From dog bite to dialysis: complement-mediated haemolytic uraemic syndrome

A previously healthy woman in her late 40s presented with rapidly progressive sepsis 4 days after a dog bite. She developed disseminated intravascular coagulation, pancytopenia and acute kidney injury, ultimately progressing to complete anuria and dialysis dependence. Blood cultures confirmed Capnocytophaga canimorsus bacteraemia. Despite an initial clinical improvement with antibiotics and supportive care, she developed sudden isolated haemolysis and persistent thrombocytopaenia. Laboratory and renal biopsy findings confirmed the presence of a thrombotic microangiopathy (TMA), and complement-mediated haemolytic uraemic syndrome (CM-HUS) was diagnosed. Following plasma exchange and initiation of eculizumab therapy, haematological remission was achieved, and her kidney function partially recovered.This case highlights C. canimorsus infection as a rare trigger of CM-HUS in immunocompetent adults and outlines the patient's diagnostic workup, the challenges of differential diagnosis and the complexity of both the clinical course and therapeutic approach in case of TMA following sepsis. .