Hemolytic Uremic Syndrome
Hemolytic uremic syndrome (HUS) is a condition caused by the abnormal destruction of red blood cells. The damaged red blood cells clog the filtering system in the kidneys which can cause severe acute kidney failure.
HUS usually develops after bloody diarrhea caused by certain bacteria. Children can also develop HUS related to certain pneumonia. There is an inherited type of HUS caused by certain mutated genes. Those are called atypical HUS requiring specific therapy. They are very rare though.
HUS could be a serious condition requiring urgent evaluation. Patients with HUS require hospital stay for close monitoring because they can develop life-threatening anemia and kidney failure. Supportive care including red blood cell transfusion are proven to be very helpful. Patients can have significantly decreased urine output or do not void at all. When this happens, they usually require a procedure called acute hemodialysis for one to two weeks or so. This requires a placement of a dialysis catheter which will be removed once the patients start to make urine again. Diarrhea associated HUS does not need specific medication. The medication for atypical HUS is called Eculizumab (Brand name Soliris) infused through the vein. It requires lifetime maintenance therapy every 2-3 weeks to prevent recurrence. A procedure called plasmapheresis is another option for atypical HUS. Plasmapheresis also requires a dialysis catheter placement to exchange certain blood component. This procedure is still used sometimes but less often nowadays, after Soliris approved by FDA.
Children with diarrhea associated HUS usually get full recovery provided timely and appropriate treatment. Outcome of pneumonia associated HUS has a higher mortality and long-term morbidity rate than those with diarrhea associated HUS, including neurological consequences and risk of developing advanced chronic kidney disease. With Soliris, patients with inherited atypical HUS have a much better outcome without developing advanced renal disease, as they used to in the past.