Teaching NeuroImage: Partially Reversible Widespread Leukoencephalopathy Associated With Atypical Hemolytic Uremic Syndrome

A 43-year-old woman presented with altered mental status and hypertension. She had a 3-day history of oliguria. The blood test detected microangiopathic hemolytic anemia, thrombocytopenia, and severe kidney injury. The absence of shiga-like toxin, ADAMTS13 autoantibodies, and normal ADAMTS13 activity were consistent with a diagnosis of atypical hemolytic uremic syndrome (aHUS) and then confirmed by a renal biopsy. Genetic tests (CFH, CFHR1-5, MCP/CD46, CFI, C3, CFB, THBD, and DGKE) were unremarkable. Nevertheless, a history of anemia and kidney failure in her younger brother suggested a genetic etiology. Brain MRI revealed extensive T2 FLAIR hyperintensities. Treatment with eculizumab and twice-weekly hemodialysis resulted in prompt mental recovery and improvement of MRI abnormalities. aHUS is an ultra-rare complement-mediated kidney disease occasionally associated with neurologic involvement.1 Less extensive T2 FLAIR abnormalities involving every CNS structure have also been reported in diarrhea-associated HUS.2 Here, we presented a case of aHUS-related widespread leukoencephalopathy partially reverting on treatment with eculizumab and hemodialysis.