Click on the alphabet and there you go!

Gait: Manner of walking.

Galactose: Sugar found in milk.

Galactosemia: Inherited disorder due to defective metabolism (processing) of the sugar galactose. Galactosemia is one of the diseases in many newborn genetic screening panels. The disease (which can be fatal, if undetected) is treated by avoiding galactose in the diet.

Gallbladder: A pear-shaped organ that stores bile. It is located below the liver.

Gallstones: Stones in the gallbladder or in the duct leading from the gallbladder to the intestine. There are many types of gallstones.

Gallstones and ERCP (Endoscopic Retrograde Cholangio-Pancreatography): A diagnostic procedure to examine diseases of the bile ducts, liver and pancreas. It is uncomfortable but not painful, is performed under intravenous sedation, usually without general anesthesia, and has a low incidence of complications. ERCP provides important diagnostic information unobtainable by other means. Therapeutic measures can often be take at the time of ERCP to remove stones in the bile ducts or to relieve obstructions of the bile ducts, so that traditional open surgeries can be avoided. ERCP is increasingly accepted as the diagnostic and therapeutic procedure of choice in identifying and removing gallstones in the bile ducts.

Gallop rhythm: Heart rhythm like the gallop of a horse.

Gamete: The sperm or egg. In humans, the gametes normally have 23 chromosomes.

Ganglion: The 2nd century Roman physician Galen first used the word ganglion to denote a nerve complex. Ganglion currently refers to an aggregation of nerve cell bodies. Another use of the word ganglion is for a tendon cyst, commonly near the wrist.

Gangrene: Gangrene is the state of death of tissue due to loss of adequate blood supply.

Gargoylism: From the French gargouille (waterspout), the word conveys the often-grotesque image of the medieval cathedral gargoyle. The term gargoylism was once applied to a condition today called Hurler syndrome.

Gas, intestinal: The complaint referred to as "intestinal gas" is a common one and the discomfort can be quite significant. Everyone has gas and eliminates it by burping or passing it through the rectum. In many instances people think they have too much gas when in reality they have normal amounts. Most people produce 1 to 3 pints of intestinal gas in 24 hours and pass gas an average of 14 times a day. It is made up primarily of odorless vapors such as carbon dioxide, oxygen, nitrogen, hydrogen, and in some families, methane. The unpleasant odor is due to bacteria in the large intestine that release small amounts of gases containing sulfur.

Gastrectomy: Surgery to remove part of all of the stomach.

Gastric: Having to do with the stomach.

Gastric atrophy: A condition in which the stomach muscles shrink and become weak. It results in a lack of digestive juices. Gastritis: Inflammation of the stomach.

Gastric cancer: Cancer of the stomach, the major organ that holds food for digestion. Stomach cancer (gastric cancer) can develop in any part of the stomach and spread to other organs. Stomach ulcers do not appear to increase a person’s risk of developing stomach cancer. Symptoms of stomach cancer are often vague, such as loss of appetite and weight. The cancer is diagnosed with a biopsy of stomach tissue during a procedure. called an endoscopy.

Gastric ulcer: A hole in the lining of the stomach corroded by the acidic digestive juices which are secreted by the stomach cells. Ulcer formation is related to H. pyloridus bacteria in the stomach, anti-inflammatory medications, and smoking cigarettes. Ulcer pain may not correlate with the presence or severity of ulceration. Diagnosis is made with barium x-ray or with the use of a viewing tube slipped through the throat to the stomach (endoscopy).

Gastritis: Inflammation of the stomach.

Gastroenteritis: Inflammation of the stomach and the intestines. Can cause nausea and vomiting and/or diarrhea. Gastroenteritis has numerous causes: including infectious organisms (viruses, bacteria, etc.), food poisoning, and stress.

Gastroenterologist: A doctor who specializes in diagnosing and treating diseases of the digestive system.

