Postpartum acquired hemophilia presenting as compartment syndrome: a diagnostic challenge in the emergency department

BACKGROUND: Acquired hemophilia A is an uncommon but potentially life-threatening bleeding disorder caused by autoantibodies against factor VIII. It can be associated with autoimmune disease, malignancy, or pregnancy. CASE REPORT: We describe a 31-year-old woman, five weeks postpartum, who presented to the emergency department with left arm pain and swelling complicated by concern for compartment syndrome. Laboratory evaluation revealed an isolated markedly prolonged partial thromboplastin time (PTT) of 86.9 s with a normal international normalized ratio, and severely reduced factor VIII activity of 1.5%. A mixing study showed no correction, and factor VIII inhibitor titer was 16 Bethesda units, confirming acquired hemophilia A. She was admitted to the intensive care unit and treated with bypassing hemostatic therapy (recombinant factor VIIa and factor VIII concentrate), tranexamic acid, corticosteroids, rituximab, and a single dose of emicizumab, with subsequent clinical and laboratory improvement. The patient was discharged home without any complications. CONCLUSIONS: Postpartum acquired hemophilia A is rare but can present with limb-threatening bleeding. This case emphasizes the importance of recognizing spontaneous postpartum hematomas as potential indicators of acquired hemophilia in the emergency setting.