Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «P»:
Pathogen: An agent of disease. A disease producer.
The term pathogen most commonly is used to refer to infectious organisms. These include bacteria (such as staph), viruses (such as HIV), and fungi (such as yeast). Less commonly, pathogen refers to a noninfectious agent of disease such as a chemical...
Pathogen inactivation: A process designed to eliminate most pathogens -- viruses, bacteria and fungi -- from water, air or donated blood. Sewage purification systems depend upon pathogen inactivation to purify water to the extent it may sometimes even be safe enough to drink. Air purification system...
Pathogen, special: See: Special pathogen....
Pathogenesis: The development of a disease. The origin of a disease and the chain of events leading to that disease....
Pathogenetic: Pertaining to the pathogenesis of a disease, to exactly how it develops and the precise chain of events leading to it....
Pathogenic: Causing disease or capable of doing it.
Pathogenic bacteria are disease-causing bacteria. For example, pathogenic E. coli are E. coli that are not innocuous (like most E. coli) but can make a person ill and even kill them.
The word "pathogenic" comes from two Greek roots: "pathos" (dise...
Pathogenicity island: The genetic element, the "island of evil", within the genome of an organism that is responsible for its capacity to cause disease (its pathogenicity). The virulence of the organism is modulated by genes harbored on this island.
For example, enterococci are part of the normal ...
Pathognomonic: A sign or symptom
that is so characteristic of a disease that it makes the
diagnosis. For example, Koplik's spots (on the buccal
mucosa opposite the lst and 2nd upper molars) are
pathognomonic of measles. The word "pathognomonic"
(pronounced patho-no-monic) comes from the Gree...
Pathologic: 1. Indicative of or caused by disease, as in a pathologic fracture, pathologic tissue, or pathologic process.
2. Pertaining to pathology, the branch of medicine that studies disease and especially the essential nature of disease....
Pathologic fracture: A bone broken, not by trauma alone, but so weakened by disease as to break with abnormal ease. Pathologic fractures are characteristic of metastatic lung and breast cancer and myeloma....
Pathological hoarding: Excessive hoarding of material goods, a condition that affects up to 40% of people with obsessive compulsive disorder (OCD). Excessive hoarders, who fill their houses with accumulations of junk, usually newspapers, bags of old clothing and lists, tend to experience more anxiet...
Pathologist: A doctor who identifies diseases by studying cells and tissues under a microscope....
Pathologist, speech-language: See: Speech-language pathologist....
Pathology: The study of disease.
Pathology has been defined as "that branch of medicine
which treats of the essential nature of disease." The word
"pathology" comes from the Greek words "pathos" meaning
"disease" and "logos" meaning "a treatise" = a treatise of
disease. The word "pathology" i...
Pathophysiology: Deranged function in an individual or an organ that is due to a disease.
A pathophysiologic alteration is a change in function as distinguished from a structural defect....