Recurrent episodes of hypoglycemia are uncommon in non-diabetic patients. The workup investigation must confirm hypoglycemia and distinguish between endogenous versus exogenous hyperinsulinism. Simultaneous measurements of plasma glucose, insulin, C-peptide, and a screen for oral hypoglycemic agents should be performed. According to the results, further imaging studies may be necessary. A 43-year-old woman suffering from recurrent hypoglycemia presented to the emergency room (ER) with a hypoglycemic coma. She has had multiple episodes of documented hypoglycemia for the last 13 years. The case was initially investigated, and laboratory studies revealed endogenous hyperinsulinism. Screening for sulfonylureas, anti-insulin and anti-insulin receptor antibodies were negative. Body imaging and positron emission tomography (PET) with 68Ga-DOTANOC did not show evidence of an insulinoma. The patient was submitted to a pancreatectomy, which revealed nesidioblastosis in the histologic examination. Since then, the patient became hyperglycemic but the insulin doses were progressively reduced until new episodes of hypoglycemia recurred and the insulin was stopped. Again, inappropriately high levels of insulin were found at the time of hypoglycemic episodes. Computed tomography (CT) and PET scans did not find evidence of an insulinoma. A C-peptide was later found to be negative and insulin ampoules were found in her possession, making a diagnosis of a factitious disorder. Although rare, factious disorders are frequently overlooked and challenging to diagnose. Since they are very resource and time-consuming, self-inflicted illnesses should always be considered and ruled out beforehand.
Keywords: adult nesidioblastosis; c-peptide; exogenous hyperinsulinism; factitious disorder; hypoglycemia.
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