D-Lactic Acidosis Presenting in Crohnʼs Disease with Short Bowel Syndrome

Abstract

Purpose: D-lactic acidosis is a rare form of lactic acidosis that can occur in individuals following jejuno-ileal bypass surgery or short bowel syndrome. Symptoms typically occur after ingestion of a high-carbohydrate meal due to glucose and starch being metabolized by the colon into D-lactic acid-with subsequent absorption into circulation and systemic acidemia. D-lactate accumulates as L-lactate dehydrogenase is unable to convert this type of lactate into pyruvate. Methods: N/A Results: 48-year-old female with Crohn's disease s/p subtotal small bowel resection 3 years ago, with resultant short bowel syndrome presented with persistent weight loss, abdominal pain, postprandial nausea, headache, confusion, blurred vision, dizziness with ataxia, intermittently ongoing for several months. She complained of feeling as if she was intoxicated, although she denied any alcohol ingestion. She had a history of intestinal intussusception and CT enterography ordered 9 days prior showed dilated loops of distal small bowel consistent with partial small bowel obstruction. Lab work revealed normal CBC, LFTs, but also metabolic acidosis with serum bicarbonate at 16mmol/L, with anion gap of 12; VBG showed pH 7.15, pCO2 44mm Hg, pO2 17mmHg, bicarb 15mmol/L. However, serum lactic acid level was normal at lmmol/L. Serum D-lactate was drawn showing elevation to 6.15mmol/L — thus confirming the diagnosis of D-lactic acidosis. She was given fluids, bicarbonate and placed on Flagyl and Levaquin for bacterial overgrowth. Her acidosis along with her neurological symptoms shortly thereafter resolved. PEG tube was placed and she was started on enteral feeding for malnutrition. Her partial SBO also resolved with supportive care. Conclusion: In individuals with intact small intestine, few carbohydrates and starch reach the colon. In patients with short bowel syndrome, glucose reaches the colon, and when in combination with bacterial overgrowth (usually gram-positive anaerobes)—D-lactic acid is formed. Episodic metabolic acidosis can occur after meals with neurological symptoms including altered mental status, dysarthria, ataxia, and concentration/memory difficulties. Patients often appear drunk in the absence of ethanol consumption. D-lactic acidosis should be considered in short bowel patients with an anion gap metabolic acidosis, a normal serum lactate; characteristic neurological findings and acidosis following food intake. Diagnosis is confirmed with special enzymatic assay measuring serum D-lactate. Treatment involves sodium bicarbonate, low carbohydrate diet and antimicrobial agents to decrease bacteria overgrowth.