Ethylene glycol poisoning — the dual gap and the race to block metabolism

Presentation

A 47-year-old man is brought to the emergency department by his partner, who found him ataxic and incoherent at home. He had appeared well earlier in the evening. On arrival he is confused and agitated, his respiratory rate is 30, his heart rate 110, his blood pressure 150/90, and his oxygen saturation 97 per cent on room air. He smells faintly of alcohol but is deteriorating faster than ethanol alone would explain, and he is now complaining of flank pain and has passed only small volumes of dark urine.

His initial blood gas shows a severe metabolic acidaemia: pH 7.10, PaCO2 18 mmHg, HCO3 6 mmol/L, base excess −22. His biochemistry shows sodium 142, chloride 98, potassium 5.8, creatinine 180, glucose 6.5. The anion gap is 38 mmol/L (corrected little, as his albumin is normal), and his osmolar gap is 35 mOsm/kg.