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 that arose in the brain as opposed to one that arose elsewhere and metastasized (spread) to the brain. The original tumor is sometimes called “the primary.”
- 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 […]
- 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 amyloidosis in many countries including the U.S. The protein deposits […]
- 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)
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 D, leading to osteoporosis. Cirrhosis (scarring of the liver) develops over time.