H. pyloriA type of bacterium that causes inflammation and ulcers in the stomach or small intestine. People with H.
hA20A monoclonal antibody that is being studied in the treatment of refractory B-cell non-Hodgkin lymphoma.
HAARTHighly active antiretroviral therapy. Treatment for human immunodeficiency virus (HIV) infection that uses a combination of several antiretroviral drugs.
HAI Prevention CollaborativeA group of facilities that are engaged in an effort to improve an outcome, in this case to reduce HAIs.
hair follicle(FOL-i-kul) A shaft or opening on the surface of the skin through which hair grows.
hairy cell leukemia(HAYR-ee SEL loo-KEE-mee-uh) A rare type of leukemia in which abnormal B-lymphocytes (a type of white blood cell) are present in the bone marrow, spleen…
Haldol(HAL-dol) A drug used to treat certain mental and neurological disorders. It is also being studied in the treatment of nausea and vomiting caused by some…
half-sibling(HAF-SIB-ling) A person's brother or sister who has one parent in common.
hallucination(huh-LOO-sih-NAY-shun) A sight, sound, smell, taste, or touch that a person believes to be real but is not real.
HalofantrineA drug used against malaria in some countries, but not recommended by CDC.
halofuginone hydrobromideA substance that is being studied for its ability to slow the growth of connective tissue and prevent the growth of new blood vessels to a solid tumor.
haloperidol(ha-loh-PAYR-ih-dol) A drug used to treat certain mental and neurological disorders.
Halsted radical mastectomy(HAWL-sted RA-dih-kul ma-STEK-toh-mee) Surgery for breast cancer in which the breast, chest muscles, and all of the lymph nodes under the arm are removed.
hamartoma(ham-ar-TOE-ma) A benign (noncancerous) growth made up of an abnormal mixture of cells and tissues normally found in the area of the body where the growth…
hand-foot syndromeA condition marked by pain, swelling, numbness, tingling, or redness of the hands or feet.
happy majorA plant whose seeds and root have been used in some cultures to treat certain medical problems. It may have antioxidant effects.
hard palate(PAL-et) The front, bony part of the roof of the mouth.
hawthorn fruitThe fruit of the hawthorn tree or bush. It has been used in some cultures to treat certain medical problems, including heart problems and gastrointestinal…
hazard ratio(HA-zurd RAY-shee-oh) A measure of how often a particular event happens in one group compared to how often it happens in another group, over time.
HCAA chemical that is formed when meat, poultry, or fish is cooked at high temperatures, such as frying, broiling, and barbecuing.
HCD20A monoclonal antibody that is being studied in the treatment of refractory B-cell non-Hodgkin lymphoma.
HCPHealthcare proxy. A type of advance directive that gives a person (such as a relative, lawyer, or friend) the authority to make healthcare decisions for…
hCRFA substance being studied in the treatment of brain cancer. It is made naturally by the hypothalamus (a part of the brain) and can also be made in the…
HDACAn enzyme that changes the way histone binds to DNA. HDAC inhibitors are being studied as a treatment for cancer. Also called histone deacetylase.
HDAC inhibitor(...in-HIH-bih-ter) A substance that causes a chemical change that stops tumor cells from dividing.
HDL (or high-density lipoprotein )A combined protein and fatlike substance. Low in cholesterol, it usually passes freely through the arteries. Sometimes called "good cholesterol."
HDRAn amount of radiation that is greater than that given in typical radiation therapy.
head and neck cancerCancer that arises in the head or neck region (in the nasal cavity, sinuses, lips, mouth, salivary glands, throat, or larynx [voice box]).
healing touchA form of complementary and alternative medicine based on the belief that a vital energy flows through the human body.
Health Care for the Homeless Health CenterA grantee funded under section 330(h) of the Public Health Service Act to provide primary health and related services to homeless individuals.
Health Care TeamA support group of health-care professionals who helps persons manage diabetes.
Health CentersCommunity-based and patient-directed organizations that serve populations with limited access to health care.
Health Insurance Continuity Program (HICP)A program primarily under Part B of the Ryan White HIV/AIDS Program that makes premium payments, co-payments, deductibles, and/or risk pool payments on…
Health LiteracyHow well a person understands and acts on healthcare decisions.
Health Resources and Services Administration (HRSA)The agency of the U.S. Department of Health and Human Services that administers various primary care programs for the medically underserved, including the…
Healthcare Associated InfectionAn infection that develops during or soon after care in a hospital, clinic, or doctor’s office, or after a home-visit by a health professional.
Healthcare providerA person who provides health services, such as, doctor, nurse, dentist, or health educator.
healthcare proxyA type of advance directive that gives a person (such as a relative, lawyer, or friend) the authority to make healthcare decisions for another person.
Healthcare-associated Infection (HAI)Healthcare-associated Infections are infections that patients acquire during the course of receiving treatment for other conditions within a healthcare…
healthy controlIn a clinical study, a person who does not have the disorder or disease being studied.
Heart AttackDamage to the heart muscle caused when the blood vessels supplying the muscle are blocked, such as when the blood vessels are clogged with fats (a…
heart cancer(hart KAN-ser) A rare cancer that develops in tissues of the heart. Also called cardiac sarcoma.
heat shock protein(... PROH-teen) One of a group of proteins that help protect cells from stresses such as heat, cold, and low amounts of oxygen or glucose (sugar).
Hedyotis diffusaAn herb used in traditional Chinese medicine to treat certain medical problems.
helical computed tomography(HEH-lih-kul kum-PYOO-ted toh-MAH-gruh-fee) A detailed picture of areas inside the body.
