Pituitary Disorders


The pituitary gland is a tiny organ, the size of a pea, found at the base of the brain. As the master gland of the body, it produces and secretes many hormones that travel throughout the body, directing certain processes stimulating other glands to produce different types of hormones. The pituitary gland controls biochemical processes important to our well-being.
The pituitary gland makes these types of hormones:

  • Prolactin - Prolactin stimulates milk production from the breasts after childbirth to enable nursing. It also affects sex hormone levels from ovaries in women and from testes in men.
  • Growth hormone (GH) - GH stimulates growth in childhood and is important for maintaining a healthy body composition and well-being in adults. In adults it is important for maintaining muscle mass as well as bone mass. It also affects fat distribution in the body.
  • Adrenocorticotropin (ACTH) - ACTH stimulates the production of cortisol by the adrenal glands. Cortisol, a so-called "stress hormone" is vital to our survival. It helps to maintain blood pressure and blood glucose levels.
  • Thyroid-stimulating hormone (TSH) - TSH stimulates the thyroid gland, which regulates the body's metabolism, energy, growth, and nervous system activity. This hormone is also vital to our survival.
  • Antidiuretic hormone (ADH) - ADH, also called vasopressin, regulates water balance. If this hormone is not released properly, it can lead to too little hormone (called diabetes insipidus), or too much hormone (called syndrome of inappropriate ADH). Both of these conditions affect the kidneys. Diabetes insipidus is different from the more well-known diabetes mellitus (including type 1 and type 2 diabetes), which affects the levels of glucose in our bodies.
  • Luteinizing hormone (LH) - LH regulates testosterone in men and estrogen in women.
  • Follicle-stimulating hormone (FSH) - FSH promotes sperm production in men and stimulates the ovaries to enable ovulation in women. Luteinizing hormone and follicle-stimulating hormone work together to cause normal function of the ovaries and testes.
Pituitary Tumours

The most frequent cause of pituitary disorders is a pituitary gland tumour. The pituitary gland is made of several cell types. Sometimes these cells grow too much or produce small growths.
These growths are called pituitary tumours, and they are fairly common in adults. The vast majority are entirely benign. However, they can interfere with the normal formation and release of hormones.
Two types of tumours exist - secretory and non-secretory. Secretory tumors produce too much of a hormone, creating an imbalance of proper hormones in the body. Non-secretory tumours cause problems because of their large size or because they interfere with normal function of the pituitary gland.
The problems caused by pituitary tumours fall into three general categories:

  • Hypersecretion - Too much of any hormone secreted into the body is usually caused by a secretory pituitary gland tumour. Many secretory tumours make too much prolactin, the hormone that triggers milk production in new mothers. Other tumours may affect the adrenal glands, making too much of the hormones that stimulate them and causing a hormone imbalance. Tumours also can make excess growth hormone or too much of the hormone that stimulates the thyroid gland leading to overproduction of thyroid hormones.
  • Hyposecretion - Too little of any hormone secreted into the body is usually caused by a non-secretory pituitary gland tumour, which interferes with the ability of the normal pituitary gland to create hormones. It can, however, also be caused by a large secretory tumour. Hyposecretion can also happen with surgery or the radiation of a pituitary gland tumour.

Tumour mass effects - As a pituitary gland tumour grows and presses against the normal pituitary gland or other areas in the brain, it may cause headaches, vision problems, or other health effects related to hyposecretion. Tumour mass effects can be seen in any type of pituitary tumour that grows large enough. Injuries, certain medications, and other conditions can also affect the pituitary gland. Loss of normal pituitary function also has been reported after major head trauma.



Secretory Tumors


There are a number of secretory tumours that are troublesome to people. A prolactinoma is the most common, accounting for about 40 percent of pituitary gland tumours. This is a tumour on the pituitary gland that produces too much prolactin, the milk hormone. While excess milk discharge from breasts is one of the symptoms of a prolactinoma, there are many other signs of this kind of tumor.

