Disorders of Adrenal Glands
Disorders of Adrenal Glands, Cushings Syndrome; Adrenal Hyperplasia Due to Excess ACTH Cushings Syndrome NOS, Iatrogenic, Idiopathic, Pituitary-Dependent, Ectopic ACTH Syndrome, Iatrogenic Syndrome of Excess Cortisol, Overproduction of Cortisol
Cushing's syndrome is a condition caused by excess corticosteroids in an individual's body. These steroids can be produced by the body itself or can result from high doses of medical steroids being administered to the individual. Cushing's syndrome is characterized by a large, round face and a thick torso with comparatively thin arms and legs. Muscle weakness, depression, hallucinations, thin skin that bruises easily and heals slowly, and purple streaks on the abdomen are also common signs and symptoms of this condition.
The adrenal glands located on top of the kidneys produce cortisol. Under normal conditions, the release of cortisol is controlled by the pituitary gland and the hypothalamus in the brain. The hypothalamus sends a hormone (corticotropin-releasing hormone or CRH) to the pituitary gland. CRH causes the pituitary gland to secrete a hormone called ACTH (adrenocorticotropic hormone). ACTH is the signal for the adrenal gland to produce cortisol.
A common cause of Cushing's syndrome is the administration of glucocorticoid drugs (such as prednisone) or ACTH for various medical reasons. This is called exogenous Cushing's syndrome. Individuals with any disease requiring prolonged use of corticosteroid medications are at increased risk of developing Cushing's syndrome. Examples of some medical conditions that are often treated with glucocorticoids or ACTH and may increase one's risk of developing Cushing's syndrome include rheumatoid arthritis, lupus, asthma, or other chronic inflammatory diseases.
When a tumor (adenoma) of the pituitary gland produces excessive amounts of ACTH, there is a subsequent release of excess cortisol by the adrenal glands. This condition is called Cushing's disease (hypercortisolism), and it accounts for about 70% of the naturally occurring (endogenous) cases of Cushing's syndrome. Another 15% of the naturally occurring cases of Cushing's syndrome are caused by release of cortisol from noncancerous (benign) or cancerous (malignant) tumors of the adrenal gland (adrenal adenoma and adrenal carcinoma). The remaining 15% of cases are caused by the production of ACTH by a tumor (either benign or malignant) located elsewhere in the body (ectopic ACTH syndrome) (Adler).
Risk: Cushing's syndrome most commonly affects adults between the ages of 20 and 50, although it can strike at any age. Although Cushing's syndrome is not inherited, some people have an inherited predisposition to tumors of the hormone-secreting glands. This predisposition places these individuals at a higher risk for Cushing's syndrome than the general population.
Cushing's disease more commonly affects women of reproductive age, but it can occur in men and women at any age (Kirk). Women are five times more likely than men to have Cushing's syndrome caused by a pituitary or an adrenal tumor (Adler).
Ectopic ACTH syndrome is caused by lung tumors (usually carcinoid) in 50% of cases. Other ACTH-producing tumors include thymomas, pancreatic islet cell carcinomas, and medullary carcinomas of the thyroid. Ectopic ACTH syndrome affects men more often than women because lung cancer occurs more frequently among men (Adler).
Incidence and Prevalence: Cushing's syndrome is relatively rare, affecting about 13 of every million individuals each year (Adler).
History: Frequent complaints include weight gain, fatigue, muscle weakness (especially of the upper arms and thighs), easy bruising, poor wound healing, thinning scalp hair, abnormal growth of body hair and purple streaking (striae) of the breasts, buttocks, lower abdomen and thighs. Individuals may also complain of excessive thirst and frequent urination. Psychiatric symptoms include mood swings, depression, and personality changes (steroid psychosis). Women may notice changes in the menstrual flow (oligomenorrhea or amenorrhea), and men may complain of decreased sex drive (libido) and inability to achieve or maintain an erection (erectile dysfunction). Often, individuals will report that routine bending, lifting, or rising from a chair has become difficult or painful.
Physical exam: High blood pressure (hypertension) is seen in over 80% of cases. There are some striking physical changes in Cushing's syndrome. The face is round and unusually red. Acne may be present. Obesity is common; 50% of individuals gain weight in the abdomen and buttocks while the arms and legs are normal. Fat pads appear over the collarbones and upper spine.
Tests: If it has been determined from the history and physical exam that the individual is not showing the signs of Cushing's syndrome from prescribed medications, further testing is carried out at two levels. First, it must be determined whether the individual has elevated levels of cortisol. A 24-hour urine collection is taken, and the amount of cortisol in the urine is measured. The cortisol level will be elevated in individuals with Cushing's syndrome. Another test is the overnight dexamethasone suppression test. Dexamethasone is a steroid medication that suppresses ACTH release and lowers the early morning levels of blood cortisol in normal individuals but has no effect in individuals with Cushing's syndrome. A newer means to detect Cushing's syndrome uses a combination of the CRH stimulation test with the dexamethasone suppression test. Cortisol levels exceeding 1.4 µg per L would be diagnostic for Cushing's syndrome. This method is reported to have a very high rate of diagnostic accuracy.