Gastroesophageal reflux: The return of stomach contents back up into the esophagus This frequently causes heartburn because of irritation of the esophagus by stomach acid. Gastroesophageal reflux disease (GERD) can lead to scarring and stricture of the esophagus, requiring stretching (dilating) of the esophagus. 10% of patients with GERD develop Barrett’s esophagus which increases the risk of cancer of the esophagus. 80% of patients with GERD also have a hiatal hernia.

Gastrointestinal (GI): Adjective encompassing the stomach and intestines.

Gastrostomy: A surgical opening into the stomach. This opening may be used for feeding usually via a feeding tube called a gastrostomy tube.

Gastroscope: A flexible, lighted instrument that is put through the mouth and esophagus to view the stomach. Tissue from the stomach can be removed through the gastroscope.

Gaucher’s disease, type 1: A progressive genetic disease caused by a defect in an enzyme. The enzyme, called glucocerebrosidase, is needed to break down the chemical glucocerebroside. The enzyme defect in persons with Gaucher’s disease (GD) leads to the accumulation of glucocerebroside in the spleen, liver, and lymph nodes. The most common early sign is enlargement of the spleen (located in the upper left abdomen). Other signs include low red blood cell counts (anemia), a decrease in blood clotting cells (platelets), increased pigmentation of the skin, and a yellow fatty spot on the white of the eye (a pinguecula). Severe bone involvement can lead to pain and collapse of the bone of the hips, shoulders, and spine. The GD gene is on chromosome 1. The disease is a recessive trait. Both parents carry a GD gene and transmit it for their child with the disease. The parents’ risk of a child with the disease is 1 in 4 with each pregnancy. This type of Gaucher’s disease (noncerebral juvenile Gaucher’s disease) is most common in Ashkenazi Jews (of European origin) and is the most common genetic disease among Jews in the United States.

GD: Gaucher’s disease.

Gene: A gene can be defined in various ways. In classical genetics, a gene is a unit of inheritance. In molecular genetics, a gene is a sequence of chromosomal DNA required to make a functional product. Humans have 50-100,000 genes.

Gene deletion: The total loss (or absence) of a gene. Gene deletion plays a role in birth defects and in the development of cancer.

Gene duplication: An extra copy of a gene. Gene duplication is a key mechanism in evolution. Once a gene is duplicated, the identical genes can undergo changes and diverge to create two different genes.

Gene, evolutionarily conserved: A gene that has remained essentially unchanged throughout evolution. Conservation of a gene indicates that it is unique and essential. There is not an extra copy of that gene with which evolution can tinker. And changes in the gene are likely to be lethal.

Gene expression: A gene speaks. When a gene is expressed, the information encoded in the gene is translated into protein or RNA structures present and operating in the cell. Expressed genes include genes that are transcribed into messenger RNA (mRNA) and then translated into protein as well as those genes that are transcribed into RNA (such transfer and ribosomal RNAs) but not translated into protein.

Gene family: A group of genes related in structure (and often in function). The genes in a family are descended from an ancestral gene. For example, the hemoglobin genes (of critical importance to red blood cells) belong to one gene family created by gene duplication and divergence.

Gene markers: Detectable genetic traits or distinctive segments of DNA that serve as landmarks for a target gene. Markers are on the same chromosome as the target gene. They must be near enough to the target gene to be genetically linked to it: to be inherited usually together with that gene, and so serve as signposts to it.

Gene mapping: Charting the relative positions of genes on a DNA molecule or chromosome and the distance, in linkage units or physical units, between them.

General paresis: A part of late ("tertiary") syphilis a decade or more after the initial infection, due to chronic inflammation of the covering and substance of the brain (meningoencephalitis) which results in progressive dementia and generalized paralysis.

Gene product: The RNA or protein that results from the expression of a gene. The amount of gene product is a measure of the degree of gene activity.

Gene testing: Testing a sample of blood (or another fluid or tissue) for evidence of a gene. The evidence can be biochemical, chromosomal, or genetic. The aim is to learn whether a gene for a disease is present or absent.

