Unusual cause of post-bariatric non-insulin-mediated hypoglycemia due to adult growth hormone deficiency

We report a 26-year-old woman, five years after sleeve gastrectomy, who presented with a two-year history of recurrent postprandial hypoglycemia. During symptomatic episodes (blood glucose as low as 37 mg/dL), she experienced adrenergic symptoms (tremors, hunger, and sweating) and neuroglycopenic symptoms (dizziness), with one brief episode of syncope. Initial evaluations showed normal liver and renal function, thyroid profile, electrolytes, and HbA1c. Adrenal insufficiency was ruled out (elevated morning cortisol), and a toxicology screen for hypoglycemic agents was negative. A supervised 72 h fast provoked symptomatic hypoglycemia at 16 h (plasma glucose: 41 mg/dL), with appropriately suppressed insulin and C-peptide levels, confirming a non-insulin-mediated hypoglycemia. Venous blood gas during hypoglycemia revealed high-anion-gap metabolic acidosis with minimal lactate elevation, plus positive ketones, consistent with a ketotic hypoglycemia. Given her short stature (144 cm) and these findings, we investigated the growth hormone (GH) axis. Insulin-like growth factor 1 (IGF-1) and IGF-binding protein 3 (IGFBP-3) were markedly low at baseline. GH levels were inappropriately low during the hypoglycemic episode. A glucagon stimulation test showed a peak GH of only 0.07 ng/mL, confirming severe GH deficiency. Other pituitary hormones were within normal ranges, and pituitary MRI showed no abnormalities. The patient was started on low-dose recombinant human GH replacement therapy, gradually titrated to normalize IGF-1. With GH therapy, her hypoglycemic episodes completely resolved and she reported improved energy and an ability to fast without symptoms.