In radiology, the uptake of energy from radiation by the tissue or medium through which it passes.

Tumors that are not deep in the brain or beneath vital structures. Inaccessible tumors cannot be approached by standard surgical techniques.

Acromegaly occurs in 2.6 % of the pituitary patient population but is difficult for some doctors to detect and treat. Acromegaly affects both men and women. In almost all cases, acromegaly is not inherited and cannot be passed on to children.

ACTH is a hormone released from the anterior pituitary gland in the brain, also known as: Serum adrenocorticotropic hormone; Adrenocorticotropic hormone. The levels of ACTH change with the body's natural 24-hour cycle of processes (circadian rhythms). An ACTH test is performed early in the morning for the most accurate results.

Sharpness or keenness. A visual acuity test will determine the smallest letters a person can read on a standardized chart held 14 - 20 feet away.

Acupuncture is among the oldest healing practices in the world. As part of traditional Chinese medicine (TCM), acupuncture aims to restore and maintain health through the stimulation of specific points on the body. In the United States, where practitioners incorporate healing traditions from China, Japan, Korea, and other countries, acupuncture is considered part of complementary and alternative medicine (CAM). CAM is a group of diverse medical and health care systems, practices, and products that are not presently considered to be part of conventional medicine. Complementary medicine is used together with conventional medicine, and alternative medicine is used in place of conventional medicine.
• Acupuncture has been practiced in China and other Asian countries for thousands of years.
• Scientists are studying the efficacy of acupuncture for a wide range of conditions.
• Relatively few complications have been reported from the use of acupuncture. However, acupuncture can cause potentially serious side effects if not delivered properly by a qualified practitioner.
• Tell your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.

Describes something that happens suddenly and for a short time. Opposite of chronic.

May or may not produce hormones in excess. Presence may affect normal glandular function.

Also known as Arginine vasopressin; Antidiuretic hormone; AVP; Vasopressin. ADH is also a test (water restriction test) that measures the amount of antidiuretic hormone (ADH) in the blood. ADH is found in the body and it is also given as a medication.
ADH is a hormone stored in the posterior pituitary gland in the brain, regulating water levels in the body. ADH interacts with the kidneys to increase total body water increasing blood volume and blood pressure. The release of ADH is controlled by cells called osmoreceptors and baroreceptors. Osmoreceptors are specialized areas in a part of the brain called the hypothalamus. These cells measure the concentration of particles in the blood. When the concentration is high, the pituitary releases more ADH, causing more water to be retained to dilute the body fluids. When the concentration is low, the pituitary releases less ADH.
The heart also senses blood volume and blood pressure, and signals the pituitary to release more ADH when blood volume or blood pressure are low and less ADH when they are high.

Adhesions are scar-like tissues that form between two surfaces inside the body. Surgery, inflammation, or injury can cause tissues to bond to other tissue or organs, similar to the forming of scar tissue. Adhesions can also form between the two surfaces. Surgery may be done to allow normal movement of the organ and reduce symptoms caused by the adhesion. However, there is a risk for more adhesions as the number of surgeries increases.

Adjuvant (therapy). Treatment given after or in addition to the primary treatment to increase the chances of a cure. Adjuvant therapy may include chemotherapy, radiation therapy, hormone therapy, or biological therapy.

The adrenal glands sit on top of the kidneys and are controlled by the pituitary gland. They produce aldosterone which regulates salt and potassium balance, cortisol which is a stress hormone, and weak sex steroids.

An allergen is a substance that can cause an allergic reaction. Allergens are substances that, in some people, the immune system recognizes as "foreign" or "dangerous" but cause no response for most people. Examples include pollen, molds, and certain foods.

A hypersensitive immune reaction to a substance that normally is harmless or would not cause an immune response in most people. An allergic response may cause harmful symptoms such as itching or inflammation or tissue injury. Also called Hypersensitivity.

A common side effect of radiation therapy to the brain and some chemical therapies.

Able to walk about and not bedridden, as in an ambulatory patient or outpatient.

Amenorrhea is the absence of a menstrual period. Primary amenorrhea is when a young woman has not yet had a period by age 16. Secondary amenorrhea describes someone who used to have a regular period but then it stopped for at least three months due to pregnancy or other factors.

Pain medications are also called analgesics. Analgesics include aspirin, acetaminophen, and ibuprofen. Every pain medicine has benefits and risks. Specific types of pain may respond better to one medication over another. Results also vary from patient to patient.

Also known as Anaphylactic reaction; Anaphylactic shock. Anaphylaxis is a life-threatening, whole-body allergic reaction. After being exposed to a substance like bee sting venom, the person's immune system becomes sensitized to that allergen. On a later exposure, an allergic reaction may occur. This reaction is sudden, severe, and involves the entire body.
Tissues in different parts of the body release histamine and other substances, causing airways to tighten and may lead to other symptoms.
anaphylactic-like reaction (anaphylactoid reaction) can be caused by drugs such as polymyxin, morphine, x-ray dye, and others. This is usually due to a toxic reaction, rather than an immune system response as in anaphylaxis.