Gene therapy: The treatment of disease by replacing, altering, or supplementing a gene that is absent or abnormal and is responsible for the disease. In studies of gene therapy for cancer, researchers are trying to bolster the body's natural capacity to combat cancer and make the tumor more sensitive to other kinds of therapy. Gene therapy, still in its early stages, holds great promise for the treatment of many diseases.

Genetic: Having to do with genes, structures found in every cell of the body. Each gene contains information that directs the activities of cells and controls the way an individual develops.

Genetic code: The correspondence of the base triplets (trios composed of A.T.G., or C.) in DNA with the amino acids. The discovery of the genetic code clearly ranks as one of the premiere events of what has been called the Golden Age of Biology (and Medicine).

Genetic screening: Testing a population to identify individuals at risk for a genetic disease or for transmitting it. Newborns may be screened for PKU (phenylketonuria), Jews for the gene for Tay-Sachs disease, Blacks for the sickle cell gene, etc.

Genital: Pertaining to the external and internal organs of reproduction. (Not to be confused with genetic.)

Genital herpes: A viral infection transmitted through intimate contact with the moist mucous linings of the genitals. This contact can involve the mouth, the vagina or the genital skin. The herpes simplex type 2 virus enters the mucous membranes through microscopic tears. Once inside, the virus travels to nerve the roots near the spinal cord and settles there permanently. When an infected person has a herpes outbreak, the virus travels down the nerve fibers to the site of the original infection and when it reaches the skin, the classic redness and blisters occur. The outbreak of herpes is closely related to the functioning of the immune system. Women who have suppressed immune systems, either through stress, disease, or medications, have more frequent and longer-lasting outbreaks. Commonly just called "herpes."

Genital warts: Warts confined primarily to the moist skin of the genitals due to viruses belonging to the family of human papilloma viruses (HPVs) transmitted through sexual contact. Most infected people have no symptoms but these viruses increase a woman’s risk for cancer of the cervix. The virus can also be transmitted from mother to baby during childbirth. HPV infection is the most common sexually transmitted disease in the United States. It is also the leading cause of abnormal PAP smears and pre-cancerous changes of the cervix in women. There is no cure for genital warts virus infection. Once contracted, the virus can stay with a person for life.

Genitourinary (GU): Pertaining to the genital and urinary systems.

Genome: All of the genetic information, the entire genetic complement, all of the DNA possessed by any organism. There is, for example, the human genome, the elephant genome, the mouse genome, the yeast genome, the genome of a bacteria, etc. Humans (and many other higher animals) actually have two genomes—a chromosomal genome and a mitochondrial genome—that together make up their genome.

Genome, chromosomal: All of the genetic information in the chromosomes of an organism. For humans, that is all of the DNA contained in our normal complement of 46 rod-like chromosomes in virtually every cell in the body. (Mature red blood cells, for one exception, have no nucleus and therefore no chromosomes). The chromosomal genome is synonymous with the nuclear genome. Together with the mitochondrial genome, it constitutes the genome of the human being.

Genome, human: All of the genetic information, the entire genetic complement, all of the DNA in a person. Humanity’s DNA is the treasury of human inheritance. It is this extraordinary repository of genetic information which the Human Genome Project in the United States and comparable programs in other countries around the world that belong to HUGO (the HUman Genome Organization) are designed to fully fathom.

Genome, mitochondrial: The genetic information contained in the circular chromosome of the mitochondrion, a structure located outside the nucleus in the cytoplasm of the cell. The mitochondrial genome and the chromosomal (nuclear) genome together constitute the entire genome.

Genomic library: A collection of clones made from a set of randomly generated overlapping DNA fragments representing the entire genome of an organism. As a molecular genetic sequel to John Steinbeck’s "Of Mice and Men", today you can have a mouse genomic library or a human genomic library.

