Amenorrhea

The failure of a woman to menstruate. Amenorrhea is the absence of a menstrual period. Primary amenorrhea is when a young woman has not yet had a period by age 16. Secondary amenorrhea describes someone who used to have a regular period but then it stopped for at...

Analgesic

A medicine used to reduce pain. Pain medications are also called analgesics. Analgesics include aspirin, acetaminophen, and ibuprofen. Every pain medicine has benefits and risks. Specific types of pain may respond better to one medication over another. Results also...

Anaphylaxis

An acute systemic allergic reaction. In severe cases, this can include potentially deadly anaphylactic shock. Also known as Anaphylactic reaction. Anaphylaxis is a life-threatening, whole-body allergic reaction. After being exposed to a substance like bee sting venom,...

Anaplasia

Characteristics of a cell that make it identifiable as a cancer cell. Malignant A change in the structure of cells and in their orientation to each other; characteristic of malignancy. Malignant cells that have returned to a more undifferentiated or primitive...