ABSTRACT
Aims:To determine whether the use of an octreotide suppression test will reliably distinguish pituitary from ectopic ACTH overproduction. Somatostatin receptors are expressed in NETs, but are downgraded in the pituitary as the result of hypercortisolaemia. Octreotide should therefore lower ACTH and cortisol levels in patients with NETs but not in patients with Cushing’s disease and pituitary tumors. Methodology:A cross sectional study was performed in 13 patents with ACTH dependent Cushing’s (8 women, 5 men) with ages ranging between 21 to 40 years were studied. Serum cortisol concentrations were measured at 0800 hrs before and during the administration of. Octreotide at a dosage of 100 mcg subcutaneously every 8 hours for 72 hours.Results:The serum cortisol concentrations returned to normal in 4 patients who were later documented to have ectopic disease, two with typical bronchial carcinoids and two with pancreatic NETs and metastatic disease. The other 9 patients had no suppression in serum cortisol concentrations and were documented later to have pituitary tumours.Conclusion:These results indicate that a short trial of octreotide will identify patients with ectopic disease as evidenced by a fall inserum cortisol levels whereas in those with Cushing’s disease and pituitary tumours serum cortisol levels remains unchanged. Recommendation: We recommend all patients with ACTH dependent Cushing’s syndrome have an octreotidesuppression test, even if the MRI shows an adenoma, so as to exclude the possibility of a pituitary incidentaloma in a patient with ectopic disease, or false localization from IPSS to the pituitary gland due to ectopic CRH secretion
ABSTRACT
Aims: To assess the effects of high dose long term cabergoline monotherapy in a patient with Cushing's disease refusing any form of surgical intervention. Presentation of the Case: A 32-year-old Omani female with hypertension, diabetes mellitus and secondary infertility of 10 years and amenorrhoea of 2 years duration, was referred with recurrent thigh abscesses. She was on 100 units of mixed insulin in two divided doses, metformin 1 gm bd, lisinopril 20 mg od, amlodipine 10 mg od and indapamide 1.5 mg od ."She had all the features of Cushing’s syndrome, with a blood pressure (BP) of 180/110 mmHg, plethoric facies, central obesity and striae". Investigations revealed diabetes, HBA1c 10.7% and ACTH-dependant Cushing’s syndrome, "cortisol 720 nmol/L (normal <624) and ACTH 14.9 pmol/L. (normal 1.6-13.8)". The pituitary MRI and computerised tomographic ( CT) scans from neck to pelvis “ were normal” A neuroendocrine tumour (NET) was deemed unlikely as serum cortisol levels did not “suppress during by a 72 hours trial” of octreotide 100 mcg 8 hourly and her serum chromogranin- A level (CgA) was normal. A diagnosis of Cushing’s disease was made. She refused inferior petrosal sinus sampling (IPSS) and any form of surgery. A trial of cabergoline was agreed upon. Her response was dramatic: On 1 mg daily initially, the serum cortisol was normal after one week, and by 4 months her blood sugar and blood pressure were normal off all other medications. The HBA1c had fallen from 10.7% to 5.4%. Shortly afterwards she became pregnant and on a reduced dose of cabergoline (1.5 mg/week), she delivered a healthy full term baby, echocardiography was normal in both mother and baby. She has now been in complete remission for more than 4 years on cabergoline 0.5 mg 3 times a week without any side effects. Conclusion: This case provides an example of successful acute and sustained primary “monotherpy” with initially high dose cabergoline in Cushing’s disease. The additional positive metabolic effects and the lack of significant side effects makes high dose cabergoline monotherapy an attractive first or second line treatment for patients with Cushing's disease.