eng Science and Education Publishing American Journal of Medical Case Reports 2374-216X 2019-07-19 7 9 200 202 10.12691/ajmcr-7-9-5 AJMCR2019795 article Abin Sajan 1 Judah Horowitz 1 Noriyuki Murakami 1 Isabel M. McFarlane Isabel.McFarlane@downstate.edu 1 State University of New York, Downstate Medical Center, Department of Internal Medicine, Brooklyn, NY 11203 USA Background: Metabolic acidosis refers to any process that increases the hydrogen ions in the body and reduces the bicarbonate concentration. Metabolic acidosis is subdivided based on presence of anion gap (AG), and AG metabolic acidosis is most often due to ketoacidosis, lactic acidosis, renal failure, or toxic ingestions. AG metabolic acidosis is frequently encountered in the clinical practice. Rarely, the underlying cause of the AG metabolic acidosis is considered a diagnostic dilemma as the established algorithm allows the physicians to identify the etiology. Case presentation: A fifty-three-year-old Black woman with well-controlled human immunodeficiency virus (HIV), hypertension, and asthma presented with recurrent episodes of severe anion gap metabolic acidosis. The patient¡¯s AG metabolic acidosis always corrected with the administration of intravenous normal saline. Laboratory studies were always negative for common causes of acidosis. Conclusion: Nucleoside reverse transcriptase inhibitors-associated lactic acidosis has been reported in the literature. The shift to anaerobic mitochondrial metabolism induced by the HIV medications used in this patient could be explain the recurrent severe metabolic acidosis. http://pubs.sciepub.com/ajmcr/7/9/5/ajmcr-7-9-5.pdf anion gap metabolic acidosis recurrent metabolic acidosis differential for metabolic acidosis nucleoside reverse transcriptase inhibitors-associated lactic acidosis