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Pituitary disorders

Background

Pituitary disorders fall into the category of endocrine disease. The pituitary gland is small and pea-shaped, and is situated at the base of the brain within a bony cup in the skull base (called the pituitary fossa). The gland is divided into two sections, the anterior (front) and posterior (back) pituitary. The anterior pituitary produces a number of hormones (chemical messengers) that have major effects on body composition, metabolism (breaking down substances in the body) and the systems in our body that allow us to reproduce (have children). These include growth hormone (GH), prolactin (PRL), adrenocorticotrophic hormone (ACTH), thyroid stimulating hormone (TSH), luteinising hormone (LH) and follicle stimulating hormone (FSH).

The activity of the pituitary gland is controlled by the hypothalamus, part of the brain which lies above the pituitary, and to which the gland is connected via the pituitary stalk.

ACTH is the most important regulator of glucocorticoid (a type of steroid) production by the adrenal glands (small hormone producing glands on top of the kidneys). TSH regulates the thyroid gland. While LH and FSH in women control the ovaries and menstrual cycle and in men regulate the activity of the testes. Growth hormone is important for normal growth in children and in adults has a number of effects on body composition and metabolism. Prolactin is required for breast milk production and also acts as a natural contraceptive in breast-feeding women. The posterior pituitary gland releases anti-diuretic hormone (ADH) and oxytocin. ADH is important in maintaining water balance, acting on the kidneys to prevent large volumes of water loss.

Credits

Medical text last written November 2008 by Dr J Webster. Last updated February 2013 by Dr J Webster, Consultant Physician and Endocrinologist, Northern General Hospital, Sheffield, UK.

Disorders of the pituitary gland

Although over 40,000 people in the UK are thought to suffer from pituitary disorders, many of the illnesses are little known outside specialist clinics. The commonest disorders of the pituitary are adenomas, benign (non-cancerous) tumours which, if left untreated, may expand very slowly over a period of several years. Pituitary adenomas can cause symptoms through overproduction of one of the pituitary hormones and, if sufficiently large, from pressure on other brain structures close by.

Overproduction of growth hormone, for example, in children causes excessive growth, a condition known as gigantism. Adults developing a growth hormone-secreting pituitary adenoma develop a condition known as acromegaly, characterised by enlargement of the hands and feet, and coarsening of facial features.

Prolactinomas, benign pituitary tumours overproducing prolactin, cause menstrual disturbances (typically infrequent or absent periods), galactorrhoea (milk leakage from the breasts) and fertility problems in women, while in men the commonest symptoms are reduced libido and erectile dysfunction.

Excessive secretion of ACTH results in a condition called Cushing's disease. There is overstimulation of the adrenal glands, resulting in excess steroid production. This has many different effects including weight gain, with a 'moon face' appearance, thinning of the skin, stretch marks, easy bruising, muscle weakness, and high blood pressure.

Some pituitary tumours are 'non-functioning' and only produce symptoms when large enough to cause pressure on adjacent structures. This can result in headache, visual disturbance (as the pituitary lies in close proximity to the optic nerves) and under-activity of the surrounding normal pituitary gland; a condition known as hypopituitarism.

Hypopituitarism may be partial or complete and its effects depend on which of the pituitary hormones are affected. TSH deficiency, for example, results in symptoms of thyroid underactivity, with fatigue (tiredness), lethargy, cold intolerance, a tendency to weight gain, constipation, dry skin and hair and impaired memory. Symptoms associated with glucocorticoid (steroid) deficiency resulting from a lack of ACTH include weakness, tiredness and fatigue, dizziness or light-headedness on standing (resulting from reduced blood pressure). Lack of LH and FSH in women causes the periods to stop and impaired fertility while, in men, the resulting lack of testosterone causes reduced libido (sex drive) and erectile dysfunction, reduced muscle.

How is it diagnosed?

Pituitary conditions often develop very slowly and, in many cases, symptoms have been present for months or even years by the time a diagnosis is made. Once a pituitary condition is suspected, initial laboratory tests can be carried out either through a GP or an endocrinologist (specialist in endocrine disorders). The type of test performed is usually indicated by the presenting signs and symptoms. Radiological imaging, usually magnetic resonance imaging (MRI) is also commonly used to detect the presence of pituitary adenomas.

How is it treated?

The most appropriate treatment depends on the tumour type. Prolactinomas are usually treated medically with drugs such as cabergoline, bromocriptine or quinagolide. These are effective in suppressing prolactin production and also shrink the pituitary tumour.

Patients with acromegaly, Cushing's disease or non-functioning pituitary tumours usually require an operation to remove the pituitary mass. If this fails to cure the condition, radiotherapy may be considered. Additional treatment options include monthly injections in acromegaly and removal of the adrenal glands in Cushing's disease.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
Pituitary disorders can affect any age group and, with the exception of certain familial syndromes (those that run in families), are not generally thought to be hereditary in origin.

Prenatal diagnosis
None.

Is there support?

The Pituitary Foundation

Patient Support and Information Helpline: 0117 370 1320
Email: helpline@pituitary.org.uk
www.pituitary.org.uk

The Foundation is a Registered Charity in England and Wales No. 1058968. It provides information and support to anyone affected by pituitary conditions, including information specifically for young people. The Foundation runs a Patient and Family Support Helpline, and an Endocrine Nurse Helpline that offers access to a specialist nurse to provide expertise and medical advice. It has a network of local support groups across the UK and the Republic of Ireland, and a group that supports younger patients and their parents. 

Group details last reviewed July 2019.