A Case of Atypical Hemolytic Uremic Syndrome in a Pregnant Patient

Atypical hemolytic uremic syndrome (HUS) is a rare but severe form of thrombotic microangiopathies (TMAs) that affects both children and adults. The clinical presentation is usually nonspecific, including a broad spectrum of symptoms ranging from abdominal pain, confusion, diarrhea, fatigue, irritability, hypertension, and lethargy. We present a case of a 36-year-old woman with medical comorbidities of asthma and pulmonary embolism who presented to our hospital in the 36th week of her pregnancy for preterm premature rupture of the membranes. The postoperative course was complicated with a sudden onset drop in hemoglobin and acute onset thrombocytopenia. Complements levels were normal while ADAMTS 13 (von Willebrand factor-cleaving protease) activity was 81% which ruled out ADAMTS 13 deficiency. No significant clinical improvement was seen after five cycles of plasmapheresis. She was later started on Eculizumab biweekly with marked improvement in biochemical and clinical status. Prompt diagnosis and treatment of atypical HUS are crucial as the prognosis is poor if untreated. The diagnosis of atypical HUS can be challenging as the classic triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury can be seen in all thrombotic microangiopathies, thus careful clinical and laboratory assessment is required to establish the diagnosis. The new treatment modality, Eculizumab, the anti-complement monoclonal antibody, has become the first-line therapy for treating atypical HUS.