Possible Adenovirus Triggered Case of Atypical Hemolytic Uremic Syndrome in a Kidney Transplant Recipient: A Case Report and A Review of the Literature.

Atypical hemolytic uremic syndrome (aHUS) is a rare disorder of the alternative complement pathway characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. It has a genetic background or may be triggered by viral infections and certain medications, such as immunosuppressants. We present a case of post-kidney transplant development of aHUS in a genetically predisposed individual with an acute adenoviral infection. A 25-year-old male with known chronic kidney failure and subsequent renal transplantation was admitted to hospital due to respiratory symptoms, fever, leukopenia, thrombocytopenia, hemolytic anemia and deteriorating renal graft function. Imaging revealed a consolidation in lower right lung lobe with pleural effusion, while bronchoscopy confirmed adenovirus infection. The findings suggested that the patient suffered from thrombotic microangiopathy, causing an acute kidney failure, aggravated by an adenoviral infection. Empirical treatment with the C5 complement component inhibitor ravulizumab was initiated, and genetic testing for complement abnormalities was performed. Following ravulizumab administration, the patient became afebrile, inflammatory markers decreased and both cytopenia and graft function improved. A CT scan marked regression of lung consolidation and effusion. Complement analysis later confirmed inherited defects predisposing to aHUS. The patient was discharged home in good condition with stable kidney allograft function. This case supports the increasing evidence linking adenoviral infections with aHUS onset and highlights the importance of considering this rare diagnosis in predisposed patients with compatible clinical and laboratory findings. Early recognition enables timely intervention, which is essential for preventing irreversible kidney damage that could be fatal.