Hemolytic Uremic Syndrome Associated with Norovirus Gastroenteritis: Case Report and Literature Review.

A previously healthy 3-year-old girl was admitted with fever, nonbloody diarrhea, vomiting for 3 days, and oliguria. Physical examination showed fatigue, pale appearance, hypertension, and mild periorbital edema. Laboratory examinations revealed anemia, thrombocytopenia, acute kidney injury, high LDH, and low haptoglobin levels. Urinalysis showed proteinuria and hematuria. Schistocytes and helmet cells were detected in the peripheral blood smear. There were no electrolyte imbalance and hypocomplementemia. Direct Coombs and viral panel were negative. Blood, urine, throat, and stool cultures were negative. Norovirus GII was positive in stool PCR, while other diarrheal agents were negative. The patient was diagnosed with norovirus gastroenteritis-induced hemolytic uremic syndrome (HUS). Furosemide was started for oliguria and hypertension, and blood pressure was controlled with oral nifedipine. On the 12th day of hospitalization, he was discharged with fully recover. To date, norovirus-associated HUS has been reported in 5 cases. Two of these are adult cases and the other three and our case are pediatric patients. In this case report and literature review, we observed that norovirus can cause HUS, especially in children, with a milder course than other types of HUS. The reason why it is more complicated in adult cases may be the presence of an additional underlying kidney disease. Since it was detected coincidentally in 1 case in the literature, it may be useful to screen for mutations in the complement pathway that may cause aHUS, if possible, in diarrhea-associated HUS caused by norovirus agents, but it was not present in our case.