[Lactic acidosis, acute renal failure and heart failure during treatment with metformin: what do we know?]

Metformin is a common medication used for the treatment of type 2 diabetes, especially in obese subjects. Clinical studies show that, in addition to the lowering effect of blood glucose, metformin reduces cardiovascular risk, does not induce weight gain and additionally, provides a unique safety strategy and efficacy in patients with diabetes and heart disease. However, this treatment is not without risks. The most feared metabolic complication is lactic acidosis that often occurs with complex and severe clinical symptoms and is associated with a high mortality risk. We detail our experience, during one year, regarding four patients with diabetes treated with metformin who developed such acute renal failure and lactic acidosis as to require hemodialysis treatment. The patients selected had previous normal renal function but a history of serious cardiovascular disease (hypertensive cardiomiopathy, ischemic revascularized and/or dilated, chronic obstructive arterial disease). We observed in all four of our patients an onset of non-related symptoms (fever, fatigue, vomiting and gastrointestinal disorders), a rapid deterioration in renal function, anuria and very high levels of lactic acid. In two patients we found acute pancreatitis. In addition to rehydration therapy, hemodialysis was started instantly with progressive rebalancing of the biohumoral status, effective recovery of spontaneous diuresis and improvement of the clinical status in three patients. Unfortunately, we had a failure during the initial hours of ward admittance, with an important clinical situation complicated by acute cardiac ischemia, abnormal heart rhythm, ending in death. Our experience provides us with elements to reflect on. Lactic acidosis is a serious metabolic disorder because it is associated with a high mortality risk. So a rapid diagnosis and a complete recognition of all the fundamental elements are important for its management. Starting hemodialysis early and prolonged treatment can solve complicated clinical status, correct acidosis and restore kidney function in patients with serious comorbidity.