Although many people think of Covid as primarily a respiratory disease, the virus that causes this disease is also capable of causing symptoms in many other organ systems throughout the body.

Can Covid affect the kidneys? How do you know if your kidneys have been damaged by Covid?

Does Covid affect the kidneys?

It’s well-established that Covid can cause damage to the kidneys. In fact, this is very common in people who have severe cases of the disease. Between 28% and 46% of patients who are hospitalized for Covid show evidence of acute kidney injury. Of these, a significant proportion have severe enough kidney damage to require dialysis.

Are there symptoms of kidney damage from Covid?

The symptoms of kidney damage from Covid depend on how severe the damage is. In more severe cases, kidney failure can occur, leading to symptoms like:

Urinating very little
Swelling in the hands and feet
Nausea and vomiting
Severe confusion
Shortness of breath
Fatigue

However, in patients who experience more mild kidney damage, there may not be obvious symptoms. The damage to the kidney might only be detectable on blood and/or urine tests that measure kidney function.

How can Covid cause kidney issues?

It’s been more than two years since the Covid-19 pandemic began, but we still don’t know everything about the virus. Researchers are still working to understand how SARS-CoV-2 (the virus that causes Covid) affects the body, including the kidneys. There are believed to be a few ways that Covid can cause kidney damage:

The virus can directly affect the kidney. Researchers have found that the virus that causes Covid is capable of entering certain cells of the kidney.
Covid increases the risk of blood clots. These can affect the blood flow to the kidney and damage it.
Patients with severe Covid often have low oxygen levels in the blood for a period of time. This can also affect the cells of the kidney and lead to damage.
The severe inflammatory response provoked by the virus can damage healthy tissues throughout the body, including the kidneys.
In severe cases of Covid, patients may experience septic shock, in which blood pressure drops rapidly. This deprives the kidneys of blood flow and can damage them.

Can the kidneys recover from damage caused by Covid?

In many patients, kidney function does return to normal after they recover from Covid. However, studies have shown that in patients hospitalized for Covid, 35% have not recovered their kidney function at the time of discharge from the hospital.

Because this is a relatively new virus, we don’t yet have good data on the long-term implications of Covid. It’s not yet known how many patients with Covid will go on to develop chronic kidney disease. However, researchers do believe that Covid increases the risk of chronic kidney disease, particularly in patients whose Covid infection is severe.

How do I know if Covid has damaged my kidneys?

Mild to moderate kidney damage may not cause any obvious symptoms in most patients. The only way to know for sure whether your kidneys have been damaged is to get a kidney function test. You can visit your doctor for a consultation, and then go to a laboratory to get blood and/or urine samples taken for the test. Another option is to order a home test kit.

FAQ

Can Covid cause kidney problems?

Kidney damage is a known side effect of Covid-19, and a significant proportion of people who are hospitalized with Covid show evidence of decreased kidney function.

Can Covid cause blood in the urine?

Blood in the urine can be a sign of kidney damage, whether this occurs due to Covid or another cause (such as high blood pressure or diabetes). Blood in the urine may make it look red, pink, or brown. Patients who have blood in the urine after Covid should have their kidney function tested

Can Covid cause kidney pain?

While certain kidney conditions, like kidney infections and kidney stones, commonly lead to pain in the area of the kidneys (the mid-back, around the bottom of the ribs), Covid typically doesn’t cause kidney pain. Instead, the kidney damage caused by Covid is more insidious, and may even occur without any obvious symptoms.

Sources

Bowe B, Xie Y, et al. Kidney Outcomes in Long COVID. J Am Soc Nephrol. 2021 Nov;32(11):2851-2862. doi: 10.1681/ASN.2021060734.

Chan L, Chaudhary K, et al. AKI in Hospitalized Patients with COVID-19. J Am Soc Nephrol

. 2021 Jan;32(1):151-160. doi: 10.1681/ASN.2020050615.

Helms L, Marchiano S. et al. Cross-validation of SARS-CoV-2 responses in kidney organoids and clinical populations. JCI Insight. 2021 Dec 22;6(24):e154882. doi: 10.1172/jci.insight.154882.

Kidney disease & COVID-19. National Kidney Foundation. https://www.kidney.org/coronavirus/kidney-disease-covid-19. Accessed 27 June 2022.

Yende S, Parikh CH. Long COVID and kidney disease. Nat Rev Nephrol. 2021 Dec;17(12):792-793. doi: 10.1038/s41581-021-00487-3.