Rapid reversal of hypoglycaemic coma despite profound metabolic acidosis

Background: Coma in patients with severe metabolic acidosis may be directly related to low blood pH resulting in impaired glucose utilization in the brain cells. We report a patient with hypoglycaemic coma and profound lactic acidosis caused by thiamine deficiency, who regained consciousness simply by means of glucose infusion despite very low blood pH. Case Report: A 56-year old man was admitted to our emergency department because of rapidly progressing dyspnea, nausea and disorientation. On examination he was comatose (Glasgow Coma scale 6). His sister reported a longstanding chronic alcohol abuse of about one bottle of vodka per day (˜280g alcohol/day) and impaired gait disturbances since months. Laboratory findings at admission are given in Table 1. Frank hypoglycaemia (50mg/dl) prompted glucose infusion and the patient immediately regained consciousness despite persistent acidosis. In an intensive care setting, lactic acidosis resolved quickly with intravenous bicarbonate and thiamine. Discussion: The role of acidosis in altered mental status is controversially discussed. Recently, low blood pH was reported to be closely related to decreased level of consciousness in children with diabetic ketoacidosis (1). Intracellular acidosis could decrease the activity of the pH dependent glycolytic enzyme phosphofructokinase, resulting in impaired glucose utilization in the brain cells (2). If so, intravenous glucose infusion would insufficiently influence the level of consciousness unless the acidosis is reversed. Therefore, some authorities recommend sodium bicarbonate (SB) infusion as a first line therapy in severe metabolic acidosis (3), even though it was demonstrated that SB can even decrease intracellular pH in the brain (4). In our case, glucose infusion led to rapid restoration of consciousness without prior compensation of metabolic acidosis. The latter quickly resolved after intravenous thiamine. Reference value At admission Blood glucose 70–115mg/dl 48 Venous blood pH 7.32–7.4 6.8 Venous lactate 0.5–2.2mmol/l 21 Base excess 2.0–3,0mmol/l 29.5 pCO 2 42–50mmHg 23.4 Serum anion gap 10–14mmol/l 36.9 References: 1. Edge JA et al . Conscious level in children with diabetic ketoacidosis is related to severity of acidosis and not to blood glucose concentration. Pediatr Diabetes 2006; 7: 11–15. 2. Trivedi B et al . Effect of pH on the kinetics of frog muscle phosphofructokinase. J Biol Chem 1966; 241: 4110–4112. 3. Rosival V. Very low blood pH is life threate