Identification and treatment of persistent immune drivers

The urgency of treatment reflects a central principle of spinal cord inflammatory disease: early inflammation may be reversible, whereas delayed treatment increases the probability of permanent structural injury.

Initial Therapeutic Assessment

Before therapy begins, clinicians must rapidly determine:

Is there spinal cord compression?
Is there infection requiring antimicrobial treatment?
Is the process inflammatory?
Are there biomarkers suggesting NMOSD or MOGAD?
Is the patient medically stable?

A practical initial evaluation includes:

MRI of the entire spinal cord,
lumbar puncture when appropriate,
autoimmune antibody testing,
infectious evaluation,
baseline functional assessment.

Treatment should not necessarily wait for every test result when neurological deterioration is occurring.

High-Dose Corticosteroid Therapy

Rationale

Corticosteroids remain the first-line treatment for acute inflammatory myelitis.

Their effects include:

suppression of inflammatory cytokines,
reduction of lymphocyte activation,
decreased blood–spinal cord barrier permeability,
inhibition of immune-cell migration.

Standard Regimen

The commonly used approach is:

Intravenous methylprednisolone

Typical dosing:

1 gram daily
for 3–5 days

followed by:

oral prednisone taper in many cases.

The precise duration varies according to:

severity,
MRI findings,
clinical response.

Mechanisms of Benefit

Corticosteroids rapidly influence multiple immune pathways.

They decrease:

T-cell activation

Reducing:

IL-2 production,
inflammatory proliferation.

Cytokine production

Including:

IL-6,
TNF-α,
interferon-γ.

Immune-cell trafficking

By reducing expression of:

adhesion molecules,
inflammatory chemokines.

Limitations of Steroid Therapy

Although steroids are highly effective in many inflammatory disorders, some patients have incomplete responses.

Reasons include:

severe axonal injury,
extensive spinal lesions,
antibody-mediated disease,
delayed treatment.

Failure to improve after steroid therapy often prompts escalation.

Plasma Exchange (PLEX)

Rationale

Plasma exchange removes circulating pathogenic substances, including:

autoantibodies,
immune complexes,
complement components,
inflammatory mediators.

PLEX is particularly important when antibody-mediated injury is suspected.

Indications

PLEX is generally considered when:

severe neurological deficits persist after steroids,
rapid progression occurs,
MRI demonstrates extensive inflammation,
NMOSD-like features are present.

Treatment Protocol

Common approaches include:

5–7 exchanges,
performed over approximately 1–2 weeks.

The procedure removes and replaces plasma while preserving cellular blood components.

Evidence Base

Although controlled trials in COVID-associated TM are lacking, PLEX has demonstrated benefit in:

severe idiopathic TM,
steroid-resistant demyelinating attacks,
NMOSD.

Clinical improvement may occur after several exchanges, although recovery may continue for months.

Intravenous Immunoglobulin (IVIG)

Mechanisms

IVIG has multiple immunomodulatory effects.

It may:

neutralize pathogenic antibodies,
inhibit complement activation,
regulate Fc receptors,
suppress inflammatory cytokines,
enhance regulatory immune pathways.

Clinical Use

IVIG may be considered when:

steroids are contraindicated,
plasma exchange is unavailable,
autoimmune mechanisms are suspected,
patients fail initial therapy.

Typical regimens involve:

2 g/kg total dose,
administered over 2–5 days.

Comparison of Steroids, PLEX, and IVIG

Therapy	Primary Action	Typical Role
Corticosteroids	Broad immune suppression	First-line therapy
Plasma exchange	Removes antibodies and inflammatory mediators	Severe or refractory disease
IVIG	Immune modulation	Alternative or adjunct therapy

Targeted Immunotherapy

The future of COVID-associated TM treatment will likely involve more precise immune targeting.

B-Cell–Directed Therapy

Rituximab

Rituximab is a monoclonal antibody targeting:

CD20-positive B lymphocytes.

Potential benefits include:

reduction of antibody production,
suppression of antigen presentation,
decreased inflammatory signaling.

Clinical Applications

Rituximab is established therapy for:

NMOSD,
autoimmune neurological disorders.

It may be considered in selected patients with:

recurrent disease,
antibody-mediated pathology,
persistent inflammation.

Complement Inhibition

Because complement activation may contribute to CNS injury, complement-targeted therapy represents an emerging strategy.

