Endocrine Abstracts

A 48-year-old Afro-Caribbean female was referred from Accident & Emergency in December 2007 with low serum potassium. She had been diagnosed elsewhere with hypertension due to primary aldosteronism at the age of 28 but was then lost to Endocrine follow-up. She reported intolerance to spironolactone – blood pressure was controlled with Amiloride until 1999 and then Amlodipine. Questioning in clinic, January 2008, revealed that she had had extensive investigations when previously assessed including CT, MRI and radioisotope scans, but these were unavailable. In March 2008, she complained of tiredness and weight gain, easy bruising and oligomenorrhoea over the preceding year. Investigations 2008: aldosterone:renin ratio>4200. MRI abdomen: 3 cm right adrenal adenoma, Iodocholesterol scan: increased tracer uptake in the region of the upper pole of the right kidney with no tracer uptake of the left adrenal consistent with hyperfunctioning right adrenal adenoma. Low dose dexamethasone suppression test (LDDST): T=0 304 nmol/l, T=+24 251 nmol/l, T=+48 232 nmol/l with suppressed ACTH<5 ng/l, supportive of adrenal Cushing’s syndrome. Twenty-four hours urinary cortisols were raised: 328 and 461 nmol/l, 24 h urinary catecholamines were normal. It was recommended that the 3 cm adenoma be removed surgically. The gold standard investigation for lateralising an adrenal source of aldosterone or cortisol is adrenal vein sampling (AVS). However, as the iodocholesterol scan showed suppression of the contralateral adrenal gland, it was extremely unlikely that the source of aldosterone and cortisol was the left adrenal. The patient was not submitted for (AVS) as she was extremely anxious and did not wish to undergo invasive testing. She underwent right adrenalectomy 23.09.2008, with steroid cover. Histology confirmed a benign adrenal cortical adenoma. She was discharged on hydrocortisone 10, 5, and 5 mg, fludrocortisone 50 mcg daily and amlodipine 10 mg od. She no longer requires potassium replacement. She will undergo Short SynACTHen test on 22.10.2008 to establish whether she can discontinue her hydrocortisone therapy. If she passes this, she will have a LDDST to confirm cure of her Cushing’s syndrome. This case illustrates that, although adrenal vein sampling is the gold standard, the presence of localising imaging of more than one modality may be sufficient to proceed to surgery.