Vol. 6, Issue 2, Part A (2024)

Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening disorder caused by a severe deficiency of the Von Willebrand factor (vWF)-cleaving protease ADAMTS13. Low levels of ADAMTS13 protein result in large vWF multimers with an increased risk of microvascular thrombosis, thrombocytopenia, and microangiopathic hemolytic anemia. Hereditary thrombotic thrombocytopenic purpura (hTTP), also known as Upshaw-Schulman syndrome, is extremely rare and has many overlapping clinical features with more common chronic immune thrombocytopenia (ITP). In this study, we report a 6-year-old boy who had intermittent ongoing thrombocytopenia and was treated as chronic ITP by multiple centers prior to presentation with a stroke. On review of the history, he had neonatal jaundice needing phototherapy and an apparent response to platelet transfusion. This atypical history and presentation with stroke and hypertension prompted us to investigate for TTP, and the final diagnosis was confirmed as hereditary TTP (hTTP). His symptoms and platelet numbers improved with regular plasma infusions and his neurological status recovered fully. This case highlights difficulties in making an early diagnosis of hTTP and the atypical features the clinician should be aware of that should alert the possibility of an alternate diagnosis in children presenting with low platelets.