Endocrine Abstracts

Introduction: Addison’s disease (AD) is a rare endocrine disorder in children, characterized by insufficient production of cortisol and aldosterone due to adrenal gland dysfunction. While electrolyte imbalances, including hyponatremia, hyperkalaemia, can occur in AD, severe hyponatremia is an unusual and challenging complication in children. We present a case of severe hyponatremia in a teenager diagnosed with AD.

Case report: 14-year-old boy presented to Emergency Department (ED) with 1-week history of recurrent vomiting, unsteady gait and extreme fatigue. He had previously undergone investigations (including Growth hormone stimulation test, MRI Pituitary) for delayed growth/puberty. In ED he was noted to be ataxic, with no other neurological deficit. He was clinically not dehydrated (heart rate 70–90/min, blood pressure 110/60 mmHg), no hyperpigmentation. His height (149.3 cm) & weight (35.65 kg) were on 1st centile. Investigations revealed very low serum sodium (Na) 95 mmol/L (135–145), normal: Potassium (K) 5.1 mmol/L / blood pH (7.34) and blood glucose (6.3 mmol/L). Urea / full blood count / liver / thyroid profile were normal. CT scan head normal. Random cortisol (23:30 hrs.) 66 nmol/L. Paired plasma (199 mOsm/kg) and Urine Osmolality (308 mOsm/kg) and urine Na (39 mmol/L) suggested renal salt wasting. Suspecting adrenal insufficiency, he was started on intravenous Hydrocortisone (2 mg/kg intravenous (i.v.) every 6 hours) and oral Fludrocortisone (100 micrograms once daily) after taking appropriate blood samples for Aldosterone, Renin, and ACTH. He was managed in High Dependency Unit with i.v. 3% & 0.9% saline. He remained haemodynamically stable, and his Na slowly increased by 8–10 mmol/L per day. He was shifted to the ward after 3 days once his serum sodium came above 130 mmol/L and HC was switched to oral dose. Pending investigations showed Renin of 4813 mIU/L, ACTH 1886 ng/L (0–46), Adrenal Antibodies positive, VLCFA – negative, confirming Addison’s Disease. He was discharged home in stable condition on oral HC, Fludrocortisone & Na supplements with sick day management training.ConclusionThis case highlights the rare and extremely serious presentation with severe hyponatremia in Addison’s disease. It emphasises the need for early recognition, timely intervention with electrolyte correction and hormone replacement therapy, which is crucial for successful management.