Hemolytic uremic syndrome (HUS) is a complication of "Shigella dysenteriae" type 1 (Shiga) infection. In 1993 Shiga resistant to ampicillin, cotrimoxazole, tetracycline and chloramphenicol was detected in patients from Najran. Coincidentally, 10 children with bloody diarrhea (BD) developed HUS.
Methodology
We defined HUS as any BD case that developed acute renal failure and anemia with fragmented red cells. We reviewed admission, laboratory, emergency room and health center logbooks from January to June 1993 to identify BD or HUS. We reviewed medical records of 44 admitted BD patients for antibiotic treatment and medical management. We interviewed parents about treatment given before hospitalization. We compared HUS cases with uncomplicated BD after adjusting for age and nutritional status.
Results
We identified 10 children with HUS among 44 children admitted with BD from March to May 1993. All HUS developed from 2 to 10 days (mean 5.6) after hospital admission. No HUS developed before hospital admission in 859 persons with BD who were not admitted. Children treated for BD with ampicillin or amoxicillin had a greater likelihood of developing HUS than those treated with other antibiotics after adjustment for nutritional status (risk ratio [RR] = 5.1, 95% confidence interval [CI] = 1.7-16). The combination of metronidazole and ampicillin or amoxicillin was highly associated with HUS (RR = 6.8, 95% CI = 2.4-21). Nalidixic acid alone or in combination with other antibiotics gave a reduced risk of HUS.
Conclusion
The association of HUS with antibiotics to which Shiga was resistant could be attributed to treatment failure. However, lack of HUS in unhospitalized children suggests that treatment may have provoked HUS. We believe that aggressive in-hospital treatment with ampicillin and metronidazole reduced numbers of competing intestinal flora, allowing a resistant Shiga to proliferate.