Diagnostic and clinical challenges of hantavirus-associated acute kidney injury

Introduction: Hantavirus infection is an uncommon zoonosis in Europe but remains an important cause of acute kidney injury, particularly in patients with environmental exposure to rodents. Renal involvement is the hallmark of the disease, although pulmonary manifestations may coexist and mimic immune-mediated pulmonary–renal syndromes, leading to diagnostic challenges in internal medicine. Case description: A 46-year-old previously healthy man living in a rural area was admitted for acute febrile illness with asthenia and myalgia. Initial investigations revealed severe thrombocytopenia and acute kidney injury with proteinuria and microscopic haematuria. A computed tomography scan of the chest and abdomen showed bilateral pulmonary abnormalities, consistent with an acute pulmonary–renal syndrome. Extensive immunological and infectious investigations excluded autoimmune disease and alternative infectious causes. Hantavirus infection was confirmed by positive IgM and IgG serology, with molecular identification of Puumala virus. Renal biopsy demonstrated moderate acute tubular necrosis with minimal interstitial inflammation and preserved glomeruli. The patient was treated with supportive care only, resulting in rapid clinical improvement and complete recovery of renal function. Conclusion: Hantavirus infection should be considered in patients presenting with acute pulmonary–renal syndrome, thrombocytopenia, and compatible epidemiological exposure. Early diagnosis allows appropriate supportive management, avoids unnecessary immunosuppressive therapy, and is associated with an excellent renal prognosis in Puumala virus infection.