The symptoms of hypopituitarism depend on the specific hormone that is lacking. For example, patients with reduced ACTH secretion have low cortisol levels, which can result in loss of appetite, weight loss, nausea, vomiting, fatigue, weakness, and lightheadedness. This condition is called "adrenal insufficiency." Patients with reduced TSH secretion have low thyroid hormone levels resulting in a condition called "hypothyroidism." Signs and symptoms of hypothyroidism can include weight gain, fatigue, dry skin, constipation, cold intolerance, and hair loss. Women of reproductive age with reduced LH and FSH secretion develop amenorrhea (absence of menstrual periods), infertility, and bone loss due to low estrogen levels. Men with low LH and FSH levels develop low testosterone levels, which results in erectile dysfunction, infertility, fatigue, body composition abnormalities (loss of muscle mass and an increase in abdominal fat), and bone loss. Low growth hormone (GH) in children leads to short stature. In adults, GH deficiency is associated with a diminished quality of life, body composition abnormalities (loss of muscle mass and an increase in abdominal fat), and low bone density. Women with low prolactin are unable to breastfeed, but there are no known adverse effects of low prolactin in men.

Hypopituitarism is caused by damage to the pituitary gland, usually from a tumor, radiation, or surgery. Traumatic brain injury and subarachnoid hemorrhages can also cause hypopituitarism. Occasionally inflammation can cause hypopituitarism, and sometimes the cause is unclear. Medications can also cause hypopituitarism. For example, high-dose steroid use can lead to adrenal insufficiency and anabolic steroid use can result in low testosterone that lasts beyond the time in which the medication is used and can be permanent. Immunotherapy used to treat some types of cancer can also cause hypopituitarism.

The complications of hypopituitarism are due to the specific hormone deficiency (see “Signs & Symptoms” above). Patients with hypopituitarism not receiving appropriate hormone replacement therapies have an increased risk of mortality.

Hypopituitarism is diagnosed by an endocrinologist using blood tests. Some of the blood tests involve complex testing protocols. The MGB Pituitary Center has a specialized testing center for this purpose.

The treatment of hypopituitarism involves replacing the deficient hormone(s) to normal. An endocrinologist experienced in this area will be able to guide you through the various treatment options for each pituitary hormone deficiency.

For patients with adrenal insufficiency, cortisol replacement is usually achieved by prescribing very low doses of either prednisone or hydrocortisone. Low doses are chosen to achieve physiologic levels, as opposed to high doses used to treat inflammatory illnesses, which can cause side effects. Hypothyroidism is treated with levothyroxine. Women of reproductive age with amenorrhea (absent menstrual periods) can be prescribed estrogen in the form of oral contraceptives or low-dose patches, if they do not have contraindications to such therapy, and depending upon their specific needs. Assisted reproductive technologies are usually needed in such causes to achieve pregnancy. Decisions regarding estrogen replacement therapy in postmenopausal women should be made in consultation with an endocrinologist. As women with hypopituitarism rarely experience hot flashes, estrogen replacement is less often needed in this group. A variety of testosterone preparations are available for men with low testosterone, but HCG therapy is necessary in men who are seeking fertility. GH replacement is discussed under "GH Deficiency".