psychosis A thought disorder in which perception of reality is grossly impaired. Symptoms can include seeing, hearing, smelling, or tasting things that are not there; paranoia; and delusional thoughts. Depending on the condition underlying the psychotic symptoms, symptoms may be constant or they may come and go. Psychosis can occur as a result of brain…
psychosis, ICU See ICU psychosis.
psychosomatic illness A situation in which the mind influences the body to create or complicate an illness.
psychotherapy The treatment of a behavior disorder, mental illness, or any other condition by psychological means. Psychotherapy may utilize insight, persuasion, suggestion, reassurance, and instruction so that patients may see themselves and their problems more realistically and have the desire to cope effectively with them. There are many different types of psychotherapy, including cognitive therapy,…
Proteus syndrome A disturbance of cell growth that causes overgrowth, asymmetry, and gigantism of bones, limbs, skin, and other organs. Its symptoms also include vascular malformations; raised, rough skin; and overgrowth of fat. John Merrick, the 19th-century Englishman known as the “elephant man,” is thought to have had Proteus syndrome. No specific treatment is available.
prothrombin A coagulation (clotting) factor that is needed for the normal clotting of blood. A cascade of biochemical events leads to the formation of the final clot. In this cascade, prothrombin is a precursor to thrombin. Also known as thrombinogen and simply pro. See also prothrombin time.
prothrombin time A test that is done to gauge the integrity of part of the blood clotting process. Prothrombin time is commonly used to screen for bleeding disorders as well as to monitor the accuracy of blood-thinning treatment (anticoagulation) with drugs such as warfarin (brand names: Coumadin, Panwarfin, Sofarin). It measures the time needed for…
proto-oncogene A normal gene that, when altered by mutation, becomes an oncogene that can contribute to cancer. See oncogene.
protozoa A parasitic single-celled organism that can divide only within a host organism. For example, malaria is caused by the protozoa Plasmodium.
proximal white subungual onychomycosis See onychomycosis, proximal white subungual.
pruritic Itchy. For example, a scab may be pruritic.
pruritus See itching.