According to studies carried out in France, the virus infects cells in the renal tubule system and can cause Fanconi syndrome, in which nutrients are lost in the urine.
Between the 6th and the 9th of June, the 57th congress of the European Renal Association – European Dialysis and Transplant Association (ERA-EDTA) took place. In the online lectures – due to the Covid-19 pandemic – scientists presented findings of how infection with the new coronavirus affects the kidneys.
One of the studies presented was led by scientists at the University of Bordeaux, in France, and says that acute kidney injury (AKI) affects up to 80% of people with severe Covid-19. According to the article, published in the Clinical Kidney Journal, the virus infects cells in the renal tubule system because they have the ACE2 receptor, which Sars-CoV-2 uses to invade human cells.
This causes the tubular cells to be damaged, which is a problem because they are responsible for ensuring the reabsorption of important substances, such as glucose, bicarbonate, potassium, phosphate, and proteins. This situation can lead, according to the study, to the so-called Fanconi syndrome, a disease in which substances and nutrients important to the body are lost in the urine.
According to the scientists, the consequences of Fanconi syndrome are disorders related to the body’s mineral balance, in addition to reduced bone density due to loss of phosphate. The disease can also cause other problems, such as blood hyperacidity, dehydration, increased thirst, and weakness.
Another research presented during the congress by scientists from the University of Lorraine, also in France, concerns precisely the relationship between Fanconi syndrome and infection by Sars-CoV-2. In the article, published in the Clinical Kidney Journal, the team explains that they analyzed 42 patients who did not have kidney problems, tested positive for the new coronavirus and went through cases of varying severity of the infection.
According to the researchers, 75% of the patients analyzed developed Fanconi syndrome to some degree. In the case of people with more severe Covid-19 conditions, 96% were affected by the kidney problem. Among those with a milder manifestation of the infection, this rate was 62%.
“Although by no means all COVID-19 patients with Fanconi syndrome developed AKI, we believe that the four markers (increased urinary excretion of protein, phosphate, uric acid and glucose), if a new occurrence, indicate specific proximal-tubular injury from which AKI can develop,” explained Raphaël Kormann, one of the researchers, in a statement.
Alberto Ortiz, editor-in-chief of the Clinical Kidney Journal, believes that patients who have had Covid-19 need to pay attention to possible permanent kidney problems they may develop. “It must also be assumed that there is an increased risk of subsequent kidney disease after SARS-CoV-2-associated Fanconi syndrome, as is also the case after acute kidney injury,” noted the expert. “For that reason, patients should always be followed-up nephrologically so that associated conditions are detected in time.”