Patient Education - Endocrine Encyclopedia
Endocrine Surgery Encyclopedia
 Definition:
Hypopituitarism is a condition caused by low levels of pituitary hormones.
Alternative Names: Pituitary insufficiency
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 secreted by the pituitary gland (and their functions) are:
- Growth hormone (GH), which stimulates growth of tissues and bone
- Thyroid stimulating hormone (TSH), which stimulates the thyroid gland to secrete
hormones that affect the body's metabolism
- Adrenocorticotropic hormone (ACTH), which stimulates the adrenal gland to secrete
cortisol; cortisol helps to maintain blood pressure and blood sugar
- Prolactin, which stimulates female breast development and milk production
- Luteinizing hormone (LH), which controls sexual function in males and females
- Follicle stimulating hormone (FSH), which controls sexual function in males
and females
- Antidiuretic hormone (ADH), which controls water loss by the kidneys
- Oxytocin, which stimulates contraction of the uterus during labor and milk release
from the breasts.
In hypopituitarism, there is an absence 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, loss of thyroid stimulating hormone leads to loss of function in the thyroid
gland.
Hypopituitarism may be caused by tumors of the pituitary gland or hypothalamus,
head trauma, brain tumor, radiation, brain surgery, stroke, subarachnoid hemorrhage
(from a burst aneurysm), or infections of the brain and the tissues that support
the brain. Occasionally, hypopituitarism is due to uncommon immune system or metabolic
diseases, such as sarcoidosis, histiocytosis X, and hemochromatosis.
Hypopituitarism is also a rare complication following pregnancy, a condition called
Sheehan's syndrome. The cause of this type of hypopituitarism is unknown.
Symptoms:
- Fatigue
- Weakness
- Sensitivity to cold
- Decreased appetite
- Weight loss
- Abdominal pain
- Low blood pressure
- Headache
- Visual disturbances
- Short stature (less than 5 feet) if onset is during a growth period
- Loss of armpit or pubic hair
- In women: cessation of menstrual periods, infertility, or failure to lactate
- In men: decreased sexual interest, loss of body or facial hair
- In children: slowed growth and sexual development
Note: Symptoms may develop slowly and may vary greatly, depending upon the severity
of the disorder, the number of deficient hormones, and their target organs.
Additional symptoms that may be associated with this disease:
- Weight gain (unintentional)
- Joint stiffness
- Hoarseness or changing voice
- Hair loss
- Facial swelling
Signs and tests:
Diagnosis of hypopituitarism must confirm low hormone levels due to an abnormality
of the pituitary gland. The diagnosis must also rule out disease of the organ affected
by this hormone.
- Cranial CT scan, revealing a tumor or abnormal mass in the pituitary gland
- Cranial MRI, revealing a tumor or abnormal mass in the pituitary or hypothalamus
- Serum luteinizing hormone (LH), decreased or normal
- Serum follicle stimulating hormone (FSH), decreased or normal
- Serum testosterone level, decreased
- Serum estradiol (estrogen), decreased
- Serum cortisol, decreased
- Serum ACTH, decreased
- T4 (thyroid hormone), decreased
- Serum thyroid stimulating hormone (TSH), decreased or normal
- Serum thyroid stimulating hormone response to thyroid-releasing hormone, decreased
- Serum growth hormone (GH), decreased
- Serum insulin-like growth factor 1 (IGF-1), decreased
In some cases, one of the hormones produced by the pituitary may be elevated in the
blood stream if a patient has a pituitary tumor which is producing an excessive amount
of that hormone. The tumor itself may be crushing the rest of the cells of the pituitary,
leading to low levels of other hormones.
Treatment:
If hypopituitarism is caused by a tumor, treatment by surgical removal, with or without
radiation therapy, may be indicated. Replacement of deficient hormones is often required
even after successful treatment of a pituitary tumor.
Hormone therapy is needed to replace hormones that are no longer made by the organs
under the control of the pituitary gland. These may include corticosteroids (cortisol),
thyroid hormone, sex hormones (testosterone for men and estrogen for women), and
growth hormone. Drugs are also available to treat associated infertility in men and
women.
Support Groups:
Expectations (prognosis):
Hypopituitarism is usually permanent and requires life-long treatment; however, a
normal life span can be expected.
Complications:
Side effects of drug therapy can develop.
Calling your health care provider:
Call your health care provider if symptoms of hypopituitarism develop.
Prevention:
In most cases, the disorder is not preventable. Awareness of risk may allow early
diagnosis and treatment.
Review Date: 5/12/2006
Reviewed By: Robert Hurd, MD, Department of Biology, College of Arts and Sciences,
Xavier University, Cincinnati, OH. Review provided by VeriMed Healthcare Network.
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