Health and Medicine Encyclopedia - Vol 13

Health and Medicine Encyclopedia

Hepatitis, Alcoholic - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Alcoholic hepatitis is an inflammation of the liver caused by alcohol. Irritation, be it from toxins or infections, causes a similar response in body organs. The response is known as inflammation and consists of: As the acute process subsides, there is either healing or lingering activity. Lingering activity—chronic disease—has a milder presentation with similar ingredients. Healing …

3 minute read

Hepatitis, Autoimmune - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis

A form of liver inflammation in which the body's immune system attacks liver cells. Autoimmunity causes the body's defense mechanisms to turn against itself. Many of the tissues in the body can be the target of such an attack. While one tissue type predominates, others may be involved in a general misdirection of immune activity, perhaps because the specific target antigen is present…

3 minute read

Hepatitis B - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hepatitis B is a potentially serious form of liver inflammation due to infection by the hepatitis B virus (HBV). It occurs in both rapidly developing (acute) and long-lasting (chronic) forms, and is one of the commonest chronic infectious diseases worldwide. An effective vaccine is available which will prevent the disease in those who are later exposed. Commonly called "serum hepatitis,�…

8 minute read

Hepatitis C - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hepatitis C is a form of liver inflammation that causes primarily a long-lasting (chronic) disease. Acute (newly developed) hepatitis C is rarely observed as the early disease is generally quite mild. Spread mainly by contact with infected blood, the hepatitis C virus (HCV) causes most cases of viral liver infection not due to the A and B hepatitis viruses. In fact, before other viral types were f…

8 minute read

Hepatitis D - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hepatitis D (or delta, the Greek letter "D"), is a form of liver inflammation that occurs only in patients who also are infected by the hepatitis B virus. Infection by the hepatitis delta virus (HDV) either occurs at the same time as hepatitis B develops, or develops later when infection by hepatitis B virus (HBV) has entered the chronic (long-lasting) stage. Delta hepatitis can be q…

6 minute read

Hepatitis, Drug-Induced - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Inflammation of the liver due to an adverse reaction with a drug. The liver is a very important organ to the body. It is a large internal organ weighing more than three pounds in the average adult. It performs over 100 functions including formation of bile, detoxification of harmful substances, vitamin storage and metabolism of carbohydrates, fats and proteins. Serious complications could arise wh…

3 minute read

Hepatitis E - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

The hepatitis E virus (HEV) is a common cause of hepatitis that is transmitted via the intestinal tract, and is not caused by the hepatitis A virus. Spread most often by contaminated drinking water, HEV infection occurs mainly in developing countries. Hepatitis E is also known as epidemic non-A, non-B hepatitis. Like hepatitis A, it is an acute and short-lived illness that can sometimes cause live…

4 minute read

Hepatitis G - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hepatitis G is a newly discovered form of liver inflammation caused by hepatitis G virus (HGV), a distant relative of the hepatitis C virus. HGV, also called hepatitis GB virus, was first described early in 1996. Little is known about the frequency of HGV infection, the nature of the illness, or how to prevent it. What is known is that transfused blood containing HGV has caused some cases of hepat…

2 minute read

Hepatitis Virus Tests - Definition, Purpose, Description, Preparation, Risks, Normal results, Abnormal results

Viral hepatitis is any type of liver inflammation caused by a viral infection. The three most common viruses now recognized to cause liver disease are hepatitis A, hepatitis B, and hepatitis non-A, non-B (also called hepatitis C). Several other types have been recognized: hepatitis D, hepatitis E, and the recently identified hepatitis G. A seventh type (hepatitis F) is suspected but not yet confir…

7 minute read

Herbalism, Traditional Chinese - Definition, Purpose, Description, Preparations, Precautions, Side effects, Research and general acceptance

Chinese herbalism is one of the major components of traditional Chinese medicine (TCM), or Oriental medicine (OM). In TCM, herbs are often used in conjunction with other techniques, such as acupuncture or massage. Chinese herbalism is a holistic medical system, meaning that it looks at treating a patient as a whole person, looking at the mental and spiritual health, as well as the physical health,…