GERD: Stands for GastroEsophageal Reflux Disease, a disorder in which there is recurrent return of stomach contents back up into the esophagus, frequently causing heartburn, a symptom of irritation of the esophagus by stomach acid. This can lead to scarring and stricture of the esophagus, which can require stretching (dilating).10% of patients with GERD develop Barrett’s esophagus which increases the risk of cancer of the esophagus. 80% of patients with GERD also have a hiatal hernia.

Germ cell tumor: A type of brain tumor.

German measles immunization: The standard MMR vaccine is given to prevent measles, mumps and rubella (German measles). The MMR vaccine is now given in two dosages. The first should be given at12-15 months of age. The second vaccination should be given at 4-6 years (or, alternatively, 11-12 years) of age. Most colleges require proof of a second measles or MMR vaccination prior to entrance. Most children should receive MMR vaccinations. Exceptions may include children born with an inability to fight off infection, some children with cancer, on treatment with radiation or drugs for cancer, on long term steroids (cortisone). People with severe allergic reactions to eggs or the drug neomycin should probably avoid the MMR vaccine. Pregnant women should wait until after delivery before being immunized with MMR. People with HIV or AIDS should normally receive MMR vaccine. Measles, mumps, and rubella vaccines may be administered as individual shots, if necessary, or as a measles-rubella combination.

Germinoma: A type of germ cell tumor.

Gestation: From conception to birth.

Giant cell arteritis: A serious disease characterized by inflammation of the walls of the blood vessels (vasculitis). The vessels affected by the inflammation are the arteries (hence the name "arteritis"). The age of affected patients is usually over 50 years of age. Giant cell arteritis can lead to blindness and/or stroke. It is detected by a biopsy of an artery. Giant cell arteritis is treated with high dose cortisone-related medications. Also called temporal arteritis or cranial arteritis.

Gingiva: The gum.

Gingivitis: Gum disease with inflammation of the gums.

Gland: A group of cells that secrete a substance needed by the body.

Glandular fever: Glandular fever is infectious mononucleosis. "Mono" and "kissing disease" are popular terms for this very common illness caused by the Epstein-Barr virus (EBV). By the time most people reach adulthood, an antibody against EBV can be detected in their blood meaning they have been infected with EBV. The illness is less severe in young children. The infection can be spread by saliva. The incubation period for "mono" is 4 to 8 weeks. Symptoms include fever, fatigue, sore throat, and swollen lymph glands. "Mono" can cause liver inflammation (hepatitis) and spleen enlargement. Vigorous contact sports should be avoided to prevent spleen rupture.

Glaucoma: An eye condition in which the fluid pressure inside the eyes rises. Untreated, it leads to vision loss or even blindness. There are several types, including open-angle glaucoma (the common adult-onset) and acute angle-closure glaucoma. The common type of glaucoma, open-angle glaucoma, is an eye disease in which the normal fluid pressure inside the eyes slowly rises, leading to vision loss or even blindness. At the front of the eye, there is a small space called the anterior chamber. Clear fluid flows in and out of the chamber to bathe and nourish nearby tissues. In glaucoma, for still unknown reasons, the fluid drains too slowly out of the eye. As the fluid builds up, the pressure inside the eye rises. Unless this pressure is controlled, it may cause damage to the optic nerve and other parts of the eye and loss of vision. Open-angle glaucoma is so named because the anterior angle of the eye stays open.

Glaucoma detection: You may know of the "air puff" test or other tests used to measure eye pressure in an eye examination. But, this test alone cannot detect glaucoma. Glaucoma is found most often during an eye examination through dilated pupils after drops are put into the eyes during the exam to enlarge the pupils. This allows the eye care professional to see more of the inside of the eye to check for signs of glaucoma.

Glaucoma, risk factors: if you belong to a high-risk group for glaucoma, have your eyes examined through dilated pupils every 2 years by an eye care professional. High-risk groups include everyone with a family history of glaucoma, everyone over the age of 60 and any Black over the age of 40. (Among Blacks, studies show that glaucoma is: 5 times more likely to occur in Blacks than in Whites and about 4 times more likely to cause blindness in Blacks than in Whites).

