Endocrine Abstracts

Clinical case: A 51 year-old caucasian woman was admitted in the emergency room of our hospital with psicomotor agitation and confusion after four days of a profuse watery diarrhea, with 5 stools per day, abdominal cramps and vomiting. She started 500 mg of aspirin on her own initiative. Her medical profile included a type 2 diabetes treated with metformin 850 mg/12 hours and glyburide 7.5 mg/day, and hypertension treated with enalapril 20 mg/day. No renal imparement was documented in annual checkup.

Clinical examination showed an agitated and confused woman, with a Glasgow coma scale of 8/15, apirexial, with dry mouth, pulse 72 bpm, blood pressure 159/75.

Progress and management: Her biochemical profile revealed a blood glucose of 41 mg/dl, creatinine 9.06 mg/dl, sodium 140 meq/l, potassium 6.8 meq/l, chlorine 93 meq/l. Venous blood gases were: pH 6.966, bicarbonate 5.3 mmol/l, base excess −25.9 mmol/l.

Calculated anion gap 41.7 mmol/l with a lactate concentration of 15.40 mmol/l (normal range 0.5–2.2 mmol/l). A diagnosis of metformin-associated lactic acidosis with acute renal failure was made and she was transferred to the Intensive Care Unit. The association of diarrhea, ACE-inhibitors and non-steroidal anti-inflammatory drugs was responsible of her acute renal failure. Aggressive volume expansion and intravenous sodium bicarbonate failed and underwent just one session of continous veno-venous haemodialysis using bicarbonate dialysate. After dialysis, renal function and acidosis started to improve. She also required ionotropic support with vasoactive drugs. Three months after this episode she is dialysis independent and her renal function has stabilized with a creatinine of 1.48 mg/dl.

Discussion: Lactic acidosis is a rare but severe complication of type 2 diabetes treated with metformin. Metformin should be stopped when acute renal failure occurs or is anticipated. Early haemodialysis is an adequate treatment to correct acidosis and eliminate accumulated metformin in acute renal failure situations.