Cushing Syndrome

Onset generally occurs in third and fourth decades.

Approximately 3–5 times more common in women than men.

5-y mortality rate from adrenal carcinomas has been estimated to be >70%.

Lyte abnormalities

Consequences of untreated Htn

Hyperglycemia

Cardiovascular disease more common

Challenges related to obesity, including airway management and IV access.

Significant osteopenia secondary to impaired calcium absorption, making positioning difficult.

Htn due to fluid retention.

Increased risk of infection as a result of corticosteroids’ immunosuppressive qualities.

Hypokalemic alkalosis, commonly seen in ectopic ACTH production.

Cushing syndrome may also occur with other disease states, including pheochromocytoma, sarcoidosis, pancreatic carcinoma, sarcoidosis, carcinoid lung tumors, and other neuroendocrine carcinomas.

Most common cause of Cushing syndrome is iatrogenic administration of exogenous glucocorticoids.

Spontaneous Cushing syndrome can result from adrenal gland hyperplasia secondary to increased ACTH production from a pituitary tumor or an ectopic nonendocrine ACTH tumor. Pituitary tumors may present with visual disturbances and have symptoms of increased ICP.

Other causes include primary gland disorders, such as adrenal adenoma or carcinoma.

Symptoms including Htn, hyperglycemia, increased intravascular volume, hypokalemia, abdominal striae, truncal obesity, telangiectasias, muscle weakness and/or wasting leading to thin extremities, osteoporosis due to impaired calcium absorption, depression, and insomnia.

Severe metabolic alkalosis is often the first clinical manifestation of ectopic ACTH-secreting tumors and may result in significant hypoventilation, myocardial depression, arrhythmias, decreased cerebral blood flow, and neuromuscular excitability.

A 24-h urine cortisol test can demonstrate elevated cortisol levels.

Dexamethasone suppression test is used to aid in differentiating pituitary adenomas from adrenal tumors. Dexamethasone causes depression of cortisol and 17-hydroxycorticosteriod levels due to a negative feedback response, which is absent with ectopic ACTH or primary gland disease.

ACTH plasma levels can also be tested directly.

Radiologic evaluation including abdominal CT scan to evaluate the adrenal glands, pituitary MRI scan with gadolinium contrast to evaluate the pituitary gland, and a chest CT scan when ectopic ACTH is the suspected etiology.