Pain is typically categorized into two broad areas: acute and chronic. Acute pain is easier to diagnose and treat than chronic pain. It usually occurs after an injury, and people in this state look like they're in pain. This type of pain usually disappears when the injury heals. If you break your nose in a fall or cut yourself in your workroom, you probably feel the pain pulsing like a silent alarm throughout your body. With acute pain, your heart rate, respiratory rate, fight-or-flight response, and sweating increase. While acute pain is severe, the good news is that it lasts a relatively short time.

Chronic pain is a lot more complex.

A Closer Look at Chronic Pain

An article on chronic pain in the Journal of the American Medical Association noted that chronic pain is expensive, mainly because of the resulting disability and absence from work. In recent studies, researchers say, "more attention has been paid to the impact of chronic pain on daily living." And what an impact it has.

What is chronic pain? A typical definition says that chronic pain is not one thing, but a condition that varies depending on the person. The variables include where the pain is, what its cause is, and how an injury heals. In some cases, the pain is simply inexplicable. However, one description is consistently applicable: All chronic pain is long-term pain that persists even after healing has occurred or when the condition that's causing the pain does not go away. This is pain beyond what doctors expect to see from a condition or injury that does clear up.

Some women with endometriosis have worse symptoms during their cycles, while others begin feeling pain a week before that. When these women describe their pain as chronic, it's because they're uncomfortable for at least 2 weeks of the month. People who get bad migraines usually experience them intermittently rather than every day. So in that way, you may perceive your migraines as not actually being chronic, but recurring. I also get migraines once a month, but I don't consider the condition chronic. Healing starts here! Chronic pain cannot have power over your thinking when you at least partly define it as something you will not allow to affect how you function.

Unlike people in the throes of acute pain, patients with chronic pain often do not appear to be in pain -- but indeed they are! Research done with chronic pain sufferers shows that some exhibit greater brain activity than healthy people when subjected to pain. This may be why they experience pain more severely. Yet, they've gotten good at "getting through" and soldiering on. Rather than seeing an elevated change in vital signs, like increased heart rate, one usually sees vegetative signs, and, not to be dismissed, such a person may appear depressed.

People with chronic pain tell me that they have sleep disturbances, decreased libido, anhedonia (an inability to feel pleasure), constipation, lethargy, and personality change; lose their appetites; and sometimes are preoccupied with their bodies. These are all classic symptoms of chronic pain. But why the pain? Often, it's due to a disease, while at other times, it's the treatment of the disease that produces the pain. When a person has any type of surgery, they can be left with a long-term pain problem secondary to scarring, or even permanent nerve damage.

Chronic or persistent pain may range from mild to severe, and it is present to some degree for long periods of time. Some people with chronic pain that is controlled by medication can have "breakthrough pain," which occurs when the medication does not work and moderate to severe pain breaks through or is felt for a short time. This can occur several times a day, even when the proper dose of medicine is given.

In treating chronic pain, it's important to understand the different potential types and mechanisms of pain.

Referred pain is felt some distance from where the pain actually originates. In other words, the site of the pain is not necessarily the source. Osteoarthritis of the hip, for example, causes pain to be experienced in the knee. In acupuncture, a form of Chinese medicine, kidney problems can be indicated by pain in the knees.