introduction to chronic pain management

Chronic Pain strikes an estimated 50-70 million people in the United States and is becoming a problem of epidemic proportion that is difficult to control. Chronic Pain can be disabling and overwhelming and can cause physical, emotional, behavioral, social, and economic stress that affects the life of the individualas well as the lives of his loved ones and caregivers.As defined by the International Association for the Study of Pain (IASP), pain is "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage."

Pain is usually divided into two categories: acute and chronic. Acute pain is a normal physiologic response that produces a sensation. The first few seconds of acute pain is our body's early warning system to avoid further injury. It is a vital protective mechanism that allows us to interact with our environment, which is full of potential dangers. For example, touching something hot quickly produces pain and a quick instinctive response to move away. Acute pain may also arise from trauma, injury, surgery and childbirth. Acute pain is usually self-limiting and disappears as the underlying condition improves or the condition is treated. Unrelieved acute pain may lead to the second category of pain, chronic pain.

Chronic pain is a condition where pain persists despite the fact that the injury has healed. Unlike acute pain, chronic pain serves no useful purpose.

Chronic pain occurs when pain signals keep firing and transmitting pain sensations from the healed injury to the central nervous system. To help clarify this, let us say that there are two types of nerve fibers, fast and slow. The fast nerve fibers are initially stimulated when, in our example, your hand touches a hot stove. The pain receptors in your skin will then send a signal to the spinal cord and a reflex occurs to withdraw the hand from the insult. This pain is usually sharp and occurs quickly. Slow nerve fibers are next activated to create a pain that is characteristically dull. During episodes of pain, a chemical inflammatory soup is brewing at nerve endings and is waiting to spill over to stimulate other nerve fibers. These inflammatory chemicals cause nerve fibers to repeatedly fire and transmit signals of pain. In chronic pain, the nerves in the peripheral and central nervous system enhance the original stimulus to far greater levels and recruit more nerves to amplify the original pain message, thus making a painful situation much worse than the original condition.

This is a simplified version to you give a basic understanding of a very complex physiologic process. The exact nature of how pain signals are processed, amplified and maintained is still being investigated. Over the years, we have gained a greater understanding of the mechanism of chronic pain that has allowed for new treatment options and medications for effective the control.

Chronic pain is typically defined as pain that lasts beyond the ordinary duration of time required for an injury to heal. The duration of time varies between six weeks to three months. This three-month milestone is often used by practitioners as the definition of chronic pain.

To better understand the complexities of chronic pain, we must look at the causes, symptoms, treatment options, prognosis, and prevention strategies.

References

Bonica JJ. The Management of Pain. 2nd ed. Philadelphia: Lea & Febiger; 1990: 234-246.

National Institute of Health – www.nih.gov NIH Manual: Management of Chronic Pain; 2001.

Woolf, CJ Pain: moving from symptom control toward mechanism specific pharmacological management. Add Intern Med 2004:441-445.

American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 4th ed. American: American Psychiatric Pub, 2000: 623-625.

Food and Drug Administration - www.fda.gov Managing Chronic Pain; 2004.

International Association for the study of Pain – www.Isap-pain.org

Posted August 2008