Helicobacter pylori(HEEL-ih-koh-BAK-ter py-LOR-ee) A type of bacterium that causes inflammation and ulcers in the stomach or small intestine.
helper T cellA type of white blood cell that helps stimulate immune system reactions. Helper T cells help activate cytotoxic T cells and macrophages by secreting…
hemagglutinin-neuraminidaseA protein found in the outer coat of paramyxoviruses. This protein helps virus particles bind to cells, making infection easier.
hemangiopericytoma(heh-MAN-jee-oh-PAYR-ih-sy-TOH-muh) A type of cancer involving blood vessels and soft tissue.
hemangiosarcomaA type of cancer that begins in the cells that line blood vessels.
HematocritThe amount of blood consisting of red blood cells, measured as a percentage.
hematogenous(HEE-muh-TAH-jeh-nus) Originating in the blood or spread through the bloodstream.
heme (heem)The part of certain molecules that contains iron. The heme part of hemoglobin is the substance inside red blood cells that binds to oxygen in the lungs…
hemihypertrophy(HEM-ee-hy-PER-troh-fee) A condition in which one side of the body or a part of one side is larger than the other.
hemilaryngectomy(HEM-ee-LA-rin-JEK-toh-mee) An operation to remove one side of the larynx (voicebox).
hemochromatosis(HEE-moh-kroh-muh-TOH-sis) A condition in which the body absorbs more iron from food than it needs.
HemodialysisThe most common form of treatment for end stage renal failure. Surgery is required to join one artery to a vein to form a larger vein called a fistula or…
hemoglobin(HEE-moh-GLOH-bin) The substance inside red blood cells that binds to oxygen in the lungs and carries it to the tissues.
HemolysisDestruction of red blood cells. Malaria causes hemolysis when the parasites rupture the red blood cells in which they have grown.
hemophagocytic lymphohistiocytosis(HEE-moh-FAG-oh-SIT-ik LIM-foh-HIS-tee-oh-sy-TOH-sis) A rare disorder in which histiocytes and lymphocytes (types of white blood cells) build up in organs…
hemophiliaGroup of hereditary disorders in which affected individuals fail to make enough of certain proteins needed to form blood clots.
hemoptysis(hee-MOP-tih-sis) Coughing or spitting up blood from the respiratory tract.
hemorrhageIn medicine, loss of blood from damaged blood vessels. A hemorrhage may be internal or external, and usually involves a lot of bleeding in a short time.
hemorrhoid(HEH-muh-ROYD) An enlarged or swollen blood vessel, usually located near the anus or the rectum.
heparin(HEH-puh-rin) A substance that slows the formation of blood clots. Heparin is made by the liver, lungs, and other tissues in the body and can also made in…
hepatectomy(HEH-puh-TEK-toh-mee) Surgery to remove all or part of the liver.
hepatic arterial infusion(heh-PA-tik ar-TEER-ee-ul in-FYOO-zhun) A procedure to deliver chemotherapy directly to the liver.
hepatic arterial occlusion(heh-PA-tik ar-TEER-ee-ul uh-KLOO-zhun) A block in blood flow to the liver. It can happen while giving chemotherapy through a catheter in the hepatic…
hepatic artery(hih-PA-tik AR-tuh-ree) The major blood vessel that carries blood to the liver.
hepatic portal veinA blood vessel that carries blood to the liver from the stomach, small and large intestines, spleen, pancreas, and gallbladder. Also called portal vein.
hepatic veno-occlusive diseaseA condition in which some of the veins in the liver are blocked. It is sometimes a complication of high-dose chemotherapy given before a bone marrow…
hepatitis(HEH-puh-TY-tis) Disease of the liver causing inflammation. Symptoms include an enlarged liver, fever, nausea, vomiting, abdominal pain, and dark urine.
hepatitis A vaccine(HEH-puh-TY-tis ... vak-SEEN) A vaccine used to prevent infection with the hepatitis A virus, which causes a serious liver disease.
hepatitis A virus(HEH-puh-TY-tis ... VY-rus) A virus that causes a serious liver disease. It is usually spread by contact with an infected person's stool by eating food he…
hepatitis B virus(HEH-puh-TY-tis ... VY-rus) A virus that causes hepatitis (inflammation of the liver). It is carried and passed to others through blood or sexual contact.
hepatitis C virus(HEH-puh-TY-tis ... VY-rus) A virus that causes hepatitis (inflammation of the liver). It is carried and passed to others through blood or sexual contact.
hepatitis D virus(HEH-puh-TY-tis ⦠VY-rus) A type of hepatitis virus that may be present in the body at the same time as the hepatitis B virus.
hepatitis delta virus(HEH-puh-TY-tis DEL-tuh VY-rus) A type of hepatitis virus that may be present in the body at the same time as the hepatitis B virus.
hepatitis E virus(HEH-puh-TY-tis ⦠VY-rus) A virus that causes hepatitis (inflammation of the liver).
hepatitis G virus(HEH-puh-TY-tis ⦠VY-rus) A virus that may be found in patients with hepatitis (inflammation of the liver).
hepatobiliaryHaving to do with the liver, bile ducts, and/or gallbladder.
hepatoblastoma(HEP-a-toh-blas-TOH-muh) A type of liver tumor that occurs in infants and children.
hepatocellular carcinoma(HEP-a-toe-SEL-yoo-ler KAR-sih-NOH-muh) A type of adenocarcinoma, the most common type of liver tumor.