Cogan syndrome A rare form of artery inflammation (arteritis) of unknown cause that affects the ear. Cogan syndrome causes problems of hearing and balance and also inflammation of the cornea and often fever, fatigue, and weight loss. Joint and muscle pains can also be present. Less frequently, the arteritis can involve blood vessels elsewhere in…
cognition The process of knowing. Cognition includes both awareness and judgment.
cognitive Having to do with thought, judgment, or knowledge.
cognitive behavior therapy A therapeutic practice that helps patients recognize and remedy dysfunctional thought patterns. One characteristic technique is exposure and response prevention, in which a patient with a phobia deliberately exposes himself or herself to the feared situation, gradually decreasing the panic response. Cognitive behavior therapy is used to treat obsessive-compulsive disorder, panic disorder,…
cognitive disability A broad term used to describe such diverse conditions as mental retardation, thought disturbances, and neurological conditions that chronically affect a certain type of perception or mental ability.
cognitive disturbance Disruption of one’s ability to think logically.
cloning, DNA The use of DNA manipulation procedures to produce multiple copies of a single gene or segment of DNA.
cloning, therapeutic See therapeutic cloning.
Clostridium difficile A bacterium that is one of the most common causes of infection of the colon in the US. Patients taking antibiotics are at risk of becoming infected with C. difficile as antibiotics can disrupt the normal bacteria of the bowel, allowing C. difficile to become established in the colon. In some people, a…
Clostridium perfringens A bacterium that is the most common cause of gas gangrene, a lethal infection of soft tissue, especially muscle. C. perfringens bacteria are toxin- and gas-producing bacteria. Before the introduction of antibiotics, a significant percentage of battlefield injuries were complicated by gas gangrene. C. perfringens also causes food poisoning and a fulminant form…
Clostridium welchii See Clostridium perfringens.
clot-dissolving medication An agent such as plasminogen-activator (t-PA) or streptokinase that is effective in dissolving clots and reopening arteries. For example, clot-dissolving medications may be used in the treatment of heart attacks, to reestablish blood flow to the heart muscle (myocardium). Also known as thrombolytic agents.