[Female patient with type 2 diabetes in coma with metabolic acidosis].

In case of impaired consciousness, metabolic acidosis with wide anion gap and elevated lactate levels a metformin associated lactic acidosis should be considered in diabetic patients. Taking into account the contraindications to metformin, lactic acidosis is a rare complication, however - if it occurs - fatal in 50-80%. The outcome of the surviving patients is good, once the acute stage is outlived due to immediate hemofiltration.