INCIDENCE OF SUBCLINICAL METHEMOGLOBINEMIA IN INFANTS WITH DIARRHEA

Study hypothesis: Infants with diarrhea are at a greater-than-recognized risk of developing methemoglobinemia. Design: Prospective clinical study. Setting: A university hospital pediatric emergency department. Participants: Consecutive infants under 6 months of age with a history of diarrhea of more than 24 hours' duration not associated with vomiting. Interventions: Blood samples were obtained for methemoglobin (MHgb) assay (normal, 0.4% to 1.5%) and electrolytes. Treatment interventions were performed as clinically indicated. Patients with elevated MHgb levels subsequently underwent hemoglobin electrophoresis to exclude congenital methemoglobinemia. Results: Forty-three patients were studied; 27 (64%) had elevated MHgb levels and 13 were cyanotic. Five patients received infusions of methylene blue for methemoglobinemia. All patients recovered without sequelae. There was a strong correlation between weight at or below the tenth percentile for age and the development of methemoglobinemia. Contrary to previous studies, there was no correlation between incidence or severity of methemoglobinemia and acidosis, hyperchloremia, or positive microbiologic studies. Conclusion: In ill infants with diarrhea, particularly those who are small for age, consideration should be given to screening for methemoglobinemia.