Eculizumab

A monoclonal antibody targeting:

complement protein C5.

It is approved for NMOSD associated with aquaporin-4 antibodies.

Its role in COVID-associated TM remains investigational.

IL-6 Pathway Modulation

IL-6 is an important inflammatory mediator in COVID-19.

Potential therapies include:

Tocilizumab

An IL-6 receptor antagonist.

Possible mechanisms:

reduce inflammatory signaling,
decrease immune-cell activation.

However, evidence specifically for TM remains insufficient.

Janus Kinase (JAK) Inhibitors

JAK inhibitors influence cytokine signaling pathways.

Examples:

baricitinib,
tofacitinib.

Potential effects:

reduce inflammatory cytokine signaling,
modulate interferon pathways.

Their role in inflammatory myelitis remains experimental.

Antiviral Therapy and Timing

A major unresolved question is whether antiviral therapy has a role in preventing inflammatory neurological complications.

Theoretical rationale:

Reducing viral replication early may decrease:

antigen exposure,
immune activation,
inflammatory triggering.

However, once autoimmune inflammation is established, immunotherapy generally becomes the primary intervention.

Neurorehabilitation

Recovery from TM is not determined solely by immune suppression. Rehabilitation is a central component of long-term care.

Physical Therapy

Goals include:

maintaining mobility,
preventing contractures,
strengthening preserved pathways,
improving balance.

Approaches include:

gait training,
resistance exercises,
balance therapy,
assistive device training.

Occupational Therapy

Focuses on:

activities of daily living,
hand function,
adaptive strategies,
workplace modification.

Spasticity Management

Spinal cord inflammation can produce spasticity.

Treatments include:

Medications

baclofen,
tizanidine.

Procedures

botulinum toxin injections,
intrathecal baclofen pumps in severe cases.

Neuropathic Pain Treatment

Persistent pain is common.

Therapeutic options include:

Gabapentinoids

gabapentin,
pregabalin.

Antidepressant-class agents

duloxetine,
amitriptyline.

Nonpharmacological approaches

cognitive behavioral strategies,
desensitization therapy,
physical rehabilitation.

Bladder and Bowel Management

Autonomic dysfunction requires specialized care.

Strategies include:

timed voiding,
intermittent catheterization,
urology consultation,
pelvic rehabilitation.

Preventing recurrent urinary infections is particularly important.

Sexual Rehabilitation

Sexual dysfunction is often overlooked.

Management may involve:

urological evaluation,
medications,
counseling,
rehabilitation strategies.

Experimental and Future Therapies

Mesenchymal Stem Cell Approaches

Potential mechanisms:

immunomodulation,
tissue repair,
neuroprotection.

Current evidence remains preliminary.

Remyelination Therapies

Future strategies may target:

oligodendrocyte precursor cells,
myelin repair pathways,
neurotrophic factors.

Neuroprotective Therapies

Potential targets include:

mitochondrial dysfunction,
oxidative stress,
excitotoxic injury.

Personalized Immunotherapy

Future management may depend on biological classification.

Patients could potentially be categorized by:

antibody profile,
cytokine pattern,
genomic susceptibility,
MRI phenotype,
CSF biomarkers.

This approach may replace broad immunosuppression with targeted therapy.

Prognosis and Treatment Response

Several factors influence outcome.

Better Prognosis

Associated with:

early treatment,
incomplete initial paralysis,
limited MRI lesions,
rapid response to steroids.

Poorer Prognosis

Associated with:

complete paralysis,
extensive spinal lesions,
delayed therapy,
severe axonal injury,
persistent bladder dysfunction.

Conclusions

Treatment of COVID-associated transverse myelitis requires rapid recognition and coordinated neurological care. Although specific randomized trials are lacking, existing evidence supports early high-dose corticosteroids followed by escalation to plasma exchange or other immunotherapies in severe or refractory cases.

The future of treatment will likely move toward precision neuroimmunology, integrating:

immune biomarkers,
genomics,
imaging,
molecular profiling.

The ultimate goal is not merely suppression of inflammation but prevention of irreversible spinal cord injury and restoration of neurological function.

