Cushing’s Disease and High Dose Cabergoline Monotherapy: Rapid and Sustained Clinical and Biochemical Improvement, with Reversal of Diabetes, Hypertension and Infertility

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.