Case Presentation: A 38 year-old woman presented with a three-day history of bloody diarrhea, left lower quadrant pain, anorexia, and nausea. She denied any sick contacts and did not eat any raw vegetables, raw or undercooked meat, frozen dinners, or restaurant food. CT abdomen and pelvis showed severe colitis and white blood cell count was 15.5. The patient was treated with cefuroxime, metronidazole, fluids, antiemetics, and narcotic analgesics. Her clostridium difficile testing was negative. Despite treatment, the patient continued to worsen with increased abdominal pain and decreased urine output. By hospital day 3, her renal function worsened, and platelets and hemoglobin decreased, which was suggestive of a thrombotic microangiopathy. Antibiotics and narcotics were discontinued. An ADAMSTS 13 level was sent and was not consistent with thrombotic thrombocytopenic purpura (TTP), but her stool culture returned positive for Escherichia coli 0157:H7. The patient’s presentation was consistent with typical hemolytic uremic syndrome (HUS). Adult and pediatric hematology, nephrology and infectious disease were consulted. Ultimately, eculizumab was given along with meningitis vaccination. Despite eculizumab, the patient had worsening mental status resulting in intubation and required hemodialysis, but the hemolysis improved.
Discussion: Diarrhea is a fairly common presentation encountered by hospitalists. When bloody diarrhea is noted, stool cultures should be ordered and antibiotics should be held (if patients are clinically stable) until shiga-toxin producing bacteria are ruled out. This is to reduce the risk of triggering HUS with antibiotics. Given hemolytic uremic syndrome has similar findings to TTP, an ADAMSTS 13 should be routinely checked as part of the work up because if positive, patients would be a candidate for plasmapheresis. Typical hemolytic uremic syndrome has a relatively good prognosis with a low mortality and with an evolution to chronic renal failure in only 10% of cases. Factors of poor prognosis include the presence of neurological symptoms and the need of renal replacement therapy at the beginning of the disease (1). Neurologic involvement is the most threatening complication and the mechanisms of damage in the CNS are frequently considered to be due to multiple factors, including local microangiopathy, hypertension, and hyponatremia (2). Eculizumab is routinely used in atypical hemolytic uremic syndrome, but case reports suggest it may be helpful in helping with hemolysis, renal function, and neurological deficits in patients with diarrhea associated hemolytic uremic syndrome (3). Hospitalists need to be aware that the medication increases susceptibility to encapsulated bacteria especially Neisseria meningitis infections. Patients who have not received vaccination will need penicillin prophylaxis and be started on a vaccine schedule.
Conclusions: Even though typical HUS predominantly affects the pediatric population, this case is a good reminder of why stool cultures should be checked, and antibiotics should be held in our adult patients with hemorrhagic colitis. In the unlikely event that they develop HUS, the disease typically has a low morbidity and mortality. Unfortunately, our patient had an uncommon progression of the disease and remains dialysis dependent. Eculizumab may be an option to help reduce disease severity, but its availability may be limited.