Hypopituitarism

Hypopituitarism means the pituitary gland makes too little of one or more of its hormones. These hormones control the adrenal glands, thyroid, ovaries or testes, growth and water balance, so the symptoms depend on which hormones are low. Common causes are pituitary tumors and their treatment (surgery or radiation), head injury, heavy bleeding during or after childbirth, inflammation of the pituitary, and some cancer immunotherapy drugs. Symptoms are often vague: tiredness, weakness, low sex drive, missed periods, feeling cold and weight changes.

Lab tests linked to hypopituitarism:

• Cortisol (7AM–9AM): a morning cortisol level. A low result can mean the pituitary isn't driving the adrenal glands.
• Luteinizing hormone (LH): a pituitary hormone that controls the ovaries and testes. It is low or inappropriately normal when the pituitary is underactive.
• Doctors also order ACTH, TSH with free T4, FSH, estradiol or testosterone, IGF-1 and prolactin. They may use stimulation tests and a pituitary MRI.

How results are read:

• The pattern matters more than any one result. In hypopituitarism, the pituitary hormone is low or normal while the hormone it controls is low.
• TSH can look normal even when the thyroid is underactive because of the pituitary, so free T4 is measured alongside it.
• A low morning cortisol suggests cortisol deficiency, and borderline results are usually followed by a stimulation test. Steroid medicines, including inhaled, injected and skin forms, can lower cortisol.
• After menopause, LH and FSH are normally high unless hormone treatment or another factor suppresses them. Unexpectedly normal or low results can suggest a pituitary problem.

When to see a doctor:

• Get emergency care for vomiting, severe weakness, confusion, dizziness or fainting in someone with known or suspected cortisol deficiency.
• Get emergency care for a sudden severe headache with vision changes.
• See a doctor about lasting tiredness, low sex drive or missed periods after a head injury, pituitary surgery or difficult childbirth.

Clinical takeaway: hypopituitarism is diagnosed from paired pituitary and target-gland hormones, with stimulation tests and an MRI used to confirm the cause.