Medical Glossary: H

Habitual Abortion

Sometimes termed spontaneous abortion, the term refers to the spontaneous, or natural termination of three or more pregnancies each occuring before the Week 20.

Habitual abortion can be the result of chronic infection, hormonal dysfunction, or uterine abnormalities such as incompetent cervix.

Habitual Miscarriage

Sometimes termed spontaneous abortion, the term refers to the spontaneous, or natural termination of three or more pregnancies each occuring before the Week 20.

Habitual miscarriage can be the result of chronic infection, hormonal dysfunction, or uterine abnormalities such as incompetent cervix.

Hb

Abbreviation of hemoglobin, a complex protein-iron compound which forms part of the red blood cells. Hemoglobin carry oxygen to the cells and return carbon dioxide to the lungs.

Concentration of hemoglobin is different for men and women, with levels of 14 - 18 g/dl and 12 - 16 g/dl respectively. It has a structure which consists of 2 chains one with 141 amino acids and the other with 146. Any alteration in the the chains of just one amino acid alters the hemoglobin properties and is associated with sickle cell anemia.

HCG

Abbreviation of human chorionic gonadotropin. HCG is a hormone released into the maternal bloodstream by the developing placenta from about six days after the last period was due (about 22 days after the last menstrual period). Its presence can be detected in the urine by a home pregancy test and a positive result indicates pregnancy. Gonadotropins are used to treat infertility, hypogonadism and nonobstructive cryptorchidism.

Heartburn

Pain and burning in the esophagus, just below the sternum. Often caused by the reflux of gastric contents into the esophagus, it can be relieved, but not cured, with antacids. It is sometimes called pyrosis.

Hegar's Sign

The gradual softening of the isthmus of the uterine cervix, the lower part of the uterus, during the first six weeks of gestation which is often used as and early sign of pregnancy.

Hematocrit

The ratio of red blood cells to total blood volume, mormally about 38% - 46% in women and 42% - 54% in men. The measurement is often used to diagnose and determine the onset of anemia.

Hemoglobin

A complex protein-iron compound which forms part of the red blood cells. Hemoglobin carry oxygen to the cells and return carbon dioxide to the lungs.

Concentration of hemoglobin is different for men and women, with levels of 14 - 18 g/dl and 12 - 16 g/dl respectively. It has a structure which consists of 2 chains one with 141 amino acids and the other with 146. Any alteration in the the chains of just one amino acid alters the hemoglobin properties and is associated with sickle cell anemia.

Hemolytic Disease

When a red blood cell comes to the end of its lifespan it breaks down and releases hemoglobin in a process known as hemolysis. Hemolytic disease, or hemolytic anemia is a disease caused by the breakdown of red blood cells, diluting the concetration of the blood.

Hemorrhage

Rapid blood loss, which may be internal or external. Blood may be lost from an artery, vein or capilliary.

Symptoms are similar to shock, and patients may have a weak pulse, be thirsty with cold clammy skin. All effort must be may to stop the bleeding, using pressure and even ice, to slow the bleeding.

Internal hemorrhaging requires medical attention, and the patient should be kept warm and rested.

Hemorrhoids

Dilation, or swelling, of the veins surrounding the rectum and in the rectal canal. They may be painful and cause bleeding during constipation and defecation. There are a number of treatments ranging from topical creams to surgery.

There is an increased incidence of hemorrhoids during pregnancy, and women are advised to avoid constipation.

Heparin

A mucoploysaccharide that is produced by the basophils and mast cells in the connective tissue surrounding the capillaries and in the lungs and liver and acts as an antithrombin factor (anticoagulant to thin the blood). It is often used by doctors to refer to heparin calcium or heparin sodium which are medications used to thin the blood.

Homan's Sign

A pain felt in the calf when the toes are flexed indicating thrombosis or blood clot in the lower leg.

Hormone

A complex chemical substance created in a part or organ of the body. When released it initiates or regulates activity in an organ or group of cells in another part of the body.

Hormones secreted by endocrine glands are transported through the bloodstream to their target organ. The amount of hormone secreted is regulated either by other hormones, by neurotransmitters, or simply when an excess of the organ's activity indicates a need to reduce the amount of the hormone produced.

Other hormones are produced locally by the organs themselves and are common in the digestive tract.

Hormone Accelerated Labor

The process of induction by administering a hormone such as oxytocin.

HSV-2

An infection whch is caused by the type 2 herpes simplex virus, also known as genital herpes simplex.

Genital herpes is normally transmitted through sexual contact. It can be transmitted to the baby during pregnancy, either through the placenta to the fetus, or to the newborn baby by direct skin contact during delivery.

Symptons include painful lesions that turn into superficial ulcers and heal in a 5 - 7 day period. The disease is self-limiting and treatment is often symptomatic. Proper hygeine is recommended to prevent secondary infections. Patients may wish to contact the National Herpes Resource Center.

Human Chorionic Gonadotropin

Human Chorionic Gonadotropin is a hormone released into the maternal bloodstream by the developing placenta from about six days after the last period was due (about 22 days after the last menstrual period). Its presence can be detected in the urine by a home pregancy test and a positive result indicates pregnancy. Gonadotropins are used to treat infertility, hypogonadism and nonobstructive cryptorchidism. Abbreviated to HCG.

Human Placental Lactogen

A protein hormone secreted by the placenta that promotes growth and is found in the bloodstream.

Hyaline Membrane Disease

A respiratory disease found in preterm babies that results from a lack of surfactant to help keep the lungs open.