Long-Term Outcomes of COVID-19–Associated Transverse Myelitis: Recovery Patterns, Persistent Disability, Neurological Sequelae, Rehabilitation Outcomes, and Relationship to Long COVID

Overview

The long-term prognosis of COVID-19–associated transverse myelitis (TM) remains an evolving area of investigation. Unlike common manifestations of COVID-19, where large longitudinal studies have rapidly accumulated, COVID-associated inflammatory spinal cord disease is sufficiently rare that current knowledge is derived primarily from case reports, small case series, systematic reviews, and extrapolation from established inflammatory myelopathies.

Available evidence indicates that outcomes are heterogeneous. Some patients experience substantial neurological recovery following immunotherapy, while others develop persistent disability resembling chronic incomplete spinal cord injury. The variability reflects differences in:

anatomical location of inflammation,
lesion length,
degree of demyelination,
axonal preservation,
immune mechanism,
timing of treatment,
age and comorbid disease,
rehabilitation intensity.

The most important determinant of long-term function is not simply whether inflammation occurred, but whether the inflammatory attack caused irreversible destruction of axons and neural circuits.

Natural History of Transverse Myelitis

The clinical course of inflammatory myelitis generally follows several phases.

Acute Phase

Duration:

hours to several weeks.

Dominant processes:

immune activation,
spinal cord edema,
inflammatory infiltration,
conduction block.

Symptoms may progress rapidly:

weakness,
sensory loss,
bladder dysfunction,
pain.

Subacute Recovery Phase

Duration:

weeks to months.

Biological processes:

resolution of inflammation,
remyelination,
axonal recovery,
neural adaptation.

Improvement during this phase often occurs in:

strength,
gait,
sensation.

Chronic Phase

Duration:

months to years.

Persistent symptoms may reflect:

axonal loss,
incomplete remyelination,
spinal cord scarring,
altered sensory processing,
autonomic dysfunction.

Motor Recovery

Motor recovery is one of the most clinically important outcomes.

Patients may recover:

independent walking,
partial strength,
improved endurance.

However, recovery may remain incomplete when there is:

severe initial paralysis,
extensive spinal cord lesions,
prolonged inflammation.

Predictors of Motor Outcome

Factors associated with better motor recovery include:

Early improvement after treatment

Patients demonstrating neurological improvement within the first weeks often have better long-term outcomes.

Preserved voluntary movement at onset

Complete paralysis at presentation is associated with a higher probability of residual disability.

Limited spinal cord injury

Shorter MRI lesions are generally associated with improved outcomes compared with extensive lesions.

Sensory Outcomes

Sensory symptoms are among the most persistent consequences of TM.

Common long-term complaints include:

numbness,
tingling,
burning pain,
altered temperature sensation,
impaired vibration sense.

Patients frequently describe:

“walking on cushions,”
inability to feel foot position,
difficulty navigating uneven ground.

These symptoms can persist even when muscle strength improves.

Neuropathic Pain After COVID-Associated TM

Neuropathic pain occurs because damaged sensory pathways generate abnormal electrical signals.

Mechanisms include:

ectopic neuronal firing,
spinal cord sensitization,
altered inhibitory pathways.

Clinical characteristics include:

burning pain,
electric shocks,
hypersensitivity,
painful response to light touch.

Management often requires multimodal therapy.

Chronic Autonomic Dysfunction

Autonomic impairment may become one of the most disabling long-term effects.

Bladder Dysfunction

Persistent urinary problems may include:

incomplete emptying,
urgency,
retention,
recurrent infections.

Long-term management may require:

urology involvement,
bladder scanning,
catheterization strategies,
medications affecting bladder function.

Bowel Dysfunction

Chronic complications include:

constipation,
impaired bowel sensation,
incontinence.

Management includes:

dietary modification,
bowel programs,
pelvic rehabilitation.

Sexual Dysfunction

Sexual dysfunction is frequently underrecognized.

Potential mechanisms include:

interruption of spinal autonomic pathways,
sensory impairment,
medication effects,
psychological effects of chronic illness.

Treatment may require multidisciplinary care.

Fatigue and Reduced Exercise Capacity

Fatigue is common after inflammatory neurological injury.

Mechanisms include:

inefficient neural conduction,
chronic immune activation,
deconditioning,
autonomic dysfunction,
sleep disturbance.

Importantly, fatigue after TM should not automatically be attributed to persistent viral infection; it may reflect neurological injury itself.

