Health A-Z

Clinical Definition Dry eye, or keratoconjunctivitis sicca, has a literal definition: dryness of the cornea and conjunctiva (i.e., the membrane covering outer eye surface). It occurs when the eyes don’t produce enough moisture, resulting in stinging, burning and irritation. Treatments ranging from artificial tears to surgery can relieve symptoms. In Our Own Words Dry eye,…

Clinical Definition Ductal carcinoma in situ, or DCIS, is non-invasive or pre-invasive breast cancer. Cells lining the ducts have developed the appearance of cancerous cells but have not invaded the ductal walls to surrounding breast tissues. The cure rate is high. In Our Own Words Ductal carcinoma in situ, or DCIS, is early stage breast…

Clinical Definition Dyslexia is a neurologically based learning disorder, which impairs comprehension and processing of written language. Dyslexia usually is characterized by difficulty with spelling, phonological processing and fluent and accurate recognition of words. Although intelligence level is usually normal, the ability to read is impaired. In Our Own Words Dyslexia is a common learning…

Clinical Definition Dyspepsia is a subjective feeling of pain or discomfort in the upper abdomen due to irritation of the stomach or processes involving the stomach. It can be acute or chronic, and treatment focuses on medications to reduce symptoms and mitigate the underlying causes, such as agents to reduce stomach acid or quell infections…

Clinical Definition Ebola virus, named after a river in Africa where it was first recognized in 1976, is typically zoonotic (i.e., animal borne, such as from monkeys) and can cause Ebola hemorrhagic fever, a serious and often fatal disease in people and animals alike. No approved anti-viral drugs are available, and the infection may result…

Clinical Definition An echocardiogram is the record of images and other data obtained through use of ultrasound technology in the investigation of the heart and great vessels, and for the diagnosis of cardiovascular lesions. In Our Own Words Echocardiography, or echo, is recorded imagery that utilizes ultrasound technology to create moving pictures of the heart,…

Clinical Definition Eczema is a chronic or recurrent inflammation of the skin, producing dryness, itchiness and flakiness manifesting as red to brownish patches; small raised bumps; and cracked, scaly or raw and inflamed skin. It may be accompanied by – or linked to – allergies, asthma or hay fever. In Our Own Words “Eczema” and…

Clinical Definition Edema is systemic swelling caused by an abnormal accumulation of fluids in the tissues of the body. Peripheral edema, which occurs in the feet, ankles and legs, is the most common. In Our Own Words Edema is defined as an excessive accumulation of watery fluid in tissues or body cavities, marked by swelling…

Clinical Definition Electrolytes are negatively and positively charged minerals and salts in the body, which assist in balancing cellular fluid levels. Proper levels of electrolytes are essential for maintaining normal pH blood levels, transmitting nerve impulses and muscle contraction. Electrolyte levels in the body may become imbalanced through emesis, excessive perspiration, endocrine disorders and kidney…

Clinical Definition Embolism refers to the occlusion of a blood vessel by an embolus (mass) that moves down the bloodstream and gets lodged in a blood vessel, causing circulation problems. In Our Own Words An embolism is when an embolus, which is a clump, bubble or mass, gets stuck in the bloodstream and causes a…

Clinical Definition An EMG, or electromyogram, is a test that measures electrical activity of the muscles and the nerves that control them during a two-part examination. It is part of an evaluation to help to detect causes of numbness, paralysis and spasm as well as facial and extremity pain. In the first part, the ability…

Clinical Definition Emphysema is a chronic respiratory disease that occurs when the alveoli of the lungs become damaged and lose their elastic properties. Respiratory function is compromised when atelectasis occurs (over-inflation of the alveoli), and damage to the alveoli interferes with gas exchange. Development of disease is due to long-term inhalation of lung irritants like…

Clinical Definition Endocarditis is an inflammation of the heart valves or the endocardium, most commonly caused by a bacterial infection. It occurs when organisms (usually bacteria, but rarely fungi) enter the bloodstream and then reach the endocardium or the valves. Without proper treatment, endocarditis can be fatal. In Our Own Words Endocarditis occurs when the…

