Hermansky-Pudlak syndrome A group of genetic diseases characterized by a deficiency of pigment in the skin and eye, a bleeding tendency resulting from a platelet storage pool deficiency, and systemic disorders related to deficient function of lysosomes. Abbreviated HPS. Albinism that occurs in the eyes results in significant reduction in visual acuity. Pulmonary fibrosis and…
hernia A general term referring to a protrusion of a tissue through the wall of the cavity in which it is normally contained. Also known as rupture.
hernia, hiatal Protrusion of the stomach up into the opening that is normally occupied by the esophagus in the diaphragm, the muscle that separates the chest cavity from the abdomen. A hiatal hernia can be congenital, or it can be acquired through strenuous physical activity. Hiatal hernias may contribute to gastroesophageal reflux disease with associated…
hemorrhagic fever, viral A set of diseases caused by viruses and characterized by the abrupt onset of high fever and chills, headache, cold and cough, and pain in the muscles, joints, and abdomen, with nausea and vomiting. Abbreviated VHF. One type of hemorrhagic fever is associated with bleeding into the kidney (hemorrhagic fever with renal…
hemorrhoids Dilated (enlarged) veins in the walls of the anus and sometimes around the rectum, usually caused by untreated constipation but occasionally associated with chronic diarrhea. Symptoms start with bleeding after defecation. If untreated, hemorrhoids can worsen, protruding from the anus. Treatment involves changing the diet to prevent constipation and avoid further irritation, the use…
Henoch-Schonlein purpura See anaphylactoid purpura.
heparin One of several glycosaminoglycans (GAGs), an anticlotting agent produced naturally by the liver and some other cells in the body. Heparin may also be purified or synthesized for use as a medication. As a drug, heparin is useful in preventing blood clots that travel from their site of origin through the bloodstream to clog…
heparin, low-weight A relatively new form of the drug heparin (brand names: Lovenox and Fragmin) that has a lower molecular weight than normal heparin. Fewer blood tests are needed for monitoring when low-weight heparin is given, as opposed to traditional unfractionated heparin. Lowweight heparin may be superior to regular (unfractionated) heparin in cases of unstable…
hepatic Having to do with the liver.
hepatic duct A duct that carries bile from the liver into the common bile duct which conveys it to the duodenum (the upper part of the small intestine). There are three hepatic ducts: the right hepatic duct (which drains bile from the right half of the liver); the left hepatic duct (which drains bile from…
hepatitis Inflammation of the liver, irrespective of the cause. Hepatitis is caused by a number of conditions, including drug toxicity, immune diseases, and viruses.
hepatitis, infectious An infectious form of hepatitis, such as hepatitis A.