Endocrine Abstracts

Background: Adrenal insufficiency and diabetes mellitus occasionally coexist, but unusual presentations can complicate diagnosis. We present a case of adrenal dysfunction with atypical autoimmune diabetes in a patient with severe obesity.

Case Presentation: A 51-year-old Afro-Caribbean woman with body weight of 156 kg and BMI 56.9, with no prior medical history was referred by the GP for rapid weight for 5 months. Random cortisol was low at 56 nmol/l. She was urgently reviewed in the ambulatory care unit. She had central and peripheral fat distribution and round face. There was no history of previous steroid exposure of any form. Hydrocortisone was started empirically and the following blood tests were requested.

: A short Synacthen test showed inadequate cortisol response (0 min = 8 nmol/l, 30 min = 112 nmol/l), confirmed onrepeat testing. She had low androstenedione and DHEAS (undetectable). Pituitary MRI demonstrated an expanded bony fossa with near-empty sella. Two months later, she was admitted in a different hospital with osmotic symptoms, fatigue and blurred vision, Serum glucose was 27 mmol/l, and ketones were 0.3. HbA1 c was 101 mmol/mol. Anti-GAD65 antibody was markedly raised (1683.4 U/mL; <5), while IA2 and ZnT8 were negative. She was treated as type 1 diabetes and commenced on Glargine and Aspart insulin.

Management and Outcome: At follow-up, she was found to have recurrent prolonged hypoglycaemia despite basal insulin reduction to 4 units. Repeat antibody testing showed anti-GAD65 >2000 U/mL, but HbA1 c normalised to 39 mmol/mol. After multidisciplinary review, insulin was stopped. She has remained off insulin to date (3 months). Her glucose control has remained good as evident by time in target of >90% on her most recent Freestyle Libre data.

Discussion: The clinical, radiological and biochemical findings suggest adrenal insufficiency, possibly from a burnt-out pituitary adenoma or silent pituitary apoplexy. Her diabetes course is atypical: anti-GAD65 was strongly positive but there was rapid insulin independence and stable glucose afterwards.

Conclusion: This case highlights the complexity of overlapping endocrine disorders. Ongoing monitoring remains crucial, with adequate patient’s education and follow up.