Primary Angiitis of Central Nervous System (PACNS) is an important cause of stroke in the young. However, establishing the diagnosis is fraught with confusion and ambiguity as it is an umbrella term for heterogeneous pathologies and presentation. The tests used are neither sensitive nor specific. Here, we present the case of a young woman who presented with multifocal infarcts initially thought to be PACNS but eventually found to have Thrombotic Thrombocytopenic Purpura (TTP)

44 year old healthy woman was admitted for nausea, vomiting and confusion found to have bilateral infarcts of cortical and subcortical structures and brainstem. Her MR Angiogram showed multifocal stenoses in medium and large vessels intracranially. Her platelets were within normal range. After extensive work-up, the most likely diagnosis was PACNS and was treated with appropriate immunotherapy.

  Over the next 6 months, she had several recurrent episodes of strokes in multiple vascular territories that failed multiple regimens of immunosuppression and unfortunately left the patient neurologically debilitated. 

  During her most recent admission, she was found to have thrombocytopenia, recurrent mitral valve endocarditis, heavy menorrhagia and lower GI bleeding. Peripheral smear revealed schistocytes and ADAMTS13 activity was critically low. She was diagnosed with Thrombotic Thrombocytopenic Purpura (TTP) and treated with plasma transfusions. Platelets and ADAMTS13 levels normalized.

TTP is a well-known hematologic cause for stroke due to deficiency of ADAMTS13 or inhibitory antibodies to ADAMTS13. TTP is characterized by thrombotic microangiopathy and neurological manifestations such as confusion, seizures and strokes. Its manifestation can be varied and some patients have near-normal platelets upon presentation. Management is with plasma transfusion or exchange and if appropriately treated in the acute phase, is characterized by marked rapid clinical improvement. Awareness and testing for TTP even with normal platelets in a young patient such as this can be lifesaving and disability preventing.