Medications

Hepar: The liver or a preparation made from it. The term hepar is not often used today. It is a direct borrowing of the Greek hepar, liver.Last Editorial Review: 10/16/2004...

HEPA - Medical

HEPA: Acronym that stands for High-Efficiency Particulate Air and for High-Efficiency Particulate Arrestor. HEPA filters are used for isolation and immunocompromise units, operating rooms, removal of allergens from the air (for hay fever, asthma, e...

HEOD - Medical

HEOD: The abbreviation for the scientific name of the insecticide dieldrin. (The scientific name for dieldrin [1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4...

Henoch-Schonlein purpura - Medical

Henoch-Schonlein purpura: See: Schonlein-Henoch purpura.Last Editorial Review: 4/27/2011 5:27:15 PM Medical Author: William C. Shiel Jr., MD, FACP, FACR ...

Henna - Medical

Henna: A coloring made from the leaves of the Egyptian privet, Lawsonia inermis. Approved only for use as a hair dye, not for direct application to the skin, as in the body-decorating process known as mehndi. This unapproved use of a color additive t...

Hendra virus - Medical

Hendra virus: A virus, formerly called equine morbillivirus, that can cause illness in horses and humans. First identified in 1994 in Australia where the virus caused the death of two patients, one of pneumonia and the other of encephalitis that deve...

Hemostasis, genetics of - Medical

Hemostasis, genetics of: Inherited factors that play a role in hemostasis, the stoppage of blood flow through a blood vessel. There is genetic regulation of proteins involved in hemostasis and atherothrombotic disorders, including myocardial inf...

Hemostasis - Medical

Hemostasis: The stoppage of bleeding or hemorrhage. Also, the stoppage of blood flow through a blood vessel or organ of the body. Hemostasis is the arrest of bleeding, whether it be by normal vasoconstriction (the vessel walls closing temporarily),...

Hemorrhoids - Medical

Hemorrhoids: See: Hemorrhoid.Last Editorial Review: 4/27/2011 5:27:15 PMHemorrhoid: A dilated (enlarged) vein in the walls of the anus and sometimes around the rectum, usually caused by untreated constipation but occasionally associated with chro...

Hemorrhoidectomy - Medical

Hemorrhoidectomy: Surgical removal of hemorrhoids (enlarged and dilated veins in and around the rectum and anus). Hemorrhoidectomy is usually reserved for severe hemorrhoids if more conservative treatment measures fail to alleviate the symptoms (burn...

Hemorrhoid - Medical

Hemorrhoid: A dilated (enlarged) vein in the walls of the anus and sometimes around the rectum, usually caused by untreated constipation but occasionally associated with chronic diarrhea. The symptoms start with bleeding after defecation. If...

Hemorrhagic fever, epidemic - Medical

Hemorrhagic fever, epidemic: A number of diseases characterized by an abrupt onset of high fever and chills, headache, cold and cough, and pain in the muscles, joints and abdomen with nausea and vomiting followed by bleeding into the kidney and el...

Hemorrhagic fever with renal syndrome - Medical

Hemorrhagic fever with renal syndrome: A number of diseases, also known as hemorrhagic fever, characterized by an abrupt onset of high fever and chills, headache, cold and cough, and pain in the muscles, joints and abdomen with nausea and vomi...

Hemorrhagic diarrhea, E. coli - Medical

Hemorrhagic diarrhea, E. coli: Bloody colitis (inflammation of the bowel) caused by E. coli, usually by the strain E. coli 0157:H7. The diarrhea is severe with painful abdominal cramps, gross blood in the stool, and lasts for 6 to 8 days. Most com...

Hemorrhagic cyst - Medical

Hemorrhagic cyst: This type of functional cyst occurs when bleeding occurs within a cyst. Symptoms such as abdominal pain on one side of the body may be present with this type of cyst. Last Editorial Review: 5/2/2008 Medical Author: ...

