Endocrine Abstracts

Case report: A 13-year-old male presented with a 10-day history of vomiting. He was haemodynamically stable. His biochemistry was evaluated revealing a sodium level of 96 mmol/l. He had been seen 2 years previously with short stature. Sodium was normal at this time. He had speech and language delay, learning difficulties and was under investigation for autism. He had reportedly salt craved for years. Potassium, urea, creatinine, and glucose were normal throughout the admission. Further investigations revealed a cortisol level of 222 nmol/l, ACTH 1438 ng/l (NR 7–63), urine Na 105 mmol/l, 17-OHP 40 nmol/l, renin >23.7 nmol/l per h (NR 0.3–2.2), aldosterone <100 pmol/l, normal VLCFA, androstendione 2.6 nmol/l (NR <2.2), FSH 0.2 IU/l, LH 0.1 IU/l, testosterone 0.4 nmol/l, and prolactin 319 mU/l (NR 56–278). Urine steroid profile showed low cortisol and high 17-OH pregnanolone, pregnatriol and 11-oxoP3, which would be consistent with 21-hydroxylase deficiency, however androgens were not elevated. A standard short Synacthen showed a flat cortisol response with normal stimulated 17-OHP.

He was treated with i.v. hydrocortisone, i.v. fluids, and sodium supplementation. His sodium levels rose slowly over 7 days to normal concentrations. He then began to exhibit slurred speech, immobile face, abnormal behaviour, aggression, ataxia, and tremor. MRI demonstrated extra pontine myelinosis and diffuse high signal in the globus pallidus, putamen, and caudate nuclei bilaterally with no diffusion restriction. The symptoms resolved over the next 8 weeks. Adrenal antibodies were positive suggestive of Addison’s disease and the patient was discharged home on hydrocortisone, fludrocortisone and sodium supplements.

Conclusion: It is rare for Addison’s disease to present with such profound hyponatraemia with normal potassium and no cardiovascular compromise. Central pontine myelinosis is typically associated with rapid corrections of sodium, although extra pontine myelinosis and basal ganglia changes have rarely been reported in adults with Addison’s disease.