Hormone Substitution after Gastric Bypass Surgery in Patients with Hypopituitarism Secondary to Craniopharyngioma

Abstract

Craniopharyngiomas (CPs) are benign brain tumors presenting frequently in childhood and are treated by surgery with or without radiotherapy. About 50% of cured patients suffer from eating disorders and obesity due to hypothalamic damage, as well as hypopituitarism, necessitating subsequent hormone substitution therapy. Gastric bypass surgery has been reported to be an efficient treatment strategy for morbid hypothalamic obesity. However, so far it is unknown whether oral hormone substitution is affected by impaired intestinal drug absorption, potentially leading to severe hypopituitarism or pituitary crisis. Four morbidly obese CP patients with panhypopituitarism treated by gastric bypass surgery were included in this retrospective analysis. Dosages of hormone substitution therapy, blood concentrations of hormones, potential complications of impaired drug absorption, and anthropometric characteristics were investigated pre- and postoperatively after 6 to 14 months and 13 to 65 months. In all CP patients (3 female/1 male; baseline body mass index, 49 ± 7 kg/m(2)), gastric bypass resulted in distinct weight loss (-35 ± 27 kg). In follow-up examinations, mean daily dosage of thyroid hormone (levothyroxinebaseline 156 ± 44 μg/day versus levothyroxinefollow-up 150 ± 30 μg/day), hydrocortisone (hydrocortisonebaseline 29 ± 12 mg/day versus hydrocortisonefollow-up 26 ± 2 mg/day), growth-hormone (somatotropinbaseline 0.9 ± 0.5 mg/day versus somatotropinfollow-up 1.0 ± 0.4 mg/day), and desmopressin (desmopressinbaseline 222 ± 96 μg/day versus desmopressinfollow-up 222 ± 96 μg/day) substitution was unchanged. No patient developed adrenal insufficiency. Oral thyroid/hydrocortisone absorption testing performed in 1 patient indicated sufficient gastrointestinal drug absorption after bariatric surgery. Our preliminary results suggest that oral hormone substitution therapy is not impaired following gastric bypass operation in CP patients with morbid obesity, indicating that it might be a safe and effective treatment strategy.