Glaucoma, symptoms of: At first, there are no symptoms. Vision stays normal, and there is no pain. However, as the disease progress, a person with glaucoma may notice the side vision gradually failing. That is, objects in front may still be seen clearly, but objects to the side may be missed. As the disease worsens, the field of vision narrows and blindness results.

Glaucoma treatment (laser): A laser beam of light is focused on the part of the anterior chamber where the fluid leaves the eye. This results in a series of small changes, which makes it easier for fluid to exit the eye. Over time, the effect of laser surgery may wear off. Patients who have this form of surgery may need to keep taking glaucoma drugs.

Glaucoma treatment (medical): Although glaucoma cannot be cured, it can usually be controlled. Medical treatment can be in the form of eyedrops or pills. Some drugs are designed to reduce pressure by slowing the flow of fluid into the eye, while others help to improve fluid drainage. The regular use of medications usually controls the increased fluid pressure. However, these drugs may stop working over time or they may cause side effects so that the eye care professional may select other drugs, change the dose, or use other means to deal with the glaucoma.

Glaucoma treatment (surgery): Surgery can also help fluid escape from the eye and thereby reduce the pressure. However, surgery is now usually reserved for patients whose pressure cannot be controlled with eyedrops, pills, or laser surgery.

Glioblastoma multiforme: A type of brain tumor.

Glioma: A name for brain tumors that begin in the glial cells, or supportive cells, in the brain. "Glia" is the Greek word for glue.

Glossitis: Inflammation of the tongue.

Glottis: The middle part of the larynx; the area where the vocal cords are located.

Glucocerebrosidase deficiency: Causes Gaucher’s disease (type 1), a progressive genetic disease due to an enzyme defect. The enzyme, glucocerebrosidase, is needed to break down the chemical glucocerebroside. The enzyme defect in persons with Gaucher’s disease (GD) leads to the accumulation of glucocerebroside in the spleen, liver, and lymph nodes. The most common early sign is enlargement of the spleen (located in the upper left abdomen). Other signs include low red blood cell counts (anemia), a decrease in blood clotting cells (platelets), increased pigmentation of the skin, and a yellow fatty spot on the white of the eye (a pinguecula). Severe bone involvement can lead to pain and collapse of the bone of the hips, shoulders, and spine. The GD gene is on chromosome 1. The disease is a recessive trait. Both parents carry a GD gene and transmit it for their child with the disease. The parents’ risk of a child with the disease is 1 in 4 with each pregnancy. This type of Gaucher’s disease (noncerebral juvenile Gaucher’s disease) is most common in Ashkenazi Jews (of European origin) and is the most common genetic disease among Jews in the United States.

Glucose: The sugar that is the chief source of energy.

Glucocorticoid: A hormone that predominantly affects the metabolism of carbohydrates and,to a lesser extent, fats and proteins (and has other effects). Glucocorticoids are made in the outside portion (the cortex) of the adrenal gland and chemically classed as steroids. Cortisol is the major natural glucocorticoid. The term glucocorticoid also applies to equivalent hormones synthesized in the laboratory.

Glucose-6-phosphate dehydrogenase (G6PD): Deficiency of G6PD is the commonest disease-causing enzyme defect in humans affecting an estimated 400 million people. The G6PD gene is on the X chromosome. Males with the enzyme deficiency develop anemia due to breakup of their red blood cells when they are exposed to oxidant drugs such as the antimalarial primaquine, the sulfonamide antibiotics or sulfones, naphthalene moth balls, or fava beans.

Glucose tolerance test (GTT): After fasting, a specific amount (100 grams) of glucose is given by mouth, and the blood levels of this sugar are measured every hour. Normally, the blood glucose should return to normal within 2 to 2 ½ hours. The GTT is considered a classic test of carbohydrate metabolism. It is much used in the diagnosis of diabetes. The GTT depends on a number of factors including the ability of the intestine to absorb glucose, the power of the liver to take up and store glucose, the capacity of the pancreas to produce insulin, and the amount of "active" insulin.

