Patient will present with → buffalo hump, moon facies, pigmented striae, obesity, skin atrophy, hypertension, weight gain, hypokalemia
↑ cortisol,↓ potassium, ↑ BP
Cushing syndrome is a constellation of clinical abnormalities caused by chronic high blood levels of cortisol or related corticosteroids
"Think of people with Cushing's Disease as "Cushy" - They have a buffalo hump, big puffy face and weight gain. Why weght gain? Cortisol stimulates fat and carbohydrate metabolism for fast energy, and stimulates insulin release and maintenance of blood sugar levels. The end result of these actions can be an increase in appetite"
Cushing's Disease: secondary - ↑ cortisol caused by a pituitary adenoma resulting in ↑ ACTH secretion.
Cushing's Syndrome: primary ↑ cortisol secretion from an adrenal tumor
Dexamethasone suppression test and 24-hour urine cortisol
- Gold standard test → Twenty-four-hour urine test: A test in which urine is collected for 24 hours to measure the amounts of cortisol. A higher than normal amount in the urine may be a sign of disease in the adrenal cortex
- Low-dose dexamethasone suppression test: A test in which one or more small doses of dexamethasone are given. The level of cortisol is checked from a sample of blood or from urine that is collected for three days. This test is done to check if the adrenal gland is making too much cortisol. In general, a clear failure to suppress cortisol levels in response to low-dose dexamethasone establishes the diagnosis.
Differentiating test for causes of Cushing's syndrome
- High-dose dexamethasone suppression test (done in response to a positive low dose test): A test in which one or more high doses of dexamethasone are given. The level of cortisol is checked from a sample of blood or from urine that is collected for three days.
- This test is done to check if the adrenal gland is making too much cortisol or if the pituitary gland is telling the adrenal glands to make too much cortisol
- If cortisol production is suppressed then this is secondary to a pituitary ACTH secreting tumor
- ACTH levels: Decreased ACTH = adrenal tumor, normal or increased ACTH means ectopic ACTH producing tumor
Cushing's disease (pituitary/secondary) is treated with transsphenoidal surgery
Cushing syndrome (primary) ectopic or adrenal tumors: tumor is removed - Ketoconazole is given in inoperable patients
Iatrogenic steroid therapy - begin gradual steroid withdrawal to prevent Addisonian crisis
adenoma of the adrenal gland
hyperplasia of the adrenal gland
carcinoma of the lung
corticosteroid therapy for suppression of inflammation
adenoma of the pituitary gland
Depression/ emotional lability