It is caused by increased plasma glucocorticoid level due to enhanced production of cortisol by the adrenal cortex. This may be the result of adrenal cortical adenoma or cancer or due to increased secretion of A.C.T.H. Adrenal hyperplasia is the most common followed by adrenal adenoma, cancer and ectopic A.C.T.H., source, pituitary tumors secreting A.C.T.H. This syndrome may occasionally occur due to iatrogenic administration of corticosteroids. Both the adrenal glands become hyperplastic and the sharp edges of the gland become thick and rounded.
Adrenal adenoma is sometimes seen in Cushing’s syndrome associated with atrophy of the remainder cortex and cortex of the opposite side. This atrophy is due to inhibition of A.C.T.H. secretion by the excess cortisol secreted by the autonomous tumor. It is mostly seen in the third and fourth decades, though its occurrence has been noticed in children below one year of age and in old individuals above 70 years of age. Cushing’s syndrome is four times more common in women than in men. Adenomas are common in women than in men.
Obesity is present in almost every case. Truncal fullness with relatively thin limbs is also there. There is excessive accumulation of fat around the head and neck. Purple striae are often seen on the abdomen and occasionally on the extremities. A large percentage of female patients become hirsute with acne and ecchymosis. Oligomenorrhoea and amenorrhea may be present.
Elevated blood pressure usually of a moderate degree is often seen in large percentage of patients. Muscle weakness and bone pain particularly backache are quite common. The bones become osteoporotic and pathological fractures may occur in advanced cases. The neurologic symptoms including headache, irritability, depression and mental symptoms are found. Many patients with Cushing’s syndrome become diabetic. Some patients may show hypercalciuria.
Investigations done to diagnose Cushing’s syndrome are-
1. Determination of free cortisol in urine, if show values in excess of 100 microgram per 24 hours suggest increased cortisol production.
2. Plasma A.C.T.H. measurement.
3. Dexamethasone suppression test.
4. Metyrapone test.
5. A.C.T.H stimulation test.
6. CT scan.
7. X-ray of the sella turcica and angiography of the adrenal.
Treatment of Cushing’s syndrome is done by-
1. Medicinal therapy.
- Pituitary irradiation.
- Transsphenoidal hypophysectomy.