Pituitary Glossary starting with D

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A surgical procedure to decrease mass effect by removing a portion of a tumor or dead tissue. See mass effect.

Surgical removal of as much of a tumor as possible. Debulking may increase the chance that chemotherapy or radiation therapy will kill all the tumor cells. It may also be done to relieve symptoms or help the patient live longer. Also called tumor debulking.


Dexamethasone. A glucocorticosteroid medication used to reduce brain tissue swelling.

Also used, in low doses, to treat adrenal insufficiency.


Refers to a surgical procedure during which bone, tissue, or tumor is removed to lessen intracranial pressure.

Decompressive craniectomy is an advanced treatment option for intracranial pressure (ICP) control in patients with traumatic brain injury.


A mature cell returning to a less mature state. See differentiate, undifferentiated.

In cancer, refers to how mature (developed) the cancer cells are in a tumor. Differentiated tumor cells resemble normal cells and tend to grow and spread at a slower rate than undifferentiated or poorly differentiated tumor cells, which lack the structure and function of normal cells and grow uncontrollably.


The amount of darkness or light in an area of a scan reflects the compactness and density of tissue.

The amount of darkness or light in an area of a scan reflects the compactness and density of tissue. Differences in tissue density are the basis for CT and MR scans.


Dual-energy X-ray absorptiometry. A technique used to measure bone mineral density, but which can also be used to measure body composition.

Dual Energy X-Ray Absorptiometry (DEXA) is a test that uses x-rays to measure the thickness of the bones in the hip, spine, wrist, heel, finger, and whole body. A DEXA scan is a screening test for osteoporosis. The scan of the whole body, spine, and hip takes about 30 minutes. The DEXA takes images while you lay comfortably on the scanner bed. DEXA scanning is not done if you weigh more than 297 lbs, the weight limit for the scanner bed. A DEXA scan of the spine or hip is not done if you have had reconstructive or replacement surgery.

Diabetes (Diabetes Insipidus)

A problem with water balance in the body causing excess urine production and great thirst, due to pituitaryhypothalamic damage. Diabetes mellitus, which has the same symptoms, is due to insufficient insulin production by the pancreas.

Diabetes Insipidus symptoms include excessive urination, thirst, and increased intake of water.

Diabetes (Diabetes Mellitus)

A metabolic disease in which carbohydrate utilization is reduced and that of lipid and protein enhanced; it is caused by an absolute or relative deficiency of insulin and is characterized, in more severe cases, by chronic hyperglycemia, glycosuria, water and electrolyte loss, ketoacidosis, and coma; long-term complications include development of disorders of the nervous system, eyes and kidneys; generalized degenerative changes in large and small blood vessels, and increased susceptibility to infection.

Two types of a highly variable disorder in which abnormalities in the ability to make and/or use the hormone insulin interfere with the process of turning dietary carbohydrates into glucose, the body’s fuel. Type I is known as insulin dependent diabetes mellitus, and type II is known as non-insulin dependent diabetes mellitus.


An expert in the practical application of diet in the prevention of disease or of a process that can lead to disease, and in the treatment of disease.

Plan and conduct food-service or nutritional programs to assist in the promotion of health and disease control. May supervise activities of a department providing large-quantity food services, counsel individuals, or conduct nutritional research.


The process cells undergo as they mature into normal cells.

Differentiated cells have distinctive characteristics, perform specific functions, and are less likely to divide. See dedifferentiate, undifferentiated.


Lacking a distinct border, not localized, spread out. Opposite of circumscribed.

Widely spread; not localized or confined. Example: Cancer treatment depends on whether the tumor is diffuse (spread throughout the brain) or focal (in one area of the brain).


Double vision.

Diplopia is a vision disorder in which two images of a single object are seen, caused from unequal action of the eye muscles.

Dopamine Agonists

Medications with predominant effects on pituitary cells that harbor receptors for the chemical transmitter dopamine.

Examples include Bromocriptine and Cabergoline.

Doppler Ultrasonography

An application of diagnostic ultrasound used to detect moving blood cells or other moving structures and measure their direction and speed of movement. The Doppler effect is used to evaluate movement by measuring changes in frequency of the echoes reflected from moving structures.

The Doppler effect is used to evaluate movement by measuring changes in frequency of the echoes reflected from moving structures. In many instances, Doppler ultrasound has replaced x-ray methods such as angiography, as a method to evaluate blood vessels and blood flow. Doppler ultrasound permits real-time viewing of blood flow that cannot be obtained by other methods. Doppler ultrasound has proved a boon in all areas of ultrasound, aiding in the evaluation of the major arteries and veins of the body, the heart, and in obstetrics for fetal monitoring.

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