Pain (Acute and Chronic)

"Nothing begins, and nothing ends,
That is not paid with moan;
For we are born in other's pain,
And perish in our own."
-- James Kenneth Stephen

Medical Author: William C. Shiel, Jr., MD, FACP, FACR
Medical Editor: Melissa Conrad Stöppler, MD

Pain is an unpleasant sensation in animals that is caused by actual or perceived injury to body tissues and produces physical and emotional reactions. Presumably, pain sensation has evolved to protect our bodies from harm by causing us to perform certain actions and avoid others. Pain might be called a protector, a predictor, or simply a hassle. In this article, I will discuss some basic concepts of pain.

We all experience pain to greater or lesser degrees at various points of our lives. It is said that pain is the most common reason patients seek medical attention. But, each of us perceives a given pain stimulus in our own unique manner. The intensity of the response to a pain stimulus is largely subjective, meaning the severity of the pain can most accurately be defined by the person with the pain, rather than by other observers.

Our individual pain perception can vary at different times, even in response to the identical stimulus. For example, an athlete during competition may not be able to feel the tissue injury of a cut or a bruise until the competition has finished. We may feel more or less pain depending on our mood, sleep pattern, hunger, or activity.

Pain is typically classified as either acute or chronic. Acute pain is of sudden onset and is usually the result of a clearly defined cause such as an injury. Acute pain resolves with the healing of its underlying cause. Chronic pain persists for weeks or months and is usually associated with an underlying condition, such as arthritis. The severity of chronic pain can be mild, moderate, or severe.

Medically Reviewed by a Doctor on 12/1/2014