The primary manifestation of CNS involvement is seizures, which can be caused by vascular damage or cerebral hemorrhage. HUS seizures can also be caused by uremia (urea and other waste products staying in the blood due to kidney failure), hyponatremia (sodium levels are low and water levels are high), or other metabolic issues.
These seizures are usually general (affecting the whole brain), but can be focal (affecting a limited area of the brain). HUS seizures are sometimes the first sign of HUS and thus can happen before the child is hospitalized. Seizures can also occur at any point when a child is exhibiting signs and symptoms of HUS or even after an apparent recovery.
Seizures caused by hemolytic uremic syndrome are usually brief and easy to control, but a child with HUS may experience status epilepticus, which is a prolonged seizure, or a series of seizures where the child does not regain consciousness. The mortality rate for HUS patients who experience seizures and/or coma is higher than for those who do not suffer these complications.
1. David G. Nathan and F. A. Oski, Hematology of infancy and childhood, W.B. Saunders Co, Philadelphia (1993).
2. Hemolytic uremic syndrome and thrombotic thrombocytopenic purpura, Marcel Dekker, Inc. New York (1992).