Having an overactive pituitary gland is called hyperpituitarism. Noncancerous (benign) tumors usually cause this condition by making the gland produce too much or too little of the hormones that control growth, reproduction and metabolism.
Most cases of hyperpituitarism (overactive pituitary gland) are caused by a pituitary tumor. No one knows what causes these tumors but possible culprits include:
Benign tumors are the most frequent cause of an overactive pituitary gland. No one knows why these tumors occur. Depending on which types of cells it affects, your pituitary gland will start to secrete excessive amounts of one or two hormones.
In some cases, pituitary tumors may result from an inherited condition known as multiple endocrine neoplasia type 1 (MEN1). This disorder also causes benign tumors of your pancreas and parathyroid glands.
In rare cases, a cancerous tumor (carcinoma) or a disorder of your hypothalamus may be the underlying cause.
Symptoms of Cushings’ syndrome
Accumulation of fat in your upper body.
Excessive facial hair in people assigned female at birth.
Pink or purplish stretch marks on your belly (abdomen).
Tendency to bruise easily.
Bones may become fragile and tend to break more easily.
Symptoms of Acromegaly
Enlarged or swollen hands and feet, causing an increase in shoe or ring size.
Change in facial structure: Your jaw and brow may stick out and your nose, tongue and lips may get bigger. Or you may see changes in the spacing of your teeth.
Skin that’s thick, coarse and oily.
Irregular periods in people assigned female at birth.
Erectile dysfunction in people assigned male at birth.
Increased risk for high blood pressure, diabetes, heart attacks and certain types of cancer.
Symptoms of hyperthyroidism may include:
Rapid or irregular heartbeat (arrhythmia).
Blood tests measure your prolactin levels. Hypothyroidism (an underactive thyroid) can also cause elevated prolactin levels, so these tests are done to rule out this possibility.
Elevated blood levels of growth hormone (GH) cause acromegaly. Two blood tests are usually used to diagnose the condition. These include a test to check the level of the insulin-like growth factor-1 (which is a more stable marker for GH) and an oral glucose tolerance test.
For Cushing’s syndrome
Cushing’s syndrome can be challenging to diagnose. Several samples of your blood, cortisol level in saliva and urine may be needed to check for cortisol levels.
Tests can determine other causes than Cushing’s disease, such as a tumor on your adrenal gland, or if cortisol levels are affected by use of anti-inflammatory drugs.
Other tests include specialized invasive blood sampling, where blood is taken from the veins of your sinuses that drain blood from your pituitary gland.
If lab tests suggest you may have a tumor, imaging tests can determine if this is the case, and if so, where the tumor is located and how big it is. Usually magnetic resonance imaging (MRI) is used. CT (computed tomography) scan may be used if you can’t have an MRI, such as if you have a pacemaker or other implant.
Medication to reduce prolactin levels and potentially shrink the tumor is usually the first recommended treatment.
Acromegaly may be treated with drugs used to lower growth hormone levels and shrink tumors along with surgical resection.
For prolactin-producing microadenomas
People with prolactin-producing microadenomas will usually receive dopamine agonist therapy medications as a first course of treatment for several months. Your provider will usually prescribe either cabergoline (Dostinex) or bromocriptine (Cycloset).
For people with prolactinomas the most common kind of adenoma 80% will have prolactin levels restored to normal. This often shrinks the tumor enough to improve vision, resolve headaches and restore menstruation and fertility. If unsuccessful, surgery is the next option.
For acromegaly or Cushing’s syndrome
People with acromegaly or Cushing’s syndrome may undergo a surgical procedure called a transsphenoidal adenomectomy
To reach your pituitary gland and remove the tumor, your surgeon will make a small cut through your nose or upper lip.
Though this procedure is very delicate, it has a success rate greater than 80% when performed by an experienced surgeon.
Transsphenoidal surgery is most effective for small tumors (less than 10 millimeters, or ⅜ inch, in diameter).
This procedure is considered safe, but all surgeries have risks, which your surgeon should talk about with you.
People with prolactinomas may need surgery to remove the tumor and take the pressure off their optic nerve. This may be done through your nose and sphenoid sinus (transsphenoidal surgery) or through open surgery (a craniotomy).
Radiation may be used for people who can’t have surgery or who have some tumor tissue left after surgery which doesn’t respond to medication. There are two approaches to radiation:
Conventional radiation therapy
Conventional radiation therapy is given in small doses over a period of four to six weeks. However, radiation treatments can damage normal tissue surrounding the tumor.
Stereotactic therapy provides a high-dose beam of radiation targeted at the tumor
It can be done in one session, causing less damage to surrounding tissue.
Most people who have radiation treatment need long-time hormone replacement therapy due to a gradual decline in the secretion of other pituitary hormones.