Definition The term yoga comes from a Sanskrit word which means yoke or union. Traditionally, yoga is a method joining the individual self with the Divine, Universal Spirit, or Cosmic Consciousness. Physical and mental exercises are designed to help achieve this goal, also called self-transcendence or enlightenment. On the physical level, yoga postures, called asanas, are designed...

Definition Yersinosis refers to infection by a genus of bacteria known as Yersinia. The two sub-types that are responsible for yersinosis are Yersinia enterocolitica and Yersinia pseudotuberculosis. The diseases produced by these organisms are called "zoonoses," because the bacteria is passed to humans from animal sources. The name Yersinia comes...

Definition A wound occurs when the integrity of any tissue is compromised (e.g. skin breaks, muscle tears,burns , or bone fractures ). A wound may be caused by an act (such as a gunshot, a fall, or a surgical procedure), by an infectious disease, or by an underlying condition. Description Types and causes of wounds are wide ranging, and healthcare professionals...

Definition Wound flushing is a method of cleaning a wound by applying pressurized water or antiseptic solutions to the tissues. It is also called irrigation. Purpose Wound flushing is used to help flush debris from a wound, lessening the risk of infection or treating an infection that already exists. If the wound is flushed with an antiseptic,...

Definition A wound culture is a laboratory test in which microorganisms from a wound are grown in a special growth medium. It is done to find and identify the microorganism causing an infection in a wound or an abscess. If a microorganism is found, more testing is done to determine how to treat the infection. Purpose Wounds are injuries to...

Definition Women's health is the effect of gender on disease and health that encompasses a broad range of biological and psychosocial issues. Description Women's health is the concept that examines gender differences in health and disease states. The average life expectancy has almost doubled for women (79 years for women and 73 years for men), when compared...

Definition Wolff-Parkinson-White syndrome is an abnormality in the electrical functioning of the heart which may cause rapid heart rates. The abnormality affects the electrical signal between the atria and ventricles. Description Blood is circulated through the heart and body by a muscular pump and valve system involving the atria and ventricles. The...

Definition Withdrawal syndrome occurs in drug and alcohol addicted individuals who discontinue or reduce the use of their drug of choice. This process of eliminating drugs and alcohol from the body is known as detoxification. Anxiety, insomnia, nausea, perspiration, body aches, and tremors are just a few of the physical and psychological symptoms...

Definition Wiskott-Aldrich syndrome (WAS) is a rare inherited disorder marked by a low level of blood platelets, eczema, recurrent infections, and a high risk of leukemia or lymph node tumors. Description WAS was named for the two physicians who first reported the disorder. In 1937, Dr. A. Wiskott, a physician working in Munich, described two affected boys of German ancestry who had repeated...

Definition Wilson disease, or WD, is a rare inherited disorder that causes excess copper to accumulate in the body. It is also known as hepatolenticular degeneration. Steadily increasing amounts of copper circulating in the blood are deposited primarily in the brain, liver, kidneys, and the cornea of the eyes. WD is fatal if it is not recognized and treated. It is...

Definition Wilms' tumor is a cancerous tumor of the kidney that usually occurs in young children. Description When an unborn baby is developing, the kidneys are formed from primitive cells. Over time, these cells become more specialized. The cells mature and organize into the normal kidney structure. Sometimes, clumps of these cells remain in their original, primitive form. If these cells begin to multiply...

Definition Wilderness medicine encompasses the prevention, diagnosis, and treatment of injuries and medical conditions that may occur during activities in remote territories. Purpose Activities that may require wilderness medicine include backpacking, cross-country skiing, mountaineering, white water rafting, scuba diving, and exploration in undeveloped...

Definition Whooping cough, also known as pertussis, is a highly contagious disease which causes classicspasms (paroxysms) of uncontrollable coughing, followed by a sharp, high-pitched intake of air which creates the characteristic whoop that is reflected in the disease's name. Description Whooping cough is caused by a bacteria called Bordetella pertussis. B. pertussis causes its most...

