Fatal cases of hemorrhagic fever with renal syndrome in Udmurtia, Russia, 2010 to 2019.

Hemorrhagic fever with renal syndrome (HFRS) continues to be a cause of death in Europe. Our aim was to describe the clinical and histopathological features of fatal HFRS in the Udmurt Republic (Udmurtia), located in the European part of Russia. This retrospective observational study included all fatal cases of HFRS that occurred in Udmurtia from January 2010 through December 2019. The most relevant clinical and autopsy data of these cases were recorded through a review of the patients' medical records and autopsy reports. During 2010-2019, Udmurtia had 41 fatal cases of HFRS of a total of 10,312 confirmed cases (case-fatality rate of 0.4%). Twenty-seven patients died in hypotensive and oliguric phases of HFRS due to refractory septic shock and acute respiratory distress syndrome. Fourteen patients died in the polyuric phase of the disease from complications of acute kidney injury or because of hospital-acquired bacterial infections. Multiorgan involvement was noted in all autopsies with variable degrees of generalized venous congestion, interstitial edema, capillary wall thickening, perivascular deposition of plasma proteins, microthrombosis formation, and perivascular hemorrhage. The more prominent histopathological features were seen in kidneys, lungs, and hypophysis.