This pattern is associated with more severe hypertension and a lower incidence of spontaneous recovery. Thrombotic thrombocytopenic purpura primarily affects females between 10 and 50 years of age. It usually begins as a flulike illness and ultimately progresses to a syndrome involving purpuric skin lesions and neurologic symptoms. Childhood hemolytic-uremic syndrome typically begins after an episode of bacterial or viral gastroenteritis. The diarrhea is frequently bloody.
Hypertension is common when renal failure is severe.
For example, adult hemolytic-uremic syndrome has been associated with pregnancy, particularly during the postpartum period, and the lupus anticoagulant may play an important pathogenetic role in this setting. A preceding episode of gastroenteritis similar to that seen in the childhood form of the syndrome may occur, but such an event is less common. Examination of the urine sediment in patients with thrombotic thrombocytopenic purpura often reveals red cells and red cell casts. In contrast, urinalysis in both children and adults with the hemolytic-uremic syndrome may be normal or near normal, perhaps because these disorders are characterized by more severe renal dysfunction, and associated oliguria or anuria could limit red cell excretion in the urine. It is important to note, however, that urinalysis is not sufficiently specific to distinguish one form of the hemolytic-uremic syndrome from another.