Alternative names for hypopituitarism
‘Hypopit’; pituitary insufficiency; partial hypopituitarism; panhypopituitarism (‘pan’ referring to all pituitary hormones being affected); anterior hypopituitarism.
What is hypopituitarism?
Hypopituitarism is failure of the pituitary gland to produce one, some, or all of the hormones it normally produces. The pituitary gland has two parts, anterior pituitary and posterior pituitary, and hormone production can be affected in both parts.
What causes hypopituitarism?
Below are listed some of the causes of hypopituitarism:
What are the signs and symptoms of hypopituitarism?
The signs and symptoms of hypopituitarism depend on which of the pituitary gland hormones are involved, to what extent and for how long. It also depends on whether the hormone deficiencies began as a child or later in adult life. Symptoms can be slow at the start and vague. It is worth understanding the normal function and effects of these hormones in order to understand the signs and symptoms of hypopituitarism. (See the article on pituitary gland.) There may also be additional symptoms due to the underlying cause of the hypopituitarism, such as the effects of pressure from a tumour.
Symptoms can include:
Low adrenocorticotropic hormone levels can lead to decreased production of cortisol by the adrenal glands. This can cause tiredness, weakness, dizziness or light-headedness, blackouts (usually as a result of low blood pressure), low blood sugar levels, low sodium levels, weight loss, loss of appetite, nausea, vomiting and diarrhoea (see the article on Addison's disease for additional details).
Low growth hormone levels will cause failure of growth in children and undue tiredness and low mood in adults as well as changes in body fat and muscle (see the article on adult growth hormone deficiency).
Low sex hormone levels (luteinising hormone and follicle stimulating hormone) will cause delay in, or absence of, puberty in children. In adult men, it causes a decrease in libido, impotence and impaired fertility due to a decreased ability to produce testosterone. In women, it causes irregular or absent menstrual periods leading to infertility. Tiredness may be a feature as well.
Low thyroid hormone levels can cause undue tiredness, weight gain, dry skin and feeling colder than usual (see the article on hypothyroidism);
Lack of anti-diuretic hormone from the posterior part of the pituitary gland results in the passing of uncontrolled large amounts of urine and causes severe thirst (see the article on diabetes insipidus).
How common is hypopituitarism?
Hypopituitarism is rare. At any given time, between 300 and 455 people in a million may have hypopituitarism. A number of endocrinologists believe that hypopituitarism is quite common after brain injuries. If this belief is confirmed, then hypopituitarism may be significantly more common than previously believed.
Is hypopituitarism inherited?
Most cases of hypopituitarism are not inherited. However, there are some very rare genetic abnormalities than can cause hypopituitarism.
How is hypopituitarism diagnosed?
Blood tests are required to check the level of the hormones which are either produced by the pituitary gland itself or peripheral endocrine glands controlled by the pituitary gland. These blood tests may be one-off samples or the patient may require more detailed testing on a day-unit. These are called ‘dynamic’ tests and they measure hormone levels before and after stimulation to see if the normal pituitary gland is working properly. They usually last between 1 to 4 hours.
If it is suspected that there is a lack of anti-diuretic hormone, the doctor may organise a water deprivation test. The patient will be deprived of water for a period of eight hours under very close supervision with regular blood and urine tests. The test may be extended to a 24 hour period if needed which means an overnight stay in hospital.
Other tests may also be organised to try and identify the underlying cause of the hypopituitarism. These could include blood tests, scans such as computerised tomography (CT) or magnetic resonance imaging (MRI) scans, and tests for vision.
How is hypopituitarism treated?
Hypopituitarism is treated by replacing the deficient hormones. Treatment will be tailored to the individual depending on which hormones they are deficient in:
Deficiency of adrenocorticotropic hormone and consequently, cortisol from the adrenal glands is treated by replacing the cortisol with hydrocortisone tablets taken by mouth in doses to be taken twice or three times a day. In the event of other illness happening at the same time, the need to increase the dose of hydrocortisone is of critical importance. It is important to remember that cortisol is life-saving and people who take hydrocortisone must carry a ‘steroid card’ and wear a ‘Medic-alert’ bracelet.
Growth hormone can be replaced in some individuals by daily self-administered injections (see the article on adult growth hormone deficiency).
Sex hormones are replaced in women by either taking the oral contraceptive pill or hormone replacement therapy. In men, testosterone is replaced using various manufactured forms of testosterone including patches, gels and injections based on people’s lifestyles and preferences. To try and restore fertility in men and women, special hormones given as injections are required with the assistance, sometimes, of a fertility specialist.
Deficiency of thyroid stimulating hormone and consequently thyroid hormones (thyroxine and triiodothyronine) is treated by taking levothyroxine tablets orally every day.
Anti-diuretic hormone is replaced by using the medicine called desmopressin which can be given as a nasal spray, tablets to be swallowed or tablets that melt in the mouth.
Are there any side-effects to the treatment?
Since the treatment of hypopituitarism only involves replacing hormones that the body should be making but is unable to, there should be no side-effects if the appropriate amounts of hormones are replaced. Patients will be monitored to ensure they are receiving the correct amount of replacement hormones. Some side-effects can occur from hormone replacement if the amount replaced is higher than the individual’s body requirements. If the patient has any concerns, they should discuss them with their doctor.
What are the longer-term implications of hypopituitarism?
People with long-term hypopituitarism will need to take daily medication and will require regular checks with an endocrinologist at an outpatient’s clinic.
People with hypopituitarism may have an impaired quality of life. Hypopituitarism is associated with an increased risk of heart disease and strokes as a result of the physical changes that occur in body fat, cholesterol and circulation. Healthy living, a balanced diet and exercise to prevent becoming overweight are essential to reduce this risk.
People with hypopituitarism also have a higher risk of developing osteoporosis or brittle bones and, therefore, have a higher risk of developing fractures from minor injuries. A diet that is rich in calcium and vitamin D along with moderate amounts of weight-bearing exercise and training are helpful in decreasing this risk.
Appropriate pituitary hormone replacement therapy can reduce all these risks.
Reviewed: January 2015