Pituitary Disorders

Introduction
Signs and Symptoms
Causes
Risk Factors
Screening and Diagnosis
Treatment

The pituitary gland is a small bean-shaped gland located at the base of your brain, somewhat behind your nose and between your ears. Despite its size, the gland influences nearly every part of your body. Its hormones help regulate important functions, such as growth, blood pressure and reproduction.

Pituitary tumors are abnormal growths that develop in the pituitary gland. Sometimes pituitary tumors can produce excess amounts of hormones. Other times, pituitary tumors can restrict the pituitary gland, causing it to produce lower levels of hormones (hypopituitarism).

Most pituitary tumors are noncancerous (benign), nonspreading growths (adenomas). Adenomas remain confined to the pituitary gland or surrounding tissues and don't spread to other parts of your body.

Treatment for pituitary tumors may involve surgery to remove the tumor. Medications or radiation therapy to control growth of a pituitary tumor also may be an option. You may also need medications to correct excess or deficient hormone production.

Hypopituitarism is a disorder in which your pituitary gland fails to produce one or more of its hormones, or doesn't produce enough of them.

The pituitary is a small bean-shaped gland located at the base of your brain, somewhat behind your nose and between your ears. Despite its size, this gland secretes hormones that influence nearly every part of your body.

In hypopituitarism, you have a short supply of one or more of these pituitary hormones. This deficiency can affect any number of your body's routine functions, such as growth, blood pressure and reproduction.

Hypopituitarism is a rare disorder. Treatment for hypopituitarism involves taking hormone replacement medications.

Pituitary tumors that produce hormones are called functioning tumors. Tumors that don't produce hormones are known as nonfunctioning pituitary tumors.

Different types of functioning tumors can develop in your pituitary gland, each causing specific signs and symptoms:

• Adrenocorticotropic hormone-producing tumors. These pituitary tumors produce the hormone adrenocorticotropin, which stimulates your adrenal glands to make the hormone cortisol. When your adrenal glands produce too much cortisol, a condition called Cushing's syndrome occurs. Signs and symptoms of Cushing's syndrome may include weight gain around your midsection and upper back, exaggerated facial roundness, a characteristic hump on the upper part of your back, high blood pressure, muscle weakness and thinning of your skin.
• Growth hormone-producing tumors. These tumors produce excess growth hormone. The physical effects from excess growth hormone (acromegaly) may include coarsened facial features, enlarged hands and feet, high blood pressure and heart problems. Accelerated and excessive growth (gigantism) may occur in children.

• Prolactin-producing tumors. Overproduction of prolactin from a pituitary tumor (prolactinoma) can cause a decrease in normal levels of sex hormones - estrogen in women and testosterone in men. Excessive prolactin in the blood (hyperprolactinemia) can affect men and women differently.

  In women, prolactinoma may cause irregular menstrual periods (oligomenorrhea), lack of menstrual periods (amenorrhea) and milky discharge from the breasts (galactorrhea).

  In men, a prolactin-producing tumor may cause male hypogonadism, which may involve signs and symptoms such as enlarged breasts (gynecomastia), erectile dysfunction (ED) or impotence, infertility, decrease in body hair, and loss of interest in sexual activity.

• Thyroid-stimulating hormone-producing tumors. When a pituitary tumor overproduces thyroid-stimulating hormone, your thyroid gland makes too much of the hormone thyroxine. This is a rare cause of hyperthyroidism, or overactive thyroid disease. Hyperthyroidism can accelerate your body's metabolism, causing sudden weight loss, a rapid or irregular heartbeat, and nervousness or irritability.

Functioning and nonfunctioning pituitary tumors may cause other signs and symptoms, including:

• Headache
• Vision changes, such as decreased peripheral vision or double vision
• Seizures
• Clear, watery nasal drainage
• Hair loss
• Cold intolerance
• Constipation
• Irritability
• Weakness
• Fatigue
• Nausea
• Vomiting
• Low blood pressure
• Unintended weight loss or gain

Hypopituitarism is often progressive. Although the signs and symptoms can occur suddenly, usually they tend to develop gradually. They are sometimes vague and subtle and may be overlooked for many months or even years.

