Cushing's Syndrome: Etiology and Manifestations

• Cushing's Syndrome results from an excess of corticosteroids, especially glucocorticoids.

Etiology

• The most common cause is iatrogenic administration of exogenous corticosteroids.
• 85% of endogenous cases are due to ACTH-secreting pituitary tumors.
• Other causes include adrenal tumors and ectopic ACTH production in tumors outside the hypothalamic-pituitary-adrenal axis, such as lung and pancreas tumors.

Functions of Adrenal Cortex

• The adrenal cortex steroid hormones include Glucocorticoids, Mineralocorticoids, and Androgens.
• Glucocorticoids regulate metabolism and increase blood glucose and are critical to physiologic stress response.
• Mineralocorticoids regulate sodium and potassium balance.
• Androgens contribute to growth and development in both genders and sexual activity in adult women.

Clinical Manifestations

• Clinical manifestations are related to excess corticosteroids.
• Weight gain is a common feature, with trunk (centripetal obesity) and face ("moon face").
• Hyperglycemia, with glucose intolerance associated with cortisol-induced insulin resistance, is a symptom.
• Increased gluconeogenesis by the liver occurs.
• Protein wasting from the catabolic effects of cortisol can leads to weakness, especially in extremities.
• Protein loss in bones can leads to osteoporosis, bone and back pain.
• Loss of collagen, delayed wound healing, mood disturbances, insomnia, irrationality, and psychosis are clinical manifestations.
• Mineralocorticoid excess can cause hypertension secondary to fluid retention.
• Adrenal androgen excess may cause pronounced acne, virilization in women, and feminization in men.
• Adrenal carcinomas manifest as menstrual disorders and hirsutism in women, and gynecomastia and impotence in men.
• Purplish red striae may appear on the abdomen, breast, or buttocks

Diagnostic Studies

• A 24-hour urine test for free cortisol measures cortisol levels; levels above 80 to 120 mcg/day in adults.
• A low-dose dexamethasone suppression test is used for borderline results of 24-hour urine cortisol.
• False-positives can occur with depression and with certain drugs.
• Plasma cortisol levels may be elevated with loss of diurnal variation.
• CT and MRI of pituitary and adrenal glands are performed.

Collaborative Care

• The primary goal is to normalize hormone secretion.
• Treatment depends on the cause, such as pituitary adenoma requiring hypophysectomy or surgical removal of tumor and/or radiation.
• Adrenal tumors or hyperplasia may require adrenalectomy.
• If Cushing syndrome develops during the use of corticosteroids, gradually discontinue therapy, decrease the dose, or convert to an alternate-day regimen.
• Gradual tapering avoids potentially life-threatening adrenal insufficiency.
• Long-term exogenous cortisol therapy is a major risk factor.
• It is important to educate patients about medication use and to monitor for side effects.

Nursing Implementation: Preoperative Care

• The patient should be in optimal physical condition, control hypertension and hyperglycemia, correct hypokalemia with diet and potassium supplements, and consume a high-protein diet to correct protein depletion.
• Teaching depends on surgical approach, including information on postoperative care such as nasogastric tube, urinary catheter, IV therapy, central venous pressure monitoring, and leg compression devices.

Nursing Implementation: Postoperative Care

• Monitor for risk of hemorrhage due to high vascularity of adrenal glands.
• Be aware that manipulation of glandular tissue may release hormones into the circulation, causing unstable BP, fluid balance, and electrolyte levels.
• Monitor for any significant changes in BP, respiration, and heart rate.

Nursing Implementation: Postoperative Care (Continued)

• Monitor fluid intake and output to assess for imbalances.
• There is a critical period for circulatory instability ranging from 24 to 48 hours.
• Monitor morning urine levels of cortisol to evaluate the effectiveness of surgery.
• Bed rest until BP is stabilized is recommended after surgery.
• Meticulous care should be taken when accessing skin, circulation, or body cavities to avoid infection; normal inflammatory responses are suppressed.

Nursing Implementation: Ambulatory and Home Care

• Provide discharge instructions based on lack of endogenous corticosteroids.
• It is important to wear a Medic Alert bracelet.
• Avoid exposure to stress, extremes of temperature, and infection.
• Lifetime replacement therapy is required for many patients after surgeries, potentially leading to Addison's disease.

Cushing's Syndrome results from excess corticosteroids. Common causes include exogenous corticosteroids and ACTH-secreting pituitary tumors. Clinical manifestations are related to excess corticosteroids, such as weight gain and characteristic fat distribution.