Clinical Definition A common urinary tract disorder for men over age 60, an enlarged prostate gland presses against the urethra (tubal transport) and can block the flow of urine from the bladder. In Our Own Words The prostate is a walnut-shaped gland at the base of the male bladder that produces a fluid that forms…

Clinical Definition Erectile dysfunction (ED) is the inability to get or maintain an erection sufficient for sexual intercourse. ED may or may not be associated with other kinds of sexual dysfunction, such as decreased libido or problems with orgasm and/or ejaculation. In Our Own Words Erectile dysfunction (ED) occurs when a man is unable to…

Clinical Definition Esophagitis is a swelling and irritation of the esophagus. As a result, swallowing can be painful or difficult. Causes can include acid reflux, vomiting, medications, infections and an allergy-associated condition known as eosinophilic esophagitis. In Our Own Words Esophagitis is inflammation and irritation of the esophagus (i.e. the tube that transports liquids and…

Clinical Definition Exercise-induced asthma is a condition in which bronchospasm, airway inflammation and increased mucus production result from physical exertion or exercise. Exercise is a trigger for asthma exacerbation for the following reasons: During physical exercise, hyperventilation and oral breathing often occur. The air is not humidified and warmed through the nasal passages. Cold, dry…

Clinical Definition The fallopian tubes are two hollow tubes attached to each side of the uterus that transport the ova from the ovary to the uterus. Sperm typically fertilize ova within the fallopian tubes, and the fertilized ovum travels to the uterus for implantation. Tubal ligation is a form of permanent contraception unless it is…

Clinical Definition Fetal alcohol syndrome, or FAS, is a collection of congenital defects, such as ventricular septal defect or atrial septal defect, facial abnormalities and other developmental problems caused by exposure of the fetus to alcohol during pregnancy. Alcohol consumption during the first trimester is most hazardous. In Our Own Words Fetal alcohol syndrome, or…

Clinical Definition Fever is a physiological response, usually to disease, characterized by elevated core body temperature outside the normal levels. The hypothalamus regulates body temperature. When a pyrogen triggers a fever, arachidonic acid metabolites are released. The metabolites affect the hypothalamus causing a complex, systemic response in the body, which then results in increased body…

Clinical Definition A uterine fibroid, or leiomyoma, is a noncancerous tumor composed of muscle and connective tissue from the uterine wall. Fibroids grow as a single nodule or in clusters, ranging from a millimeter to more than 20 centimeters in diameter. Bleeding is a common presenting symptom. Not all fibroids need treatment, but treatments include…

Clinical Definition Fibromyalgia is a disorder of unknown etiology marked by widespread pain in muscles, tendons and joints all over the body. The condition is also involved with sleep patterns, depression, fatigue and psychological distress. While the exact cause is unknown, one theory proposes that chronic stress contributes to the onset of the disorder, once…

Clinical Definition Flatulence is gas in the intestines or stomach that is expelled from the anus.  Gas in the digestive tract originates from the normal breakdown of undigested foods by bacteria that normally live in the colon, as well as from swallowing air. While some gas is expelled by burping or belching, other gas is…

Clinical Definition Flora are bacteria and other microorganisms that live on the skin and inside the body. The term refers most frequently to bacteria that inhabit the gastrointestinal tract. In Our Own Words Flora are essentially tiny bugs, or bacterium, that live both inside the body and outside on the skin. Particular kinds of flora…

Clinical Definition Food poisoning is the term used to describe an acute illness caused by ingesting contaminated food. The causative agent in food is usually bacteria, parasites or viruses. Bacteria that commonly cause food poisoning include Escherichia coli and Campylobacter. Food poisoning often causes gastrointestinal symptoms. In Our Own Words Whether we like it or…