Relationship Between COVID-Associated TM and Long COVID

Long COVID, or post-acute sequelae of SARS-CoV-2 infection (PASC), includes persistent symptoms occurring after acute infection.

Common manifestations include:

fatigue,
cognitive dysfunction,
dysautonomia,
exercise intolerance,
sensory symptoms,
neuropathic complaints.

COVID-associated TM may represent one clearly defined neurological phenotype within a broader spectrum of postinfectious immune dysfunction.

Distinguishing TM From Other Long COVID Neurological Syndromes

Small-Fiber Neuropathy

Features:

burning pain,
tingling,
autonomic symptoms.

Differences:

normal spinal MRI,
peripheral nerve involvement.

Dysautonomia

Features:

heart-rate abnormalities,
blood-pressure instability,
orthostatic intolerance.

Differences:

no inflammatory spinal cord lesion.

Cognitive Dysfunction

Features:

memory problems,
attention difficulty,
slowed processing.

Differences:

primarily central network dysfunction rather than focal spinal injury.

Rehabilitation and Functional Recovery

Rehabilitation is a critical determinant of outcome.

The nervous system retains the ability to adapt through:

neuroplasticity,
cortical reorganization,
strengthening of preserved pathways.

Physical Rehabilitation

Goals include:

maximizing mobility,
preventing secondary disability,
improving balance.

Therapies include:

Gait training

May involve:

treadmill therapy,
body-weight support systems,
assistive devices.

Strength conditioning

Targets:

preserved muscles,
endurance,
cardiovascular function.

Balance training

Particularly important when proprioception is impaired.

Occupational Therapy

Occupational therapy addresses:

hand function,
self-care,
home safety,
adaptive equipment.

Examples:

bathroom modifications,
mobility aids,
energy conservation strategies.

Psychological and Cognitive Support

Chronic neurological disability can affect:

mood,
independence,
quality of life.

Appropriate care includes:

psychological support,
pain coping strategies,
social support.

Biomarkers Predicting Recovery

Future prognostic tools may include:

MRI Biomarkers

Potential predictors:

lesion length,
spinal cord swelling,
enhancement pattern,
degree of atrophy.

Neurofilament Light Chain

Elevated levels may indicate:

axonal injury,
poorer neurological recovery.

GFAP

May reflect:

astrocytic injury,
inflammatory severity.

Immune Profiles

Future studies may examine:

cytokine patterns,
autoantibody signatures,
immune-cell phenotypes.

Recurrence Risk

Most postinfectious TM cases are monophasic.

However, recurrence requires evaluation for:

NMOSD,
MOGAD,
multiple sclerosis,
systemic autoimmune disease.

Patients with:

recurrent attacks,
persistent antibody positivity,
characteristic MRI patterns,

may require long-term immunotherapy.

Mortality and Severe Disability

Although uncommon, severe COVID-associated TM can result in:

permanent paralysis,
respiratory impairment,
severe autonomic dysfunction.

Mortality is usually related not to spinal inflammation itself but to:

complications of immobility,
infection,
underlying systemic illness.

Aging and Recovery

Age is an important prognostic factor.

Older individuals may experience:

reduced remyelination capacity,
decreased neuroplasticity,
greater vascular vulnerability,
slower rehabilitation response.

This does not preclude recovery but may influence expectations.

Future Directions in Outcome Research

Future studies should include:

Large international registries

to determine:

true incidence,
treatment response,
disability outcomes.

Standardized neurological outcome measures

Including:

Expanded Disability Status Scale (EDSS),
Functional Independence Measure (FIM),
walking assessments.

Longitudinal imaging

Tracking:

lesion resolution,
spinal cord atrophy,
remyelination.

Molecular profiling

Integrating:

genomics,
immune biomarkers,
imaging.

Conclusions

COVID-19–associated transverse myelitis is a rare but potentially disabling inflammatory spinal cord disorder. Long-term outcomes vary widely, ranging from near-complete neurological recovery to persistent disability requiring lifelong supportive care.

The major determinants of prognosis are:

severity of initial injury,
speed of diagnosis,
timing of immunotherapy,
extent of axonal damage,
effectiveness of rehabilitation.

Future advances will likely come from precision medicine approaches that identify the specific immune pathways active in each patient and allow targeted intervention before irreversible spinal cord injury occurs.

