Methemoglobinemia and consumption of vegetables in infants

Objective. To assess clinical and epidemiologic data of 7 infants diagnosed with acquired methemoglobinemia at the pediatric emergency department between 1993 and 1998. All cases were attributed to the consumption of mixed vegetables. Methods. Medical records were reviewed to collect anamnestic data; history of food ingestion; and results of physical examination, pulse oximetry, gasometry, cooximetry, urinalysis, and outcome. Local health authorities provided information on nitrate concentration in running water and in vegetables of common consumption in the area. Results. The mean age of the patients was 8.14 months (range: 7-13). None of the infants was undernourished, had diarrhea, or was given any drug. Drinking water showed a nitrate concentration of 3 to 6 ppm. All were fed homemade puree of mixed vegetables, prepared in advance and kept in the refrigerator for 12 to 27 hours. Silver beets were a common ingredient. No case showed metabolic acidosis. Methemoglobin level ranged between 10% and 58%. Three cases had nitrituria. Silver beets in our area were the vegetables with the highest nitrate concentration (mean: 3200 mg/kg). Conclusions. Consumption of silver beets and incorrect storage of homemade purees of mixed vegetables were potential causes of methemoglobinemia in this series. The disease may occur in children older than 6 months of age. Nitrituria in a cyanotic infant may suggest the diagnosis of methemoglobinemia.