[Metformin-associated lactic acidosis with acute renal failure in type 2 diabetes mellitus].
METHODS
An 83-year-old patient was admitted to our hospital because of gastrointestinal symptoms, mental confusion and dysarthria. The patient suffered from type 2 diabetes mellitus and was taking metformin. A mild renal insufficiency was known. On admission, we found impaired consciousness, Kussmaul breathing, a body temperature of 32.1 degrees C, and hemodynamic instability. Laboratory testing revealed lactic acidosis (pH 6.71, base excess--30, standard bicarbonate 4.0 mmol/l, lactate 24.4 mmol/l) and acute renal failure with a creatinine of 10.6 mg/dl and blood urea nitrogen of 134 mg/dl. Electrolytes were not altered; the blood glucose was elevated (147 mg/dl). According to history, physical examination, and laboratory testing the diagnosis metformin-induced lactic acidosis with acute renal failure was made. This diagnosis was confirmed by an elevated level of metformin. As soon as possible a bicarbonate hemodialysis was initiated. After 8 hours of hemodialysis the acid-base metabolism was almost balanced and the vigilance of the patient normalized. No further sessions of hemodialysis were needed and insulin therapy was started.


CONCLUSIONS
Metformin-induced lactic acidosis is a common side effect in patients with renal insufficiency. For an early diagnosis, clinical symptoms of intoxication should be well known by physicians and patients. First-line therapy for correction of lactic acidosis and effective elimination of metformin is bicarbonate hemodialysis. Sodium bicarbonate infusions are not able to correct the acid-base metabolism sufficiently. For prevention the renal function should be monitored closely and metaformin therapy should be stopped, if a deterioration of renal function is observed.
Berner
Beate
B
Abteilung Nephrologie und Rheumatologie, Zentrum Innere Medizin, Georg-August-Universität Göttingen. bberner@gwdg.de
Hummel
Klaus M
KM
Strutz
Frank
F
Ritzel
Uwe
U
Ramadori
Guiliano
G
Hagenlocher
Sven
S
Kleine
Peter
P
Müller
Gerhard A
GA
D000140:Acidosis, Lactic / Q000139:chemically induced* / Q000175:diagnosis; D058186:Acute Kidney Injury / Q000139:chemically induced* / Q000175:diagnosis; D000368:Aged; D000369:Aged, 80 and over; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D006801:Humans; D007677:Kidney Function Tests; D008297:Male; D008687:Metformin / Q000009:adverse effects* / Q000627:therapeutic use; D006435:Renal Dialysis; D012307:Risk Factors
D008687:Metformin