Cushing syndrome

Definition

Cushing syndrome is a disorder that occurs when your body is exposed to high levels of the hormone cortisol. It may also occur if you take too much cortisol or other steroid hormones.

See also: Cushing's disease (pituitary Cushing's)

Alternative Names

Hypercortisolism

Causes, incidence, and risk factors

Cushing syndrome may be caused by taking too much corticosteroid medications, such as prednisone and prednisolone. These drugs are used to treat conditions such as asthma and rheumatoid arthritis.

Other people develop Cushing syndrome because their bodies produce too much cortisol, a hormone normally made in the adrenal gland. Causes of too much cortisol are:

• Cushing's disease, when the pituitary gland makes too much of the hormone ACTH. ACTH then signals the adrenal glands to produce cortisol. Tumor of the pituitary gland may cause this condition.
• Tumor of the adrenal gland
• Tumor elsewhere in the body that produces cortisol
• Tumors elsewhere in the body that produce ACTH (such as the pancreas, lung, and thyroid)

Symptoms

Most people with Cushing syndrome will have:

• Upper body obesity (above the waist) and thin arms and legs
• Round, red, full face (moon face)
• Slow growth rate in children

Skin changes that are often seen:

• Acne or skin infections
• Purple marks (1/2 inch or more wide) called striae on the skin of the abdomen, thighs, and breasts
• Thin skin with easy bruising

Muscle and bone changes include:

• Backache, which occurs with routine activities
• Bone pain or tenderness
• Collection of fat between the shoulders (buffalo hump)
• Thinning of the bones, which leads to rib and spine fractures
• Weak muscles

Women with Cushing syndrome often have:

• Excess hair growth on the face, neck, chest, abdomen, and thighs
• Menstrual cycle becomes irregular or stops

Men may have:

• Decreased fertility
• Decreased or no desire for sex
• Impotence

Other symptoms that may occur with this disease:

• Mental changes, such as depression, anxiety, or changes in behavior
• Fatigue
• Headache
• High blood pressure
• Increased thirst and urination

Signs and tests

Blood sugar and white blood cell counts may be high. Potassium level may be low.

Laboratory tests that may be done to diagnose Cushing syndrome and identify the cause are:

• Serum cortisol levels
• Salivary cortisol levels
• Dexamethasone suppression test
• 24-hour urine for cortisol and creatinine
• ACTH level
• ACTH (cosyntropin) stimulation test

Tests to determine the cause or complications may include:

• Abdominal CT
• ACTH test
• Pituitary MRI
• Bone density, as measured by dual x-ray absorptiometry (DEXA)

High cholesterol, including high triglycerides and low high-density lipoprotein (HDL) may also be present.

Treatment

Treatment depends on the cause.

Cushing syndrome caused by corticosteroid use:

• Slowly decrease the drug dose (if possible) under medical supervision.
• If you cannot stop taking the medication because of disease, your high blood sugar, high cholesterol levels, and bone thinning or osteoporosis should be closely monitored.

Cushing syndrome caused by a pituitary tumor or tumor that releases ACTH:

• Surgery to remove the tumor
• Radiation after removal of a pituitary tumor (in some cases)
• You may need hydrocortisone (cortisol) replacement therapy after surgery, and possibly continued throughout your life

Cushing syndrome due to an adrenal tumor or other tumors:

• Surgery to remove the tumor
• If the tumor cannot be removed, medications to help block the release of cortisol

Expectations (prognosis)

Removing the tumor may lead to full recovery, but there is a chance that the condition will return.

Survival for people with ectopic tumors depends on the tumor type. Untreated, Cushing syndrome can be life-threatening.

Complications

• Diabetes
• Enlargement of pituitary tumor
• Fractures due to osteoporosis
• High blood pressure
• Kidney stones
• Serious infections

Calling your health care provider

Call your health care provider if you have symptoms of Cushing syndrome.

References

Stewart PM. The adrenal cortex. In: Kronenberg HM, Shlomo M, Polonsky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. Philadelphia, Pa: Saunders Elsevier;2008:chap 14.

Carroll T, Raff H, Findling JW. Late-night salivary control measurement in the diagnosis of Cushing's syndrome. Nat Clin Pract Endocrinol Metab. 2008;4:344-350.