Acute Caremiddle twist
A 63-year-old woman with type 2 diabetes presents with two days of vomiting and upper abdominal pain, during which she has eaten almost nothing. She takes metformin, dapagliflozin and perindopril, and drinks two glasses of wine most evenings. She is alert and breathing deeply. A venous gas shows pH 7.19, bicarbonate 10 mmol/L and an anion gap of 24 mmol/L. Glucose is 9.6 mmol/L, capillary ketones 5.1 mmol/L, lactate 1.0 mmol/L and creatinine 71 micromol/L. Which one of the following best accounts for her metabolic acidosis?