  Definition A white blood cell (WBC) count determines the concentration of white blood cells in the patient'sblood. A differential determines the percentage of each of the five types of mature white bloodcells.   Purpose This test is included in general health examinations and to help investigate a variety of illnesses. An elevated...

Definition Whiplash is a sudden, moderate-to-severe strain affecting the bones, discs, muscles, nerves, or tendons of the neck. Description The neck is composed of seven small bones. Known as the cervical spine, these bones: ·         support the head ·         help maintain an unobstructed enclosure for the spinal...

Definition Wheezing is a high-pitched whistling sound associated with labored breathing. Description Wheezing occurs when a child or adult tries to breathe deeply through air passages that are narrowed or filled with mucus as a result of: ·         allergy ·         infection ·        ...

Definition West Nile virus is a mosquito-borne viral illness that can manifest with varying seriousness, ranging from no symptoms or mild flu-like symptoms to brain damage and death. Description West Nile virus (WNV) is a mosquito-borne flavivirus belonging to the Japanese encephalitis serocomplex, which includes St. Louis encephalitis, Murray Valley encephalitis, and...

Definition Weight loss drugs are medications that may help an obese person lose weight in combination with a low-calorie diet and physical activity. Purpose More than 60% of American adults are overweight or obese. Since the 1980s the number of overweight people has increased steadily and the number of obese people has almost doubled. Excess weight and...

Definition Wegener's granulomatosis is a very rare disease that affects many different organs and systems of the body. It mainly attacks the respiratory system (sinuses, nose, windpipe, and the lungs) and the kidneys. One of the main features of the disease is an inflammation of the blood vessels (vasculitis). The inflammation narrows the blood vessels and reduces the blood flow to the affected organs. This...

Definition The Wechsler intelligence tests are a widely used series of intelligence tests developed by clinical psychologist David Wechsler. Purpose The Wechsler Intelligence Scales for Children (regular, revised, and third edition) and Wechsler Preschool and Primary Scale of Intelligence are used as tools in school placement, in...

Definition Warts are small, benign growths caused by a viral infection of the skin or mucous membrane. The virus infects the surface layer. The viruses that cause warts are members of the human papilloma virus (HPV) family. Warts are not cancerous but some strains of HPV, usually not associated with warts, have been linked with cancer formation. Warts are...

Definition Waldenstrom's macroglobulinemia is a rare, chronic cancer of the immune system that is characterized by hyperviscosity, or thickening, of the blood. Description Waldenstrom's (Waldenstrom, Waldenstroem's) macroglobulinemia (WM) is a lymphoma, or cancer of the lymphatic system. It was first identified in 1944, by the Swedish physician Jan GostaWaldenstrom,...

Definition Inflammation of the vagina and vulva most often caused by a bacterial, fungal, or parasitic infection. Description Vulvovaginitis, vulvitis, and vaginitis are general terms that refer to the inflammation of the vagina and/or vulva (the external genital organs of a woman). These conditions can be caused by bacterial, fungal, or parasitic infections. Also, vulvovaginitis can...

Definition Vulvodynia is chronic pain of the vulva, the external or visible region of the female genitalia, in the absence of vulvar or vaginal infection or skin disease. Description As with other types of chronic pain, vulvodynia can have a significant impact on the quality of life. The disease may interfere with daily activities including sitting, walking, physical exercise, and...

Definition Vulvar cancer refers to an abnormal, cancerous growth in the external female genitalia. Description Vulvar cancer is a rare disease that occurs mainly in elderly women. The vulva refers to the external female genitalia, which includes the labia, the opening of the vagina, the clitoris, and the space between the vagina and anus (perineum). There are...

