Endocrine Abstracts

Case History: A 26 year old female underwent Roux-en-Y gastric bypass (RYGB) surgery for intractable peptic ulcer disease on a background of obesity. She had a history of 40kg weight gain over 8 years (weight 123 kg, BMI 41.1 kg/m²), hypertension, depression, insomnia and newly diagnosed type 2 diabetes. Following surgery, weight loss was disappointing (nadir 112 kg, −11 kg, −8.9%TBW, −22.9%EBW, BMI 37.5 kg/m²) and diabetes and hypertension failed to remit. She developed chronic abdominal pain and her psychiatric condition worsened with episodes of self harm. On review in the medical clinic, violaceous striae and proximal myopathy prompted investigation. Endocrine investigations (LDDST and IPSS) led to a diagnosis of ACTH-dependent (pituitary) Cushing’s.

Intervention: Trans-nasal, trans-sphenoidal hypophysectomy (TSS), May 2017. Her weight on day of surgery was 121 kg. Excised tissue was histologically confirmed as corticotroph adenoma.

Post-op investigation results: Day 1 and 2 post-op morning cortisol results of <30 nmol/l were strongly indicative of curative surgery, she was discharged on hydrocortisone 10 mg BD. Subsequent insulin tolerance testing (nadir glucose 1.9 mmol/l, peak cortisol 8 nmol/l, peak growth hormone 0.67 mcg/l) indicated pituitary-adrenal and growth hormone insufficiency. Baseline biochemical tests indicated intact pituitary-gonadal and thyroid axes.

Post-op clinical results: 7 months post TSS, her hypertension and diabetes is in remission. Her weight has dropped from 121 to 97 kg (−24 kg, −19.8%TBW, −52.2%EBW). Her chronic abdominal pain has improved, though she has required intensive psychiatric input to stabilise her anxiety-depression following a deliberate self-poisoning episode. She was admitted with Addisonian crisis (despite professed adherence to hydrocortisone). This episode and symptomatic fatigue/malaise on attempts to reduce her glucocorticoids have resulted in a hydrocortisone dose requirement of 35 mg/day.

Discussion: This case illustrates the perils of a missed diagnosis of secondary obesity and the powerful effect of glucocorticoids on appetite and weight. Her experience on hydrocortisone replacement raises the possibility that her gastric bypass procedure is impairing absorption of hydrocortisone and increasing the risk of Addisonian crisis.