What is the pituitary gland?
What is the pituitary gland and what does it do?
Your pituitary gland is about the size of a pea and is situated in a bony hollow, just behind the bridge of your nose. It is attached to the base of your brain by a thin stalk.
The hypothalamus, which controls the pituitary by sending messages, is situated immediately above the pituitary gland.
The pituitary gland is often called the master gland because it controls several other hormone glands in your body, including the thyroid and adrenals, the ovaries and testicles.
It secretes hormones from both the front part (anterior) and the back part (posterior) of the gland. Hormones are chemicals that carry messages from one cell to another through your bloodstream.
If your pituitary gland is not producing sufficient amounts of one or more hormones this is called hypopituitarism. If on the other hand you are over producing certain hormones, then you would have features due to the over production of the specific hormone concerned.
This serves as a communications centre for the pituitary gland, by sending messages or signals to the pituitary in the form of hormones which travel via the bloodstream and nerves down the pituitary stalk. These signals, in turn, control the production and release of further hormones from the pituitary gland which signal other glands and organs in the body.
The hypothalamus influences the functions of temperature regulation, food intake, thirst and water intake, sleep and wake patterns, emotional behaviour and memory.
What can go wrong with my pituitary gland?
The most common problem with the pituitary gland occurs when a benign tumour (used to describe a ‘growth’), also called an adenoma, develops.
Pituitary tumours are not 'brain tumours'. The term benign is used by doctors to describe a swelling which is not cancerous. Some pituitary tumours can exist for years without causing symptoms and some will never produce symptoms.
Most pituitary tumours occur in people with no family history of pituitary problems and the condition is not usually passed on from generation to generation. Only very occasionally are tumours inherited - for example, in a condition known as multiple endocrine neoplasia (MEN1).
By far the most common type of tumour (about half of all cases) is the ‘non-functioning’ tumour.
This is a tumour which doesn’t produce any hormones itself. It can cause headaches and visual problems or it can press on the pituitary gland, causing it to stop producing the required amount of one or more of the pituitary hormones. This effect can also occur following treatment you are given for a tumour, such as surgery or radiotherapy.
Alternatively, your pituitary tumour may begin to generate too much of one or more hormones.
The more common pituitary conditions include acromegaly, Cushing's, diabetes insipidus, hypogonadism, hypopituitarism and prolactinoma - please see our individual booklets about these conditions for further information.
Other pituitary conditions
This type of tumour or cystic mass is quite rare and congenital (from birth). It exerts pressure on the hypothalamus which lies just above the pituitary gland and is responsible for releasing hormones that start and stop the release of pituitary hormones.
Faster growing craniopharyngiomas affect children whilst slower growing ones affect adults. This type of tumour can cause headaches and vision problems and can affect hunger, thirst and sleep patterns.
Onset of puberty and growth hormone production in children can also be affected, plus growth hormone production may also be affected in adults.
In Rathke's Cleft Cyst, the Rathke's pouch eventually forms the pituitary gland and normally closes early in foetal development. A remnant may persist as a cleft that lies within the pituitary gland and occasionally this remnant gives rise to a fluid-filled large cyst called Rathke's Cleft Cyst (RCC).
This condition is more usually seen in adults but can occur at any age. Arachnoid Cysts and Cystic Pituitary Adenomas are other rare cyst-like tumours.
Empty Sella Empty Sella Syndrome
(ESS) is a disorder that involves the ‘sella turcica’ – a bony structure at the base of the brain that surrounds and protects the pituitary gland.
ESS would show up on an MRI scan revealing a sella turcica that appears to be empty. There are two types of ESS: primary and secondary.
Primary ESS happens when a small anatomical defect above the pituitary gland increases pressure in the sella turcica and causes the gland to flatten out. The pituitary gland may be smaller than usual. Primary ESS can be associated with obesity and high blood pressure in women. The function of the pituitary gland is usually normal and may be an incidental finding when a brain MRI scan is done for other reasons.
