Alyce M Richard1, James H Diaz2, Alan David Kaye3. 1. Louisiana State University School of Medicine, New Orleans, LA. 2. School of Public Health, Louisiana State University Health Sciences Center, New Orleans, LA ; Department of Anesthesiology, Louisiana State University Health Sciences Center, New Orleans, LA. 3. Department of Anesthesiology, Louisiana State University Health Sciences Center, New Orleans, LA ; Department of Pharmacology, Louisiana State University Health Sciences Center, New Orleans, LA.
Abstract
BACKGROUND: Nitrates in drinking water are generally considered the sole source of nitrite poisoning with methemoglobinemia in infantile methomoglobinemia (IM). However, IM, which occurs during the first 4 months of life, is actually a constellation of cyanosis and hypoxia associated with methemoglobinemia that can result from several other causes. METHODS: This review reexamines the role of nitrate levels in drinking water as a cause of IM and identifies other sources of nitrates that can affect public health and cause chronic diseases. RESULTS: Causes of IM include nitrites in foods, environmental chemical exposures, commonly prescribed pharmaceuticals, and the endogenous generation of oxides of nitrogen. Infants with congenital enzyme deficiencies in glucose-6-phosphate dehydrogenase and methemoglobin reductase are at greater risk of nitrite-induced methemoglobinemia from nitrates in water and food and from exposures to hemoglobin oxidizers. CONCLUSION: Early epidemiological studies demonstrated significant associations between high groundwater nitrate levels and elevated methemoglobin levels in infants fed drinking water-diluted formulas. However, more recent epidemiological investigations suggest other sources of nitrogenous substance exposures in infants, including protein-based formulas and foods and the production of nitrate precursors (nitric acid) by bacterial action in the infant gut in response to inflammation and infection.
BACKGROUND:Nitrates in drinking water are generally considered the sole source of nitritepoisoning with methemoglobinemia in infantile methomoglobinemia (IM). However, IM, which occurs during the first 4 months of life, is actually a constellation of cyanosis and hypoxia associated with methemoglobinemia that can result from several other causes. METHODS: This review reexamines the role of nitrate levels in drinking water as a cause of IM and identifies other sources of nitrates that can affect public health and cause chronic diseases. RESULTS: Causes of IM include nitrites in foods, environmental chemical exposures, commonly prescribed pharmaceuticals, and the endogenous generation of oxides of nitrogen. Infants with congenital enzyme deficiencies in glucose-6-phosphate dehydrogenase and methemoglobin reductase are at greater risk of nitrite-induced methemoglobinemia from nitrates in water and food and from exposures to hemoglobin oxidizers. CONCLUSION: Early epidemiological studies demonstrated significant associations between high groundwater nitrate levels and elevated methemoglobin levels in infants fed drinking water-diluted formulas. However, more recent epidemiological investigations suggest other sources of nitrogenous substance exposures in infants, including protein-based formulas and foods and the production of nitrate precursors (nitric acid) by bacterial action in the infant gut in response to inflammation and infection.
Authors: Lt Jessica L Wall; Lt Joshua B Wong; Lt Kyle J Kinderknecht; Cpt Leslie K Farrior; Daniel S Gabbay Journal: Can Fam Physician Date: 2016-02 Impact factor: 3.275