Definition Von Willebrand disease is caused by a deficiency or an abnormality in a protein called vonWillebrand factor and is characterized by prolonged bleeding. Description The Finnish physician Erik von Willebrand was the first to describe von Willebrand disease(VWD). In 1926 Dr. von Willebrand noticed that many male...

Definition Vocal cord paralysis is the inability to move the vocal cords and the resulting loss of vocal cord function. Description The vocal cords are a pair of tough, fibrous bands that lie across the air column in the middle of the voice box. They assist three functions: breathing, swallowing, and speaking. When vocal cords vibrate, they produce sound, allowing us to speak. Vocal cords...

Definition Vocal cord nodules and polyps are noncancerous growths on the vocal cords that affect the voice. Description The vocal cords, located in the voice box in the middle of the neck, are two tough, fibrous bands that vibrate to produce sound. They are covered with a layer of tissue that is similar to skin. With use, this layer thickens. With heavy use, the thickening...

Definition Vitrectomy is the surgical removal of the vitreous (transparent gel that fills the eye from the iris to the retina). Purpose The bulk of the contents of the eyeball is a clear jelly-like substance that is susceptible to several afflictions that impair vision by damaging its transparency. ·         Infections ·        ...

Definition Vitiligo is a condition in which a loss of cells that give color to the skin (melanocytes) results in smooth, white patches in the midst of normally pigmented skin. Description Vitiligo is a common, often inherited disorder characterized by areas of well-defined, milky white skin. People with vitiligo may have eye abnormalities and also have...

Definition Vitamins are organic components in food that are needed in very small amounts for growth and for maintaining good health. The vitamins include vitamins D, E, A, and K (fat-soluble vitamins), and folate (folic acid ), vitamin B12, biotin, vitamin B6, niacin, thiamin, riboflavin, pantothenic acid, and vitamin C (ascorbic acid) (water-soluble vitamins). Vitamins are...

Definition Vitamin toxicity is a condition in which a person develops symptoms as side effects from taking massive doses of vitamins. Vitamins vary in the amounts that are required to cause toxicity and in the specific symptoms that result. Vitamin toxicity, which is also called hypervitaminosis or vitamin poisoning, is...

Definition Vitamins are small organic molecules that are necessary for many biochemical reactions in the body. For example, many vitamins participate as cofactors in enzyme reactions within the cells. They must be obtained through diet, microorganisms in the gut or sunlight since humans cannot synthesize them. Vitamin tests measure the levels of certain vitamins in...

Definition Vitamin K deficiency exists when chronic failure to eat sufficient amounts of vitamin K results in a tendency for spontaneous bleeding or in prolonged and excessive bleeding with trauma or injury.Vitamin K deficiency occurs also in newborn infants, as well as in people treated with certain antibiotics. The protein in the body most...

Definition Vitamin E deficiency is a very rare problem that results in damage to nerves. When vitamin E deficiency does occur, it strikes people with diseases that prevent the absorption of dietary fats and fat-soluble nutrients. Since vitamin E is a fat-soluble vitamin, it has some of the properties of fat. Description The recommended dietary...

Definition Vitamin D deficiency exists when the concentration of 25-hydroxy-vitamin D (25-OH-D) in the blood serum occurs at 12 ng/ml (nanograms / milliliter), or less. The normal concentration of 25-hydroxy-vitamin D in the blood serum is 25-50 ng/ml. When vitamin D deficiency continues for many months in growing children, the disease...

Definition Vitamin B6 is used by the body as a catalyst in reactions that involve amino acids. Vitamin B6deficiency is rare, since most foods eaten contain the vitamin. Description Vitamin B6 is a water-soluble vitamin. The recommended dietary allowance (RDA) for vitamin B6 is 2.0 mg/day for the adult man and 1.6 mg/day for the adult woman. Vitamin B6 in the diet generally...

Definition Vitamin A deficiency exists when the chronic failure to eat sufficient amounts of vitamin A or beta-carotene results in levels of blood-serum vitamin A that are below a defined range. Beta-carotene is a form of pre-vitamin A, which is readily converted to vitamin A in the body. Night blindness is the...

