Coronavirus 2019 (COVID-19) hit headlines as a novel respiratory virus that traveled quickly through Wuhan, China, making its way to other countries by early 2020. By March 1st, COVID-19 was declared a pandemic. Most of the common symptoms of COVID-19 include fever, shortness of breath, and a dry cough that can last up to two weeks. While most of the symptoms are respiratory, some studies have also found diminished renal function in a subset of patients who have contracted the virus. 

The kidneys are two bean shaped organs found below the rib cage and are responsible for filtering blood, removing waste, and balancing the electrolytes in the body. It is no surprise that while your body is fighting a virulent virus like COVID-19, your kidneys can be affected in multiple ways. Recent studies have shown that the main cause for kidney damage during the battle between your body and COVID-19 is through what immunologists call a “cytokine storm.”

When your body is infected with a foreign pathogen, immune cells are recruited to fight it off. Like a general sending a signal to his soldiers when there is an enemy, immune cells do the same by releasing signals, cytokines, to recruit more immune cells to help fight. A common cytokine released is IL6, which induces inflammation. However, when too much IL6 is released, the body suffers from a “cytokine storm,” which is when the immune system attacks the body causing severe organ failure. A recent study shows that increased IL6 release from the epithelium of the renal tubules was found in COVID-19 positive patients who also had acute kidney injury (AKI). 

As mentioned before, because the kidneys are responsible for keeping the body in a balanced state, it is often involved in organ crosstalk. Respiratory symptoms are common with a COVID-19 diagnosis. A study conducted in Wuhan shows that 68% of COVID-19 positive patients who report having acute respiratory distress and no history of renal disease have developed AKI. This is because of the close relationship between the alveoli in the lungs and the renal tubules, also called the lung and kidney axis. This means there is potential for  bidirectional damage. 

There is also ‘crosstalk’ between the heart and kidney. The inflammatory response caused by IL6 can also cause cardiomyopathy or weakening of the heart, making it more difficult for the heart to effectively pump blood throughout the body. Decreased blood flow to the kidneys decreases the GFR, glomerular filtration rate, a measurement of how quickly and efficiently the kidney is filtering blood. The kidneys have an intricate relationship with all the organs in the body, so it is easily affected when other organs are fighting foreign infections. 

So who is at risk? While anyone can catch COVID-19 and become seriously ill with many complications, there are some risk factors that can make the virus more dangerous for certain people. Studies show that age, severity of illness, diabetes, and increased BMI are all factors for kidney damage with COVID-19. Kidney transplant and dialysis patients are at a greater risk because they are immunosuppressed. If you are worried about your kidney health and how COVID-19 can affect your kidneys, please call 714-435-0150 to schedule an appointment via telemedicine.