What is an underactive pituitary gland?
Your pituitary gland is located on the underside of your brain. It releases eight hormones. Each of these hormones plays a role in how your body function. These functions range from stimulating bone growth to prompting your thyroid gland to release hormones that control your metabolism.
Hormones produced by the pituitary gland include:
- Adrenocorticotropic hormone (ACTH) triggers cortisol production and the chemical reaction that makes your body produce adrenaline and noradrenaline.
- Antidiuretic hormone (ADH) controls your blood pressure and conserves the fluids in your body.
- Follicle-stimulating hormone (FSH) stimulates the growth of ovarian follicles in women and sperm production in men.
- Growth hormone (GH) makes children grow, and maintains body structure and metabolism in adults.
- Luteinizing hormone (LH) is responsible for fertility, puberty, and menstruation in women.
- Oxytocin is important in childbirth and lactation. It may also play a large role in human behavior.
- Prolactin has over 300 uses in the body.
- Thyroid-stimulating hormone (TSH) regulates the production of hormones in the thyroid.
Hypopituitarism occurs when your pituitary gland does not release enough of one or more of these hormones.
Trauma may cause your pituitary gland to stop producing enough of one or more of its hormones. For example, if you had brain surgery, a brain infection, or a head injury, may affect your pituitary gland.
Certain tumors can also affect the function of this gland. These include:
Some other possible causes of hypopituitarism include:
- sarcoidosis (a chronic lung disease)
- hemochromatosis (a hereditary disease characterized by too much iron in the body)
- histiocytosis X (a rare autoimmune disorder where immune cells attack the organs)
- stroke (cerebrovascular accident)
- lymphocytic hypophysitis (an autoimmune disease characterized by inflammation of the pituitary gland)
- blood loss during childbirth (Sheehan syndrome)
- radiation treatments
- traumatic brain injury in newborns, infants, and children
There may also be other causes of hypopituitarism. And in some cases hypopituitarism, the cause may be unknown.
The symptoms of hypopituitarism depend on which hormones your pituitary gland is not producing enough of. For example, if the pituitary gland does not produce enough growth hormone in a child, they may have a permanently short stature. If it doesn’t produce enough follicle-stimulating hormone or luteinizing hormone, it might cause problems with sexual function, menstruation, and fertility.
If your doctor thinks you may have hypopituitarism, they will use a blood test to check your levels of the hormones the pituitary gland produces. They may also check for hormones your pituitary gland stimulates other glands to release.
For example, your doctor may check your T4 levels. Your pituitary gland doesn’t produce this hormone, but it releases TSH, which stimulates your thyroid gland to release T4. Having low levels of T4 indicates you may have a problem with your pituitary gland.
Your doctor may prescribe specific medications before doing blood tests. These medications will stimulate your body’s production of specific hormones. Taking them before the test can help your doctor better understand your pituitary gland function.
Once your doctor determines which hormone levels are low, they must check the parts of your body (target organs) those hormones affect. Sometimes, the problem isn’t with your pituitary gland, but rather with the target organs.
Your doctor may also perform imaging tests, such as a CT scan or MRI scan on your brain. These tests can help your doctor figure out if a tumor on your pituitary gland is affecting its function.
This condition is best managed by an endocrinologist. There is no single course of treatment because this condition may affect a number of hormones. In general, the goal of treatment is to bring all your hormone levels back to normal.
This may involve taking medications to replace the hormones your pituitary gland is not producing properly. In this case, your doctor will need to check your hormone levels regularly. This allows your doctor to adjust the doses of medications you’re taking to make sure you’re getting the correct dose.
If a tumor is causing your pituitary problems, surgery to remove the tumor may restore your hormone production to normal. In some cases, getting rid of a tumor will also involve radiation therapy.