ABSTRACT
BACKGROUND: Metformin-associated lactic acidosis is a rare but serious complication of taking metformin. Making the diagnosis in the emergency department requires vigilance because the presentation can mimic other diseases. CASE REPORT: We present a case of a patient with diabetes who presented moribund with symptoms and signs consistent with mesenteric ischemia. This diagnosis was seemingly confirmed through computed tomography, and as a result the patient was brought to surgery for emergent exploratory laparotomy. Our patient made a remarkable recovery upon initiation of hemodialysis, demonstrating the need to initiate this life-saving procedure early. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Metformin levels are rarely available in the setting of the emergency department. Clinicians must remain alert, recognize that imaging studies may be misleading, and consider hemodialysis early in addition to surgical interventions.
Subject(s)
Acidosis, Lactic/etiology , Mesenteric Ischemia/etiology , Metformin/adverse effects , Acidosis, Lactic/blood , Creatinine/analysis , Creatinine/blood , Diabetes Mellitus, Type 2/drug therapy , Emergency Service, Hospital/organization & administration , Female , Humans , Hypoglycemic Agents/adverse effects , Hypoglycemic Agents/therapeutic use , Lactic Acid/analysis , Lactic Acid/blood , Laparotomy/methods , Mesenteric Ischemia/surgery , Metformin/therapeutic use , Middle AgedABSTRACT
Huntington disease results from an expanded polyglutamine region in the N terminus of the huntingtin protein. HD pathology is characterized by neuronal degeneration and protein inclusions containing N-terminal fragments of mutant huntingtin. Structural information is minimal, though it is believed that mutant huntingtin polyglutamine adopts ß structure upon conversion to a toxic form. To this end, we designed mammalian cell expression constructs encoding compact ß variants of Htt exon 1 N-terminal fragment and tested their ability to aggregate and induce toxicity in cultured neuronal cells. In parallel, we performed molecular dynamics simulations, which indicate that constructs with expanded polyglutamine ß-strands are stabilized by main-chain hydrogen bonding. Finally, we found a correlation between the reactivity to 3B5H10, an expanded polyglutamine antibody that recognizes a compact ß rich hairpin structure, and the ability to induce cell toxicity. These data are consistent with an important role for a compact ß structure in mutant huntingtin-induced cell toxicity.