12 minute read

Herbalism, Western - Definition, Purpose, Description, Preparations, Precautions, Side effects, Research and general acceptance

Western herbalism is a form of the healing arts that draws from herbal traditions of Europe and the Americas, and that emphasizes the study and use of European and Native American herbs in the treatment and prevention of illness. Western herbalism is based on physicians' and herbalists' clinical experience and traditional knowledge of medicinal plant remedies preserved by oral tradit…

18 minute read

Hereditary Fructose Intolerance - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hereditary fructose intolerance is an inherited condition where the body does not produce the chemical needed to break down fructose (fruit sugar). Fructose is a sugar found naturally in fruits, vegetables, honey, and table sugar. Fructose intolerance is a disorder caused by the body's inability to produce an enzyme called aldolase B (also called fructose 1-phosphate aldolase) that is neces…

3 minute read

Hereditary Hemorrhagic Telangiectasia - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hereditary hemorrhagic telangiectasia is an inherited condition characterized by abnormal blood vessels which are delicate and prone to bleeding. Hereditary hemorrhagic telangiectasia is also known as Rendu-Osler-Weber disease. The term telangiectasia refers to a spot formed, usually on the skin, by a dilated capillary or terminal artery. In hereditary hemorrhagic telangiectasia these spots occur …

1 minute read

Hernia - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Hernia is a general term used to describe a bulge or protrusion of an organ through the structure or muscle that usually contains it. There are many different types of hernias. The most familiar type are those that occur in the abdomen, in which part of the intestines protrude through the abdominal wall. This may occur in different areas and, depending on the location, the hernia is given a differ…

9 minute read

Hernia Repair - Definition, Purpose, Precautions, Description, Preparation, Aftercare, Risks, Normal results

Hernia repair is a surgical procedure to return an organ that protrudes through a weak area of muscle to its original position. Hernias occur when a weakness in the wall of the abdomen allows an organ, usually the intestines, to bulge out of place. Hernias may result from a genetic predisposition toward this weakness. They can also be the result of weakening the muscle through improper exercise or…

7 minute read

Herniated Disk - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Disk herniation is a rupture of fibrocartilagenous material (annulus fibrosis) that surrounds the intervertebral disk. This rupture involves the release of the disk's center portion containing a gelatinous substance called the nucleus pulposus. Pressure from the vertebrae above and below may cause the nucleus pulposus to be forced outward, placing pressure on a spinal nerve and causing cons…

10 minute read

Hiccups - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hiccups are the result of an involuntary, spasmodic contraction of the diaphragm followed by the closing of the throat. Hiccups are one of the most common, but thankfully mildest, disorders to which humans are prey. Virtually everyone experiences them at some point, but they rarely last long or require a doctor's care. Occasionally, a bout of hiccups will last longer than two days, earning …

3 minute read

High-Risk Pregnancy - Definition, Description, Diagnosis, Treatment, Prognosis, Prevention

A high risk pregnancy is one in which some condition puts the mother, the developing fetus, or both at higher-than-normal risk for complications during or after the pregnancy and birth. A pregnancy can be considered a high-risk pregnancy for a variety of reasons. Factors can be divided into maternal and fetal. Maternal factors include age (younger than age 15, older than age 35); weight (pre-pregn…

6 minute read

Hirschsprung's Disease - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hirschsprung's disease, also known as congenital megacolon or aganglionic megacolon, is an abnormality in which certain nerve fibers are absent in segments of the bowel, resulting in severe bowel obstruction. Hirschsprung's disease is caused when certain nerve cells (called parasympathetic ganglion cells) in the wall of the large intestine (colon) do not develop before birth. Without…

7 minute read

Hirsutism - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis

Excessive growth of facial or body hair in women is called hirsutism. Hirsutism is not a disease. The condition usually develops during puberty and becomes more pronounced as the years go by. However, an inherited tendency, over-production of male hormones (androgens), medication, or disease, can cause it to appear at any age. Women who have hirsutism usually have irregular menstrual cycles. They …

2 minute read

Histiocytosis X - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis

Histiocytosis X is a generic term that refers to an increase in the number of histiocytes, a type of white blood cell, that act as scavengers to remove foreign material from the blood and tissues. Since recent research demonstrated Langerhan cell involvement as well as histiocytes, this led to a proposal that the term Langerhans Cell Histiocytosis (LCH) be used in place of histiocytosis X. Either …

