Endocrine Abstracts

JOINT3370

Introduction: The most common cause of ACTH-dependent Cushing’s syndrome is Cushing’s disease (CD) due to an ACTH-producing tumor in the pituitary gland Bilateral petrosal sinus sampling (BPSS) is the gold standard for determining the source of hypercortisolism. There is limited information about desmopressin use in the literature. In this case, BPSS protocol performed because there was a lesion that could not be clearly distinguished in imaging, despite evaluating the clinical and laboratory findings.

Case: A 12-year-old girl presented to our clinic with complaints of weight gain over the past year, absence of height increase, and hair growth on her face, back, and genital area. Her height was 145 cm (-1.0 SDS), weight was 55 kg (+1.3 SDS), and body mass index was 26.9 kg/m² (2.12 SDS). Physical examination revealed a moon-shaped face, plethoric appearance, abdominal striae, acanthosis nigricans in the axilla, and buffalo hump. A high basal cortisol level (29 µg/dl), ACTH level (91 pg/ml) was detected. Diurnal rhythm was disrupted. Cortisol levels were not suppressed in the dexamethasone suppression test (single dose, 1 mg, orally) (12,8 µg/dl) and the low-dose dexamethasone test (7,82 µg/dl). The decrease in cortisol levels after the low-dose dexamethasone suppression test was less than 50%. Twenty-four-hour urinary cortisol level (374 µg/day) was high. The adrenal glands appeared normal on ultrasound. No significant pathology was detected on the pituitary MRI. In intravenous desmopressin-stimulated BPSS, samples taken from the right pituitary showed significantly elevated ACTH levels (Table-1), leading to a diagnosis of Cushing’s disease. Surgery was planned.

Conclusion: In cases of hypercortisolism related to ACTH where imaging results are inconclusive, a BPSS should be performed. When CRH is not available for BPSS, the use of desmopressin appears to be safe.