Hemorrhagic - Medical

Hemorrhagic: Pertaining to bleeding or the abnormal flow of blood. The patient may have an internal hemorrhagic problem that is not be visible or the patient may have an external hemorrhagic problem that is therefore visible on the outside of the b...

Hemorrhage, subarachnoid - Medical

Hemorrhage, subarachnoid: Bleeding within the head into the space between two membranes that surround the brain. The bleeding is beneath the arachnoid membrane and just above the pia mater. (The arachnoid is the middle of three membranes around the b...

Hemorrhage - Medical

Hemorrhage: Bleeding or the abnormal flow of blood. The patient may have an internal hemorrhage that is invisible or an external hemorrhage that is visible on the outside of the body. Bleeding into the spleen or liver is internal hemorrhage. Bleed...

Hemoptysis - Medical

Hemoptysis: Spitting or coughing up blood or bloody-stained sputum. Pronounced he-MOP-ti-sis. The word "hemoptysis" comes from the Greek "haima" for "blood" + "ptysis" meaning "a spitting" = a spitting of blood. The source of the blood is from the...

Hemopoietic - Medical

Hemopoietic: See: Hematopoietic.Last Editorial Review: 3/5/2004 Hematopoietic: Pertaining to hematopoiesis...

Hemophobia - Medical

Hemophobia: An abnormal and persistent fear of blood. Sufferers of this very common phobia dread the sight of their own blood, the sight of the blood of another person or an animal, and sometimes printed or filmed images of blood or even thoughts of ...

Hemophilia heterozygote - Medical

Hemophilia heterozygote: See: Hemophilia carrier.Last Editorial Review: 8/4/2003 Medical Author: Melissa Conrad Stöppler, MD Melissa Co...

Hemophilia carrier - Medical

Hemophilia carrier: A female carrying a mutant gene for hemophilia on one of her two X chromosomes and a normal allele on her other X chromosome. Hemophilia carriers have concentrations of clotting factor VIII or IX of about 50% of normal and, hence,...

Hemophilia B - Medical

Hemophilia B: Hemophilia due to deficiency of coagulation factor IX in the blood which results in prolonged oozing after minor and major injuries, tooth extractions, or surgery. There is renewed bleeding after the initial bleeding has stopped. The ...

Hemophilia A - Medical

Hemophilia A: Classic hemophilia, due to profound deficiency of factor VIII, a blood factor necessary to normal clotting. The hemophilia A gene is on the X chromosome, so females carry the gene. Each son of a female carrier stands a 50% chance...

Hemophilia - Medical

Hemophilia: A group of inherited bleeding disorders in which the ability of blood to clot is impaired. See: Hemophilia A; Hemophilia B. Last Editorial Review: 4/27/2011 5:27:15 PM Medical Author: Melissa Co...

Hemophagocytic lymphohistiocytosis - Medical

Hemophagocytic lymphohistiocytosis: A rare, cancer-like disorder in which both histiocytes and lymphocytes start to proliferate and attack body tissues or organs. It can be an inherited condition, or it can occur as a result of immunosuppress...

Hemolytic uremic syndrome - Medical

Hemolytic uremic syndrome: A condition characterized by the breakup of red blood cells (hemolysis) and kidney failure. There is clumping of platelets (the blood cells responsible for clotting) within the kidney's small blood vessels with resultant is...

Hemolytic jaundice, congenital - Medical

Hemolytic jaundice, congenital: Known also as hereditary spherocytosis (HS), this is a genetic disorder of the red blood cell membrane clinically characterized by anemia, jaundice (yellowing) and splenomegaly (enlargement of the spleen). In HS the r...

Hemolytic disease of the newborn - Medical

Hemolytic disease of the newborn: Abnormal breakup of red blood cells in the fetus or newborn. This is usually due to antibodies made by the mother directed against the baby's red cells. It is typically caused by Rh incompatibility, that is ...