5 minute read

Histoplasmosis - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Histoplasmosis is an infectious disease caused by inhaling the microscopic spores of the fungus Histoplasma capsulatum. The disease exists in three forms. Acute or primary histoplasmosis causes flu-like symptoms. Most people who are infected recover without medical intervention. Chronic histoplasmosis affects the lungs and can be fatal. Disseminated histoplasmosis affects many organ systems in the…

7 minute read

Hives - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Hives is an allergic skin reaction causing localized redness, swelling, and itching. Hives is a reaction of the body's immune system that causes areas of the skin to swell, itch, and become reddened (wheals). When the reaction is limited to small areas of the skin, it is called "urticaria." Involvement of larger areas, such as whole sections of a limb, is called "angioe…

3 minute read

Hodgkin's Disease - Definition, Description, Demographics, Causes and symptoms, Diagnosis, DOROTHY MENDENHALL (1874–1964), Treatment, Alternative treatment

Hodgkin's disease is a rare lymphoma, a cancer of the lymphatic system. Hodgkin's disease, or Hodgkin's lymphoma, was first described in 1832 by Thomas Hodgkin, a British physician. Hodgkin clearly differentiated between this disease and the much more common non-Hodgkin's lymphomas. Prior to 1970, few individuals survived Hodgkin's disease. Now, however, the majo…

21 minute read

Holistic Medicine - Definition, Origins, Purpose, Description, Preparations, Precautions, Side effects, Research and general acceptance, Training and certification

Holistic medicine is a term used to describe therapies that attempt to treat the patient as a whole person. That is, instead of treating an illness, as in orthodox allopathy, holistic medicine looks at an individual's over-all physical, mental, spiritual, and emotional well-being before recommending treatment. A practitioner with a holistic approach treats the symptoms of illness as well as…

11 minute read

Holter Monitoring - Definition, Purpose, Precautions, Description, Preparation, Aftercare, Risks, Normal results, Abnormal results

Holter monitoring is continuous monitoring of the electrical activity of a patient's heart muscle (electrocardiography) for 24 hours, using a special portable device called a Holter monitor. Patients wear the Holter monitor while carrying out their usual daily activities. Holter monitoring is used to help determine whether someone has an otherwise undetected heart disease, such as abnormal …

4 minute read

Holtzman Ink Blot Test - Definition, Purpose, Precautions, Description, Normal results

The Holtzman Inkblot Technique (HIT) is a projective personality assessment test for persons ages five and up. The HIT is used to assess the personality structure of a test subject. It is sometimes used as a diagnostic tool in assessing schizophrenia, depression, addiction, and character disorders. Psychometric testing requires a clinically trained examiner. The HIT should be administered and inte…

2 minute read

Homeopathic Medicine, Acute Prescribing - Definition, Purpose, Description, Preparations, Precautions, Side effects, Research and general acceptance

Acute homeopathic prescribing is that part of homeopathy that treats illness which has an abrupt onset and needs immediate attention. In homeopathic medicine, acute refers primarily to the speed of onset and self-limiting character of the disorder rather than its seriousness. Colds, influenza, sore throats, insect stings, cuts, bruises, vomiting, diarrhea, fever, muscle aches, and short-term insom…

11 minute read

Homeopathic Medicine, Constitutional Prescribing - Definition, Purpose, Description, Preparations, Precautions, Side effects, Research and general acceptance

Constitutional homeopathic prescribing, also called classical prescribing, is a holistic system of medicine that has been practiced for more than 200 years. Unlike acute homeopathic prescribing, constitutional prescribing refers to the selection and administration of homeopathic preparations over a period of time for treatment related to what practitioners call miasmic disorders, those caused by a…

12 minute read

Homeopathy - Definition, Purpose, Description, Precautions, Side effects, Research and general acceptance

Homeopathy, or homeopathic medicine, is a holistic system of treatment that originated in the late eighteenth century. The name homeopathy is derived from two Greek words that mean "like disease." The system is based on the idea that substances that produce symptoms of sickness in healthy people will have a curative effect when given in very dilute quantities to sick people who exhib…