Secondary ESS is the result of the pituitary gland regressing within the cavity after an injury, surgery or radiation therapy. Individuals with secondary ESS may have symptoms that are due to the loss of pituitary functions, for example loss of periods, infertility, fatigue and intolerance to stress and infection.
In children, ESS can be associated with early onset of puberty, growth hormone deficiency and pituitary tumours.
MRI scans are useful in evaluating ESS and differentiating it from other disorders that produce an enlarged sella.
Sheehan’s Syndrome is also known as postpartum hypopituitarism, or postpartum pituitary insufficiency and may occur in a woman who has severe uterine haemorrhage during childbirth.
The resulting severe blood loss causes tissue death in her pituitary gland and leads to hypopituitarism following the birth. If a woman’s pituitary gland is starved of blood due to her bleeding severely during childbirth, the gland may lose its ability to function properly.
Conditions that increase the risk of an obstetric haemorrhage include multiple pregnancies (twins or triplets) and abnormalities of the placenta.
Blood tests would establish hormone levels and a scan to rule out other abnormalities of the pituitary such as a tumour.
Multiple Endocrine Neoplasia (MEN)
MEN syndromes are inherited disorders (passed down in families).
The disorder causes more than one gland in the body’s endocrine system to develop growths. The affected glands may then produce abnormally increased amounts of hormones which in turn cause a variety of different symptoms.
Diagnosis is made when a patient has two or more growths common to MEN, or a patient has only one growth, but there is a family history of MEN.
There is a patient group dedicated to providing support to those affected by MEN, for further information please see www.amend.org.uk.
Another cause of hypopituitarism that may be associated with pregnancy is lymphocytic hypophysitis.
This is due to inflammation in the pituitary caused by immune cells. The reasons why this occurs is not understood.
With modern obstetric practice the occurrence of hypopituitarism after childbirth, though uncommon, is more frequently due to this condition than Sheehan’s syndrome.
Many pituitary problems are caused by a benign tumour and an operation is often the best course of action - and surgical methods are continually improving.
We can reassure you that surgery carried out by a specialist neurosurgeon is safe and a relatively straightforward procedure.
Most tumours are removed by making a small incision inside your nostril, or under the upper lip. This surgery is called ‘transsphenoidal surgery’. By using this route, the surgeon can see your pituitary without disturbing the main part of your brain.
The operation will usually require about five days in hospital and you should be up and about the day after surgery, eating normally. You will be on a drip for a day or two and may also be given antibiotics to prevent any infection in your nose. Recovery times do vary according to the individual, with an average of perhaps four to eight weeks off from work, if employed.
Sometimes pituitary tumours need other surgical approaches and for this and for further and more detailed information please read our Surgery & Radiotherapy Booklet.
Radiotherapy for pituitary conditions
This follow-up treatment is sometimes used as a follow up to surgery, or it can be recommended instead of surgery.
Please be assured that the use of radiotherapy does not mean that you have cancer.
Most radiotherapy is accomplished over several weeks with an initial visit to have an individual mask made which guides the radiotherapist accurately to where the X-rays will be focussed. Radiotherapy can also be given in a focused beam (e.g. ‘Gamma knife’ or ‘X-knife-Linac’) as a single treatment, but this is not appropriate for all tumours.
For further and more detailed information please read our Surgery & Radiotherapy Booklet.
Medical therapy Most people with a pituitary condition will require treatment with drugs, either on their own or in addition to surgery and/ or radiotherapy. These drugs may be used to reduce the levels of a hormone that your pituitary is overproducing, or to replace a hormone that your pituitary is under producing.
Please see our following section on hormones.
Follow-up treatment for pituitary conditions
Most people with a pituitary tumour and/ or condition will have regular check-ups at a specialist endocrine clinic for the rest of their life.
These check-ups enable the specialist to monitor your condition and pick up any changes as soon as possible. In most patients their condition remains stable after initial treatment(s).
Regrowth of a pituitary tumour can occasionally occur if it was not possible to remove the entire tumour during surgery. The chance of this happening is lower if you had radiotherapy after your operation. If regrowth does occur, you may need another operation, or radiotherapy; all cases are individual and can vary.