[Hemolytic and uremic syndrome in the child]

Hemolytic and uremic syndrome (HUS) is characterized by the association of hemolytic anemia with sckizocytes, thrombopenia and renal involvement secondary to thrombotic microangiopathy. The typical form is the most frequent in children occurring after an episode of diarrhea caused by Escherichia coli. Other microorganisms may be responsible for HUS such as Shigella dysenteriae or streptococcus pneumoniae. Acute renal failure is reversible in most cases, but long-term renal sequelae are seen in one third of patients when the anuria at onset of disease has lasted more than one week. Treatment of typical HUS is only supportive (blood transfusion, treatment of acute renal failure). Atypical HUS is less frequent but of poorer prognosis. Atypical HUS may be associated with mutations in complement regulator genes, von Willebrand factor-cleaving protease deficiency, congenital intracellular defects of vitamin B12 metabolism or may be of unknown origin. Familial forms are frequent. Recurrence of HUS following renal transplantation is exceptional in the typical form but is frequent in atypical HUS.