15 minute read

Hookworm Disease - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hookworm disease is an illness caused by one of two types of S-shaped worms that infect the intestine of humans (the worm's host). Two types of hookworm are responsible for hookworm disease in humans. Necator americanus and Ancylostoma duodenale have similar life cycles and similar methods of causing illness. The adult worm of both Necator americanus and Ancylostoma duodenale is about 10 mm…

4 minute read

Hormone Replacement Therapy - Definition, Purpose, Precautions, Description, Preparation, Aftercare, Risks, Normal results

Hormone replacement therapy (HRT) is the use of synthetic or natural female hormones to make up for the decline or lack of natural hormones produced in a woman's body. HRT is sometimes referred to as estrogen replacement therapy (ERT), because the first medications that were used in the 1960s for female hormone replacement were estrogen compounds. In order to understand how HRT works and th…

15 minute read

Hospital-Acquired Infections - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

A hospital-acquired infection is usually one that first appears three days after a patient is admitted to a hospital or other health-care facility. Infections acquired in a hospital are also called nosocomial infections. About 5–10% of patients admitted to hospitals in the United States develop a nosocomial infection. Hospital-acquired infections are usually related to a procedure or treatm…

8 minute read

Human-Potential Movement - Definition, Purpose, Precautions, Description, Risks, Normal results

The human-potential movement is a term used for humanistic psychotherapies that first became popular in the 1960s and early 1970s. The movement emphasized the development of individuals through such techniques as encounter groups, sensitivity training, and primal therapy. Although the human-potential movement and humanistic therapy are sometimes used as synonyms, in reality, humanistic therapy pre…

3 minute read

Human Bite Infections - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Human bite infections are potentially serious infections caused by rapid growth of bacteria in broken skin. Bites—animal and human—are responsible for about 1% of visits to emergency rooms. Bite injuries are more common during the summer months. In adults, the most common form of human bite is the closed-fist injury, sometimes called the "fight bite." These injuries res…

3 minute read

Human Chorionic Gonadotropin Pregnancy Test - Definition, Purpose, Description, Precautions, Preparation, Aftercare, Risks, Abnormal results, Normal results

The most common test of pregnancy involves the detection of a hormone known as human chorionic gonadotropin (hCG) in a sample of blood or urine. To determine whether or not a woman is pregnant. Shortly after a woman's egg is fertilized by her male partner's sperm and is implanted in the lining or the womb (uterus), a placenta begins to form. This organ will help nourish the developin…

6 minute read

Human Leukocyte Antigen Test - Definition, Purpose, Precautions, Description, Preparation, Risks, Normal results, Abnormal results

The human leukocyte antigen test, also known as HLA, is a test that detects antigens (genetic markers) on white blood cells. There are four types of human leukocyte antigens: HLA-A, HLA-B, HLA-C, and HLA-D. The HLA test is used to provide evidence of tissue compatibility typing of tissue recipients and donors. It is also an aid in genetic counseling and in paternity testing. This test may have to …

3 minute read

Huntington Disease - Definition, Description, Diagnosis, Treatment, Prognosis

Huntington disease is a progressive, neurodegenerative disease causing uncontrolled physical movements and mental deterioration. The disease was discovered by George Huntington of Pomeroy, Ohio, who first described a hereditary movement disorder. Huntington disease is also called Huntington chorea, from the Greek word for "dance," referring to the involuntary movements that develop a…

7 minute read

Hydatidiform Mole - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis

A hydatidiform mole is a relatively rare condition in which tissue around a fertilized egg that normally would have developed into the placenta instead develops as an abnormal cluster of cells. (This is also called a molar pregnancy.) This grapelike mass forms inside of the uterus after fertilization instead of a normal embryo. A hydatidiform mole triggers a positive pregnancy test and in some cas…

5 minute read

Hydrocelectomy - Definition, Purpose, Precautions, Description, Preparation, Aftercare, Risks, Normal results, Abnormal results