Signs and symptoms of hypopituitarism vary, depending on which pituitary hormones are deficient. The signs and symptoms may include:

• Fatigue
• A decline in energy
• Muscle weakness
• Nausea
• Constipation
• Weight loss or gain
• A decline in appetite
• Abdominal discomfort
• Sensitivity to cold or difficulty staying warm
• Visual disturbances
• Loss of underarm and pubic hair
• Joint stiffness
• Hoarseness
• Facial puffiness
• Thirst and excess urination
• Low blood pressure
• Headaches

If you're a man, you may also have signs and symptoms such as:

• Loss of interest in sexual activity
• Erectile dysfunction
• Decrease in facial or body hair

If you're a woman, you may develop:

• Irregular or stopped menstrual periods
• Infertility
• Inability to produce milk for breast-feeding

Children may experience stunted growth, short stature and slowed sexual development.

The pituitary gland is part of your endocrine system, which consists of glands that produce hormones that regulate processes throughout your body. Besides the pituitary gland, the endocrine system includes the thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries (in females) and testicles (in men).

The cause of pituitary tumors remains unknown. Pituitary tumors are almost always noncancerous (benign), which means they don't spread to other parts of your body, but they can increase in size. Because they grow in such limited space, they can compress and damage the normal pituitary tissue, interfering with hormone production. A tumor can also compress an optic nerve - the nerve that transmits visual information from your eye to your brain - slowly causing loss of vision.

The pituitary gland is part of your endocrine system, which consists of glands that produce hormones that regulate processes throughout your body. The hormones secreted by the pituitary gland help regulate important functions such as growth, blood pressure and reproduction. For example, the pituitary secretes:

• Growth hormone (GH). This hormone controls bone and tissue growth and maintains the appropriate balance of muscle and fat tissue.
• Anti-diuretic hormone (ADH). By regulating urine production, this hormone manages water balance in your body. A deficiency of ADH results in a condition called diabetes insipidus, causing excess urination and thirst.
• Thyroid-stimulating hormone (TSH). This hormone stimulates your thyroid gland to produce key hormones that regulate your metabolism. Shortage of TSH results in an underactive thyroid gland (hypothyroidism).
• Luteinizing hormone (LH). In men, LH regulates testosterone production. In women, it fosters production of estrogen.
• Follicle-stimulating hormone (FSH). Working in tandem with LH, FSH helps stimulate sperm production in men and egg development and ovulation in women.
• Adrenocorticotropic hormone (ACTH). This hormone stimulates your adrenal glands to produce cortisol and other hormones. Cortisol helps your body deal with stress and influences many body functions, affecting blood pressure, heart function and your immune system.
• Prolactin. This hormone regulates the development of female breasts, as well as the production of breast milk.

Hypopituitarism is frequently triggered by a tumor of the pituitary gland. As pituitary tumors increase in size they can compress and damage pituitary tissue, interfering with hormone production. A tumor can also compress the optic nerves, causing visual disturbances.

The cause of hypopituitarism can also be other diseases and events that damage the pituitary, such as:

• Head injuries
• Brain tumor
• Brain surgery
• Radiation treatment
• Autoimmune inflammation (hypophysitis)
• Stroke
• Infections of the brain, such as meningitis
• Tuberculosis
• Infiltrative diseases, such as sarcoidosis, which is an inflammatory disease occurring in various organs; histiocytosis X, in which abnormal cells cause scarring in numerous parts of the body, such as the lungs and bones; and hemochromatosis, which causes excess iron deposition in the liver and other tissues
• Severe loss of blood during childbirth, which may cause damage to the front part of the pituitary gland (Sheehan's syndrome, or postpartum hypopituitarism)
• Genetic mutations resulting in impaired pituitary hormone production

Diseases of the hypothalamus, a portion of the brain located just above the pituitary, also can cause hypopituitarism. The hypothalamus produces hormones of its own that directly affect the activity of the pituitary.

In some cases, the cause of hypopituitarism is unknown.

Although pituitary tumors can occur at any age, they're most likely to occur in older people. People with a family history of multiple endocrine neoplasia type 1 (MEN 1) have an increased risk of pituitary tumors. In MEN 1, multiple tumors occur in various glands of the endocrine system.

If your doctor suspects a pituitary disorder, he or she will likely order several tests to check levels of various hormones in your body. Your doctor may also want to check for hypopituitarism if you've had a recent head injury that might have put you at risk of damage to your pituitary gland.

