High Anion Gap Metabolic Acidosis in Suicide: Don't Forget Metformin Intoxication—two Patients' Experiences

Abstract

Lactic acidosis is a well-recognized side effect of metformin, especially in patients with renal failure. Only a few cases of deliberate self-poisoning with metformin have been described in the literature. We report two patients who took a large dose of metformin in an attempt to harm themselves and both of them presented with severe lactic acidosis. The first patient was admitted because of taking large amounts of her father's unknown drug for suicide. Arterial blood gas showed severe metabolic acidosis with high anion gap and blood lactate level which metformin intoxication was documented. She died of multiple organ failure although we provided aggressive management including continuous renal replacement therapy. The second case, a type 2 diabetic patient, was sent to the emergency department after taking 110 tablets of metformin (500 mg). Arterial blood gas showed severe metabolic acidosis with high anion gap and blood lactate level. Hypotension and consciousness disturbance occurred later. After one session of hemodialysis, she recovered completely. In our experiences, metformin intoxication should be suspected when patients presented by wide anion gap metabolic acidosis after suicide attempt by taking drugs. Hemodialysis or continuous renal replacement should be initiated as soon as possible in addition to other supportive care.

Laktatacidose und akutes Abdomen bei Biguanidintoxikation

“…Gerade in der entscheidenden Frühphase können diese Symptome sehr uncharakteristisch sein. Die differenzialdiagnostische Abgrenzung zur Metformin-assoziierten Laktatacidose ist gerade bei älteren Patientin schwierig, da sich die Risikoprofile ähneln.Die im Vordergrund stehende Differenzierung zwischen hypoxischer und nichthypoxischer Laktatacidose unter Beachtung der Anionenlücke[7] ist bei Patienten im Schock nicht eindeutig mög-lich. Beim Vorliegen einer Laktatacidose sollte die Kombination von Metformintherapie und pathologisch erhöhten Nierenretentionsparametern zum Verdacht einer Metformin-assoziierten Laktatacidose führen.…”

Hyperglycemia After Metformin Overdose: A Case Report

“…Another potential complicating factor was the elevated osmolal gap in our patient. An unexplained osmolal gap may be seen in several severe diseases, including shock or sepsis, and it was also seen in four out of nine cases of fatal metformin toxicity, providing an alternate explanation for its presence [11,12]. On the other hand, there was no historical evidence supporting the ingestion of any alcohol other than methanol, nor calcium oxalate crystalluria from ethylene glycol.…”

Case Files from the University of California San Diego Health System Fellowship Coma and Severe Acidosis: Remember to Consider Acetaminophen

“…In such cases, a depressed level of consciousness may occur following several hours of lucidity, although typically it is in the setting of cardiovascular instability [47,[52][53][54][55][56]. Hypothermia, as observed in our patient, has also been well described in acute metformin overdoses [47,54,[57][58][59][60]. Similar to ethylene glycol, at most institutions including our own, metformin measurements are send out tests, with results being available days after empiric clinical management decisions are necessary.…”