Gluteal: Pertaining to the buttock region formed by the gluteal muscles (gluteus maximus, medius, and minimus).

Gluten: A protein found in wheat or related grains and many foods that we eat. Gluten can be found in a large variety of foods including soups, salad dressings, processed foods and natural flavorings. Unidentified starch, binders and fillers in medications or vitamins can be unsuspected sources of gluten.

Gluten enteropathy: A condition also called celiac sprue whereby the absorption of food nutrients through the small intestine is impaired because of an immune (allergic) reaction to gluten, a protein found in wheat or related grains and many other foods. Frequent diarrhea and weight loss can be symptoms. A skin condition called dermatitis herpetiformis can be associated with celiac sprue. The most accurate test for the condition is a biopsy of the involved small bowel. Treatment is avoidance of gluten in the diet. For stubborn sprue, medications are used.

Goiter: Enlargement of the thyroid gland. A goiter is not cancerous. A goiter can be associated with normal, elevated (hyperthyroidism) or decreased (hypothyroidism) thyroid hormone levels in the blood.

Goiter, diffuse toxic: Graves’ disease, the most common cause of hyperthroidism, too much thyroid hormone.

Goiter, iodide: Just as too little iodine can cause thyroid disease, so may prolonged intake of too much iodine also lead to the development of goiter (swelling of the thyroid gland) and hypothyroidism (abnormally low thyroid activity). Certain foods and medications contain large amounts of iodine. Examples include seaweed; iodine-rich expectorants (such as SSKI and Lugol’s solution) used in the treatment of cough, asthma, chronic pulmonary disease; and amiodarone (Cardorone), an iodine-rich medication used in the control of abnormal heart rhythms (cardiac arrhythmias).

Goiter, toxic multinodular: Condition in which the thyroid gland contains multiple lumps (nodules) that are overactive and produce excess thyroid hormones. This condition is also known as Parry’s disease or Plummer’s disease.

Golfer’s cramp: A dystonia that affects the muscles of the hand and sometimes the forearm and only occurs when playing golf. Similar focal dystonias have also been called typist’s cramp, pianist’s cramp, musician’s cramp, and writer’s’s cramp. Golfer’s cramp provides a reason to switch to tennis (and get tennis elbow).

"Good" cholesterol: High-density lipoprotein (HDL) cholesterol.

Gonadotropin, human chorionic (hCG): A human hormone made by chorionic cells (in the fetal part of the placenta), hCG is directed at the gonads and stimulates them. hCG becomes detectable (by immunologic means) within days of fertilization and forms the foundation of the common pregnancy tests. The level of hCG in maternal serum also enters as one component in the "double" and the "triple" screens used during pregnancy to assign risks of Down syndrome and other fetal disorders.

Gonorrhea: A bacterial infection transmitted by sexual contact. Gonorrhea is one of the oldest known sexually transmitted diseases (STDs). In women infected with this bacteria (Neisseria gonorrhoeae), 25-40% will also be infected with another bacteria that can cause another STD called chlamydia. Gonorrhea is NOT transmitted from toilet seats. More than half of women infected with gonorrhea do not have any symptoms. If symptoms occur, they may include burning or frequent urination, yellowish vaginal discharge, redness and swelling of the genitals, and a burning or itching of the vaginal area. Untreated, gonorrhea can lead to severe pelvic infections.

Gottron's sign: Gottron's sign is a scaly, patchy redness over the knuckles and is seen in patients with dermatomyositis, an inflammatory muscle disorder. (see polymyositis).

