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Definition  

Cushing's syndrome is a hormonal disorder. It is caused by prolonged exposure to the hormone cortisol.

Hormones are chemicals in the body. Cortisol is a common hormone. In normal doses it helps the body manage stress and infection.

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Causes  

Prolonged or excess exposure to cortisol as a result of:

  • Long-term use of corticosteroid hormones such as cortisone or prednisone
  • Tumor or abnormality of the adrenal gland, which causes the body to produce excess cortisol
  • Tumor or abnormality of the pituitary gland, which causes the body to produce excess cortisol (in the case of a pituitary tumor , it is called Cushing's disease)
  • Rarely, tumors of the lungs, thyroid, kidney, pancreas, or thymus gland produce hormones that trigger the syndrome
Pituitary and Adrenal Glands  
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Risk Factors  

Factors that increase your risk of Cushing's syndrome include:

  • Chronic use of corticosteroid medicines
  • Age: 20-50 years
  • Sex: female (much more common in women)
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Symptoms  

Although symptoms may vary, common symptoms of Cushing's syndrome are:

  • Weight gain of the upper body and trunk
  • Face shaped like a moon
  • Skin changes:
    • Darkening of the skin
    • Purple stretch marks
    • Easy bruising
  • Excess hair growth or acne in women
  • Menstrual disorders, especially infrequent or absent periods
  • Diminished fertility and libido
  • High blood pressure
  • Water retention or swelling
  • High blood sugar or diabetes
  • Tiredness or fatigue
  • Personality changes or mood swings
  • Muscle weakness
  • Osteoporosis or brittle bones
  • Skeletal growth retardation in children
  • Increased thirst
  • Frequent urination
  • Psychosis
  • Low back pain
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Diagnosis  

The doctor will ask about your symptoms and medical history. A physical exam will be done.

Tests for Cortisol Levels  
  • 24-hour urinary free cortisol level—Urine is collected for 24 hours and tested.
  • Late-evening cortisol saliva/blood level—Saliva or blood is collected around 11 pm and tested.
  • Dexamethasone suppression test—A synthetic cortisol called dexamethasone is taken by mouth; blood and urine samples may be taken overnight or over several days.
Tests to Determine Cause of Cushing's Syndrome  
  • CRH stimulation test
  • ACTH level
  • High-dose dexamethasone suppression test
X-rays and Scans  

These tests may show whether there is a tumor in the pituitary or adrenal glands or another area of the body. Common imaging tools include:

  • MRI scan —a test that uses magnetic waves to make pictures of the inside of the body
  • CT scan —a type of x-ray that uses a computer to make pictures of structures inside the body
  • Chest x-ray —which may detect tumors in the lungs
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Treatment  

Treatment of Cushing's syndrome depends on the cause.

Treatments include:

  • Surgical removal of tumor
  • Surgical removal of part, all, or both adrenal glands
  • Radiation for some persistent tumors
  • Gradual withdrawal of cortisone-type drugs under close medical supervision
  • Drugs that decrease cortisol production or block the functioning of other adrenal products
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Prevention  

Work with your doctor to keep use of corticosteroid drugs to a minimum.