Health A-Z

Ventricular Fibrillation


Ventricular Septal Defect (VSD)Hole in the heart


Ventricular Tachycardia


Vernal Keratoconjunctivitis






Viral Infection


Vital Signs






Vulvar Cancer


Walking Pneumonia (Atypical Pneumonia)

Clinical Definition Walking pneumonia (atypical pneumonia) is an infectious disease characterized by pulmonary infiltrates. Walking pneumonia is usually clinically milder than other types of pneumonia. The causative agent may vary but is often mycoplasma bacterium. The infection is contagious, and transmission is usually by respiratory droplets from an infected individual. In Our Own Words Walking


Clinical Definition A wart is an abnormal fibrous growth, visible on the skin and caused by a viral infection. Types include common, flat warts, plantar and venereal (Condyloma acuminatum) warts. Caused by direct contact with the contagious human papilloma virus (HPV), warts can spread from person-to-person or via direct contact with an object used by

Weight-Bearing Exercise

Clinical Definition Family practice, Internal medicine, Orthopedics In Our Own Words Weight-bearing exercise can be low-impact, such as stair-step machines, or high-impact, such as running. Bearing weight helps build strong bones and reduces the risk of osteoporosis, the ”brittle bone” disease that can affect both men and women as they age.  Weight-bearing exercise can also

West Nile virus

Clinical Definition West Nile virus is an arthropod-borne flavivirus that is transmitted by mosquitos. Most infected individuals are asymptomatic, but some develop a mild febrile illness; more rarely, individuals develop serious illness such as West Nile meningo-encephalitis. In Our Own Words The West Nile virus is an infection spread by mosquitos. Endemic to Africa, the

Wheat Allergy

Clinical Definition Wheat allergy occurs when the immune system responds in a defensive way to wheat gluten and other proteins. On ingestion, the immune system begins to create specific IgE antibodies against the offending protein. On subsequent consumption, the antibodies bind their target(s), which triggers release of histamines and other chemical signals from immune cells,


Clinical Definition Whiplash is an abrupt flexion or extension movement of the cervical spine. It can potentially damage or strain the neck muscles and ligaments through traumatic movement beyond the natural range of motion. In Our Own Words Whiplash is a condition that occurs when the neck is thrown forward and then backwards in a

Whipworm Infection

Clinical Definition Whipworm infection is a parasitic infection of the large intestine. The causative agent is a nematode of the genus Trichuris. Transmission usually occurs as a result of contact with soil contaminated with whipworm eggs. In some instances, infected individuals may be asymptomatic. In other cases, the infection is characterized by gastrointestinal symptoms, including

Whooping Cough

Clinical Definition Whooping cough is a highly contagious respiratory disease caused by the bacterium Bordetella pertussis. It is characterized by a violent, uncontrollable coughing that makes it difficult to breathe. In Our Own Words Whooping cough occurs when bacteria attach to and damage the cillia in the upper respiratory tract, releasing toxins that cause inflammation.

Wisdom Teeth

Clinical Definition Wisdom teeth (third molars) are the final set of teeth to develop in human beings, and they tend to become impacted and require removal. In Our Own Words Wisdom teeth, also known as third molars, are the final set of human teeth to develop. They are called wisdom teeth because they usually emerge


Clinical Definition Withdrawal is defined as the physical or psychological response to the sudden absence or reduction of a substance that can be addicting, such as alcohol, nicotine or drugs. Among the potential symptoms of alcohol withdrawal are depression and anxiety. A more severe form of alcohol withdrawal is known as delirium tremens or DTs.

X Chromosome

Clinical Definition The X chromosome is a sex chromosome, which determines gender. Typically, each cell in the body has 23 pairs of chromosomes, or a total of 46, with 22 somatic pairs and one pair of sex chromosomes.  Females have two X chromosomes; males have one X and one Y. In Our Own Words The


Clinical Definition An x-ray is a medical imaging procedure, which utilizes electromagnet radiation in order to create images of internal structures of the body. The radiation passes through the body and is absorbed differently based on the density of the structure. X-rays are used diagnostically in order to identify fractures, consolidations and other internal abnormalities.


Clinical Definition Xanthoma is a skin condition in which fatty deposits form beneath the epidermis. While the deposits themselves are not dangerous, they can be indicative of a serious underlying medical condition. Because xanthomas are typically caused by elevated levels of blood lipids, patients with xanthoma may have metabolic disorders such as diabetes, primary biliary


Clinical Definition Xerosis is a dermatologic condition often linked with pruritus and becomes much more common with age, most often affecting the legs, elbows and forearms.  Pruritus sets in as xerosis is easily irritated; the condition is exacerbated by overuse of soaps, perfumes or hot baths. In Our Own Words Xerosis is the medical term


Clinical Definition Xerostomia is an oral condition in which your mouth is extremely dry, resulting from an inadequate flow of saliva, which may affect enjoyment of food and impact the health of your teeth. Saliva fights bacterial build-up in the mouth. In Our Own Words Dry mouth, technically known as xerostomia, occurs when the mouth

Y Chromosome

Clinical Definition The Y chromosome is a sex chromosome, which determines gender. Typically, each cell in the body has 23 pairs of chromosomes, or a total of 46, with one pair of sex chromosomes.  Males typically have one X and one Y; females typically have two X chromosomes. In Our Own Words The Y chromosome

Yeast Infection

Clinical Definition A localized infection caused by fungi of the genus Candida, especially C. albicans, yeast infections may occur in both men and women and manifest as superficial infections located in moist parts of the body: skin folds, oral mucous membranes, respiratory tract, the vagina. Rarely, more serious systemic infections and endocarditis may be due to Candida. In Our

Yellow Fever

Clinical Definition Yellow fever is a serious, potentially-fatal viral infection transmitted by mosquitoes. Travelers to endemic areas, especially in South America and tropical sub-Saharan Africa, may be candidates for vaccination against yellow fever. If a person is bitten by an infected mosquito, symptoms usually develop within one week. In Our Own Words Yellow fever is


Clinical Definition Zinc is a naturally occurring element and an essential nutrient in cellular metabolism, specifically for the immune system, the reproductive system and other neurological functions. In Our Own Words Zinc is an essential trace mineral found in every cell in the body. Zinc supports the immune system and also helps the body produce

Zoster Virus

Clinical Definition Zoster virus, or Varicella-zoster virus, is a virus that causes varicella and herpes zoster, which are better known as chicken pox and shingles. In Our Own Words Zoster virus, also known Varicella-zoster virus, is a highly infectious virus and the cause of chicken pox and shingles. Once youve had chicken pox, the zoster virus


Clinical Definition A zygote is the union of a sperm and egg cell. It contains all the genetic information needed to form a human being, with half of the information originating from the egg and half from the sperm. The zygote travels down the fallopian tube and divides to become a blastocyst and eventually an

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