Gout: Condition characterized by abnormally elevated levels of uric acid in the blood, recurring attacks of joint inflammation (arthritis), deposits of hard lumps of uric acid in and around the joints, and decreased kidney function and kidney stones. Uric acid is a breakdown product of purines, that are part of many foods we eat. The tendency to develop gout and elevated blood uric acid level (hyperuricemia) is often inherited and can be promoted by obesity, weight gain, alcohol intake, high blood pressure, abnormal kidney function, and drugs. The most reliable diagnostic test for gout is the identification of crystals in joints, body fluids and tissues.

Gout, tophaceous: A form of chronic gout. Nodular masses of uric acid crystals (tophi) are deposited in different soft tissue areas of the body. Even though tophi are most commonly found as hard nodules around the fingers, at the tips of the elbows, and around the big toe, tophi nodules can appear anywhere in the body. They have been reported in unexpected areas such as in the ears, vocal cords, or around the spinal cord!

Gouty arthritis: An attack that is usually extremely painful of joint inflammation due to deposits of uric acid crystals in the joint fluid (synovial fluid) and joint lining (synovial lining). Intense joint inflammation occurs as white blood cells engulf the uric acid crystals, causing pain, heat, and redness of the joint tissues. The term "gout" commonly is used to refer to these painful arthritis attacks but gouty arthritis is only one manifeatation of gout.

Graft: Healthy skin, bone, or other tissue taken from one part of the body to replace diseased or injured tissue removed from another part of the body.

Graft-versus-host disease: A reaction of donated bone marrow against a patient's own tissue. Also called GVHD.

Granuloma: Any of a number of forms of localized nodular inflammation in tissues which have a typical pattern when the involved tissue examined under a microscope. Granulomas typically are caused by a variety of chemical, biologic, or physical irritants of the tissue.

Granuloma, fish bowl: Localized nodular skin inflammation (small reddish raised areas of skin) caused by a bacterium called mycobacterium marinum. Fish bowl granuloma is typically acquired by occupational or recreational exposure to salt or fresh water, often resulting from minor trauma during caring for aquariums. The diagnosis is suggested by the history of exposure and confirmed by culturing tissue specimens which yield the microscopic organism, mycobacterium marinum. The infection can be treated with a variety of antibiotics, including doxycycline, minocycline, clarithromycin, rifampin, and trimethoprim-sulfamethoxazole. Also called "swimming pool granuloma."

Granuloma, swimming pool: Localized nodular skin inflammation (small reddish raised areas of skin) caused by a bacterium called mycobacterium marinum. Swimming pool granuloma is typically acquired by occupational or recreational exposure to salt or fresh water, often resulting from minor trauma during caring for aquariums. The diagnosis is suggested by the history of exposure and confirmed by culturing tissue specimens which yield the microscopic organism, mycobacterium marinum. The infection can be treated with a variety of antibiotics, including doxycycline, minocycline, clarithromycin, rifampin, and trimethoprim-sulfamethoxazole. Also called "fish bowl granuloma."

Granulomatous enteritis: Crohn’s disease, a chronic inflammatory disease of the intestine primarily in the small and large intestines but which can occur anywhere in the digestive system between the mouth and the anus. Named after Burrill Crohn who described the disease in 1932. The disease usually affects persons in their teens or early twenties. It tends to be a chronic, recurrent condition with periods of remission and exacerbation. In the early stages, Crohn’s disease causes small scattered shallow crater-like areas (erosions) called apthous ulcers in the inner surface of the bowel. With time, deeper and larger ulcers develop, causing scarring and stiffness of the bowel and the bowel becomes increasingly narrowed, leading to obstruction. Deep ulcers can puncture holes in the bowel wall, leading to infection in the abdominal cavity (peritonitis) and in adjacent organs.When only the large intestine (colon) is involved, the condition is called Crohn’s colitis. When only the small intestine is involved, the condition is called Crohn’s enteritis. When only the end of the small intestine (the terminal ileum) is involved, it is termed terminal ileitis. When both the small intestine and the large intestine are involved, the condition is called Crohn’s enterocolitis (or ileocolitis). Abdominal pain, diarrhea, vomiting, fever, and weight loss can be symptoms. Crohn’s disease can be associated with reddish tender skin nodules, and inflammation of the joints, spine, eyes, and liver. Diagnosis is by barium enema, barium x-ray of the small bowel, and colonoscopy. Treatment includes medications for inflammation, immune suppression, antibiotics, or surgery. (The disease is also called regional enteritis).

