Definition Tracheoesophageal fistula (TEF) is commonly a birth defect, with the trachea connected to the esophagus. In most cases, the esophagus is discontinuous, causing immediate feeding difficulties. TEFs may develop in adult life, secondary to the invasion of cancer in the area. In addition, TEFs may be deliberately constructed with surgery to aid talking in a patient who has the larynx...

Definition Trabeculectomy is a surgical procedure that removes part of the trabeculum in the eye to relieve pressure caused by glaucoma. Purpose Glaucoma is a disease that injures the optic nerve, causing progressive loss of vision. Presently, glaucoma is a major cause of blindness in the United States If caught early, glaucoma-related blindness is easily prevented. However, since it does not produce...

Definition Toxoplasmosis is an infectious disease caused by the one-celled protozoan parasiteToxoplasma gondii. Although most individuals do not experience any symptoms, the disease can be very serious, and even fatal, in individuals with weakened immune systems. Description Toxoplasmosis is caused by a one-celled protozoan parasite known...

Definition Toxic shock syndrome (TSS) is an uncommon, but potentially serious, illness that occurs when poisonous substances (toxins) produced by bacteria enter the bloodstream. The toxins cause a type of blood poisoning that results in high fever , symptoms of shock, and potentially organ failure. Description Initially toxic shock syndrome was associated with...

Definition Toxic epidermal necrolysis is a rare condition that causes large portions of the epidermis, the skin's outermost layer, to detach from the layers of skin below. A reaction to a medication is the primary cause. Description Toxic epidermal necrolysis (TEN) begins with fever, cough, and other nonspecific symptoms, and is soon followed by purplish, bloody-looking...

Definition Tourette syndrome (TS) is an inherited disorder of the nervous system, characterized by a variable expression of unwanted movements and noises (tics). Description The first references in the literature to what might today be classified as Tourette syndrome largely describe individuals who were wrongly believed to be possessed by the devil. In 1885 Gilles de laTourette, a French...

Definition When patients cannot use their gastrointestinal tracts for nutrition, parenteral nutrition may be used to maintain or improve the patient's nutritional status. This form of intravenous treatment provides all the nutrients that are delivered to the patient. This treatment may be temporary or long-term. Purpose The harmful effects of malnutrition on the overall health of a patient...

Definition Torticollis (cervical dystonia or spasmodic torticollis) is a type of movement disorder in which the muscles controlling the neck cause sustained twisting or frequent jerking. Description In torticollis, certain muscles controlling the neck undergo repetitive or sustained contraction, causing the neck to jerk or twist to the side. Cervical dystonia causes forward twisting, and is called...

Definition The TORCH test, sometimes called the TORCH panel, belongs to a category of blood tests called infectious-disease antibody titers. A titer is the serial dilution of antibodies (protein molecules or immunoglobulins produced by the immune system in response to specific disease agents) found in blood serum that determines their level of concentration. Antibodies are proteins produced...

Definition Topical anesthesia is a condition of temporary numbness caused by applying a substance directly to a surface of the body. Loss of feeling occurs in the specific areas touched by the anesthetic substance. Purpose Topical anesthesia typically either relieves existing pain from a body surface or prevents pain during medical examinations or procedures. Body surfaces...

Definition A toothache is any pain or soreness within or around a tooth, indicating inflammation and possible infection. Description A toothache may feel like a sharp pain or a dull ache. The tooth may be sensitive to pressure, heat, cold, or sweets. In cases of severe pain, identifying the problem tooth is often difficult. Any patient with a toothache should see a dentist...

Definition A tooth restoration is any artificial substance or structure that replaces missing teeth or part of a tooth in order to protect the mouth's ability to eat, chew, and speak. Restorations include fillings, inlays, crowns, bridges, partial and complete dentures, and dental implants. Purpose Restorations have somewhat different purposes depending on their extensiveness....

  Definition Tooth extraction is the removal of a tooth from its socket in the bone. Purpose Extraction is performed for positional, structural, or economic reasons. Teeth are often removed because they are impacted. Teeth become impacted when they are prevented from growing into their normal position in the mouth by gum tissue, bone, or other teeth. Impaction is a common reason...

Definition Tooth decay, which is also called dental cavities or dental caries, is the destruction of the outer surface (enamel) of a tooth. Description Tooth decay results from the action of bacteria that live in plaque. Plaque is a sticky, whitish film formed by a protein in saliva (mucin) and sugary substances in the mouth. The plaque bacteria sticking...

Tonsillitis is an inflammation or infection of the tonsils, caused by either bacteria or viruses. Tonsils, which function to prevent infections in the body, are oval-shaped masses of lymph gland tissue located on both sides of the back of the throat. They act like filters to trap bacteria and viruses entering the body through the mouth and sinuses. When tonsillitis occurs, the tonsils usually...

Definition Tonsillectomy and adenoidectomy (T & A) are surgical procedures to remove the tonsils from the back of the mouth or adenoids from the back of the nasal cavity—both are are part of the lymphatic system, which is responsible for fighting infection. These operations are often performed together and are usually done on children. T & As are the most common childhood operations. Purpose Tonsillectomy Tonsils...

Definition Tissue typing is a group of procedures that determines the type of histocompatibility antigens on a person's cells or tissues. This procedure is typically used prior to transplantation of tissues or organs. Purpose Tissue typing is done prior to transplantation to ensure as close a match as possible between the donor and the recipient. If the histocompatibility antigens do...

Definition Tinnitus is a condition where the patient hears ringing, buzzing, or other sounds without an external cause. Patients may experience tinnitus in one or both ears or in the head. Description Tinnitus affects as many as 40 million adults in the United States. It is defined as either objective or subjective. In objective tinnitus, the doctor can hear the sounds as well as the...

Definition Tilt table testing is a medical test designed to study how the human heart adapts to changes in position. Purpose The American College of Cardiology considers the use of head-up tilt table testing to be the best means of evaluating symptoms and potential treatment for vasovagal syncope . More than 7 million Americans suffer from common fainting...

Definition Thyroiditis is inflammation of the thyroid gland, a butterfly-shaped organ next to the windpipe. Description The thyroid is the largest gland in the neck. It produces, secretes, and stores thyroxine (T4), a hormone that influences the metabolism of just about every body process. When the thyroid gland is functioning properly, hormone release is carefully regulated. When bacteria or viruses invade...

Definition Thyroidectomy is a surgical procedure in which all or part of the thyroid gland is removed.The thyroid gland is located in the forward part of the neck (anterior) just under the skin and in front of the Adam's apple. Purpose All or part of the thyroid gland may be removed to correct a variety of abnormalities of the gland. If the patient...

Definition Thyroid ultrasound is an imaging technique used for diagnosing suspected thyroid disease. It uses harmless, high-frequency sound waves to form an image. The sound waves are reflected by thyroid tissue to form a picture of internal structures. It is not invasive and involves no radiation. Purpose The thyroid gland is an organ located in front of the neck. It plays...