Severe immune thrombotic thrombocytopenic purpura with neurologic involvement: a case report

Immune thrombotic thrombocytopenic purpura (iTTP) is a rare but life-threatening thrombotic microangiopathy caused by severe ADAMTS13 deficiency due to anti-ADAMTS13 autoantibodies. Although its annual incidence is low, iTTP is a hematologic emergency requiring urgent recognition and treatment because delayed therapy may lead to rapid clinical deterioration, severe organ injury, or death. Neurologic involvement is common and may be severe. Although contemporary management increasingly incorporates caplacizumab, some patients are still treated with therapeutic plasma exchange (TPE), immunosuppression, and intensive supportive care because of disease severity or limited drug availability. We report a severe case of iTTP with prominent neurologic involvement managed in a real-world setting without caplacizumab. A 67-year-old man presented with fatigue, jaundice, and impaired consciousness. On admission, laboratory testing showed hemoglobin 51 g/L, platelet count 11 × 10⁹/L, lactate dehydrogenase 1448 U/L, total bilirubin 83.3 µmol/L with predominant indirect hyperbilirubinemia, and serum creatinine 78 µmol/L. Peripheral blood smear examination showed schistocytes, supporting microangiopathic hemolytic anemia. The PLASMIC score was 6, indicating a high pretest probability of severe ADAMTS13 deficiency. ADAMTS13 activity was markedly reduced to 1.37%, and the inhibitory anti-ADAMTS13 antibody was positive, supporting the diagnosis of iTTP. During hospitalization, the patient developed multifocal cerebral ischemia and superficial venous thrombosis of the right upper extremity. After admission to the intensive care unit, daily TPE was initiated promptly and combined with high-dose glucocorticoids, rituximab, and short-course intravenous immunoglobulin, together with comprehensive supportive care including mechanical ventilation, nutritional support, and staged anticoagulation. Before the first TPE session, 400 mL of fresh frozen plasma was infused as bridging plasma therapy. The early platelet response was delayed, and the patient was considered to have refractory iTTP during the acute course. On repeat testing, ADAMTS13 activity remained severely reduced at 2.48%, whereas the inhibitory antibody became negative. The patient was discharged on hospital day 38 and remained free of clinical relapse or neurologic sequelae through day 66 of follow-up. This case illustrates the real-world management of severe iTTP with neurologic involvement in a setting where caplacizumab was unavailable. Prompt initiation of available therapy together with structured ICU support was associated with multiorgan stabilization and favorable neurologic recovery. However, this case also highlights the gap between resource-limited real-world practice and contemporary caplacizumab-based, ADAMTS13-guided management strategies. Serial ADAMTS13 assessment remains important for disease evaluation and follow-up. Not applicable.