Granulomatous ileitis: Crohn’s disease involving the ileum (the lowest portion of the small intestine).

Graves’ disease: The most common cause of hyperthyroidism (too much thyroid hormone), Graves’ disease is due to a generalized (diffuse) overactivity (toxic) of the whole enlarged thyroid gland (goiter); it is also commonly known as diffuse toxic goiter. There are three components to Graves’ disease: hyperthyroidism, protrusion of the eyes (ophthalmopathy), and skin lesions (dermopathy). Ophthalmopathy can cause sensitivity to light and a feeling of "sand in the eyes." With further protrusion of the eyes, double vision and vision loss may occur. The ophthalmopathy tends to worsen with smoking. Dermopathy is a rare, painless, reddish lumpy skin rash that occurs on the front of the leg. Graves’ disease can run in families. Factors that can trigger Graves’ disease include stress, smoking, radiation to the neck, medications (such as interleukin-2 and interferon-alpha), and infectious organisms such as viruses. Graves’ disease can be diagnosed by a typical thyroid scan (diffuse increase uptake), the characteristic triad of ophthalmopathy, dermopathy, and hyperthyroidism, or blood testing for TSI (Thyroid Stimulating Immunoglobulin) level which is abnormally high.

Gray matter: The cortex of the brain which contains nerve cell bodies. The gray matter is in contrast to the white matter, the part of the brain that contains myelinated nerve fibers. The gray matter is so named because it in fact appears gray. The white matter is white because that is the color of myelin, the insulation covering the nerve fibers. In "The Mysterious Affair at Styles" (1920), Agatha Christie first quoted the fictional Belgian detective Hercule Poirot in regard to his gray matter: "’This affair must be unravelled from within.’ He tapped his forehead. ‘These little grey cells. It is "up to them"—as you say over here.’"

Groin: The area where the thigh meets the hip.

Growing pains: Mysterious pains in growing children, usually in the legs. These pains are similar to what the weekend gardener suffers from on Monday—an overuse type of problem. If in playing, children exceed their regular threshold, they will be sore, just like an adult. Growing pains are typically somewhat diffuse (vs. focal) and are not associated with physical changes of the area (such as swelling, redness, etc.). The pains are usually easily relieved by Messages, Tylenol (acetaminophen), or rest. If the pains persist past a week or there are physical changes, the child should be seen by a physician.

Guanine (G): One member of the base pair G-C (guanine-cytosine) in DNA.

Gum disease: Inflammation of the soft tissue (gingiva) and abnormal loss of bone that surrounds the teeth and holds them in place. Gum disease is caused by toxins secreted by bacteria in "plaque" that accumulate over time along the gum line. This plaque is a mixture of food, saliva, and bacteria. Early symptoms of gum disease include gum bleeding without pain. Pain is a symptom of more advanced gum disease as the loss of bone around the teeth leads to the formation of gum pockets. Bacteria in these pockets cause gum infection, swelling, pain, and further bone destruction. Advanced gum disease can cause loss of otherwise healthy teeth.

Gynecologic oncologists: Doctors who specialize in treating cancers of the female reproductive organs.

Gynecologist: A doctor who specializes in treating diseases of the female reproductive organs.

Gynecology: The word comes from the Greek gyno, gynaikos meaning woman + logia meaning study, so gynecology literally is the study of women. However, these days gynecology does not address all of women’s medicine but focuses on disorders of the female reproductive organs.

Gynecomastia: Excessive development of the male breasts. Temporary enlargement of the breasts is not unusual or abnormal in boys during adolescence or during recovery from malnutrition. Gynecomastia may be abnormal as, for example, in Klinefelter’s syndrome.