Clinical Definition A fracture is a condition in which the alignment of a bone in the skeletal system is broken or disrupted. Fractures are usually caused by excessive force on the bone due to trauma. Individuals with medical conditions, such as osteoporosis, that weakens the bones are at an increased risk of bone fractures. There…

Clinical Definition Fungi such as yeast and mold can act as pathogens or produce toxins, living as parasites on plants and animals. Fungi can cause an inflammatory condition known as a fungal infection. In Our Own Words As with bacteria, fungi can be good or bad, and they are virtually everywhere in our environment. A…

Clinical Definition A person’s gait is a series of rhythmical alternating movements of the trunk and limbs, which result in the forward progression of the center of gravity. In Our Own Words The way in which a person walks or runs, including the speed, stride length, posture and foot movements, is referred to as his…

Clinical Definition Gangrene is the death of tissue in part of the body because it has lost its blood supply as the result of injury, infection or other causes. Gas gangrene, a severe form that can progress rapidly and become lethal, is caused by the bacterium Clostridium perfringens and is more likely to affect those with underlying…

Clinical Definition Gastric bypass is a surgical intervention for obese patients or for patients with combination of a higher BMI and an obesity-related health problem such as uncontrollable type 2 diabetes. Of the many procedures, the Roux-en-Y gastric bypass is the most common. The surgeon creates a small pouch by dividing the upper end of…

Clinical Definition Gastroenterology is study of the normal function and diseases of the esophagus, colon, rectum, pancreas, gallbladder, bile ducts and liver. The science of gastroenterology involves a detailed understanding of the normal actions of the gastrointestinal organs, including movement of material through organs, digestion, waste removal and organ function. In Our Own Words Gastroenterology…

Clinical Definition GERD, Gastroesophageal reflux disease, is a digestive disorder that causes gastric contents to reflux from the stomach back up to the esophagus, and usually occurs when the lower esophageal sphincter muscle fails to contract properly. Prolonged exposure to gastric contents can lead to complications and esophageal tissue damage, such as erosive esophagitis and Barrett’s…

Clinical Definition Gingivitis is inflammation of the gums caused by bacterial growth in the mouth. If not properly treated, it can progress to periodontal disease and end up destroying the tissue that supports the teeth, leading to tooth loss. In Our Own Words Gingivitis is the early stage of gum disease caused by the buildup…

Clinical Definition Glaucoma is an eye disease that can lead to blindness. Often associated with higher pressures of the aqueous humor (clear fluid) that circulates inside the front part of the eye, when pressure builds, it can potentially damage the optic nerve, interfering with transmission of images to the brain. In Our Own Words Glaucoma…

Clinical Definition Gonorrhea, a common sexually transmitted infection (STI), is a bacterial infection that affects both men and women. Left untreated, in women it can spread to the uterus or fallopian tubes, triggering pelvic inflammatory disease, infertility and an increased risk of tubal pregnancies; in men, it can contribute to epididymitis and sometimes scarring and…

Clinical Definition A grand mal seizure is a generalized seizure, involving both sides of the brain and loss of consciousness. It is characterized by two main phases, including the tonic phase and the clonic phase. The tonic phase consists of the sudden onset of muscle rigidity. The seizure then progresses into the clonic phase, which…

Clinical Definition Graves’ disease is a syndrome in which the sufferer has a thyroid gland that produces excessive amounts of thyroid hormone. This thyroid hormone controls bodily functions such as digestion, metabolism, body temperature and heart rate. In Our Own Words The thyroid gland, at the front of the neck, is crucial in regulating heart…

Clinical Definition Gynecomastia is an abnormal development of the mammary glands in males. The condition is different from an enlarged breast area due to obesity and an increase in adipose tissue. Gynecomastia is usually benign and may develop unilaterally or bilaterally. In Our Own Words Gynecomastia is the abnormal enlargement of breasts in men or…

Clinical Definition H. pylori is a bacterium that can infect the stomach or duodenum (first part of the small intestine), causing inflammation, irritation and ulcers. Infection with H. pylori is also a risk factor for some gastric cancers. The infection can be treated with antibiotics and acid-reducing medication. In Our Own Words H. pylori bacteria…

