Characterization and outcome following Puumala virus infection: a retrospective analysis of 75 cases.

Background: Infection with the Puumala virus (PUUV), which belongs to the Hantavirus family, is a common but often neglected cause of acute kidney injury (AKI) in endemic areas of Europe. The objective of the present study was to systematically analyse clinical presentation and renal outcomes following PUUV infection.

Methods: In a retrospective study, we analysed data from 75 patients who were admitted to two large hospitals in Germany over an 8-year period and who tested positive for PUUV infection. Clinical and laboratory data were collected from patient files; creatinine levels before admission and during follow-up were obtained from phone calls.

Results: Patients were between 16 and 82 years old (average +/- SD, 40.4 +/- 13.4) with a male to female ratio of 2.5:1. They showed a wide variety of clinical presentations with renal failure being the cause of admission in only 50%. AKI developed in 95% of patients who showed maximum creatinine levels of 4.3 +/- 0.3 mg/dl. Four patients required temporary dialysis, and one patient died from pulmonary complications. Thrombocytopaenia (137 +/- 11 x 10(3)/microl) was present in almost all cases, and elevated levels of lactate dehydrogenase (LDH) and C-reactive protein (CRP) were observed in 57 and 100% of patients, respectively. Urinalysis revealed mild to nephrotic proteinuria in 85%, which was often associated with haemoglobinuria. All patients showed full recovery of renal function and return to pre-existing normal serum creatinine levels.

Conclusion: In a majority of cases, PUUV infection results in thrombocytopenic AKI. Fever is a requirement for diagnosis, while elevated LDH and CRP values are also frequently observed. Overall, early renal outcomes were excellent.