Syndrome hémolytique et urémique chez l’enfant

The haemolytic and uremic syndrome is caracterized by the association of hemolytic anemia with schizocytes, thrombopenia and renal involvement secondary to thrombotic microangiopathy. The typical form is the most frequent in children occuring after an episode of diarrhea caused by Escherichia coli. Other germs 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 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 factor H gene mutations, von Willebrand factor-cleaving protease deficiency, congenital intracellular defects of vitamine B12 metabolism or may be of unknown origin. Familial forms are frequent. Recurrence of HUS following renal transplantation is exceptional in typical forms but is frequent in atypical HUS.