Clinical Definition Halitosis is a dental health condition characterized by odorous breath. It may occur due to oral pathology, such as poor oral hygiene, dental infections and gum disease. Some systemic diseases, such as renal and kidney disease, may also cause halitosis. In other instances, halitosis is the result of ingestion of certain foods. In…

Clinical Definition Hammertoe or hammertoe syndrome describes a sometimes-painful condition in which a toe bends, curling up and under, resembling a hammer. The toe is initially still flexible, but as the condition progresses, it may become rigid and require surgical intervention. In Our Own Words Hammertoe, also called hammertoe syndrome, can be caused by a…

Clinical Definition Hay fever, also called seasonal allergic rhinitis or simply rhinitis, is the most prevalent type of allergy. It is caused by an IgE-mediated immune response to allergens that are airborne and inhaled. The condition is marked by sneezing, a runny nose and itching. Avoiding exposure to the allergen; taking over-the-counter or prescription medicines;…

Clinical Definition The ventricles are the two lower chambers of the heart. In Our Own Words The heart is divided in two halves by a wall or septum. Each half of the heart has a smaller upper chamber (atrium) and a larger lower chamber (ventricle). The ventricles receive blood from the atria. The right half…

Clinical Definition Heat stroke is the most severe of three types of heat emergencies, also including heat cramps and heat exhaustion. Heat stroke can cause shock, brain damage, organ failure and death. Fever, irrational behavior and confusion are common. In Our Own Words Heat stroke is the most severe form of heat-related illness and can…

Clinical Definition Hematuria, or blood in the urine, indicates that red blood cells are present. Even if you cannot see blood, you might have microscopic blood in your urine. Normally, the kidneys prevent blood from entering urine, but blood coming from the kidneys or other parts of the urinary tract (ureters, bladder, prostate, urethra) can…

Clinical Definition A hernia is a bulge or protrusion of one organ or tissue through a wall or partition that normally contains it or holds it in. Hernias can develop in any number of locations in the human body, but often involve a portion of the gastrointestinal tract bulging through the abdominal/pelvic wall. In Our…

Clinical Definition HIV, or human immunodeficiency virus, is a retrovirus that destroys the vital CD4 + T-cells of the immune system. Destruction of CD4 cells decreases immune system function and leaves patients susceptible to infections and disease. The infection can progress into acquired immunodeficiency syndrome (AIDS) if CD4+ T cells decrease to less than 200…

Clinical Definition Homeopathic medicine is a system of alternative medicine based on the theory that utilizing potentiated substances, which in larger amounts would cause illness in healthy people, will allow or stimulate the body to heal itself. Homeopathic medicines are often made from plants and minerals and are used to treat a wide variety of…

Clinical Definition Human papilloma virus (HPV) is a common infection caused by the papovaviridae family of viruses. There are many types of human papilloma viruses. More than 40 types of HPV are transmitted sexually and can affect the genitals. Genital HPV is associated with certain types of malignancies, including cervical neoplasia, laryngeal and anogential carcinomas.…

Clinical Definition Hyperthyroidism is a endocrine-based condition that occurs when your level of thyroid hormones, T3 and T4, are above normal, and your thyroid-stimulating hormone (TSH) is low. In Our Own Words Located in the lower part of your neck, your thyroid gland produces hormones that regulate your body temperature and control your heart rate…

Clinical Definition Hyperventilation is an increase in alveolar ventilation. It can lead to hypocapnia if carbon dioxide is removed from the blood in excess of production. Hyperventilation may be caused by physical or emotional stimuli. In Our Own Words Hyperventilation is increased breathing, which may lead to low levels of carbon dioxide in the body.…

Clinical Definition A hysterectomy is a surgical operation to remove the uterus and possibly other reproductive organs, such as the ovaries and/or fallopian tubes. In Our Own Words There are many reasons why women undergo a hysterectomy to remove the uterus, and possibly other reproductive organs. Medical reasons may include severe endometriosis and uterine fibroids,…

