Symptoms of Hemolytic Uremic Syndrome
In typical HUS, gastroenteritis occurs with abdominal cramping, vomiting and profuse bloody, watery diarrhea, as a symptom up to a week before the onset of HUS. This may cause significant dehydration, weakness and lethargy, as well as electrolyte imbalances because of the loss of sodium, potassium, and chloride in the vomit and diarrhea. These symptoms may resolve before the onset of anemia and the kidney failure symptoms of HUS.

The anemia and uremia usually present with weakness, lethargy, and sleepiness. Seizures may occur. Purpura or small areas of bleeding in the skin may be seen because of low platelet counts (thrombocytopenia).