Massive insulin overdose managed by monitoring daily insulin levels.

We present a case of a significant insulin overdose that was managed by monitoring daily plasma insulin levels. A 39-year-old male with poorly controlled diabetes mellitus presented to the Emergency Department via emergency medical services after an attempted suicide by insulin overdose. In the attempted suicide, he injected 800 U of insulin lispro and 3800 U of insulin glargine subcutaneously over several parts of his abdomen. The patient was conscious upon arrival to the emergency department. His vital parameters were within normal range. The abdominal examination, in particular, was nonfocal and showed no evidence of hematomas. He was awake, alert, conversant, tearful, and without any focal deficits. An infusion of 10% dextrose was begun at 100 mL/h with hourly blood glucose (BG) checks. The patient was transferred to the intensive care unit where his BG began to decrease and fluctuate between 50 and 80 mg/dL, and the rate of 10% dextrose was increased to 200 mL/h where it was maintained for the next 48 hours. The initial plasma insulin level was found to be 3712.6 uU/mL (reference range 2.6-31.1 uU/mL). At 10 hours, this had decreased to 1582.1 uU/ml. On five occasions, supplemental dextrose was needed when the BG was <70 mg/dL. Thirty-four hours after admission, the plasma insulin level was 724.8 uU/mL. Fifty-eight hours after admission, the plasma insulin level was 321.2 uU/mL, and the 10% dextrose infusion was changed to 5% dextrose solution at 200 mL/h. The plasma insulin levels continued to fall daily to 112.7 uU/mL at 80 hours and to 30.4 uU/mL at 108 hours. He was transferred to an inpatient psychiatric facility 109 hours after initial presentation. Monitoring daily plasma insulin levels and adjusting treatment on a day-to-day basis in terms of basal glucose infusions provides fewer opportunities for episodic hypoglycemia. Furthermore, it was easier to predict daily glucose requirements and eventual medical clearance based on the plasma levels.