Hydrocelectomy is a surgical procedure to remove a hydrocele. A hydrocele is collected fluid in the membrane surrounding the testes. Hydrocelectomy is performed to relieve the pain or reoccurrence of a hydrocele. Normally, hydroceles are not very painful. They tend to be a soft swelling in the membrane surrounding the testes. As the hydrocele grows, the scrotum gets larger. Hydroceles do not damag…

2 minute read

Hydrocephalus - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis

Hydrocephalus is an abnormal expansion of cavities (ventricles) within the brain that is caused by the accumulation of cerebrospinal fluid. Hydrocephalus comes from two Greek words: hydros means water and cephalus means head. There are two main varieties of hydrocephalus: congenital and acquired. An obstruction of the cerebral aqueduct (aqueductal stenosis) is the most frequent cause of congenital…

6 minute read

Hydronephrosis - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Hydronephrosis is the swelling of the kidneys when urine flow is obstructed in any of part of the urinary tract. Swelling of the ureter, which always accompanies hydronephrosis, is called hydroureter. Hydronephrosis implies that a ureter and the renal pelvis (the connection of the ureter to the kidney) are overfilled with urine. The kidneys filter urine out of the blood as a waste product. It coll…

5 minute read

Hydrotherapy - Definition, Purpose, Description, Preparations, Precautions, Side effects, Research and general acceptance

Hydrotherapy, or water therapy, is the use of water (hot, cold, steam, or ice) to relieve discomfort and promote physical well-being. Hydrotherapy can soothe sore or inflamed muscles and joints, rehabilitate injured limbs, lower fevers, soothe headaches, promote relaxation, treat burns and frostbite, ease labor pains, and clear up skin problems. The temperature of water used affects the therapeuti…

11 minute read

Hyperaldosteronism - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Hyperaldosteronism is a disorder which is defined by the body's overproduction of aldosterone, a hormone that controls sodium and potassium levels in the blood. Its overproduction leads to retention of salt and loss of potassium, which leads to hypertension (high blood pressure). Also known as Conn's syndrome, primary aldosteronism, and secondary aldosteronism, this disorder takes se…

5 minute read

Hypercalcemia - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hypercalcemia is an abnormally high level of calcium in the blood, usually more than 10.5 milligrams per deciliter of blood. Calcium plays an important role in the development and maintenance of bones in the body. It is also needed in tooth formation and is important in other body functions. Normally, the body maintains a balance between the amount of calcium in food sources and the calcium alread…

8 minute read

Hypercholesterolemia - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Hypercholesterolemia refers to levels of cholesterol in the blood that are higher than normal. Cholesterol circulates in the blood stream. It is an essential molecule for the human body. Cholesterol is a molecule from which hormones and steroids are made. It is also used to maintain nerve cells. Between 75 and 80% of the cholesterol that circulates in a person's blood-stream stream is made …

8 minute read

Hypercoagulation Disorders - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hypercoagulation disorders (or hypercoagulable states or disorders) have the opposite effect of the more common coagulation disorders. In hypercoagulation, there is an increased tendency for clotting of the blood, which may put a patient at risk for obstruction of veins and arteries (phlebitis or pulmonary embolism). In normal hemostasis, or the stoppage of bleeding, clots form at the site of the …

4 minute read

Hyperemesis Gravidarum - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Hyperemesis gravidarum means excessive vomiting during pregnancy. In pregnant women, nausea and vomiting (morning sickness) are common, affecting up to 80% of pregnancies. Hyperemesis, or extreme nausea and excessive vomiting, occur in about 1% of pregnancies. This condition causes uncontrollable vomiting, severe dehydration, and weight loss for the mother. However, hyperemesis gravidarum rarely c…

3 minute read

Hyperhidrosis - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis

A disorder marked by excessive sweating. It usually begins at puberty and affects the palms, soles, and armpits. Sweating is the body's way of cooling itself and is a normal response to a hot environment or intense exercise. However, excessive sweating unrelated to these conditions can be a problem for some people. Those with constantly moist hands may feel uncomfortable shaking hands or to…

2 minute read

Hyperkalemia - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

The normal concentration of potassium in the serum is in the range of 3.5 to 5.0 mM. Hyperkalemia refers to serum or plasma levels of potassium ions above 5.0 mM. The concentration of potassium is often expressed in units of milliequivalents per liter (mEq/L), rather than in units of millimolarity (mM). Both units mean the same thing when applied to concentrations of potassium ions. A normal adult…

