HYPOPITUITARY AND PITUITARY REPLACEMENT HORMONES

What is pituitary?

It is a small pea size gland situated in a hollow bony pouch, at the base of the brain, at the back of the bridge of the nose. It is the master gland of the endocrine system and controls the functions of most of the other endocrine glands.

The pituitary produces TSH which circulates to the thyroid stimulating this gland in your neck to make and release thyroid hormones called Thyroxine and Tri-iodothyronine

This hormone stimulate the adrenal glands (small endocrine glands situated on the top of your kidneys) to produce cortisol. This is a steroid hormone which is essential for the everyday activities and health. Lack of cortisol causes severe fatigue and lack of appetite with weight loss.

This has effects on the various tissue of the body. In children, it is essential to reach the normal growth. In adult, it appears to maintain normal energy levels and to keep body tissue such a muscle and bones strong and healthy.

These include Follicular Stimulating Hormone (FSH) and Luteinising Hormone (LH).These hormones have effects on the ovaries, uterus, and on the testes in man. These hormones regulate and control the male and female hormones, menstrual cycles, ovulation, sperm production and fertility.

This hormone stimulates the breasts and regulates milk production. It is normally produced in very high levels during the pregnancy and breast- feeding. This hormone can be responsible for irregular or absent menstrual periods and the lack of libido.

This hormone circulates to the kidneys where it regulates the amount of urine produced. Too little ADH causes continual thirst and copious output of urine day and night.

What causes hypopituitarism?.

1. A pituitary tumour (called an adenoma)
2. Surgery in the region of the pituitary,
3. Damage of the pituitary by trauma such as road accidents
4. Radio therapy to the pituitary gland itself or part of the brain close to the pituitary gland eventually damages normal pituitary tissue
5. Damage to the pituitary gland by the blocked blood supply, bleeding, significant pressure from the surrounding, inflammation or infiltrations
6. Auto immune attack on the pituitary gland
7. Damage of the pituitary by the infection, e.g meningitis, encephalitis, tuberculosis
8. Isolated deficiency of one of the hormone since birth

It will depend on the type of the hormone(s) involved and degree of the impairment. All the features you will notice with the low hormone levels are usually very vague and it is important not to jump to the conclusion. The specialist will perform the necessary tests to find out which hormones are not being produced.

• Low cortisol level can cause weight loss, diarrhoea,loose bowels, low blood pressure, blackout and undue tiredness
• Low GH will cause failure of growth and undue tiredness and weakness in adults
• Low sex hormone level will cause impotence, irregular or absent menstrual periods. Lethargy and sweats may be a feature
• Low thyroid hormone will cause dry skin, undue tiredness.
• Lack of ADH causes severe thirst and copious amounts of urine

What tests will be required?

• Blood tests to check for the basic hormone levels.
• You will need a special test called COMPLETE PITUITARY FUNCTION TEST. This test measures the pituitary hormones before and after stimulation to find out which are working normally and which are not. In some patients a prolonged GLUCAGON TEST may be performed with a short SYNACTHEN TEST.
• If there is any suspicion of the involvement of the ADH hormone, WATER DEPRIVATION TEST will be performed
• Vision field check.The optic nerve which relays images from your eye to your brain passes very close to the pituitary gland. Tumours of the pituitary gland can expand causing pressure on this nerve and this will cause impaired vision initially involving the periphery of the vision. This is checked by a special computerised light screen. Dots of light appear on the screen and the patient has to identify when they are seen.
• MRI or CT scan of the pituitary and surrounding structures.

.What is the treatment for hypopituitarism?

This is to replace deficient hormones.

• ACTH and Cortisol are replaced by hydrocortisone taken orally either twice daily or three times daily.
• TSH and Thyroid Hormones are replaced by taking Thyroxine orally daily
• Sex hormones are replaced in women by the contraceptive pill or HRT. For fertility special hormones are required given by injection. In males testosterone, the male hormone, can be given by patches, injection or orally. Usually patches or injection are the preferred option. In some clinics pellets of hormone may be implanted below the skin every 6 months. For fertility males require regular injections of special hormones.
• Growth hormone may be replaced in some by daily injection
• ADH is replaced by the medicine DDAVP (desmopressin) given as nasal spray or tablets

The Pituitary Foundation
PO Box 1944
Bristol, BS99 2UB.
Tel/Fax 0117 927 3355

e-mail- helpline@pitpat.demon.co.uk

or www.pituitary.org.uk

You could also try the following websites:

http://www.jeffersonhealth.org/diseases/endo/hypopit.htm
http://www.mdadvice.com/library/symp/illness400.html
http://www.adam.com/ency/article/000343.htm

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Ó NHS Tayside; 2006; version 1.0

Disclaimer; no liability whatsoever is accepted for information given and all such information, especially with regard to drug usage (UK version provided), must be checked with a person’s health provider.