Endocrine Abstracts

Section 1: A 57 year old gentleman was referred to the endocrinology clinic with hyponatraemia. His past medical history included hip dislocation and Peyronie’s disease. He was very anxious. He did not smoke or drink alcohol, and he was taking Ibuprofen, paracetamol and amitriptyline 75 mg ON. He had raised urinary sodium and was diagnosed with SIADH. As part of a routine workup he was found to have a raised morning cortisol. The patient had a BMI of 21 and had no abdominal striae or evidence of bruising. He was normotensive, had a normal HBA1c and a normal DEXA scan. His hyponatraemia improved with fluid restriction and no obvious cause was found for his SIADH.

Section 2: Results: MRI head: normal

0900 h Cortisol: 704–927 nmol/l (119–619 nmol/l)

Midnight Salivary cortisol: 6.7 nmol/l, 2.7 nmol/l

24 h urine collection for cortisol: 390 nmol/24 h

Cortisol binding globulin: 44.3 mg/l (27.1–52.3 mg/l)

Low Dose DST: Cortisol 627 (Time 0) 201 (48 h), ACTH 41 (time 0) 31 (48 h)

(Immediately followed by) High Dose DST: Cortisol 17 (48 h) ACTH <5 (48 h)

Dexamethasone Suppression Test 2 g 6 hourly for 48 h then CRH test:

Section 3: Results and treatment: The result of the dexamethasone-CRH test pointed towards pseudocushings but he clinically he had no signs of Cushings. He was referred to a tertiary centre who diagnosed glucocorticoid receptor defect, CRD which can cause increased anxiety.

Section 4: Cortisol receptor deficiency is a rare disorder, first described by G Chrousos, which is either inherited or sporadic. It has been attributed to various different receptor loci meaning that the clinical spectrum of CRD can be broad. In this case, there appears to be no negative clinical consequences due to the chronically raised cortisol. However, in other patients high levels of circulating glucocorticoid can cause considerable consequences such as mineralocorticoid excess, female androgenisation and infertility. This opens up the possibility of treatment modalities such as low dose dexamethasone. Therefore, understanding and interpretation of hypercortisolaemia without phenotypic translation, and awareness of CRD, could lead improved diagnosis and management of potential complications.