5 minute read

Hyperlipoproteinemia - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Hyperlipoproteinemia occurs when there is too much lipid (fat) in the blood. Shorter terms that mean the same thing are hyperlipidemia and hyperlipemia. Dyslipidemia refers to a redistribution of cholesterol from one place to another that increases the risk of vascular disease without increasing the total amount of cholesterol. When more precise terms are needed, hypercholesterolemia and hypertrig…

11 minute read

Hypernatremia - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

The normal concentration of sodium in the blood plasma is 136–145 mM. Hypernatremia is defined as a serum sodium level over 145 mM. Severe hypernatremia, with serum sodium above 152 mM, can result in seizures and death. Sodium is an atom, or ion, that carries a single positive charge. The sodium ion may be abbreviated as Na+ or as simply Na. Sodium can occur as a salt in a crystalline solid…

5 minute read

Hyperopia - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hyperopia (farsightedness) is the condition of the eye where incoming rays of light reach the retina before they converge into a focused image. When light goes through transparent but dense material like the materials of the eye's lens system (the lens and cornea), its velocity decreases. If the surface of the dense material is not perpendicular to the incoming light, as is the case with th…

5 minute read

Hyperparathyroidism - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Parathyroid glands are four pea-sized glands located just behind the thyroid gland in the front of the neck. The function of parathyroid glands is to produce a hormone called parathyroid hormone (parathormone), which helps regulate calcium and phosphorous in the body. Hyperparathyroidism is the overproduction of this hormone. Thyroid glands and parathyroid glands, despite their similar name and pr…

5 minute read

Hyperpigmentation - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prevention

Hyperpigmentation is the increase in the natural color of the skin. Melanin, a brown pigment manufactured by certain cells in the skin called melanocytes, is responsible for skin color. Melanin production is stimulated by a pituitary hormone called melanocyte stimulating hormone (MSH). Other pigments appear in the skin much less often. Darkened spots on the skin come in several varieties. The most…

4 minute read

Hypersensitivity Pneumonitis - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hypersensitivity pneumonitis refers to an inflammation of the lungs caused by repeated breathing in of a foreign substance, such an organic dust, a fungus, or a mold. The body's immune system reacts to these substances, called antigens, by forming antibodies, molecules that attack the invading antigen and try to destroy it. The combination of antigen and antibody produces acute inflammation…

8 minute read

Hypersplenism - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hypersplenism is a type of disorder which causes the spleen to rapidly and prematurely destroy blood cells. The spleen is located in the upper left area of the abdomen. One of this organ's major functions is to remove blood cells from the body's bloodstream. In hypersplenism, its normal function accelerates, and it begins to automatically remove cells that may still be normal in func…

4 minute read

Hypertension - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Hypertension is high blood pressure. Blood pressure is the force of blood pushing against the walls of arteries as it flows through them. Arteries are the blood vessels that carry oxygenated blood from the heart to the body's tissues. As blood flows through arteries it pushes against the inside of the artery walls. The more pressure the blood exerts on the artery walls, the higher the blood…

12 minute read

Hyperthyroidism - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Alternative treatment, Prognosis, Prevention

Hyperthyroidism is the overproduction of thyroid hormones by an overactive thyroid. Located in the front of the neck, the thyroid gland produces the hormones thyroxine (T4) and triiodothyro-nine (T3) that regulate the body's metabolic rate by helping to form protein ribonucleic acid (RNA) and increasing oxygen absorption in every cell. In turn, the production of these hormones are controlle…

5 minute read

Hypertrophic Cardiomyopathy - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention

Cardiomyopathy is an ongoing disease process that damages the muscle wall of the lower chambers of the heart. Hypertrophic cardiomyopathy is a form of cardiomyopathy in which the walls of the heart's chambers thicken abnormally. Other names for hypertrophic cardiomyopathy are idiopathic hypertrophic subaortic stenosis and asymmetrical septal hypertrophy. Hypertrophic cardiomyopathy usually …

4 minute read