Blood tests can help detect deficits in hormones as a result of pituitary failure. For example, these tests can identify low levels of thyroid, adrenal or sex hormones, and determine that these low levels are associated with inadequate pituitary hormone production.

Your doctor may also suggest that you go to a specialized endocrine clinic to undergo stimulation or dynamic testing. These tests check your body's secretion of hormones after you've taken certain medications that can stimulate hormone production.

Your doctor may also recommend:

• Brain imaging. A computerized tomography (CT) or magnetic resonance imaging (MRI) scan of your brain can detect a pituitary tumor or other structural abnormality.
• Vision tests. These tests can determine if growth of a pituitary tumor has impaired your sight or visual fields.
• X-ray. In children, an X-ray of the hand and wrist can measure whether the bones are growing normally.

Blood tests detect the overproduction or deficiency of hormones as a result of a pituitary tumor. Other tests can determine the type of tumor, if it has grown and how much. Additional tests your doctor may recommend include:

• Brain imaging. A computerized tomography (CT) or magnetic resonance imaging (MRI) scan of your brain can detect a pituitary tumor.
• Vision testing. Such tests can determine if growth of a pituitary tumor has impaired your sight or peripheral vision.
• Bone imaging. In children, an X-ray of the hand and wrist can measure whether bone growth is normal.

In addition, your doctor may refer you for more extensive testing to a doctor who specializes in treating disorders of the endocrine system (endocrinologist).

Treatment for a pituitary tumor depends on the type of tumor, its size and how far it has grown into your brain. Your age and overall health also are factors. Because pituitary tumors can cause serious problems by putting pressure on your brain, treatment often is necessary. Early detection of pituitary tumors is key to successful treatment.

Treatment often involves a team of medical experts, including:

• A brain surgeon (neurosurgeon)
• An ear, nose and throat surgeon (otorhinolaryngologist)
• A doctor who specializes in disorders of the endocrine glands (endocrinologist)
• A doctor who specializes in interpreting medical images (radiologist)
• A doctor who specializes in radiation therapy (radiation oncologist)
• A doctor who specializes in the nervous system (neurologist)

Doctors generally use surgery, radiation therapy and medications, either alone or in combination, to treat a pituitary tumor and return hormone production to normal levels.

Surgery
The most common treatment for pituitary tumors is surgery. Surgical removal of a pituitary tumor usually is necessary if the tumor is pressing on an optic nerve, which can cause loss of vision. The success of surgery depends on the tumor type, its location, its size, and whether the tumor has invaded surrounding tissues. The two main surgical techniques for treating pituitary tumors are:

• Transsphenoidal hypophysectomy. With this approach, a doctor usually can reach and remove the tumor through your nose and sinuses without an external incision. No other part of your brain is affected, and there's no visible scar. However, very large tumors may be difficult to remove with this procedure, especially if a tumor has invaded nearby nerves or brain tissue.
• Transcranial hypophysectomy. During this procedure, the tumor is removed through the upper part of your skull by way of an incision in your scalp. It's easier to reach large or more complicated tumors using this procedure.

Radiation therapy
Radiation therapy uses high-energy X-rays to destroy tumors. It can be used after surgery or alone as primary treatment if surgery isn't an option. Radiation therapy can be beneficial if a tumor persists or returns after surgery and causes signs and symptoms that medications don't relieve. Methods of radiation therapy include:

• External beam radiation. This form of radiation therapy delivers radiation in small increments over a period of time. A series of treatments, usually five times a week over a four- to six-week period, are performed on an outpatient basis. While this therapy is often effective, it may take years to fully control the tumor growth and hormone production. Radiation therapy may also damage remaining normal pituitary cells and normal brain tissue, particularly near the pituitary gland.
• Gamma-knife radiosurgery. This type of radiation therapy focuses radiation beams precisely on the tumor without an incision. Radiation beams that are the exact size and shape of the tumor are delivered into the tumor with the aid of special brain-imaging techniques. With gamma-knife radiosurgery, a minimal amount of radiation comes in contact with healthy tissue surrounding the tumor, decreasing the risk of damage to normal tissue.

