Cushing’s syndrome – Quick revision card

Adrenal gland hyperfunction Cortisol made by the central zone or zona fasciculate

Prolonged exposure to high circulating levels of cortisol is Cushing’s syndrome

Exogenous – prolonged use of glucocorticoids

Endogenous – excessive cortisol production by adrenal glands – this can be ACTH dependent ( majority 80 % ) or ACTH independent ( due to benign or malignant adrenal tumors )

ACTH secreting pituitary tumors is called Cushing’s disease Ectopic ACTH secretion by neoplasms

Cushing’s Disease
 most frequent cause of Cushing’s syndrome
 ACTH ( adrenocorticotrophic hormone ) hypersecretion due to a corticotroph adenoma causing corticol hypersecretion

Cortisol excess – obesity ( centripetal ) facial plethora , rounded face , buffalo hump fatigue , weakness protein wasting ( thin skin , abdominal purple to red and wide cutaneous striae , east bruising , slow healing , muscle wasting ) osteoporosis ( bone wasting leading to fractures ) raised blood pressure depression , mood swings , emotional reactivity loss of libido , erectile dysfunction in men , irregular menstrual cycle , infertility , hyperhidrosis , hirsutism impaired immunity ( repeated infections ) back pain

R/O exogenous sources mild hypokalaemia may be noted due to mineralocorticoid effect of steroids verification of endogenous hyercortisonilism by tests as
○ late night salivary cortisol
○ 24 hr urine free cortisol
○ low dexamethasone suppression test

REFERENCES

1. Chaudhry HS, Singh G. Cushing Syndrome. [Updated 2021 Jul 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022  Available from: https://www.ncbi.nlm.nih.gov/books/NBK470218/
2. Lynnette K. Nieman, Beverly M. K. Biller, James W. Findling, John Newell-Price, Martin O. Savage, Paul M. Stewart, Victor M. Montori, The Diagnosis of Cushing’s Syndrome: An Endocrine Society Clinical Practice Guideline, The Journal of Clinical Endocrinology & Metabolism, Volume 93, Issue 5, 1 May 2008, Pages 1526–1540, https://doi.org/10.1210/jc.2008-
3. Castinetti, F., Morange, I., Conte-Devolx, B. et al. Cushing’s disease. Orphanet J Rare Dis 7, 41 (2012). https://doi.org/10.1186/1750-1172-7-41
4. Lonser RR, Nieman L, Oldfield EH. Cushing’s disease: pathobiology, diagnosis, and management. J Neurosurg. 2017 Feb;126(2):404-417. doi: 10.3171/2016.1.JNS152119. Epub 2016 Apr 22. PMID: 27104844.