Clinical Definition Immunity is the protection against pathogens or infectious diseases. Immunity develops after antibodies to the disease are produced in the body. Types of immunity include innate, adaptive, active and passive. Active immunity refers to protection from a disease through a previous infection or through vaccinations. Passive immunity occurs when the antibodies come from…

Clinical Definition Incontinence is the loss of voluntary control of bowel movements or urination. Incontinence is a symptom or condition, rather than a disease, and can be caused by a variety of different processes, including damage to the sphincter muscles, anal surgery, certain medications, systemic diseases, chemotherapy or conditions that affect the functioning of the…

Clinical Definition Indigestion, or dyspepsia, is a burning or painful feeling in the upper belly or abdomen that typically occurs after meals. Many different etiologies are possible, including digestive tract ulcer. More typically, though, the symptoms of indigestion come from excessive eating, rapid eating, eating high-fat foods or eating while stressed. In Our Own Words…

Clinical Definition Influenza is a highly contagious respiratory illness caused by viruses that produce mild to severe symptoms that are sometimes life-threatening. While influenza is most prevalent during winter months, ”flu season” actually starts in late fall and persists until spring. In Our Own Words Influenza viruses are contagious respiratory illnesses that infect your nose,…

Clinical Definition An ingrown hair occurs when a hair does not follow the normal follicle channel and instead grows at an abnormal angle turning back towards the skin. This abnormal pattern causes the hair to penetrate the skin and leads to inflammation and possibly suppuration. In Our Own Words An ingrown hair is a common…

Clinical Definition An intestinal obstruction is an occlusion of the bowel, which prohibits normal movement of intestinal contents through the digestive track. It can be a partial or complete blockage. Intestinal obstructions are usually due to an ileus or a mechanical cause, such as a neoplasia or adhesion. Complications, such as infection and an electrolyte…

Clinical Definition Ischemia is an insufficient blood supply to an organ or part of the body, adversely affecting blood flow and oxygen delivery, such as in myocardial ischemia. Visceral ischemic syndromes, also known as intestinal or mesenteric ischemic syndromes, occur when blood flow to the gastrointestinal system is decreased. In Our Own Words Ischemia is…

Clinical Definition The small intestine is a 22-foot-long tube that breaks down food and consists of three segments, including the jejunum. The jejunum lies between the duodenum (i.e., the upper part of the small intestine) and the final section, known as the ileum. Along with the ileum, the jejunum is mainly responsible for nutrients being…

Clinical Definition Jock itch is a common dermatophyte infection affecting the groin area.  It is most common in adolescent males. In Our Own Words Jock itch is a type of fungal infection similar to ringworm. It can be found around the groin and upper inner thigh. Dermatophyte fungi like to live on moist areas of…

Clinical Definition A joint is the point of articulation between two or more rigid skeletal components, which usually allows movement. Joints consist of the synovial membrane, fluid and fibrous tissue. Joints are classified functionally and structurally, and provide mechanical support. Synovial joints, which move freely, are the most common joint in the human body. In Our…

Clinical Definition Joint sprain is the stretching or tearing of the connective tissue that connects bone to bone and supports the joints, also known as a ligament. It’s often confused with a strain, defined as an injury to a muscle or tendon, the cord of tissue that attaches muscle to bone. Pain, bruising, swelling and…

Clinical Definition The jugular veins include the internal and external jugular, which are major blood vessels, located on each side of the neck. These veins transport deoxygenated blood from the neck, face and head back to the heart. In a physical exam, distention of the jugular veins can be a clinical sign of heart failure.…

Clinical Definition Kawasaki disease is a febrile illness and a type of vasculitis that primarily affects children. Kawasaki disease does not appear to be contagious, and the etiology is unknown. The condition also causes inflammation of the hands and feet. Its association with vasculitis is responsible for acquired heart disease in some children. In Our…