Hypopituitarism
When the pituitary gland makes too few hormones
Quick Facts
- Type: Hormone (endocrine) disorder
- Gland involved: Pituitary gland
- Problem: Too little of one or more hormones
- Main treatment: Hormone replacement
Overview
Hypopituitarism is a condition in which the pituitary gland does not produce enough of one or more of its hormones. The pituitary is a small gland at the base of the brain often called the master gland because it controls other hormone-producing glands, including the thyroid, adrenal glands, and reproductive organs, as well as growth and water balance.
When pituitary hormones are deficient, the glands they control may also slow down, affecting metabolism, growth, the stress response, reproduction, and more. The condition can involve one hormone or several. Symptoms depend on which hormones are low. With hormone replacement, most people can manage hypopituitarism well and live full lives.
Symptoms
Symptoms depend on which hormones are deficient and can develop slowly:
- Low thyroid-stimulating hormone: Fatigue, weight gain, cold intolerance, and constipation.
- Low adrenal-stimulating hormone (ACTH): Fatigue, weakness, low blood pressure, weight loss, and poor response to stress or illness.
- Low sex hormones: Loss of menstrual periods, infertility, reduced sex drive, and erectile difficulties.
- Low growth hormone: In children, slowed growth; in adults, fatigue and changes in body composition.
- Low antidiuretic hormone: Excessive thirst and urination (diabetes insipidus).
A sudden, severe shortage of adrenal hormones (adrenal crisis) is a life-threatening emergency.
Causes
Hypopituitarism has many possible causes that damage or disrupt the pituitary gland or the part of the brain that controls it (the hypothalamus):
- Pituitary tumors: Tumors or their treatment (surgery or radiation) can impair hormone production.
- Head injury or brain surgery
- Bleeding or reduced blood flow to the pituitary, including a serious complication around childbirth
- Inflammation or infiltration of the gland
- Radiation therapy to the head
- Genetic or developmental conditions
Sometimes no cause is found.
Risk Factors
- A pituitary tumor or other brain tumor
- Previous brain surgery or radiation to the head
- Serious head injury
- Severe blood loss around childbirth
- Certain infections or inflammatory conditions affecting the brain
Diagnosis
Diagnosis involves blood tests that measure pituitary hormones and the hormones of the glands they control, often at specific times of day. Because levels can be subtle, stimulation tests are sometimes used to see how the pituitary responds.
If hypopituitarism is confirmed, imaging such as an MRI of the brain looks for a tumor or other cause affecting the pituitary or hypothalamus. The pattern of which hormones are low helps guide both diagnosis and treatment.
Treatment
The main treatment is to replace the hormones that are missing, tailored to the specific deficiencies:
- Cortisol replacement: Steroid medication for low adrenal hormones, with extra doses during illness, injury, or surgery to prevent a crisis.
- Thyroid hormone replacement for low thyroid function.
- Sex hormone replacement as appropriate, with specific treatments for fertility when desired.
- Growth hormone replacement for children and selected adults.
- Treatment for water balance (such as desmopressin) if antidiuretic hormone is deficient.
Treating the underlying cause, such as removing a tumor, is also important. People typically need lifelong monitoring and dose adjustments.
When to See a Doctor
See a doctor for persistent unexplained fatigue, weight changes, loss of menstrual periods, low sex drive, excessive thirst and urination, or other symptoms that may suggest a hormone deficiency, especially after a head injury, brain surgery, or radiation to the head.
Seek emergency care for signs of an adrenal crisis: sudden severe weakness, vomiting, abdominal pain, confusion, very low blood pressure, or collapse. This is life-threatening and needs immediate treatment. People with known adrenal hormone deficiency should carry medical identification and know how to use emergency steroid dosing.
Frequently Asked Questions
What does the pituitary gland do?
The pituitary is a small gland at the base of the brain that controls many other hormone-producing glands, including the thyroid, adrenal glands, and reproductive organs, as well as growth and water balance. That is why it is often called the master gland.
What are the symptoms of hypopituitarism?
Symptoms depend on which hormones are low and may include fatigue, weight changes, cold intolerance, low blood pressure, loss of menstrual periods, reduced sex drive, slowed growth in children, and excessive thirst and urination. They often develop slowly.
How is hypopituitarism treated?
The main treatment is replacing the missing hormones, such as cortisol, thyroid hormone, sex hormones, growth hormone, or medication for water balance, tailored to the deficiencies. Treating the underlying cause, like a tumor, is also important, and lifelong monitoring is usually needed.
What is an adrenal crisis?
An adrenal crisis is a life-threatening emergency caused by a sudden severe shortage of cortisol. Signs include severe weakness, vomiting, abdominal pain, confusion, and very low blood pressure. It requires immediate emergency treatment with steroids.
Can hypopituitarism be cured?
It often cannot be cured, but it is usually well managed with hormone replacement, which most people take long term. In some cases, treating the underlying cause can restore part of the gland's function.
References
- MedlinePlus, U.S. National Library of Medicine. Hypopituitarism.
- Mayo Clinic. Hypopituitarism — Symptoms and causes.
- The Endocrine Society.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).