Delayed Recognition of Thrombotic Thrombocytopenic Purpura Following Platelet Transfusion: A Clinical Pitfall.

Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening thrombotic microangiopathy caused by severe ADAMTS13 deficiency, usually due to autoantibody-mediated inhibition. Its presentation is heterogeneous and often lacks the classic pentad, leading to diagnostic delays. Neurological symptoms may predominate, masking the underlying hematologic emergency. In our case, a 37-year-old previously healthy woman presented with acute headache, speech disturbance, and altered mental status. Despite normal neuroimaging, laboratory tests revealed severe thrombocytopenia and normocytic anemia. Lack of response to erythrocyte and platelet transfusions prompted further evaluation, revealing microangiopathic hemolytic anemia with elevated lactate dehydrogenase, undetectable haptoglobin, indirect hyperbilirubinemia, reticulocytosis, and normal coagulation parameters. A PLASMIC score of 6/7 indicated a high probability of severe ADAMTS13 deficiency. Treatment with high-dose corticosteroids was initiated immediately, followed by plasma exchange and rituximab. ADAMTS13 activity confirmed severe deficiency at 0.3%, supporting the diagnosis of acquired TTP in the clinical context. The patient achieved rapid remission and complete neurological recovery. This case highlights the importance of early recognition of microangiopathic hemolysis and prompt treatment without waiting for confirmatory ADAMTS13 results to reduce morbidity and mortality.