Working up serious hypoglycemia involves measurement of both insulin and C-peptide (the cleaved by-product of endogenous proinsulin) to assess for hyperinsulinemia and distinguish endogenous (e.g. insulinoma) from exogenous (e.g. Munchausen’s) causes. “Nurse” is a common Munchausen tip-off (someone with the know-how and skills to pull it off well).

Classic factitious disorder Q

Health care worker (nurse) with dramatic hypoglycemia and some signs of mental illness (+ risky drinking, + stress, + young woman)

To check for exogenous insulin, look for C-peptide.

C-peptide is a cleavage byproduct of endogenous insulin production. If high insulin and normal or low C-peptide --> exogenous insulin = factitious disorder

Kind of a Step 1 question