A 66-year-old male with chronic alcoholism presented with tremor, gait disturbance, memory impairment, insomnia, decreased appetite, and confusion. The patient had been taking lithium daily for treatment of bipolar disorder. Brain CT showed no specific abnormality, and serum lithium and ammonia levels were 3.63 mEq/L (therapeutic range, 0.6~1.2 mEq/L) and $85{mu}g/dL$ (reference range: $19{sim}54{mu}g/dL$), respectively. Therefore, the initial differential diagnosis included chronic lithium intoxication, hepatic encephalopathy, Wernicke encephalopathy, or alcohol withdrawal syndrome. Even with the provision of adequate hydration, the patient's neurologic status did not show improvement, so that lactulose enema, thiamine replacement, and continuous venovenous hemodiafiltration (CVVHDF) were started on the third admission day. By the fifth admission day he had made a rapid neurologic recovery, and was discharged on the 20th admission day. Therefore, CVVHDF might be a treatment for patients with chronic lithium intoxication, because, even if serum lithium concentration is normal, lithium concentration in the brain may be different from that of the serum.
Metformin is antihyperglycemic, not hypoglycemic. It causes neither insulin release from the pancreas nor hypo glycemia, even when taken in large doses. But, there are several reports of metformin-associated lactic acidosis (MALT). We present a case report of severe lactic acidosis most probably resulting from high doses of metformin in a patient with no known contraindications for metformin. A 43-year-old female was admitted to the emergency department due to a metformin overdose. She had diabetes for 6 years, well-controlled with metformin and novolet. One hour before admission, she impulsively took 50g metformin (100 mg or 100 tablets). Physical examination for symptoms revealed only irritability, and laboratory evaluation revealed only mild leukocytosis. After one hour the patient was drowsy, and arterial blood gas analysis showed severe lactic acidemia Seven hours after ED arrival, she commenced hemofiltration treatment and was admitted to the intensive care unit. Continuous venovenous hemodiafiltration was initiated. Forty-eight hours later, full clinical recovery was observed, with return to a normal serum lactate level. The patient was discharged from the intensive care unit on the third day. A progressive recovery was observed and she was discharged from the general word on the thirteenth day.