Key Points Stroke is common in hereditary thrombotic thrombocytopenic purpura (TTP) patients, occurring in 25% to 31% of patients. In hereditary TTP patients, the age of occurrence of first stroke (median, 19 years) is similar to that for sickle cell anemia patients.

We describe how infants and children with hereditary and acquired autoimmune thrombotic thrombocytopenic purpura (TTP) initially present and how they can be promptly diagnosed and effectively managed. These are uncommon disorders that are commonly misdiagnosed and can be rapidly fatal. TTP is caused by a severe deficiency of the plasma protease, A disintegrin and Metalloprotease with a ThromboSpondin type 1 motif, member 13 (ADAMTS13). Measurement of ADAMTS13 activity is becoming easily accessible. A common presentation of hereditary TTP is neonatal severe hemolysis and hyperbilirubinemia. However, the median age of diagnosis is not until 5.5 years. Plasma is effective treatment for exacerbations and for prophylaxis. Plasma may be replaced by recombinant ADAMTS13 when it becomes available. Acquired TTP is more frequent in older children, in whom it is more common in girls and is commonly associated with systemic lupus erythematosus. For acquired TTP, plasma exchange and immunosuppression are the current treatment for acute episodes; caplacizumab is now commonly used in adults and may replace plasma exchange.

No abstract

The current pandemic due to coronavirus disease 2019 (COVID‐19) has posed an unprecedented challenge for the medical communities, various countries worldwide, and their citizens. Severe acute respiratory syndrome coronavirus 2 has been studied for its various pathophysiological pathways and mechanisms through which it causes COVID‐19. In this study, we discussed the immunological impact of COVID‐19 on the hematological system, platelets, and red blood cells.

Hereditary thrombotic thrombocytopenic purpura (hTTP) is a rare disorder caused by severe ADAMTS13 deficiency. Major morbidities and death at a young age are common. Although ADAMTS13 replacement can prevent morbidities and death, current regimens of plasma prophylaxis are insufficient. We identified 226 patients with hTTP in 96 reports published from 2001 through 2020. In 202 patients the age at diagnosis was reported; 117 were female, 85 were male. The difference was caused by diagnosis of 34 women during pregnancy, suggesting that many men and nulliparous women are not diagnosed. Eighty-three patients had severe jaundice at birth; hTTP was suspected and effectively treated in only 3 infants. Of the 217 patients who survived infancy, 73 (34%) had major morbidities, defined as stroke, kidney or cardiac injury, that occurred at a median age of 21 years. Sixty-two patients had stroke; 13 strokes occurred in children ≤10 years old. Of the 54 patients who survived their initial major morbidity and were subsequently followed, 37 (69%) had sustained or subsequent major morbidities. Of the 39 patients who were followed past age 40, 20 (51%) had experienced a major morbidity. Compared to age and gender-matched United States population, probability of survival was lower at all ages, beginning at birth. Prophylaxis was initiated in 45 patients with a major morbidity; in 11 (28%) a major morbidity recurred after prophylaxis had begun. Increased recognition of hTTP and more effective prophylaxis begun at a younger age are required to improve health outcomes.