Hypopituitarism causes a variety of symptoms and conditions based on the hormone or hormones not being produced by the pituitary gland.
Hormones produced and/or released by the pituitary gland include:
- Adrenocorticotropic hormone (ACTH). This hormone stimulates the adrenal gland to release cortisol, which maintains blood pressure and blood sugar and allows the body to cope with physical stress. Failure to produce this hormone is dangerous and life-threatening. Symptoms include fatigue, nausea, vomiting, weight loss, low blood sugar and low blood pressure. These symptoms may develop or worsen with physical stress such as an infection, fever or injury.
- Antidiuretic hormone (ADH). This hormone controls water loss by the kidneys. The hypothalamus (a part of the brain) makes antidiuretic hormone (ADH), but the hormone is stored in and released by the pituitary gland. Symptoms of low or no production of ADH include extreme thirst and excretion of abnormally large amounts of urine (diabetes insipidus).
- Follicle stimulating hormone (FSH). This hormone controls sexual function and fertility in males and females. Low levels of follicle stimulating hormone (FSH) result in delayed puberty or hypogonadism (failure of the testes or ovaries to function). Hypogonadism in males is marked by lack of body hair, underdeveloped genitals, breast development and low muscle strength and bulk. A small number of people have a lifelong deficiency of both FSH and luteinizing hormone (LH), called isolated hypogonadotropic hypogonadism (iHH), or isolated gonadotropin deficiency (IGD). This condition is typically present at birth. Hypogonadism in females is marked by underdeveloped breasts, inability to menstruate and infertility.
- Luteinizing hormone (LH). This hormone also controls sexual function and fertility in males and females and results in delayed puberty or hypogonadism.
- Oxytocin. This hormone causes the uterus to contract during labor and the breasts to release milk. Deficiency of this hormone does not affect children.
- Prolactin. This hormone stimulates female breast development and milk production in females. Deficiency of this hormone does not affect children.
- Growth hormone (GH). This hormone stimulates growth of tissues and bone. Children with growth hormone (GH) deficiency usually have short stature.
- Thyroid stimulating hormone (TSH). This hormone tells the thyroid gland to release hormones that control body metabolism. Thyroid stimulating hormone (TSH) deficiency leads to a form of hypothyroidism.
Hypopituitarism may be congenital (present at birth) or acquired (developed later in life). Congenital hypopituitarism is caused by a missing, underdeveloped or incorrectly located pituitary gland. Acquired hypopituitarism is often caused by damage to the pituitary gland. Conditions that may damage the pituitary gland include brain infection, brain hemorrhage, head trauma, stroke or a tumor in the brain, pituitary gland or hypothalamus. Brain surgery or radiation treatment may also cause damage to the pituitary gland.
Diagnosis of Hypopituitarism
Doctors at Riley at IU Health use the following exams and tests to diagnose hypopituitarism:
- Physical exam. The doctor can look for the physical signs of hypopituitarism associated with particular hormone deficiencies.
- Blood test. The doctor can perform a blood test to check the levels of all the hormones produced by the pituitary gland. A blood test will tell the doctor which hormones are not being produced.
- Magnetic resonance imaging (MRI).The doctor may order a magnetic resonance imaging (MRI) test. The MRI provides images of the brain and can show if there is a pituitary tumor or other structural abnormality in the brain.
- Stimulation test. The doctor may use medicine to stimulate certain hormones and then test the body's secretion of those hormones.