  The benefits of gamma-knife radiosurgery, like those of external beam radiation, often aren't immediate and may take months or years to be fully effective. Gamma-knife radiosurgery is a relatively new treatment for pituitary tumors, but early results have been encouraging. However, doctors can't use this therapy if the tumor is very close to an optic nerve or other sensitive structures.

Medications
Treatment with medications (drug therapy) may help to block excess hormone secretion and sometimes shrink certain types of pituitary tumors:

• Prolactin-producing tumors (prolactinomas). The drugs bromocriptine (Parlodel) and cabergoline (Dostinex) can treat these types of tumors by decreasing prolactin secretion and often reducing the size of the tumor. These drugs are often so effective in treating these types of tumors that surgery isn't necessary.
• Growth hormone-producing tumors. Two classes of drugs are available for these types of pituitary tumors. Drugs known as somatostatin analogs (Sandostatin, others) cause a decrease in growth hormone production and may decrease the size of the tumor. Pegvisomant (Somavert) blocks the effect of excess growth hormone on the body. These medications are especially useful if surgery has been unsuccessful in normalizing growth hormone production.

If a pituitary tumor has resulted in decreased hormone production, or if removal of a pituitary tumor has lowered hormone production, you may need to take replacement hormones to maintain normal hormone levels.

Watchful waiting
In watchful waiting - also known as observation, expectant therapy or deferred therapy - you may need regular follow-up tests to monitor for evidence of progression of your pituitary tumor. Watchful waiting involves no active medical treatment. Medications, radiation therapy and surgery aren't used. Watchful waiting may be an option if your tumor isn't causing any signs or symptoms.

Watchful waiting may be particularly appropriate if you're older, in poor health or both. Many people with pituitary tumors function normally without treatment and without the tumor causing other problems. If you're younger, watchful waiting can also be an option as long as you know the facts and accept the possibility of your tumor changing or growing during the observation period, possibly requiring medical treatment. You and your doctor can weigh the risk of symptoms developing versus treatment intervention.

Successful treatment of the underlying condition causing hypopituitarism may lead to a complete or partial recovery of your body's normal production of pituitary hormones. The usual treatment for pituitary tumors is surgery to remove the growth. In some instances, doctors also recommend radiation treatment.

If hormone deficiencies persist after treatment, then you'll need prescriptions of one or more hormone replacement medications. These drugs are considered as "replacement" rather than treatment, because the dosages are set to match the amounts that your body would normally manufacture if it didn't have a pituitary problem. Treatment is usually lifelong.

Hormone replacement medications may include:

• Corticosteroids. These drugs, such as hydrocortisone or prednisone, replace the adrenal hormones that aren't being produced because of an adrenocorticotropic hormone (ACTH) deficiency. You take them by mouth.
• Levothyroxine (Levoxyl, Synthroid, others). This medication replaces deficient thyroid hormone levels caused by low or deficient TSH production.
• Sex hormones. These include testosterone in men and estrogen or a combination of estrogen and progesterone in women. Testosterone is administered through the skin with either a patch, a gel or by injection. Female hormone replacement can be administered with either pills or patches.
• Desmopressin (DDAVP). You take these hormones to replace ADH and to reduce your body's loss of water through frequent urination. This is taken by nasal spray or pills.
• Growth hormone. Also called somatropin, growth hormone is taken through an injection beneath your skin. It promotes growth, thus producing more normal height in children. Adults with a growth hormone deficiency may also benefit from growth hormone replacement, but they won't become taller.

If you've become infertile, preparations containing LH and FSH, also called gonadotropins, can be administered by injection to stimulate ovulation in women and sperm production in men.

A doctor who specializes in endocrine disorders (endocrinologist) may regularly monitor the levels of these hormones in your blood to ensure you're getting adequate - but not excessive - amounts of these hormones.

Your doctor will advise you to adjust your dosage of corticosteroids if you become seriously ill or experience major physical stress. During these times, your body would ordinarily produce extra cortisol hormone. The same kind of fine-tuning of dosage may be necessary when you have the flu, experience diarrhea or vomiting, or have surgery or dental procedures. Adjustments in dosage may also be necessary during pregnancy or with marked changes in weight. You may need periodic CT or MRI scans as well to monitor a pituitary tumor or other diseases causing the hypopituitarism.

Wear a medical alert bracelet or pendant, and carry a special card, notifying others - in emergency situations, for example - that you're taking corticosteroids and other medications.