Definition:
Cushing syndrome is a condition caused by prolonged exposure to high levels of cortisol, leading to metabolic disturbances and characteristic physical changes (Jameson et al., 2022). It can result from endogenous overproduction of cortisol or exogenous glucocorticoid use.
Causes:
- Exogenous (Most Common): Long-term corticosteroid use (e.g., prednisone) for conditions like autoimmune diseases (McCance & Huether, 2019).
- Endogenous (Less Common):
- Cushing Disease (ACTH-dependent): Pituitary adenoma secreting excessive adrenocorticotropic hormone (ACTH), leading to increased cortisol production.
- Ectopic ACTH Syndrome: Non-pituitary tumors (e.g., small cell lung cancer) producing ACTH.
- Adrenal Tumors: Adrenal adenomas or carcinomas producing cortisol independently of ACTH.
Signs and Symptoms
- Physical Changes:
- Moon face, buffalo hump (fat accumulation in face and upper back)
- Central obesity with thin extremities
- Purple striae (stretch marks) on the abdomen, breasts, and thighs
- Hirsutism (excess hair growth) in women
- Thinning skin with easy bruising (McCance & Huether, 2019).
- Metabolic & Systemic Effects:
- Hyperglycemia & Insulin Resistance → Increased risk of diabetes
- Hypertension → Due to cortisol’s mineralocorticoid effects
- Muscle Weakness & Osteoporosis → Due to protein breakdown and calcium loss
- Immunosuppression → Increased risk of infections
- Mood Changes → Depression, anxiety, irritability (Jameson et al., 2022).
Diagnosis
- 24-Hour Urinary Free Cortisol Test: Confirms excess cortisol.
- Low-Dose Dexamethasone Suppression Test: Evaluates cortisol suppression; failure to suppress suggests Cushing syndrome.
- ACTH Levels: Differentiates ACTH-dependent (Cushing disease, ectopic ACTH syndrome) from ACTH-independent causes (adrenal tumors).
- Imaging: MRI (for pituitary adenomas) or CT scan (for adrenal tumors) (Hammer & McPhee, 2019).
Treatment
- Exogenous Cushing Syndrome: Gradual tapering of corticosteroids to prevent adrenal insufficiency.
- Cushing Disease (Pituitary Adenoma): Transsphenoidal surgery to remove the tumor.
- Adrenal Tumors: Surgical removal of the affected adrenal gland.
- Ectopic ACTH Syndrome: Treatment of the underlying malignancy (Jameson et al., 2022).
- Pharmacological Management:
- Ketoconazole, metyrapone, or mitotane to reduce cortisol levels when surgery is not an option.
NCLEX Key Points
✅ Monitor Blood Glucose: Risk for hyperglycemia and diabetes.
✅ Assess for Infection: Cortisol suppresses immune function.
✅ Monitor Electrolytes: Risk for hypokalemia and hypertension.
✅ Ensure Safety: Risk for fractures due to osteoporosis.
✅ Educate on Corticosteroid Use: Gradual tapering to prevent adrenal crisis (Hammer & McPhee, 2019).
References
- Hammer, G. D., & McPhee, S. J. (2019). Pathophysiology of disease: An introduction to clinical medicine (8th ed.). McGraw-Hill.
- Jameson, J. L., Fauci, A. S., Kasper, D. L., Hauser, S. L., Longo, D. L., & Loscalzo, J. (2022). Harrison’s principles of internal medicine (21st ed.). McGraw-Hill.
- McCance, K. L., & Huether, S. E. (2019). Pathophysiology: The biologic basis for disease in adults and children (8th ed.). Elsevier.