Focal Segmental Glomerulosclerosis and Collapsing Glomerulopathy after Covid 19 Infection.

Introduction. Focal segmental glomerulosclerosis (FSGS) is defined as an increase in the mesangial matrix in some glomeruli with obliteration of capillary lumens, sclerosis, hyalinosis, foam cells, and adhesions to the Bowman's capsule. Collapsing glomerulopathy is a morphologic variant of focal segmental glomerulosclerosis (FSGS) characterized by segmental and global collapse of the glomerular capillaries, marked hypertrophy and hyperplasia of podocytes, and severe tubulointerstitial disease. Actually secondary collapsing glomerulopathy is a heterogeneous group including numerous causes: viruses, toxins and drugs such as heroin and pamidronate. Case reports. We report on two cases with glomerular disease after COVID-19 infection. The first patient, 53 years old male, with nephrotic syndrome and histopathologic features of glomerular capillary collapse. He was admitted in our department with nephrotic syndrome and renal failure. Several months ago, he had COVID-19 infection and was treated for COVID-19 pneumonia, but he had not symptoms for any renal disease. In following months, the patients manifested symptoms such as nausea, dysuria and light malleolar edema. Laboratory findings presented increased values of BUN 27mmol/l, creatinine 453 µmol/l, with proteinuria 4,6 g/24h. In order to identify the cause for these results, renal biopsy was performed with diagnose of collapsing glomerulopathy. The patient was followed up for a period of 6 months and treated with corticosteroid therapy. The values for creatinine were decreased to 195 µmol/l, with proteinuria 1 g/24h. After that the patient was stable, but with slowly increasing values for creatinine up to 242µmol/l and proteinuria 0,61 g/24h, for a period of the next several months. Second case was a patient 58 years old, male with pulmo- renal syndrome, with bilateral pneumonia and acute kidney injury. COVID 19 infection was established with BUN 36 mmol/l and serum creatinine up to 586 µmol/l. Several weeks the patient was treated with hemodialysis. After that the patient was stable, the values for BUN and serum creatinine were still higher but without necessity for dialysis treatment. Proteinuria of 1,98 g/24hours still remained and renal biopsy was performed. Focal segmental glomerulosclerosis was diagnosed. The follow up in next several months included therapy with corticosteroids, after that with cyclosporin, with effect on improved kidney function with BUN 14 mmol/l, creatinine 156 µmol/l and values for proteinuria of 0,96 g/24hours. Conclusion. SARS-CoV-2 associated renal disease seems to have different outcome and follow up despite the treatment. Renal biopsy may be crucial along with the molecular testing for COVID 19. [ABSTRACT FROM AUTHOR]