Sunday 28 August 2011

Cushing's Syndrome

Definition

Cushing's syndrome is a condition caused by excess amounts of cortisol adenoma or cancer resulting from hypersecretion of the adrenal cortex which may result from a hypersecreting adrenal tumor, ectopic ACTH, or prolonged exposure to high therapeutic doses of glucocorticoids or prolonged exposure to high therapeutic doses of glucocorticoids.

Etiology

exogenous

the most common cause of Cushing's syndrome is iatrogenic or exogenous glucocorticoid use.

Endogenous
cases may be either
ACTH dependent (e.g., ACTH-secreting pituitary adenoma or ectopic ACTH-secreting neoplasm)
or
ACTH independent (e.g., adrenal adenoma, adrenal carcinoma)


Sign or Symptom

Decreased libido in men and women
Obesity or weight gain
Plethora
Round face
Menstrual changes
Hirsutism
Hypertension
Ecchymoses
Lethargy, depression
Striae
Weakness
Electrocardiographic changes or atherosclerosis
Dorsal fat pad
Edema
Abnormal glucose tolerance
Osteopenia or fracture
Headache
Backache
Recurrent infections
Abdominal pain
Acne
Female balding





Diagnosis

Urine free cortisol excretion during 24 hours is a good screening test

Dexamethasone Suppression Tests
It involves giving dexamethasone, 1 mg, orally between 2300 and midnight and measurement of plasma cortisol concentration between 0800 and 0900 the following morning.




Treatment

Surgical Therapy

The optimal treatment of Cushing's syndrome is surgical resection of the lesion that is producing excessive ACTH or cortisol

Radiation Therapy

Medical Therapy

Combination of Surgical and Medical Therapy is to be used

Medical therapy alone is rarely appropriate for Cushing's disease because it requires close monitoring and adjustment of dose and has low long-term efficacy.

Patients with ectopic ACTH secretion can be cured if the tumor can be removed and is not metastatic. Otherwise, adrenalectomy or medical therapy is chosen. Adrenalectomy is appropriate when the patient cannot tolerate the cost, medical toxicity, or adverse psychological effects of long-term medical therapy and monitoring or if the patient requires rapid correction of hypercortisolism. Adrenalectomy is appropriate when maximal daily doses of ketoconazole (1600 mg), aminoglutethimide (2 g), and metyrapone (2 g) given in combination do not render the patient eucortisolemic.

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