Cushing syndrome S1 Vol.4, No.1, February 2014 Disclaimer: Clinical Practice Guidelines are developed to be of assistance to health care professionals by providing guidance and recommendations for particular areas of practice. The Guidelines should not be considered inclusive of all proper approaches or methods, or exclusive of others. The Guidelines cannot guarantee any specific outcome, nor do they establish a standard of care. The Guidelines are not intended to dictate the treatment of a particular patient. Treatment decisions must be made based on the independent judgment of health care providers and each patient’s individual circumstances. The Endocrine Society makes no warranty, express or implied, regarding the Guidelines and specifically excludes any warranties of merchantability and fitness for a particular use or purpose. The Society shall not be liable for direct, indirect, special, incidental, or consequential damages related to the use of the information contained herein. ©Endocrine Society of Sri Lanka Sri Lanka Journal of Diabetes, Endocrinology and Metabolism 2014; 1: 1-12 Cushing syndrome Authors: Dr. Noel Somasundaram, Dr. Henry Rajaratnam, Prof. Chandrika Wijeyarathne, Dr. Prasad Katulanda, Dr. Uditha Bulugahapitiya, Dr. Sajith Siyambalapitiya, Dr. Charles Antonypillai, Dr. Manilka Sumanathilake, Dr. Chaminda Garusinghe, Dr. Dimuthu Muthukuda, Dr. M. W. S. Niranjala, Dr. Kavinga Gunawardena, Dr. Nayananjani Karunasena, Dr. W. S. T. Swarnasri, Dr. M. Aravinthan, Dr. D. C. Kottahachchi, Dr. N. A. S. Ariyawansa, Dr. L. D. Ranasinghe, Dr. K. D. Liyanarachchi List of abreviations ACTH Adreno Cortico Trophic Hormone BIPPS Bilateral Inferior Petrosal Sinus Sampling CS Cushing Syndrome CD Cushing Disease HDDST High Dose Dexamethasone Suppression Test HPA AXIS Hypothalamo Pituitary Adrenal Axis LDDST Low Dose Dexamethasone Suppression Test ODST Overnight Dexamethasone Suppression Test UFC Urine Free Cortisol GFR Glomerular Filtration Rate CRH Corticotropin Releasing Hormone PCOS Polycystic Ovary Syndrome TSS Transphenoidal Surgery Introduction Cushing syndrome (CS) comprises symptoms and signs associated with prolonged exposure to inappropriately elevated levels of free plasma glucocorticoids. Iatrogenic CS is the most common form. Endogenous CS, may be caused by either excess ACTH secretion or independent adrenal overproduction of cortisol. Epidemiology Endogenous CS is a very rare entity, with an annual inci- dence of 2-3 cases per million individuals. The female: male ratio is 3:1. In patients whom initial cure was not obtained, a 2 to 3 fold increase in mortality is reported. Clinical features of CS CS often presents a diagnostic challenge, particularly in the early stages when the signs and symptoms are non- specific. As the clinical features are non-specific, pres- ence of highly discriminative clinical features (Table 1) should prompt further biochemical tests. Clinical guidelines: The Endocrine Society of Sri Lanka