“Hemolytic” means that red blood cells (RBCs) break apart with our own blood stream. “Uremic” means kidney failure. HUS, somewhat rare, can occur with a wide variety of illnesses, but is most commonly due by certain strains of the bacteria E. coli, which causes a diarrhea 5-10 days before (usually diarrhea with blood). The germ then begins to produce a toxin that affects the whole body.
Most cases happen in children under 5 years old. It makes the news when there are outbreaks. Undercooked contaminated meat in fast food restaurants led to deaths in the early 1990s, others have occurred from unpasteurized commercial fruit juice, raw bean sprouts, raw milk, spinach, and prepackaged cookie dough. It has also been acquired person-to-person, from swimming in contaminated lakes, and in petting zoos.
We’d suspect the illness in somebody who simply became very sick, leading us to obtain common blood tests that wind up showing anemia with hemolysis, kidney failure, and low platelets. A history of recent diarrhea would lead to tests for the bacterial toxin. Complications of HUS can include seizures and strokes. There is no specific treatment besides IV fluids, blood transfusions & often dialysis. About 5% to 10% of patients die, the vast majority recover completely, some wind up with permanent hypertension.
One big issue is that when a person first becomes ill with diarrhea, giving antibiotics or anti-diarrheal medications (to “stop up the bowel”) make it easier for HUS to occur afterwards. Patients and families of children with diarrhea urge us to prescribe such medicines, even though they almost never help (the “treatment” for most illnesses with diarrhea is, well, the diarrhea itself, our bodies’ way of getting rid of unwanted germs). However, antibiotics are key to treating Shigella bacteria, which also causes bloody diarrhea. Shigella causes fever, E. coli doesn’t.