Once the diagnosis of Cushing's syndrome is established, a second level of testing is carried out to determine the cause of the disease: a tumor of the pituitary gland or adrenal glands or a tumor that stimulates the adrenal glands through ectopic ACTH secretion. A test called the CRH stimulation test is often performed to help distinguish individuals with Cushing's syndrome due to pituitary adenomas from those with ectopic ACTH syndrome or cortisol-secreting adrenal tumors.
In the CRH stimulation test, individuals are given an injection of CRH. Those with a pituitary adenoma usually experience a rise in blood levels of ACTH and cortisol. This response is rarely seen in people with ectopic ACTH syndrome and practically never in those with cortisol-secreting adrenal tumors.
Routine chest x-rays are done, along with CT of the chest in suspected cases of ectopic ACTH production. A CT of the adrenal glands can show an adrenal tumor, or in the case of a pituitary tumor that stimulates both glands, enlarged adrenal glands. MRI of the pituitary gland is done in cases of suspected pituitary tumors. Pituitary adenomas are only seen on 50% of MRI tests, so it is important that the biochemical testing is thorough before surgery (Kirk).
Blood tests may also show high levels of sugar (hyperglycemia), fat (hyperlipidemia), or potassium (hyperkalemia) and abnormal numbers of certain white blood cells (neutrophilia, lymphopenia).
If the condition is caused by overmedication, it is treated by reducing the dosage of glucocorticoids or changing the medication. When the underlying cause is a benign or malignant tumor of the adrenal gland, the tumor must be surgically removed.
The treatment of choice for tumors of the pituitary gland is surgical removal. Irradiation of the pituitary gland has a lower success rate and a higher rate of complications, and notable improvement may not be noted for a year or more. Hormone replacement therapy usually follows surgery and, in some cases, must be continued for life.
Medical treatment (chemotherapy) is usually not recommended as the primary treatment for Cushing's syndrome but is an alternative if surgery is not possible and may be used with radiation treatments to hasten better results. If the cause of Cushing's syndrome is ectopic ACTH, treatment is directed at the underlying disease.
Before the introduction of effective therapy approximately 50% of patients with untreated Cushing's syndrome died within 5 years. Now with appropriate medical intervention, the outcome of endogenous Cushing's is generally good. Cushing's secondary to ACTH-producing tumors of the adrenal gland are often treated by surgical removal of the adrenal gland, which has a 100% cure rate. However, Cushing's secondary to ACTH-producing tumors of the lung generally has a poor outcome (Stewart 522).
Cushing's syndrome is complicated by high blood pressure, diabetes, increased susceptibility to infections, emotional disturbances, and metastasis of cancerous tumors. The bones become fragile (osteoporosis), and compression fractures of the spine are common.
No restrictions or accommodations should be necessary once the individual returns to work.
If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.
- On exam, are symptoms present such as hypertension, red, round face, acne, and weight gain in the abdomen and buttocks or fat pads over the collarbones and upper spine? Does individual have a thick torso with comparatively thin arms and legs?
- Does individual also have muscle weakness, thin skin that bruises easily and heals slowly, and purple streaks on the abdomen, breasts, buttocks and thighs?
- Does individual have a pituitary tumor, adrenal tumor, small cell lung cancer, thymomas, pancreatic islet cell carcinomas, or medullary carcinomas of the thyroid?
- Is individual being treated with glucocorticoid drugs for another condition?
- Does individual have a family history of tumors of the hormone-secreting glands?
- Does individual complain of weight gain, fatigue, thinning scalp hair, excessive body hair, excessive thirst, and frequent urination?
- Does individual have mood swings, depression, hallucinations, and personality changes?
- Does individual have oligomenorrhea or amenorrhea? Decreased libido? Impotence? Does individual report that routine bending, lifting, or rising from a chair is difficult or painful?
- Were cortisol levels tested? Was individual tested for the presence of cortisol-secreting tumors?
- Was an overnight dexamethasone suppression test done? Was a combination CRH stimulation and dexamethasone suppression test done to confirm the diagnosis? CT or MRI? Comprehensive blood testing? Was inferior petrosal sinus sampling done?
- Were conditions with similar symptoms ruled out?
- Is the condition caused by overmedication? Is the dosage of glucocorticoids reduced or the medication changed?
- Is the condition caused by a tumor? Was it surgically removed? Is individual on hormone replacement therapy?
- Does individual have any conditions that may affect ability to recover?
- Have any complications developed, such as high blood pressure, diabetes, infections, emotional disturbances, metastasis of tumors, osteoporosis, and compression fractures of the spine?
Adler, Gail. "Cushing Syndrome." eMedicine. Eds. William Chiang, et al. 17 Aug. 2004. Medscape. 28 Sep. 2004 http://emedicine.com/emerg/topic117.htm.
Kirk, Lawrence F., et al. "Cushing's Disease: Clinical Manifestations and Diagnostic Evaluation." American Academy of Family Physicians. 28 Sep. 2004 http://www.aafp.org/afp/20000901/1119.html.
Stewart, Paul M. "Therapeutic Corticosteroids." Williams Textbook of Endocrinology. Eds. R. H. Williams and Reed P. Larsen. 10th ed. Philadelphia: Elsevier, Inc., 2003. 508-525. MD Consult. Elsevier, Inc. 28 Sep. 2004 http://home.mdconsult.com.