Abstract
The hemolytic uremic syndrome (HUS) comprises hemolytic anemia, acute renal failure,
and thrombocytopenia. It is the most frequent cause of acute renal failure in childhood.
Ninety percent of the patients have a diarrheal prodrome, and are referred to as having
typical HUS. Approximately 10% exhibit the so-called atypical HUS. Typical HUS is
caused by shigatoxin-producing Escherichia coli. The toxin, bound to the globotriosyl ceramide cell receptor and internalized, interferes
with protein synthesis, predominantly of endothelial cells. The main target is the
kidney, but nearly every organ system can be involved. The most common extrarenal
involvement is damage to the central nervous system. The central event is probably
an insult to the endothelial cell with consecutive loss of antithrombogenic properties.
The von Willebrand factor, activation of platelets via platelet-activating factor,
other growth factors (eg, interleukins 1, 6, 8), nitric oxide, lipopolysaccharides,
activated polymorphonucleated neutrophils, and the metabolites of the arachidonic
acid cascade (eg, prostaglandin I2) are believed to be involved in the pathogenic cascade.
Controlled therapeutic trials with heparin, dipyridamole, aspirin, and urokinase have
not been associated with improved outcome. Antibiotics have not yielded any benefit.
Plasma infusions and plasma exchange appear to be efficacious, and are justified in
cases of atypical HUS and thrombotic thrombocytopenic purpura. Binding of the toxin
to the intestinal lumen, and thereby inhibition of enteral reabsorption, is under
investigation.
Keywords:
Hemolytic uremic syndrome - thrombotic thrombocytopenic purpura - childhood -
Escherichia coli
- shigatoxin - von Willebrand factor