Future Research Directions and Conclusions: Biomarker Discovery, Genomic Medicine, Precision Immunotherapy, and the Future of COVID-19–Associated Neuroimmunology

Overview

The emergence of COVID-19–associated transverse myelitis (TM) has highlighted both the remarkable complexity of human immune responses and the limitations of current approaches to inflammatory neurological disease. Although SARS-CoV-2 infection has resulted in hundreds of millions of exposures worldwide, inflammatory spinal cord disease remains extremely uncommon. This paradox provides an important scientific opportunity: understanding why a normally protective antiviral immune response becomes, in rare individuals, a destructive autoimmune process.

Future progress will depend on moving beyond descriptive case reports toward integrated systems biology approaches combining:

genomics,
transcriptomics,
proteomics,
immunology,
neuroimaging,
computational biology,
longitudinal clinical observation.

The ultimate objective is to develop a framework of precision neuroimmunology, in which treatment is tailored to the specific biological mechanisms active in each patient.

Current Knowledge Gaps

Despite rapid advances, many fundamental questions remain unresolved.

1. Why Do Only Rare Individuals Develop Transverse Myelitis?

The rarity of COVID-associated TM suggests that several conditions must converge.

Possible contributors include:

genetic predisposition,
abnormal immune regulation,
prior autoimmune tendency,
viral characteristics,
environmental triggers,
aging-related immune changes.

Future research must identify the combination of factors that transforms normal antiviral immunity into pathological inflammation.

2. Is SARS-CoV-2 a Direct Cause or an Immune Trigger?

One of the most important scientific questions is whether SARS-CoV-2 directly damages spinal tissue or primarily triggers immune-mediated injury.

Current evidence favors:

immune activation,
autoimmunity,
vascular inflammation,

rather than direct viral destruction.

However, several possibilities remain:

Direct viral effects in a subset of patients.
Immune-mediated injury in most patients.
Combined mechanisms.

Resolving this question requires:

tissue studies,
advanced viral detection methods,
molecular pathology.

3. Are There Distinct Biological Subtypes?

Current diagnostic categories may group together several different disorders.

COVID-associated TM may include:

Autoantibody-mediated disease

Features:

B-cell activation,
complement involvement,
antibody biomarkers.

Potential therapy:

B-cell depletion,
complement inhibition.

T-cell dominant inflammation

Features:

cytokine activation,
cellular infiltration.

Potential therapy:

T-cell pathway modulation.

Vascular-inflammatory disease

Features:

endothelial injury,
microvascular dysfunction.

Potential therapy:

vascular protection,
anti-inflammatory strategies.

Identifying these subtypes would dramatically improve treatment selection.

Genomic Medicine and Risk Prediction

Whole-Genome Sequencing

Future studies should evaluate patients with COVID-associated TM using:

whole-genome sequencing,
exome sequencing,
genome-wide association studies.

Potential discoveries may include variants affecting:

HLA antigen presentation,
interferon responses,
immune checkpoints,
complement regulation.

Polygenic Risk Scores

Rather than searching for a single causative mutation, researchers may develop risk profiles based on multiple genetic variants.

A future risk model might incorporate:

HLA profile,
interferon pathway genes,
autoimmune susceptibility variants,
inflammatory markers.

Such approaches could identify individuals with increased vulnerability to immune-mediated complications.

Single-Cell Immunology

Traditional laboratory tests measure average immune responses.

Single-cell technologies allow analysis of individual immune cells.

Potential discoveries include:

pathogenic T-cell populations,
abnormal B-cell clones,
inflammatory macrophage states.

Methods include:

single-cell RNA sequencing,
single-cell epigenomics,
immune receptor sequencing.

Proteomics and Biomarker Discovery

Proteomics evaluates thousands of proteins simultaneously.

Potential biomarkers include:

Cytokine signatures

Examples:

IL-6,
IL-17,
TNF-α,
interferon-related proteins.

Neural injury markers

Including:

Neurofilament light chain (NfL)

Marker of:

axonal injury.

GFAP

Marker of:

astrocyte injury.

Autoantibody profiles

Future antibody panels may distinguish:

NMOSD,
MOGAD,
postinfectious TM,
other autoimmune disorders.

Advanced Neuroimaging

MRI remains central to diagnosis, but future imaging approaches may provide deeper biological information.