  • Changes in menstrual cycle or complete loss of periods
  • Headaches
  • Infertility
  • Milk discharge from breasts that is unrelated to giving birth
  • Problems with vision
  • Vaginal dryness or pain during intercourse
  • Reduced sex drive
  • Osteoporosis or bone loss
  • Inadequate function of the testes in males leading to the inability to get or maintain an erection
  • Infertility

About 80 to 90 percent of prolactinoma patients can be treated successfully with a dopamine agonist drug, of which the most commonly used is called cabergoline. The use of this kind of drug should eliminate or reduce symptoms of a high prolactin level, return your prolactin levels to normal, help restore normal function to the pituitary, and usually reduce the pituitary gland tumour size.
This medication is taken in tablet form. Your doctor will monitor your prolactin levels and make adjustments, if necessary, depending on prolactin levels symptoms and tumour size. The most common side effects are nausea and dizziness. Sometimes drug treatment is ineffective, however, so your doctor might recommend surgery. Radiation therapy is rarely used with large tumours. Some patients with very small tumours, which are stable in size and do not have any associated symptoms, may be monitored carefully without treatment.

Acromegaly and gigantism (see under Growth Hormone Disorders)

Cushing's disease

Cushing's disease occurs when a pituitary tumour is associated with hypersecretion of pituitary ACTH, causing too much cortisol by the adrenal glands. While Cushing's disease is uncommon, it is significant in that its effects can be dramatic and life threatening.

  • Muscle weakness
  • Purple stretch marks
  • Rapid and unexplained weight gain with a rounder face and abdomen often with thin legs or extremities
  • Increased fat in your neck and above your collar bone and upper back
  • Memory loss or not being able to think clearly
  • Menstrual cycle disorders
  • Skin changes and red cheeks
  • Osteoporosis
  • Depression
  • Mood and behaviour disorders
  • High blood sugar levels
  • Hypertension, or high blood pressure

An individual with Cushing's disease must have personalized treatment, tailored to his or her needs. This treatment may mean a combination of medication, surgery, and radiation. The first line therapy is surgical and cure rates with an experienced neurosurgeon are more than 90 percent. A patient will typically have transsphenoidal microsurgery through the nasal sinuses.
Patients who are not cured but have proven pituitary Cushing's disease usually have repeat surgery. When surgery does not work, radiation therapy may treat any remaining tumor mass. Medication to block the adrenal glands is typically used while waiting for the radiation to have an effect. The adrenal glands are rarely removed. Your doctor may prescribe additional medication to treat high blood pressure, high glucose levels, or additional problems brought on by this disorder.

TSH-secreting tumoors

A TSH-secreting pituitary gland tumour secretes too much thyroid-stimulating hormone, which then causes the thyroid gland to become overactive and make too much thyroid hormone, causing hyperthyroidism. These tumours are very rare.

  • Heart palpitations
  • Fast heart beat
  • Irregular menstrual cycle
  • Headaches
  • Visual disturbances
  • Difficulty sleeping
  • More frequent bowel movements
  • Inability to tolerate heat
  • Excessive sweating
  • Fatigue
  • Weight loss
  • Nervousness

The first treatment for these tumours is usually transsphenoidal microsurgery, through the nasal sinuses. Unless the tumour is large, surgery alone can typically provide a complete cure. Even so, you will need a long follow-up period with your doctor to be sure the treatment has worked.
If surgery does not remove the entire tumour, octreotide is an effective medication. Radiation therapy also may be prescribed. The radiation will destroy the remaining tumour, but the process is slow. Patients also may need additional drug therapy to lower thyroid hormone levels.



