Metformin-associated lactic acidosis.

A 58-year-old female with known type 2 diabetes mellitus continued to take her usual medications, including metformin, an ACE inhibitor and a non-steroidal anti-inflammatory drug, while suffering from diarrhoea and vomiting. On presentation to the emergency department, she was found to have a profound lactic acidosis, cardiovascular instability and acute kidney injury. Despite a pH of 6.6, lactate of 14 mmol/L and a brief asystolic cardiac arrest, supportive treatment and the use of renal replacement therapy resulted in rapid improvement in her acid-base abnormalities and haemodynamic parameters. Metformin-associated lactic acidosis is a rare but life-threatening complication of diabetes management. Patient education and awareness amongst clinicians are paramount in the prevention and treatment of this condition.