D-Lactic Acidosis

Abstract

To present 2 cases of D-Lactic Acidosis with different presentation. Chart review after informed consent. Case 1: 47 year old male with history of vertigo and jejunoileal bypass surgery in 1975 presented with mental status changes, vertigo – unresponsive to meclizine, irritability, gait ataxia, and slurred speech. Physical exam was unremarkable. Laboratory values showed: anion gap 22, bicarbonate 11, ABG showing pH 7.15, pCO2 19, and O2 saturation 93%. Lactic acid, salicylate levels, urine and serum toxicology screen, urine and serum ketones, methanol, and ethylene glycol were all normal. Serum creatinine 1.3, and serum ammonia level 65 and normal LFTs while D-lactic acid level of 2.46 mmol/L. Metronidazole, vancomycin, sodium bicarbonate infusion and a low carbohydrate diet improved patient's condition. D-lactic acid levels of 1.09 mmol/L at discharge. Case 2: 35 year old male had orchiectomy in 1997 for testicular teratoma treated with chemotherapy. In 2003, he presented with symptoms of small bowel obstruction secondary to retroperitoneal recurrence of teratoma, leading to surgical resection. On post-operative day 21, obstipation lead to re-exploration and gastrojejunostomy with enterosomy. His subsequent hospital course was uneventful and he was discharged on regular diet. In 2006, he presented with early satiety and abdominal discomfort. He was started on ciprofloxacin by his surgeon with some improvement. This raised the possibility of D-lactic acidosis, confirmed by an anion gap of 13.5, serum bicarbonate 14.5 and D-lactic acid level of 1.31 mm/L. He improved with low carbohydrate diet and flagyl. D-Lactic acidosis, is a rare entity associated with short bowel syndrome, short bowel surgery, or jejuno-ileal bypass. Mechanisms include overgrowth of gram-positive anaerobes that produce D-lactate, and malabsorption in the proximal small bowel leading to carbohydrate fermentation. Symptoms are mainly neurological, but may be insidious. Diagnosis is by history, anion gap acidosis, normal lactate levels but increased D-lactate levels, and sometimes an elevated urine anion gap. Acute treatment is a low carbohydrate diet, antibiotics, sodium bicarbonate, and rehydration. Extreme cases may require hemodialysis or surgical intervention such as reversal of jejuno-ileal bypass, intestinal lengthening, or colon resection. Any patient with a history of short bowel surgery or bypass presenting with neurological symptoms or unexplained anion gap acidosis should be a candidate for workup of D-lactic acidosis.