Non-Secretory Tumors

Non-functioning adenoma

While some tumours of the pituitary are troublesome because they secrete too many hormones that upset the balance of good health, other tumours of the pituitary do not secrete hormones. Instead, they cause health problems because of their size and location. A non-functioning adenoma is one example.
This nonfunctioning adenoma may cause headaches and vision problems. This type of pituitary gland tumour also may cause hyposecretion, so the pituitary does not produce enough of the hormones necessary for good health. A non-functioning adenoma often is found when doctors obtain an MRI after a head injury or for some other reason. The symptoms of non-functioning adenomas fall into two categories - tumour mass effects or hyposecretion effects.

Tumour mass effects

  • Visual field disturbances, most commonly loss of peripheral vision, at the edges of your vision range
  • Headaches
  • Abnormal control of eye movements

Hyposecretion effects

  • Loss of appetite
  • Weight loss or weight gain
  • Fatigue
  • Irregular menstrual cycle
  • Infertility
  • Reduced sex drive
  • Impotence or failure to get or maintain an erection
  • Inadequate function of the ovaries or testes
  • Frequent urination during night
  • Joint pains
  • Dizziness
  • Low blood pressure

The first therapy your doctor probably will recommend is transsphenoidal microsurgery, through the nasal sinuses, especially if your vision is disturbed or you have compressed nerves around your brain, inside of your skull. After surgery, visual field problems improve in the majority of patients.
Hormone replacement may be necessary to correct the hormone imbalance and restore normal hormone levels. If you have significant tumour remaining or the tumour regrows, you may need more surgery and/or radiation therapy.

Craniopharyingiomas and Rathke's cleft cysts

Craniopharyngiomas and Rathke's cleft cysts are lesions that are non-cancerous growths, but they may be mistaken for a pituitary gland tumour on an MRI scan. While they are not tumours, they can interfere with normal pituitary processes in much the same way. They are relatively common during childhood, but can grow and cause problems in adults.

Symptoms of Craniopharyngiomas and Rathke's cleft cysts are similar:

  • Growth failure in children
  • Delayed puberty in children
  • Reduced or loss of sex drive
  • Constipation
  • Nausea
  • Frequent urination
  • Excessive thirst
  • Obesity
  • Headaches
  • Menstrual irregularities/loss of menstrual cycle
  • Milk discharge from breasts not related to childbirth
  • Body temperature regulation problems
  • Fatigue
  • Increased drowsiness
  • Dry skin
  • Low blood pressure
  • Visual disturbances
  • Confusion
  • Personality changes

The primary treatment is surgery. The goal is to completely remove the pituitary gland tumour or cyst and preserve normal pituitary, brain, and visual function. If the mass located in the area of the pituitary, the surgery probably will be through your nasal sinuses (transsphenoidal). If the tumour is found above your pituitary, your surgeon may have to go in through the skull. If the tumour cannot be completely removed, radiation treatment may be recommended.



Pituitary Disorders Lifestyle and Prevention

Always take your medications or follow your course of hormone therapy as directed.  If you seem to be experiencing previous symptoms again or a different set of symptoms, call your physician. You may need further treatment or your dose of medication may need to be adjusted. Remember that sometimes symptoms take a while to disappear. Some symptoms may never go away. Ask your doctor if you have questions or frustrations about your progress after treatment.

You will also need to keep up with your regular physician visits and monitoring of your condition. Keeping the proper balance of hormones in your body is important for normal functioning. Most people who have had pituitary gland tumours treated go on to live normal lives, as long as they follow their doctor's advice.

Diseases of the pituitary gland may have psychological aspects. These may include symptoms of depression, moodiness, nervousness, and reduced sex drive. Many of these symptoms will improve once you receive treatment for your pituitary condition. It is important that you communicate with your doctor about any symptoms you may be experiencing. You may also seek additional professional help and the support of a patient group or counsellor to help you cope with these symptoms.

There is little a person can do to prevent pituitary gland tumours from forming except in the case of severe injury or trauma to the head. Anything you can do to protect your head and the pituitary gland will help to preserve your hormonal system and potentially save your life.