Delayed diagnosis of congenital thrombotic thrombocytopenic purpura in a patient with recurrent strokes

Congenital thrombotic thrombocytopenic purpura (cTTP) is caused by ADAMTS13 mutations and associated with high risk of microvascular thrombosis. A 58 year old female had an ischemic stroke during hormonal fertility, and a TIA a year after. She suffered another stroke 18 years later while on warfarin. Four months after she developed severe thrombocytopenia, mild anemia, and increased LDH. Blood film showed schistocytes. She was hospitalized with presumptive TTP. ADAMTS 13 activity was undetectable without inhibitor. She developed another stroke and received plasma exchange. A homozygote ADAMTS 13 mutation was identified. Despite plasma, the ADAMTS13 activity remained < 10% and she had another stroke. Recombinant ADAMTS13 therapy was obtained through compassionate use. She receives weekly infusions maintaining ADAMTS13 trough levels above 10% without thrombotic recurrences. This case underscores the need to recognize cTTP as a cause of cryptogenic strokes, and the diagnostic value of the peripheral blood film. rADAMTS13 replacement may prevent recurrences.