Definition Total blindness is the inability to tell light from dark, or the total inability to see. Visual impairment or low vision is a severe reduction in vision that cannot be corrected with standard glasses or contact lenses and reduces a person's ability to function at certain or all tasks. Legal blindness (which is actually a severe visual impairment)...

Definition Vision training, also known as vision therapy or orthoptics, consists of a variety of programs to enhance visual performance. It includes treatments for focusing, binocularity, and eye movement problems. Vision training is generally provided by an optometrist (O.D.). Purpose While visual acuity refers to how clearly each eye can see, vision training...

Definition Vibriosis is a disease caused by an infection with bacteria of the Vibrio genus, most commonlyVibrio parahemolyticus or Vibrio vulnificus. Vibrio bacteria cause diarrhea, skin infections, and/or blood infections. The diarrhea-causing Vibrio parahemolyticus is a relatively harmless infection, butVibrio vulnificus infection,...

Definition Vesicoureteral reflux (VUR) refers to a condition in which urine flows from the bladder, back up the ureter, and back into the kidneys. Description The normal flow of urine begins in the collecting system of each kidney. Urine then flows out of each kidney and into a tube called the ureter. Each ureter leads into the bladder, where the urine collects until it is passed...

Definition Ventricular tachycardia (V-tach) is a rapid heart beat that originates in one of the lower chambers (the ventricles) of the heart. To be classified as tachycardia, the heart rate is usually at least 100 beats per minute. Description A rapid heart rate can originate in either the left or right ventricle. Ventricular tachycardia which lasts more than 30 seconds is referred...

Definition Ventricular shunt is a surgical procedure in which a tube is placed in one of the fluid-filled chambers inside the brain (ventricles). The fluid around the brain and the spinal column is called the cerebrospinal fluid. When infection or disease causes an excess of this cerebrospinal fluid in the ventricles, the shunt is placed to drain it and thereby relieve...

Definition A ventricular septal defect is a hole in the wall of the heart (septum) that separates the left lower chamber (left ventricle) from the right lower chamber (right ventricle). The hole allows blood to flow from the left ventricle to the right ventricle instead of entering the aorta for distribution throughout the body. Ventricular septal defect is...

Definition Ventricular fibrillation is a very rapid, uncoordinated, ineffective series of contractions throughout the lower chambers of the heart. Unless stopped, these chaotic impulses are fatal. Description When the ventricles begin to quiver and do not employ coordinated contractions, the heart is said to be fibrillating. In this condition the ventricles cannot pump blood from the heart. Ventricularfibrillation (V-fib)...

Definition A ventricular ectopic beat (VEB) is an extra heart-beat originating in the lower chamber of the heart. This beat, also called a premature ventricular contraction (PVC), occurs before the beat triggered by the heart's normal function. Description Ventricular ectopic beats are common and do not indicate a problem in people without heart...

Definition A ventricular assist device (VAD) is a mechanical pump used for temporary blood circulation support. It decreases the workload of the heart while maintaining adequate flow and blood pressure. Purpose A VAD is a temporary life-sustaining device. VADs can replace the left ventricle (LVAD), the right ventricle (RVAD), or both ventricles (BIVAD). They are used when...

Definition Ventricular aneurysm is a complication of a heart attack (myocardial infarction). It is a ballooning of a section of a blood vessel in the heart that first appears several days or weeks after an acute myocardial infarction. Description A myocardial infarction occurs when a section of the heart wall is deprived of blood and dies (undergoes necrosis,...

Definition Venous insufficiency is described as abnormal blood flow through veins that can cause local damage, damage to affected legs, or death. Description Syndromes related to venous insufficiency are caused by valve incompetence. Venousinsufficiency is a chronic (long term) condition. The number of new and existing cases is dependent on age and...