Acute

Meaning an usage of the word acute as it applies to the medical field.

There are two main usages of the term acute in the medical field.
 

Most of the time the term acute is used by doctors it means sudden. An acute disease or condition is one that came on suddenly. Arthritis usually develops over a period of time. If you wake up one morning to find swollen joints the doctor may describe this as a acute form of arthritis.

The second usage is to describe things like pain. It still carries the concept of sudden but can also describe severity. A pain can be acute because it suddenly comes out of nowhere. It can also be acute because it is a sharp or severe pain. Still to accurately use the term it would mean that the level of pain suddenly became more severe.