Hypopituitary

• Hypopituitarism is a condition in which the pituitary gland (a small gland at the base of the brain) does not produce one or more of its hormones or not enough of them.
• This condition may occur because of disease in the pituitary or hypothalamus (a part of the brain that contains hormones that control the pituitary gland).
• When there is low or no production of all the pituitary hormones, the condition is called panhypopituitarism.
• This condition may affect either children or adults.
• The pituitary gland sends signals to other glands (eg, thyroid gland) to produce hormones (eg, thyroid hormone). The hormones produced by the pituitary gland and other glands have a significant impact on the body’s functions, such as growth, reproduction, blood pressure, and metabolism (the physical and chemical processes of the body).
• When one or more of these hormones is not produced properly, the body’s normal functions can be affected.
• Some of the hormones, like cortisol and thyroid hormone may require prompt treatment, whereas others may not be life threatening.
• The pituitary gland produces several hormones. Some of the important hormones are as follows:
  • Adrenocorticotropic hormone (ACTH) is a hormone that stimulates the adrenal glands (glands on the kidneys that produce hormones). ACTH triggers the adrenal glands to release a hormone called cortisol, which regulates metabolism and blood pressure.
  • Thyroid-stimulating hormone (TSH) is a hormone that stimulates production and secretion of thyroid hormones from the thyroid gland (a gland in the hormone system). Thyroid hormone regulates the body’s metabolism and is important in growth and development.
  • Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are hormones that control sexual function in males and females. They are also known as gonadotropins or sex hormones (eg, estrogen, testosterone).
  • Growth hormone (GH) is a hormone that stimulates normal growth of bones and tissues.
  • Prolactin is a hormone that stimulates milk production and female breast growth.
  • Antidiuretic hormone (ADH) is a hormone that controls water loss by the kidneys.
• In hypopituitarism, one or more of these pituitary hormones is missing. The lack of hormone results in a loss of function of the gland or organ that it controls.

A loss of function of the pituitary gland or hypothalamus results in low or absent hormones. Tumors can cause damage to the pituitary gland or hypothalamus and can therefore result in a loss of function. Damage to the pituitary gland can also be caused by radiation, surgery, infections (eg, meningitis), or various other conditions. In some cases, the cause is unknown.

Some persons may have no symptoms or a gradual onset of symptoms. In other persons, the symptoms may be sudden and dramatic. The symptoms depend on the cause, rapidity of onset, and the hormone that is involved.

• ACTH deficiency: Symptoms include fatigue, low blood pressure, weight loss, weakness, depression, nausea, or vomiting.
• TSH deficiency: Symptoms include constipation, weight gain, sensitivity to cold, decreased energy, and muscle weakness or aching.
• FSH and LH deficiency: In women, symptoms include irregular or stopped menstrual periods and infertility. In men, symptoms include loss of body and facial hair, weakness, lack of interest in sexual activity, erectile dysfunction, and infertility.
• GH deficiency: In children, symptoms include short height, fat around the waist and in the face, and poor overall growth. In adults, symptoms include low energy, decreased strength and exercise tolerance, weight gain, decreased muscle mass, and feelings of anxiety or depression.
• Prolactin deficiency: In women, symptoms include lack of milk production, fatigue, and loss of underarm and pubic hair. No symptoms are seen in men.
• ADH deficiency: Symptoms include increased thirst and urination.

Call the doctor or health care practitioner if any symptoms develop.

The doctor or health care practitioner may perform blood tests to determine which hormone level is low and to rule out other causes. The following tests may be performed:

• ACTH and Cortrosyn stimulation test
• TSH and thyroxine test
• FSH and LH and either estradiol or testosterone (whichever is appropriate for the patient)
• Prolactin test
• GH stimulation test

An MRI or CT scan of the pituitary gland may be obtained to determine if a tumor is present.

In children, X-rays of the hands may be taken to determine if bones are growing normally.

Medical treatment consists of hormone replacement therapy and treatment of the underlying cause.

Drugs used to treat hypopituitarism replace the deficient hormone.

• Glucocorticoids (eg, hydrocortisone) are used to treat adrenal insufficiency resulting from ACTH deficiency.
• Thyroid hormone replacement therapy is used for hypothyroidism (a condition in which thyroid production is low). Drugs, such as levothyroxine (eg, Synthroid, Levoxyl), may be used. In the drug’s active form, it influences growth and development of tissues.
• Sex hormone deficiency is treated with sex-appropriate hormones (eg, testosterone, estrogen).
  • Testosterone replacement therapy (eg, Andro-LA, Androderm) is used in men. Testosterone promotes and maintains the development of secondary sexual characteristics (eg, facial hair) in males with androgen deficiency.
  • Estrogen replacement therapy (eg, Premarin) with or without progesterone is used in women. Estrogens are important in developing and maintaining the female reproductive system and secondary sexual characteristics (eg, breast development).
• GH replacement therapy (eg, Genotropin, Humatrope) is used for children as appropriate. Growth hormone stimulates linear growth and growth of skeletal muscle and organs. GH therapy may also be used in adults, but this will not make them grow taller.

Surgery may be performed depending on the type, size, and location of the tumor.

Checkups with the doctor or health care practitioner are important. The doctor may need to adjust the dose of hormone replacement therapy.

If hormone replacement therapy is adequate, the prognosis is good. Complications are often related to the underlying disease.