BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by hemolysis, thrombocytopenia, and renal dysfunction. It is a disease related to genetic mutations in the alternative complement pathway and has a distinct pathophysiology but is difficult to differentiate from other thrombotic microangiopathies.

CASE REPORT: We present a case of a 59-year-old female patient who presented with accelerated hypertension, acute renal failure, hemolysis, and encephalopathy. She was managed with antihypertensive medication, but her encephalopathy did not improve. Evaluation resulted in our impression of the disease being atypical hemolytic-uremic syndrome. The patient continued to be managed with good blood pressure control and later was started on eculizumab, but evaluation of response to therapy was hindered by the patient’s non-compliance with therapy and follow-up appointments.

CONCLUSIONS: We have a very limited understanding of the genetics and epidemiology of atypical HUS, and the overlapping clinical features sometimes delay diagnosis and initiation of appropriate treatment of this rare disease.

Keywords: Diagnosis, Differential, Atypical Hemolytic Uremic Syndrome - therapy, Algorithms