Authors: C. John Sperati, M.D., M.H.S. Posted May 28, 2022 John’s Hopkins Health

COVID-19 Kidney Damage: A Known Complication

Some people suffering with severe cases of COVID-19 will show signs of kidney damage, even those who had no underlying kidney problems before they were infected with the coronavirus. Signs of kidney problems in patients with COVID-19 include high levels of protein or blood in the urine and abnormal blood work.

Studies indicate more than 30% of patients hospitalized with COVID-19 develop kidney injury, and more than 50% of patients in the intensive care unit with kidney injury may require dialysis. Sperati says early in the pandemic, some hospitals were running short on machines and sterile fluids needed to perform dialysis.

“As general treatments for patients with COVID-19 have improved, the rates of dialysis have decreased. This has helped to alleviate shortages, although intermittent supply chain disruptions remain a concern.

“Many patients with severe COVID-19 are those with co-existing, chronic conditions, including high blood pressure and diabetes. Both of these increase the risk of kidney disease,” he says.

But Sperati and other doctors are also seeing kidney damage in people who did not have kidney problems before they got infected with the virus.

How does COVID-19 damage the kidneys?

The impact of COVID-19 on the kidneys is complex. Here are some possibilities doctors and researchers are exploring:

Coronavirus might target kidney cells

The virus itself infects the cells of the kidney. Kidney cells have receptors that enable the new coronavirus to attach to them, invade, and make copies of itself, potentially damaging those tissues. Similar receptors are found on cells of the lungs and heart, where the new coronavirus has been shown to cause injury.

Too little oxygen can cause kidneys to malfunction

Another possibility is that kidney problems in patients with the coronavirus are due to abnormally low levels of oxygen in the blood, a result of the pneumonia commonly seen in severe cases of the disease.

Cytokine storms can destroy kidney tissue

The body’s reaction to the infection may be responsible as well. The immune response to the new coronavirus can be extreme in some people, leading to what is called a cytokine storm.

When that happens, the immune system sends a rush of cytokines into the body. Cytokines are small proteins that help the cells communicate as the immune system fights an infection. But this sudden, large influx of cytokines can cause severe inflammation. In trying to kill the invading virus, this inflammatory reaction can destroy healthy tissue, including that of the kidneys.

COVID-19 causes blood clots that might clog the kidneys

The kidneys are like filters that screen out toxins, extra water and waste products from the body. COVID-19 can cause tiny clots to form in the bloodstream, which can clog the smallest blood vessels in the kidney and impair its function.