Growths in the pituitary gland. Pituitary tumours are rare, and mostly noncancerous, but tumour enlargement can put pressure on the optic nerves, causing visual defects.
The causes of pituitary tumours are unknown. They may lead to inadequate hormone production, causing problems such as cessation of menstrual periods or reduced sperm production. They may also cause the gland to produce excess hormone. Overproduction of growth hormone causes gigantism or acromegaly; too much thyroid-stimulating hormone (TSH) can lead to hyperthyroidism. Investigations include blood tests, X-rays, MRI of the pituitary, and usually also vision tests. Treatment may be by surgical removal of the tumour, radiotherapy, hormone replacement, or a combination of these techniques. The drug bromocriptine may be used; it can reduce production of certain hormones and shrink some tumours.
An endocrine gland somewhat behind the eyes and suspended from the front of the brain. The front section, the anterior pituitary, makes and secretes a number of controlling hormones that affect the rate of oxidation; the preference for fats, sugars, or proteins for fuel; the rate of growth and repair in the bones, connective tissue, muscles, and skin; the ebb and flow of steroid hormones from both the gonads and adrenal cortices. It does this through both negative and positive feedback. The hypothalamus controls these functions, secreting its own hormones into a little portal system that feeds into the pituitary, telling the latter what and how much to do. The hypothalamus itself synthesizes the nerve hormones that are stored in the posterior pituitary, which is responsible for squirting them into the blood when the brain directs it to. These neurohormones act quickly, like adrenalin, to constrict blood vessels, limit diuresis in the kidneys, and trigger the complex responses of sexual excitation, milk letdown in nursing, and muscle stimulus in the uterus (birthing, orgasm, and menstrual contractions), prostate, and nipples.... pituitary
Cancerous or noncancerous tumours in the adrenal glands, usually causing excess secretion of hormones. Adrenal tumours are rare. Tumours of the adrenal cortex may secrete aldosterone, causing primary aldosteronism, or hydrocortisone, causing Cushing’s syndrome. Tumours of the medulla may cause excess secretion of adrenaline and noradrenaline. Two types of tumour affect the medulla: phaeochromocytoma and neuroblastoma, which affects children. These tumours cause intermittent hypertension and sweating attacks. Surgical removal of a tumour usually cures these conditions.... adrenal tumours
Cancerous or noncancerous growths in the intestine. Cancerous tumours commonly affect the large intestine (see colon, cancer of; rectum, cancer of); the small intestine is only rarely affected. Lymphomas and carcinoid tumours (leading to carcinoid syndrome) may sometimes develop in the intestine; noncancerous tumours include polyps in the colon, and adenomas, leiomyomas, lipomas, and angiomas in the small intestine.... intestine, tumours of
acute intrapituitary haemorrhage, usually into an existing tumour, presenting as severe headache and collapse. It is a medical emergency. Due to the sudden expansion in size of the gland with the haemorrhage, it is accompanied by lesions of the cranial nerves running close to the pituitary gland, causing paralysis of the muscles of the orbit and occasionally the face. Anterior pituitary insufficiency usually results, but posterior pituitary function survives. Surprisingly, pituitary function usually recovers.... pituitary apoplexy
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