CUSHING’S SYNDROME
1. Description of the disorder
The clinical picture produced by prolonged increases in plasma glucocorticoids was described Harvey Cushing, and is called Cushing’s syndrome. It may be (adrenocorticotropic hormone) ACTH-independent or ACTH-dependent. The causes of ACTH-independent Cushing’s syndrome include glucocorticoid-secreting adrenal tumors and prolonged administration of exogenous glucocorticoids for diseases such as rheumatoid arthritis. The causes of ACTH-dependent Cushing’s syndrome include ACTH-secreting tumors of the anterior pituitary gland and tumors of other organs, usually the lungs, that secrete ACTH (ectopic ACTH syndrome) or CRH (2001).
Suprarenal cortical hyperplasia is the most common cause of Cushing’s syndrome, the clinical manifestations of which include moon-shaped face, truncal obesity, abnormal hairiness (hirsutism), and hypertension; if the syndrome occurs later in life, it may result from an adenoma or carcinoma of the cortex (Snell). The increased adrenal hormone production of Cushing’s syndrome is responsible for the round or moon face with red cheeks that is characteristic of Cushing’s syndrome (2003).
2. Anatomy
Patients with Cushing’s syndrome are protein-depleted as a result of excess protein catabolism. The skin and subcutaneous tissues are therefore thin, and the muscles are poorly developed. Wounds heal poorly, and minor injuries cause bruises and eccymoses. The hair is thin and scraggly. Many patients with the disease have some increase in facial hair and acne, but this is caused by the increased secretion of adrenal androgens and often accompanies the increase in glucocorticoid secretion (2001). Excessive hair growth may be present in the mustache and sideburn areas and on the chin (2003).
Body fat is redistributed in a characteristic way. The extremities are thin, but fat collects in the abdominal wall, face, and upper back, where it produces a “buffalo hump.” As the thin skin of the abdomen is stretched by the increased subcutaneous fat depots, the subdermal tissues rupture to form prominent reddish-purple striae. These scars are seen normally whenever there is a rapid stretching of skin (e.g. around the breasts of girls at puberty or in the abdominal wall during pregnancy), but in normal individuals, the striae are usually inconspicuous and lack the intense purplish color (2001).
Cushing’s syndrome is characterized biochemically by excess production of glucocorticoids and clinically by central obesity, moon face, buffalo hump, diabetes mellitus, osteoporosis, hypertension, plethora, hirsutism, amenorrhea, acne, weakness and emotional liability ( 1998).
3. Target group
Cushing’s syndrome is relatively rare and most commonly affects adults aged 20 to 50. An estimated 10 to 15 of every million people are affected each year.
4. Diagnostic testing
The full blown symptom complex of Cushing’s syndrome constitutes a not easily missed clinical syndrome. The differential diagnosis of the major categories of Cushing’s syndrome are dexamethasone suppression tests and plasma ACTH levels.
Tests to confirm high cortisol levels include cortisol and urine tests, dexamethasone suppression test and tests fro serial serum cortisol levels. Tests to determine the cause includes ACTH tests, cranial MRI or cranial CT scan which may show anterior pituitary tumor, and abdominal CT which may show adrenal mass. General findings for Cushing’s syndrome include elevated glucose test, low potassium test and elevated white blood cell count.
5. Health promotion strategies
Treatment of Cushing’s syndrome depends on the cause of excess cortisol. If the cause is long-term use of a medication being used to treat another disorder, the physician may reduce the dosage until symptoms are under control. Surgery or radiotherapy may be used to treat pituitary adenomas. Surgery, radiotherapy, chemotherapy, immunotherapy, or a combination of these may be used to treat ectopic ACTH syndrome. The aim of surgical treatment is to cure hypercortisolism by removing the tumor while minimizing the chance of endocrine deficiency or long-term dependence on medications.
Tumor removal may lead to full recovery, but there is a chance of recurrence. Survival for people with ectopic tumors depends upon the overall outcome associated with the particular tumor type. Untreated, Cushing’s syndrome can lead to death.
6. Follow up
If ACTH secretion cannot be easily decreased by the usual treatments for Cushing’s syndrome, the only satisfactory treatment is usually bilateral partial (or even total) adrenalectomy. The patient may need steroid replacement therapy after surgery because they may no longer be producing sufficient amounts of cortisol in the adrenal glands. Administration of adrenal steroids will make up for any insufficiency that develops.
7. Long term care
The various forms of Cushing’s syndrome are eminently treatable however the condition usually requires long-term care and follow up. Some patients may require life long steroid replacement therapy. As previously stated, Cushing’s syndrome is potentially fatal if left untreated.
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