Alternative names for hypopituitarism

‘Hypopit’; pituitary insufficiency; partial hypopituitarism; panhypopituitarism (‘pan’ referring to all pituitary hormones being affected); anterior hypopituitarism

What is hypopituitarism?

The pituitary gland is a small gland located at the base of the brain that makes several hormones that have important functions in the body. Hypopituitarism is a condition in which the pituitary gland fails to produce of one or more of these hormones.

What causes hypopituitarism?

Hypopituitarism has many possible causes:

• Tumours either in the pituitary gland (these are nearly always benign), or from non-pituitary regions that extend into the pituitary glands (e.g., craniopharyngioma, or from other cancers that spread)
• A side-effect of treatment for pituitary tumours (e.g., pituitary surgery or radiotherapy)
• Damage to the pituitary gland from surgery or radiation therapy to the head (e.g., for the treatment of leukaemia or other brain tumours)
• Damage to the blood supply to/from the pituitary gland due to blockage or bleeding (e.g., pituitary apoplexy)Injury/trauma to the head, or stroke
• Genetic conditions affecting the pituitary gland’s ability to produce certain hormones
• Inflammation of the pituitary gland (hypophysitis)Infiltration of the pituitary gland (histiocytosis X, or Langerhans cell histiocytosis)
• Infections e.g., tuberculosis
• Genetic abnormalities of the pituitary gland
• Hypopituitarism can also be idiopathic, which means no cause was identified

What are the signs and symptoms of hypopituitarism?

Hypopituitarism can range from being asymptomatic to causing severe symptoms such as collapse and coma. The signs and symptoms of hypopituitarism depend on which part of the pituitary gland is 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. The start of symptoms can be slow and vague. Understanding the normal function and effects of these hormones can help explain the symptoms seen when they are not produced anymore, such as in 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. Here are some examples of symptoms of hypopituitarism, according to what hormone is not being produced:

• ACTH: Low levels of adrenocorticotropic hormone (ACTH) can lead to decreased production of cortisol by the adrenal glands. This can cause tiredness, weakness, dizziness or light-headedness, blackouts, 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 of similar condition where the adrenal gland does not work properly).
• GH: Low growth hormone (GH) levels cause failure of growth in children (short stature), tiredness, low mood, changes in body fat and muscle mass in adults as well as a decrease in general wellbeing (see the article on adult-onset growth hormone deficiency).
• LH/FSH: Low gonadotrophin levels (i.e., luteinising hormone (LH) and follicle stimulating hormone (FSH) will cause delay in, or absence of, puberty in children. In men, lower level of these hormones leads to less testosterone being produced by the testes, leading to a decrease in libido, impotence and impaired fertility. In women, it causes less oestrogen being produced by the ovaries, leading to irregular or absent menstrual periods and impaired fertility. Tiredness may also be a feature.
• TSH: Low thyroid stimulating hormone (TSH) levels can lead to decreased production of thyroid hormones by the thyroid gland. This can cause undue tiredness, weight gain, dry skin and feeling colder than usual (see article on hypothyroidism).
• ADH: Lack of anti-diuretic hormone (ADH; also known as vasopressin from the posterior part of the pituitary gland) results in the uncontrolled passing of large amounts of urine and causes severe thirst (see article on diabetes insipidus).

How common is hypopituitarism?

Hypopituitarism is rare. At any given time, only between 300 to 455 out of every one-million people have hypopituitarism. Hypopituitarism is more common after certain situations (e.g., after brain injuries or postpartum haemorrhage i.e., bleeding after childbirth).

Is hypopituitarism inherited?

Most cases of hypopituitarism are not inherited. However, there are some very rare genetic abnormalities that can cause hypopituitarism.

How is hypopituitarism diagnosed?

Blood tests are used to check the level of hormones that are either produced by the pituitary gland itself, or by other endocrine glands outside the brain controlled by the pituitary gland hormones. These blood tests may be one-off samples or the patient may require more detailed testing, called ‘dynamic’ or ‘provocative’ tests where hormone levels are measured before and after stimulation to see if the pituitary gland is working properly. If it is suspected that there is a lack of anti-diuretic hormone (ADH) (as can be the case with Diabetes Insipidus), 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 tests of blood, urine and body weight. The test may be extended up 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 vision tests, or imaging scans such as magnetic resonance imaging (MRI) of the pituitary gland.

How is hypopituitarism treated?

Hypopituitarism is treated by replacing the deficient hormones. Treatment is tailored to the individual depending on which hormones they are deficient in.

• Deficiency of adrenocorticotropic hormone (ACTH) and consequently, cortisol from the adrenal glands, is treated by replacing the cortisol with steroid tablets, such as either hydrocortisone or prednisolone. These are taken one to three times per day. Replacing this cortisol is lifesaving. People who take cortisol must carry a ‘steroid card’ and wear A ‘Medic-alert’ bracelet/tag.
• Growth hormone (GH) deficiency can be treated in some individuals by daily self-administered injections (see the article on adult-onset growth hormone deficiency).
• Deficiency of LH / FSH leads to decreased sex hormones, which are replaced in women by either taking the oral contraceptive pill or hormone replacement therapy to restore regular menstrual bleeds, or with gonadotrophins during fertility treatment. In men, testosterone is replaced using various forms of testosterone including patches, gels and injections based on the patient’s lifestyles and preferences. Testosterone tablets can be used in special cases. To try and restore fertility in both men and women, special hormones given as injections are required, usually supervised by a fertility specialist.
• Deficiency of thyroid stimulating hormone (TSH) and consequently thyroid hormones (thyroxine and triiodothyronine) is treated by taking levothyroxine tablets orally every day.
• Anti-diuretic hormone (ADH) is replaced by using a medicine called desmopressin, which can be given as a nasal spray, tablet, or injection.

Are there any risks 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 minimal risks if the appropriate amounts of hormones are replaced. Patients are monitored to ensure that they are receiving the correct amount of replacement hormones. Some side-effects could occur from hormone replacement if the amount replaced is higher than the individual’s body requirements, which depend on the specific hormone being replaced. If the patient has any concerns, they should discuss them with their doctor. Careful monitoring and medical follow up are required to avoid the effects of either under or over replacement.

What are the longer-term implications of hypopituitarism?

In some cases, hypopituitarism can be a short-term condition. People with long-term hypopituitarism will need to take daily medication and will require regular checks with an endocrinologist at an outpatient’s clinic. They may require hospital admissions in emergency cases. 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, smoking cessation, a balanced diet and exercise are essential to reduce this risk. People with hypopituitarism also have a higher risk of developing osteoporosis (also referred to as 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, monitoring and follow up can reduce all these risks.

Are there patient support groups for people with hypopituitarism?

Pituitary Foundation may be able to provide advice and support to patients and their families dealing with hypopituitarism.