The proportion of individuals in a population having a disease or characteristic. Prevalence is a statistical concept referring to the number of cases of a disease that are present in a particular population at a given time, whereas incidence refers to the number of new cases that develop in a given period of time.
Abnormally persistent erection of the penis in the absence of desire. Treatments include medications, anesthesia, and drainage of blood from the penis.
- Preventive medicine
Medical practices that are designed to avert and avoid disease. For example, screening for hypertension and treating it before it causes disease is good preventive medicine. Preventive medicine takes a proactive approach to patient care.
First or foremost in time or development. The primary teeth (the baby teeth) are those that come first. Primary may also refer to symptoms or a disease to which others are secondary. A primary tumor is one that is at the original site at which it arose. For example, a primary brain tumor is one […]
- 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 amebas migrate to the brain. Symptoms can include headache, fever, stiff neck and seizures. Most cases occur […]
- Primary amenorrhea
Absence of menstruation. Amenorrhea is conventionally divided into primary and secondary amenorrhea. With primary amenorrhea, menstruation never takes place. It fails to occur at puberty. With secondary amenorrhea, menstruation starts but then stops. The absence of menstruation during pregnancy is a form of physiologic amenorrhea, physiologic in the sense that it is completely normal and […]