Acute pain is pain with a sudden onset, which can serve as a warning of a threat to the body or as a warning of disease.
A threat to the body would be something such as burning your hand while taking something out of the oven. A warning of disease could be pain caused by something such as infected appendix.
Acute pain is seen as pain that lasts longer than six months, and which does not go away as something such as an operation incision or a broken bone heals.
For obvious reasons, acute pain is preferable to most people: even though it can be extremely painful, such as sustaining a serious burn, one knows that the wound will probably heal and that the pain will eventually diminish and finally go away altogether.
But all pain, whether chronic or acute, is subjective. It can be difficult to describe, but in the end the patient can give little more than an impression of what it is he/she is feeling. A doctor can touch a painful area, but is still dependent on the reaction of the patient to determine the pain levels. Two people can experience different pain levels from the same injury.
Our experience of pain is influenced by our cultural learning, psychological aspects of particular situations, our own medical history, whether our attention is diverted and many other psychological factors. In short, as a result of many different reasons, people have different pain thresholds. And there is no really objective way to measure pain than from the patient him/herself.
Physiological signs of pain include increased pulse rate, elevated blood pressure, dilated pupil size sweating, writhing, facial grimacing, and moaning. However, doctors in emergency units are only too aware that these symptoms can also be those of drug withdrawal.
Several pain rating scales have been developed over the years. The first two are self-rating. These include the following:
Numerical scales, where patients are asked to rate their pain from naught to 10, where naught represents a pain-free state, and 10 the worst pain that one could imagine.
The facial expression scale. This scale contains various facial expressions, and patients are asked to select the one that most closely resembles the pain they feel. This is useful when dealing with patients who speak other languages, or who may not be numerate. It can also be used when dealing with children.
Verbal rating scale. This relies on a person choosing particular words to describe their own pain as accurately as they can. While this might not provide an objective measurement, it can be handy when records of the same patient are compared.
Observer scales. The physiological signs of pain are measured by a healthcare worker. This is often used when patients who cannot effectively communicate the level of pain that they are feeling.
Read: What is the difference between acute and chronic pain?
Doctors use pain-scales to find out whether the pain the patient is feeling is mild, moderate or severe, and to help them decide on which medications will be most effective. It is also often used to measure the effectiveness of pain relief medications in post-operative patients, or those who suffer from chronic pain.
As it is difficult to provide any objective measure of either acute or chronic pain, healthcare workers are often alerted by the fluctuations in how patients rate their own pain. The more accurate and truthful someone’s rating, the more effective the pain relief can be.
Diagnosing chronic pain
Sources: ncbi.nlm.nih.gov; pain.about.com; webmd.com