Rates of mortality and relapse was lower in adolescent patients with acquired thrombotic thrombocytopenic purpura (TTP) than that of adult patients, but larger studies are needed to evaluate long-term consequences of the disease, according to the results of study published in the journal Thrombosis Research.

The aim of this study was to focus on this population to evaluate complications and outcomes of this disease. This retrospective study evaluated data from the Pediatric Health Information Systems database of 99 adolescent patients with acquired TTP diagnosed between 2009 and 2020. The primary outcomes were in-hospital mortality and relapse, and secondary outcomes included hemorrhagic and thrombotic complications during hospitalization.

The median age of the cohort at initial hospital admission was 16 (range, 13.5-17.0) and 65% of patients were female. There were 44% of patients who were White, 35% who were Black, 9.1% who were Asian, and 25% who were Hispanic or Latino. An underlying contributing comorbidity was present among 41% of patients, which most commonly included a rheumatologic condition, cancer, or a transplant.

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Among the 99 patients, there were 123 instances of hospitalization, with 69% of admission requiring critical care for a median of 2 days and the overall length of stay for a median of 14 days. There were 27% of hospitalizations that required mechanical ventilation and 1.6% that required ECMO. The rate of in-patient mortality was 6%. A greater risk of mortality was associated with cancer, but not other comorbidities.

Relapse occurred among 20% of patients with a median time from the initial hospital admission for TTP to relapse of 33 days. The presence of comorbidities was not associated with risk for relapse.

There were 29% of patients who experienced a hemorrhagic complication, which most commonly presented as subcutaneous/hematomas or mucocutaneous. The presence of a contributing comorbidity was associated with an increased risk of a hemorrhagic complication with a rate of 37% compared with 14% among patients without a comorbidity (P =.004).

There were 15% of patients who experienced a thrombotic complication, which was not associated with presence of a comorbidity. The majority of thromboses affected deep veins in the extremities and thoracic veins.

The treatment of TTP was systemic steroids with therapeutic plasmapheresis for 90% of admissions. Other therapies included rituximab in 49.6% of cases, cyclophosphamide in 11%, acetylcysteine in 4%, and caplacizumab in 1.6%.

The authors concluded “this study provides a greater understanding of TTP in

adolescence, with significant rates of in-hospital mortality and disease relapse, though lower than that seen in adult registries.” However, they added that “long-term prospective studies are needed to understand the long-term consequences of adolescent-onset acquired TTP.”


Cohen CT, Zobeck M, Kim TO, et al. Adolescent acquired thrombotic thrombocytopenic purpura: An analysis of the Pediatric Health Information System database. Thromb Res. 2023;222:63-67. doi: 10.1016/j.thromres.2022.12.011