Health A-Z

Ventricular Fibrillation

Clinical Definition Ventricular fibrillation is a life-threatening cardiac arrhythmia, marked by rapid, unsynchronized depolarization of the ventricles. Contractions are uncoordinated and ineffective at maintaining proper circulation and blood pressure. Ventricular fibrillation leads to cardiac arrest if not treated immediately. In Our Own Words Ventricular fibrillation is an abnormal heart rhythm, which can be fatal if not reversed

Ventricular Septal Defect (VSD)Hole in the heart

Clinical Definition Ventricular septal defect is a congenital cardiac condition in which the septum separating the ventricles has an abnormal opening, allowing blood to flow directly between the ventricles. Oxygenated blood is shunted back into the pulmonary circulation, which can lead to pulmonary congestion. Clinical presentation and treatment depend on the size of the opening.

Ventricular Tachycardia

Clinical Definition Ventricular tachycardia is a cardiac arrhythmia, originating in the right or left ventricle of the myocardium. Due to the rapid rhythm the myocardium is not able to fill with blood prior to contraction. This prevents blood from circulating through the body efficiently. Ventricular tachycardia may develop due to cardiomyopathy, coronary artery disease or

Vernal Keratoconjunctivitis

Clinical Definition Vernal keratoconjunctivitis is a relatively rare eye disorder involving the palpebral conjunctiva and/or the limbus of the eye. It occurs bilaterally and an allergic response may play a major role. The condition most frequently affects boys and young men in dry subtropical climates. Cobblestone papillae may develop on the upper palpebra. Intense itching,


Clinical Definition Vertebroplasty is a surgical procedure used to treat compression fractures of the spine including the lumbar or thoracic spine. The procedure involves injecting a medical grade surgical cement into the vertebral body, which is intended to stabilize the fracture and decrease pain. In Our Own Words Osteoporosis and other conditions may cause the


Clinical Definition Vertigo is a neurological condition characterized by the perception of dizziness, light-headedness, loss of balance, blurred vision and nausea. In many cases, episodes are triggered by a sudden, biomechanical change in the positioning of the head. In Our Own Words What we may call dizziness can actually be further classified into a bunch

Viral Infection

Clinical Definition Viruses may gain access to the body through various routes, including the digestive, reproductive and respiratory system. Viruses that are pathogenic to humans begin to use the host’s cells to reproduce and cause disease. Viral receptors attach and penetrate healthy cells and use those cells in order to replicate. The severity of a

Vital Signs

Clinical Definition Vital signs are measurements of the body’s basic functions, taken to evaluate the general physical health of a person, track progress during treatment or offer information about possible disease states. The four main vital signs are blood pressure, body temperature, pulse (or heart rate) and respiration (breathing rate). In Our Own Words Vital


Clinical Definition Vitamins are essential organic compounds that an organism requires in small doses for survival. In Our Own Words Vitamins are organic nutrients your body needs to function properly. There are 13 classified vitamins, which fall into two categories: water-soluble or fat-soluble. Fat-soluble vitamins include vitamins A, D, E and K, are stored in


Clinical Definition Vitiligo is a skin disease that most commonly affects epidermis on the face and body and causes skin to lose pigment when melanocytes die (i.e., lightening and sometimes turning white). Vitiligo may affect the hair, inside of the mouth and in some cases, even the eyes. The disease swath can expand over time

Vulvar Cancer

Clinical Definition Vulvar cancer is a rare form of cancer in which malignant cells form in the tissues of the vulva. While it can occur at any age, it is most common in older, postmenopausal women. In Our Own Words Vulvar cancer most often occurs on the inner edges of the labia, which is the

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 you’ve 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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