A change in the structure of cells and in their orientation to each other; characteristic of malignancy. Malignant cells that have returned to a more undifferentiated or primitive form.

An aneurysm is an abnormal bulge or “ballooning” in the wall of an artery. Arteries are blood vessels that carry oxygen-rich blood from the heart to other parts of the body. An aneurysm may grow and become large enough to burst, causing bleeding inside the body that is dangerous and often fatal. Aneurysms can occur in arteries in the brain, heart, intestine, neck, spleen, back of the knees and thighs, and in other parts of the body. Stroke is caused by the bursting of an aneurysm in the brain.

Diagnostic imaging method that shows the blood flow through the heart and primary vessels. It is used to evaluate patients for cardiovascular surgery. A contrast medium is introduced using a catheter inserted into a heart chamber and a series of X-ray images taken to show where the flow narrows, indicating a blockage of a blood vessel by atherosclerosis.

Angiogenesis is the formation of new blood vessels. Angiogenesis is a process controlled by certain chemicals produced in the body. Some of these chemicals stimulate cells to repair damaged blood vessels or form new ones. Other chemicals, called angiogenesis inhibitors, signal the process to stop. The study of natural and synthetic angiogenesis inhibitors, or antiangiogenic agents is important since tumors cannot grow or spread without the formation of new blood vessels.

An angiogram is a procedure that introduces a contrast medium and Xrays to show the blood flow through the heart and primary vessels (such as the aorta or vena cava). An angiogram is used evaluate the arteries or veins in the arms, legs, chest, or belly.

Angiography is a test used to detect blockages of the arteries or veins. A cerebral angiogram can detect the degree of narrowing or obstruction of an artery or blood vessel in the brain, head, or neck. It is used to diagnose stroke and to determine the location and size of a brain tumor, aneurysm, or vascular malformation. This test is usually performed in a hospital outpatient setting and takes up to 3 hours, followed by a 6- to 8-hour resting period. The patient, wearing a hospital or imaging gown, lies on a table that is wheeled into the imaging area. While the patient is awake, a physician anesthetizes a small area of the leg near the groin and then inserts a catheter into a major artery located there. The catheter is threaded through the body and into an artery in the neck. Once the catheter is in place, the needle is removed and a guide wire is inserted. A small capsule containing a radiopaque dye (one that is highlighted on x-rays) is passed over the guide wire to the site of release. The dye is released and travels through the bloodstream into the head and neck. A series of x-rays is taken and any obstruction is noted. Patients may feel a warm to hot sensation or slight discomfort as the dye is released.

Unlike angioplasty, which is an invasive procedure, angiography breaks the skin only for the insertion of a needle for administering a radiopaque catheter and positioning under fluoroscopic control. Also see angiographic.

May involve balloon dilation, mechanical stripping of the inside of the blood vessel, forceful injection of an elastic filamentous protein, or placement of a stent.

Anorexia nervosa is characterized by a distortion of body image and intense fear of gaining weight, causing emaciation and a lack of menstruation among girls and women, and extreme eating disorders involving self-induced vomiting, misuse of laxatives, diuretics or enemas.

Symptom common to tumors of the frontal lobe of the cerebral hemispheres.

Produces a number of hormones that affect other tissues and glands including ACTH, GH, LH, FSH, Prolactin, TSH.

Antibodies are a type of protein made by plasma cells (a type of white blood cell) in response to an antigen, or foreign substance. A single antibody can bind to only one specific antigen to help destroy the antigen. Antibodies can work in several ways, depending on the nature of the antigen. Some antibodies destroy antigens directly; others help white blood cells destroy the antigen.

A drug that helps prevent blood clots from forming; externally administered agents that prevent blood clotting. Also called blood thinner.

The use of anticoagulant drugs to reduce or prevent intravascular or intracardiac clotting.

An Antigen is a substance that causes the immune system to make a specific immune response. An antigen may be a foreign substance from the environment such as chemicals, bacteria, viruses, or pollen. An antigen may also be formed within the body, as with bacterial toxins or tissue cells.

Adult onset as in patients with growth hormone deficiency occurring in adulthood. Also referring to adult onset diseases such as type 2 diabetes.

Sleep apnea is a common sleep disorder characterized by brief interruptions of breathing during sleep. Episodes usually last 10 seconds or more and occur repeatedly throughout the night. People with sleep apnea will partially awaken as they struggle to breathe, but in the morning they will not be aware of the disturbances in their sleep. The most common type of sleep apnea is obstructive sleep apnea (OSA), caused by relaxation of soft tissue in the back of the throat that blocks the passage of air. Central sleep apnea (CSA) is caused by irregularities in the brain’s normal signals to breathe. Most people with sleep apnea will have a combination of both types. The hallmark symptom of the disorder is excessive daytime sleepiness. Additional symptoms of sleep apnea include restless sleep, loud snoring (with periods of silence followed by gasps), falling asleep during the day, morning headaches, trouble concentrating, irritability, forgetfulness, mood or behavior changes, anxiety, and depression. Not everyone who has these symptoms will have sleep apnea, but it is recommended that people who are experiencing even a few of these symptoms visit their doctor for evaluation. Sleep apnea is more likely to occur in men than women, and in people who are overweight or obese.

