(Cushing's Disease; Hypercortisolism)
Definition
Cushing's syndrome is a hormonal disorder caused by prolonged exposure to the hormone cortisol. It is called Cushing's disease when it is caused by a pituitary tumor. All other causes of the condition are termed Cushing's syndrome.
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
• Rarely, tumors of the lungs, thyroid, kidney, pancreas, or thymus gland produce hormones that trigger the syndrome
Pituitary and Adrenal Glands
Risk Factors
A risk factor is something that increases your chance of developing a disease or condition.
Risk factors include:
• Chronic use of corticosteroid medicines
• Age: 20-50 years
• Sex: female (much more common in women)
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:
o Darkening of the skin
o Purple stretch marks
o 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
Diagnosis
The doctor will ask about your symptoms and medical history, and perform a physical exam.
Tests may include:
24-hour Urinary Free Cortisol Level
Urine is collected for 24 hours, and then tested for cortisol.
Late-evening Cortisol Saliva Level
A saliva sample is collected at around 11 pm and tested for cortisol level.
Dexamethasone Suppression Test
A synthetic cortisol, called dexamethasone, is taken by mouth either overnight or for several days. Depending on the length of the test, or the dose of dexamethasone administered, blood or urine cortisol levels are measured at specific intervals.
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
Treatment
Treatment of Cushing's syndrome depends on the cause.
Treatments include:
• Surgical removal of tumor
• Radiation for some persistent tumors
• Gradual withdrawal of cortisone-type drugs (under close medical supervision)
• Drugs to suppress adrenal gland function
Prevention
Work with your doctor to keep use of corticosteroid drugs to a minimum.
