A B C D E F G H I J K L M N O P R S T U V W

HYPOPITUITARISM - PITUITARY TUMOURS

What is Hypopituitarism ?

The pituitary is a pea-sized gland located behind the root of the nose and attached to the base of the brain. It makes a number of hormones which enter the blood circulation, and then have an effect elsewhere in the body. Some hormones work directly on body tissues (like growth hormone). Others work by stimulating other hormone-producing glands: the thyroid, the adrenals and the sex glands (testes and ovaries). Damage to the pituitary from a number of causes can reduce the function of one or more of these hormones. In children, growth hormone shortage results in poor growth; in adults it may produce shaky feelings by causing a low blood-sugar level. Low thyroid (TSH) and adrenal stimulating hormone (ACTH) levels reduce the hormone activity of the thyroid and adrenal glands causing tiredness and weakness. Reduced sex gland stimulating hormone (follicle-stimulating hormone: FSH and luteinizing hormone: LH) decreases sex gland hormones, which stops periods in women and reduces sexual function in both sexes. More severe pituitary damage can reduce the water-balance hormone called antidiuretic hormone (ADH), resulting in excessive quantities of urine as well as thirst. Tumours which develop in the pituitary cause symptoms which depend on their size. Very small ones are probably quite common. They may occur in as many as 1 in 10 normal people and mostly cause no symptoms. Larger ones may interfere with the hormone function of the pituitary. Very large ones can press on the optic nerves which carry messages from the eye to the brain. They may produce loss of part of the image in one or both eyes. If very large, they can even cause blindness. Some pituitary tumours overproduce a particular hormone : ACTH excess causes Cushing’s syndrome; growth hormone excess causes a condition called acromegaly. A particularly common over-producing tumour makes the hormone prolactin. These conditions are all described in separate leaflets.

How does Hypopituitarism occur ?

Apart from the tumours mentioned above, other causes of pituitary damage include severe bleeding from the womb after childbirth or damage from other diseases or tumours near near the pituitary gland. Sometimes the pituitary gland just shrinks, especially with advancing age. Reduced pituitary function may also follow either surgery for tumours near the pituitary or result from radiotherapy to the brain for another condition.

Why does Hypopituitarism occur ?

The cause of pituitary tumours is not known. Severe bleeding at childbirth is now rare. When it occurs, however, blood is drained away from the pituitary which then shrinks.

Treatment Involved for Hypopituitarism

Special x-rays (CT) or scans (MRI) are done to see whether there is a tumour, and how large it is. Very precise tests of blood and urine are usually needed to work out exactly what hormones need to be replaced. Growth hormone is given mainly to children to restore and maintain growth: it is given daily or three times a week by injection (since it is not absorbed by mouth). Increasingly adults too are given growth hormone replacement, since it has been shown that muscular and bone strength as well as general wellbeing are affected in people with this deficiency. In women below age 50, sex hormones (estrogens ) are often given to produce regular periods and protect bone strength. In men, sex hormone ( testosterone ) is given either by tablets, injection or insertion of pellets every 2 weeks to 6 months. The dosage is adjusted on the basis of blood tests. Thyroid deficiency is treated with thyroxine tablets, usually in doses of 50 to 200 micrograms a day. Adrenal deficiency calls for the use of hydrocortisone (cortisol) tablets, usually in daily doses of 15 to 40 milligrams spread through the day. Doses must never be missed! Excessive urination produced by deficiency of ADH (called diabetes insipidus) is treated either with a nasal spray or tablets of the drug desmopressin . None of these replacement hormones cause side-effects if used in correct dosage. If a tumour is causing the condition, it may be treated by operation. This can often be done through the nose. Sometimes, however, it is considered better to remove it by an operation performed through the skull. Some tumours (prolactinomas) can be shrunk by tablet treatment. Details of this disorder are described elsewherein a separate leaflet. Other tumours require x-ray treatment either instead of or as well as operation. This does not mean that they are malignant: pituitary tumours are almost the only type of benign tumour which responds to radiotherapy.

During Treatment for Hypopituitarism

Regular appointments to see the specialist for check blood test and sometimes x-rays or scans are usually required. A change of tablet doses is usually needed from time to time. Tablets should be carefully checked after each visit to the pharmacist. Any stress (emotional, accident or infection) calls for a bigger dose of hydrocortisone (or other steroid): double the usual dose for mild problems, triple it for severe conditions, especially with fever. You must contact your general practitioner (or the nearest casualty department) if unwell, particularly with vomiting. It may be that an urgent injection of steroid is then required. A bracelet or pendant identification is a good idea. It needs to state that you are taking cortisone . Remember: steroids (cortisone and similar drugs) should never be stopped unless specifically advised by a specialist that this is safe.

After Treatment for Hypopituitarism

After treatment of a pituitary tumour, you may notice very little change. If hormone treatment was required before an operation, it must usually be continued lifelong. If a tumour was pressing on the optic nerves affecting vision, this often improves and can return to normal. Sadly, vision may be permanently lost if a large tumour has been present for a long time. After radiotherapy, it is common for even normal pituitary tissue to be affected by the radiation treatment, causing progressive deficiency of pituitary hormones. It is for this reason that regular (usually annual), careful assessments of pituitary function must be made so that appropriate treatment can be introduced at the correct time.

If Hypopituitarism is Left Untreated

Treatment of any adrenal or thyroid shortage is absolutely essential. Tiredness, collapse, and then coma could occur without regular daily treatment. Sex hormone shortage is not dangerous, but the strength of bones as well as sexual function depends on them. Their need is somewhat reduced in older age. The water-balance condition could be treated by just drinking more. Using the correct hormone, however, completely removes any risk of dehydration. Vision may be lost if larger pituitary tumours which press on the optic nerves are not treated. Smaller ones can sometimes be left and just watched by doing CT or MRI scans at regular intervals.

Effects on Family of Hypopituitarism

They will see the improvement when the condition is treated. When travelling, someone needs to know that a steroid injection may be needed in case of severe illness. It may be worth taking along an ampoule or two of hydrocortisone (l00 mg): it makes it easier for any visiting doctor.