Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «P»:
Primary amebic meningoencephalitis
Primary amebic meningoencephalitis: A rare, but fatal infection of the central nervous system caused by Naegleria fowleri, an ameba that inhabits freshwater lakes, rivers and hot springs. The disease results when ameba-contaminated water incidentally enters the nose during aquatic activities and ame...
Primary amenorrhea: Absence of menstruation.
Amenorrhea is conventionally
divided into primary and secondary amenorrhea. With primary
menstruation never takes place. It fails to occur at
amenorrhea, menstruation starts but then stops. The absence
Primary amyloidosis: A disorder of plasma cells (special white blood cells that produce antibodies), this is one of a group of diseases (called amyloidosis) in which protein deposits (amyloid) accumulate in one or more organ systems in the body. Primary amyloidosis is the most common type of amyloi...
Primary atelectasis: Failure of the lung to expand fully at birth. In contrast to secondary atelectasis in which there is partial
or complete collapse of a lung that once had expanded, as may happen
after chest surgery....
Primary biliary cirrhosis (PBC)
Primary biliary cirrhosis (PBC): A liver disease caused by an
abnormality of the immune system. Small bile ducts within the liver become inflamed and
obliterated. Backup of bile causes intense skin itching and yellowing of the skin
(jaundice). Lack of bile decreases absorption of calcium and vitamin...
Primary care: The "medical home" for a
patient, ideally providing continuity and integration of health care.
All family physicians and most pediatricians and internists are in
primary care. The aims of primary care are to provide
the patient with a broad spectrum of care, both preventive and
Primary care provider
Primary care provider: In insurance parlance, a
physician chosen by or assigned to a patient, who both
provides primary care and acts as a gatekeeper to control
access to other medical services....
Primary cataract: See: Cataract, primary....
Primary ciliary dyskinesia
Primary ciliary dyskinesia: The immotile cilia syndrome, a condition in which poorly functioning cilia (hairlike projections from cells) in the respiratory tract contribute to retention of secretions and recurrent infection. The condition is inherited as an autosomal recessive trait and is due to mu...
Primary dentition: The set of 20 first (deciduous) teeth. The
primary dentition is as opposed to the secondary (permanent) dentition. At birth, both
sets of dentition are evident by X-ray. ...
Primary HIV infection
Primary HIV infection: The first few months after infection with HIV (the human immunodeficiency virus).
During primary HIV infection, seroconversion occurs -- the appearance of detectable antibodies to HIV in the blood. It normally takes several weeks to several months for antibodies to the virus t...
Primary immunodeficiency disease
Primary immunodeficiency disease: A disorder caused by an inherited flaw in the immune system that increases the susceptibility to infections. Primary immunodeficiency diseases are unlike secondary or acquired immune deficiency diseases, which are caused by infectious, chemical or radiological agent...
Primary liver cancer, adult
Primary liver cancer, adult: A tumor in which the cancer starts during adulthood in cells in the liver. Also called hepatocellular carcinoma.
Primary liver cancer is different from cancer that has metastasized (spread) from another place in the body to the liver.
The signs and symptoms may incl...
Primary progressive aphasia
Primary progressive aphasia: An atypical dementia characterized by a relentless dissolution of language with memory relatively preserved. The diagnosis of primary progressive aphasia is based on the presence of a progressive disorder of language, with preservation of other mental functions and of ac...
Primary sclerosing cholangitis
Primary sclerosing cholangitis: A chronic
disorder of the liver in which the ducts carrying bile from the liver
to the intestine, and often the ducts carrying bile within the liver,
become inflamed, thickened, scarred (sclerotic), and obstructed. This
relentlessly progressive process can in t...