An arrhythmia is a problem with the speed or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm. A heartbeat that is too fast is called tachycardia. A heartbeat that is too slow is called bradycardia.

Atherosclerosis is a disease in which plaque builds up on the insides of the arteries. Arteries are blood vessels that carry oxygen-rich blood to the heart and other parts of the body.
Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, plaque hardens and narrows the arteries. The flow of oxygen-rich blood to organs and other parts of the body is reduced. This can lead to serious problems, including heart attack, stroke, or even death.
Cerebral arteriosclerosis is the result of thickening and hardening of the walls of the arteries in the brain. Symptoms of cerebral arteriosclerosis include headache, facial pain, and impaired vision.

Arteries that carry blood to the brain are the carotid arteries—one on each side of the neck—that divide into internal and external carotid arteries. The internal carotid arteries supply oxygen-rich blood to the brain. The external carotid arteries supply oxygen-rich blood to the face, scalp, and neck. Carotid artery disease is a condition in which a fatty material called plaque (plak) builds up inside the carotid arteries.

Arthritis is caused by inflammation, of the tissue lining the joints. Some signs of inflammation include redness, heat, pain, and swelling. In some types of arthritis, the joints involved can become severely damaged. There are different types of arthritis. In some diseases in which arthritis occurs, other organs, such as the eyes, the chest, or the skin, can also be affected.

A neurological examination assesses motor and sensory skills, the functioning of one or more cranial nerves, articulation, hearing, vision, coordination and balance, mental status, and changes in mood or behavior, among other abilities.

A structure or substance not normally present but produced by an external agent or action, such as a structure seen in a microscopic specimen after fixation that is not present in the living tissue. For example, in radiology, the appearance on an x-ray of a surgical metal clip that obscures the clear view of an anatomical structure.

Aspiration as a medical procedure is the removal of fluid or tissue through a needle, called a needle biopsy, Breathing in a foreign object (such as sucking food into the airway) The term can also refer to a medical procedure that removes substances from an area of the body such as air, body fluids, or bone fragments.

Presenting no obvious symptoms of the disease. Many pituitary patients however, do have mild symptoms that are simply not recognized by treating physicians.

Atherosclerosis is a disease in which plaque (plak) builds up on the insides of the arteries. Arteries are blood vessels that carry oxygen-rich blood to the heart and other parts of the body. Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, plaque hardens and narrows the arteries. The flow of oxygen-rich blood to the organs and other parts of the body is reduced. This can lead to serious problems, including heart attack, stroke, or even death.

Atrophic vaginitis is an inflammation of the vagina due to thinning and shrinking tissues and a decrease in lubrication. Atrophic vaginitis is typically caused by a decrease in estrogen levels that normally drop after menopause. The disorder may occur in younger women after surgical removal of the ovaries. Some women may develop the condition immediately after childbirth or while breastfeeding, due to low estrogen levels at these times.

Muscle atrophy can be caused by lack of physical exercise (Disuse atrophy), and can be reversed by exercise. But the second and most severe type of muscle atrophy is neurogenic atrophy. It occurs when there is injury or disease to a nerve. This type of muscle atrophy tends to occur more suddenly than disuse atrophy. Diseases affecting the nerves that control muscles are poliomyelitis (polio), amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), and Guillain-Barre syndrome.

In radiology; the loss of energy of a beam of radiant energy due to absorption, scattering, beam divergence, and other causes as the beam propagates through a medium.

An audiology exam tests the ability to hear sounds by intensity (volume or loudness) and tone (the speed of sound wave vibrations). Sound waves move to the nerves of the inner ear and then the brain and can travel to the inner ear by air conduction (the ear canal, eardrum, and bones of the middle ear) or bone conduction (through the bones around and behind the ear).

Taken from an individual's own blood, tissues, cells, or DNA.

Kallmann syndrome is a condition characterized by delayed or absent puberty and an impaired sense of smell. This disorder is a form of hypogonadotropic hypogonadism (HH), which is a condition affecting the production of hormones that direct sexual development. Males with hypogonadotropic hypogonadism are often born with an unusually small penis (micropenis) and undescended testes (cryptorchidism). At puberty, most affected individuals do not develop secondary sex characteristics, such as the growth of facial hair and deepening of the voice in males. Affected females usually do not begin menstruating at puberty and have little or no breast development. In some people, puberty is incomplete or delayed.

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females. Females have two copies of the X chromosome, while males have one X and one Y chromosome.

Numerous nodes around the axillary (below the shoulder joint) veins which receive the lymphatic drainage from the upper limb, scapular region and pectoral region (including mammary gland); they drain into the subclavian trunk.