Hypopituitarism is a condition in which the pituitary gland does not produce normal amounts of some or all of its hormones.
Causes, incidence, and risk factors
The pituitary gland is a small structure that is located just below the brain. It is attached by a stalk to the hypothalamus , the area of the brain that controls its function.
The hormones released by the pituitary gland (and their functions) are:
- Adrenocorticotropic hormone (ACTH) -- stimulates the adrenal gland to release cortisol; cortisol helps to maintain blood pressure and blood sugar
- (ADH) -- controls water loss by the kidneysAntidiuretic hormone
- (FSH) -- controls sexual function and fertility in males and femalesFollicle stimulating hormone
- (GH) -- stimulates growth of tissues and boneGrowth hormone
- (LH) -- controls sexual function and fertility in males and femalesLuteinizing hormone
- Oxytocin -- stimulates the uterus to contract during labor and the breasts to release milk
- -- stimulates female breast development and milk productionProlactin
- (TSH) -- stimulates the thyroid gland to release hormones that affect the body's Thyroid stimulating hormone
In hypopituitarism, there is a lack of one or more pituitary hormones. Lack of the hormone leads to loss of function in the gland or organ that it controls. For example, no TSH leads to loss of function in the thyroid gland.
Hypopituitarism may be caused by:
- Brain surgery
- Brain tumor
- Head trauma
- Infections of the brain and the tissues that support the brain
- (from a burst aneurysm)Subarachnoid hemorrhage
- Tumors of the pituitary gland or hypothalamus
Occasionally, hypopituitarism is due to uncommon immune system or metabolic diseases, such as:
Hypopituitarism is also a rare complication after pregnancy, a condition called Sheehan's syndrome.
Note: Symptoms may develop slowly and may vary greatly, depending upon:
- The number of hormones that are missing and the organs they affect
- The severity of the disorder
Other symptoms that may occur with this disease:
Signs and tests
To diagnose hypopituitarism, there must be low hormone levels due to a problem with the pituitary gland. The diagnosis must also rule out diseases of the organ that is affected by this hormone.
Levels of a pituitary hormone may be high in the bloodstream if you have a pituitary tumor that is producing too much of that hormone. The tumor may crush other cells of the pituitary, leading to low levels of other hormones.
If hypopituitarism is caused by a tumor, you may need surgery to remove the tumor, with or without radiation therapy.
You will need lifelong hormone therapy to replace hormones that are no longer made by organs under the control of the pituitary gland. These may include:
- Corticosteroids (cortisol)
- Growth hormone
- Sex hormones (testosterone for men and estrogen for women)
- Thyroid hormone
Drugs are also available to treat related infertility in men and women.
Hypopituitarism is usually permanent and requires lifelong treatment. However, you can expect a normal life span.
Side effects of drug therapy can develop. In severe illness, failing to take extra corticosteroids can be life-threatening.
Calling your health care provider
Call your health care provider if you develop symptoms of hypopituitarism.
In most cases, the disorder is not preventable. Awareness of risk may allow early diagnosis and treatment.
Melmed S, Kleinberg D, Ho K. Pituitary physiology and diagnostic evaluation. In: Kronenberg H, Melmed S, Polonsky KS, Larsen PR, eds. . 12th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 8.