Hydatiform Mole

A rare condition in which the egg fails to develop after implantation in the uterine wall. Although there is no baby, the placenta and chorionic villi continue to develop. It is characterized by bleeding during the early and middle pregnancy, and if a miscarriage does not result the growth must be removed.

Hydramnios

A disorder consisting of excess amniotic fluid ocurring in less than 1% of all pregnancies. It is easily diagnosed by palpation, ultrasound, or x-ray. Causes include maternal disorders including toxemia of pregnancy and diabetes mellitus.

Fetal disorders such as anomalies of the gastrointestinal tract, respiratory tract and cardiovascular system may also alter the exchange of amniotic fluid causing hydramnios.

There is increased incidence of premature rupturing of the membranes, premature labor and perinatal mortality. Treatment includes periodic amniocentesis.

Hydrocephalus

A congenital abnormality in which excessive fluid collects on the brain enlarging the skull. Surgical treatment with a survival rate greater than 80% involves a combination of procedures including correction of the ventricular obstruction, reduction of the production of cerbralspinal fluid and the installation of shunts to drain excess fluid to the right atrium of the heart or peritoneal cavity.

Hyperactivity

Sometimes called attention deficit disorder or minimum brain dysfunction, it is a syndrome that affects primarily children and adolescents and is characterized by learning disabilities. The symptoms are associated with functional deviations of the central nervous system, while lacking signs of major neurologic or psychiatric disturbance.

Symptoms include inpaired perception, conceptual, language, memory and motor skills. Hyperactivity and decreased attention span are common.

The condition is ten times more common in boys and result from genetic factors, biochemical imbalances or perinatal injury or disease. While there is no cure, syptoms eventually subside and treatment includes medication and a modified diet.

Hyperbilirubinemia

Greater than normal quantities of the bile pigment bilirubin in the blood. Hyperbilirubinemia is characterized by jaundice, anorexia and malaise.

Causes include liver disease or biliary obstruction but is also the result of excessive destruction of red blood cells. Treatment is dependent on the underlying cause.

Hyperemesis Gravidarum

A term used to describe severe cases of morning sickness. It is most common between the sixth and fourteeth weeks, caused by hormonal changes in the body.

To minimize discomfort eat small meals that are easy to digest, taking care not to allow the stomach to be empty. Hospitalization may be required.

Hyperglycemia

A higher than normal concentration of sugar in the bloodstream. Although most commonly associated with diabetes mellitus, the condition also occurs in newborns as a result of the administration of glucocorticoid hormones and with an excess infusion of intravenous glucose solutions.

Hypertension

A common disorder in which blood pressure is elevated and persistently exceeds 140/90 mmHg. In pregnancy this can reduce blood supply to the fetus. Also known as high blood pressure.

Hyperthermia

A condition in which body temperature is higher than normal. It can either be induced therapeutically or iatrogenically (caused by treatment or diagnostic procedures).

Hyperthyroidism

A condition in which increased levels of the thyroid hormone are found in the bloodstream.

Hypertonicity

A term used to describe a solution in which the solute is found in higher than normal concentrations. A hypertonic saline solution contains elevated levels of salt.

Hyperventilation

A condition in which abnormally heavy breathing can result in too much carbon dioxide being flushed from the bloodstream upsetting the normal chemical balance of the blood.

The result is hypocapnia and respiratory alkalosis which can lead to chest pain, dizziness, faintness and numbness of the fingers and toes.

Hypnosis

A state that resembles normal sleep that can be induced with varying degrees of success in patients. It is usually induced by the monotonous repetition of words and gestures. While used more frequently in psychotherapy it is sometimes used in medicine to reduce pain and promote relaxation.

Hypnotics

A series of drugs used to relax anxious or agitated patients, ideally without inducing unconciousness although they all induce drowsiness. Minor tranquilizers, sometimes referred to as anti-anxiety agents, include chlordiazepoxide, dizepam and hydroxyzine. They have strong potential for addiction. Also known as tranquilizers.

Hypoglycemia

A condition in which the amount of glucose in the bloodstream falls below normal levels. It can be caused by excessive administration of insulin, either naturally or medically, or by dietary deficiency.

Treatment includes the intake of glucose, either in orange juice if the patient is concious, or by intravenous drip if unconcious.

It is sometimes found in babies who have experienced a difficult delivery, are preterm, or born of diabetic mothers. It can be artificially induced in labor if the mother is administered glucose promoting the release of insulin which breaks the sugar down. The baby may need to be given extra sugar.

Hypoplasia

A term used to describe an incomplete or underdevelopment of an organ or tissue. It is usally caused by a decrease in the number of cells. The most common types of hypoplasia are cartillage-hair hypoplasia and enamel hypoplasia.

Hypotension

A condition in which blood pressure is not sufficient to adequately oxygenate the tissues. Causes include an expanded intravascular space, a decreased intravascular volume, or a diminished cardiac thrust. Also known as low blood pressure.

Hypothermia

A potentially dangerous condition in which the body temperature falls to below 96° F (35° C). It is usually the result of prolonged exposure to cold. Symptoms include shallow respiration and a faint heart rate resulting in increased palor and the appearance of death.

Treatment includes a slow warming of the body and hospitalization to treat any metabolic abnormalities that may result. The term is also used to describe a procedure in which the body temperature is deliberately and carefully reduced with cooling mattresses or ice in preparation for some surgical procedures.

Hypothyroidism

Reduced levels of the thyroid hormone in the bloodstream.

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