Diffusion Tensor Imaging

May evaluate:

axonal integrity,
tract disruption.

Magnetization Transfer Imaging

May assess:

myelin content,
remyelination.

Positron Emission Tomography (PET)

Potentially useful for measuring:

microglial activation,
inflammation.

Artificial Intelligence and Imaging Analysis

Machine-learning systems may identify patterns not visible to human observers.

Applications may include:

predicting recovery,
distinguishing inflammatory from vascular injury,
guiding therapy.

Therapeutic Research Priorities

Beyond Broad Immunosuppression

Current therapies suppress inflammation broadly.

Future therapies aim for selective intervention.

Targeting Specific Immune Pathways

Potential targets include:

IL-6 signaling

May benefit patients with cytokine-driven inflammation.

Complement inhibition

Potentially useful in antibody-mediated disease.

B-cell therapies

May benefit patients with persistent antibody-driven autoimmunity.

JAK-STAT modulation

May regulate excessive cytokine signaling.

Neuroprotection and Repair

Suppressing inflammation is only part of the therapeutic goal.

Future treatments must also promote:

axonal survival,
remyelination,
neural regeneration.

Oligodendrocyte Repair Strategies

Potential approaches:

stimulating oligodendrocyte precursor cells,
enhancing myelin repair pathways,
reducing oxidative injury.

Mitochondrial Protection

Inflammatory diseases produce:

oxidative stress,
impaired energy metabolism.

Mitochondrial therapies may protect vulnerable axons.

Stem Cell and Regenerative Approaches

Experimental approaches include:

mesenchymal stem cells,
neural progenitor therapies,
regenerative biomaterials.

At present, these remain investigational.

Relationship to Long COVID Research

The study of COVID-associated TM intersects with broader long COVID research.

Shared biological themes include:

immune dysregulation,
endothelial dysfunction,
autoantibody production,
persistent inflammatory signaling,
autonomic abnormalities.

However, TM differs from many long COVID syndromes because it involves:

objective spinal cord inflammation,
structural neurological injury,
MRI abnormalities.

Understanding TM may therefore provide a model for studying severe immune-mediated neurological complications after infection.

International Research Priorities

A coordinated global research strategy should include:

1. International registries

Collecting:

clinical features,
MRI findings,
laboratory data,
treatment responses,
outcomes.

2. Standardized definitions

Researchers should distinguish:

confirmed inflammatory myelitis,
possible myelitis,
nonspecific neurological symptoms.

3. Longitudinal follow-up

Patients should be followed for:

years rather than months.

Important outcomes:

disability,
recurrence,
cognitive effects,
autonomic function.

Ethical and Clinical Considerations

As with all rare adverse neurological events, scientific communication must balance two principles:

Recognition

Rare complications must be:

identified,
investigated,
treated.

Context

Risk estimates must be interpreted appropriately.

Large-scale evidence indicates that SARS-CoV-2 infection itself produces substantially broader neurological risks than vaccination, while rare inflammatory events after immune stimulation remain important areas for continued surveillance.

Final Conclusions

COVID-19–associated transverse myelitis represents a rare but biologically significant example of immune-mediated neurological injury following viral exposure. Current evidence indicates that SARS-CoV-2 can act as an immune trigger capable of initiating inflammatory spinal cord disease in susceptible individuals.

The disorder appears to result from a complex interaction among:

viral immune activation,
host genetics,
autoimmune susceptibility,
cytokine signaling,
vascular dysfunction,
neural vulnerability.

The pathology involves:

inflammatory-cell infiltration,
demyelination,
oligodendrocyte injury,
variable axonal damage,
disruption of spinal cord barriers.

Diagnosis requires:

neurological localization,
MRI confirmation,
CSF analysis,
autoimmune evaluation,
exclusion of alternative causes.

Treatment remains centered on:

rapid immunosuppression,
escalation therapy when necessary,
intensive rehabilitation.

The future of this field will depend on identifying biological subtypes and replacing empiric therapy with precision approaches guided by:

genomic risk,
immune biomarkers,
advanced imaging,
molecular profiling.

COVID-associated transverse myelitis has become a powerful example of the broader challenge facing modern medicine: understanding how protective immunity can occasionally become pathogenic. The lessons learned from this rare disorder may extend beyond SARS-CoV-2 and improve understanding of autoimmune neurological disease as a whole.

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