• Are there different kinds of pain?
• What is chronic pain?
• How is chronic pain evaluated?
• What causes chronic pain?
• How is chronic pain treated?
• What drugs are most commonly recommended for chronic pain?
• Can chronic pain be treated without drugs?
• Is it better to treat the cause of chronic pain or treat the pain itself?

Are there different kinds of pain?

Yes. Health-care providers classify pain by its duration (how long it lasts), by its quality (how it feels) or by its location (where in the body it originates and where it is felt).

Acute pain (that is, pain of brief length or recent occurrence) usually has a clear source, starts suddenly and goes away quickly. You experience acute pain when you touch a hot surface, stub your toe or cut yourself. Your blood pressure, heart rate and breathing rate often increase with acute pain. Acute pain tells you to pay attention. In short, some part of your body needs help.

Chronic pain can last months to years. It may come and go or remain constant. In addition, it may disturb sleep, decrease appetite and lead to depression. Chronic pain is not always useful; the pain message has been sent and received, yet it keeps being sent over and over again. Some common causes of chronic pain include arthritis, cancer and some back problems.

Pain has many different forms. It can be dull, sharp, shooting, cramping, diffuse or well-localized. This is because different parts of the body send different types of signals to the brain. For instance, a throbbing headache and a broken ankle are both painful, but the type of pain tends to be different because of different types of pain sensors and pain pathways involved.

What is chronic pain?

In its broadest definition, pain is any unpleasant sensation. Chronic pain is an unpleasant sensation that lasts at least two months; it may go on for years.

You consciously experience pain when special pain receptors transmit an electrical message (like an alarm) to the brain. Chronic pain is quite different from acute (new or sudden) pain. In cases of acute pain, a pain message may be sent to the spinal cord before it reaches the brain; a protective reflex often follows. For example, you may move your finger away from a hot stove even before the alarm message has reached your brain. In such cases, the muscles near the source of the pain automatically contract to avoid any harm. Thus, acute pain helps protect the body from serious injury. The benefit of chronic pain is less obvious, and in fact it often serves no useful purpose.

How you experience pain varies depending on where it started and how it traveled. Sometimes you may find it difficult to locate the source of pain. Why? Pain can be "referred"; that is, it may originate in one area but be felt elsewhere. For example, you may feel pain in your legs that is caused by a problem in your lower back.

Realize that pain is not the same for everyone. For instance, some people can tolerate more or less pain than others can. Some individuals respond better or worse to pain medications.

How is chronic pain evaluated?

The cause of pain is sometimes difficult to identify. Your health-care provider will try to identify the cause by asking you to describe your symptoms in detail. He or she will perform a physical examination and may recommend diagnostic testing, such as X-ray or magnetic resonance imaging (MRI). There are no diagnostic tests to prove that pain exists, although the results of such tests may suggest a cause.

Moreover, patients often have problems describing their pain in words. And differences in physiology and psychology affect the way each individual perceives pain. Therefore, no single event will cause the exact same pain experience in two people. A number of instruments are available to help measure chronic pain, ranging from simple rating scales to detailed survey instruments that are especially helpful for research studies.

Trying to sort out whether pain is "real" is not particularly helpful. Unless a person is consciously fabricating symptoms to his or her health-care provider, all pain is real.

What causes chronic pain?

There are many causes of chronic pain, although occasionally the underlying cause is not clear. The type of pain you are experiencing is often a clue to its cause; for example, chronic pain that is burning or tingling is often the result of nerve disease (neuropathy). Even when the cause cannot be identified, it is still important to exclude serious or dangerous causes. Some of the most common types of chronic pain and their causes include the following:

• Back pain — The cause of back pain is often uncertain, although muscle spasm, muscle strain, arthritis and disk disease are thought to account for most cases. Rarely, a dangerous condition such as a tumor or an infection can cause back pain.
• Headache — Tension, migraine and caffeine withdrawal are among the most common causes of headache. Arthritis in the neck, muscle spasm and eye problems may also contribute. Rarely, a serious condition such as a brain tumor, infection (including meningitis) or temporal arteritis causes headache.
• Joint pain — Although this type of pain usually accompanies arthritis, this symptom may also be caused by other common conditions, including bursitis, tendonitis, fibromyalgia and degenerative joint disease.
• Muscle pain — The most common causes of muscle pain (also called myalgia) include overuse or strain, injury, viral infection and fibromyalgia.

How is chronic pain treated?

Pain treatment usually begins after the cause of pain is identified. However, therapy can start even if the cause of pain is unknown. Avoiding activities that seemed to trigger your pain may be appropriate. For example, simply taking a break from playing baseball might treat chronic shoulder discomfort.

Your health-care provider may prescribe a variety of drugs or may even recommend surgery to treat your painful condition. But pain can sometimes be treated without drugs or surgery. Because each person differs in his or her response to pain, a health-care provider must tailor treatment to the individual.

What drugs are most commonly recommended for chronic pain?

Pain-relieving drugs are known as analgesics. Examples range from acetaminophen (Tylenol) to narcotics (morphine, codeine). Experts believe that some analgesic drugs interfere with pain signals to the brain. Other analgesics, such as nonsteroidal anti-inflammatory drugs (aspirin, ibuprofen), reduce inflammation in addition to interfering with pain signals.

Narcotics are the most powerful pain treatments and are reserved for the most intense pain. They may cause serious side effects, may be addictive and often cause constipation. Another problem with narcotics is that, over time, the dose may become ineffective. Higher and higher doses may be required, leading to an increased risk of side effects.

Other drugs such as anesthetic nerve blocks, muscle relaxants, antidepressants and anticonvulsants (drugs used to treat seizures) may be effective against certain types of pain. Newer agents include capsaicin cream (applied to the skin at the site of pain) and tramadol (an oral analgesic). Specialized pain centers typically offer a combination of treatment modalities, including injections of anesthetic agents and corticosteroids into the area of pain along with transcutaneous electrical nerve stimulation (TENS).

Can chronic pain be treated without drugs?

Nondrug treatments for pain include:

• Physical therapy, including stretching or exercise
• Application of heat or cold
• Complementary or alternative therapy (acupuncture, massage)
• Relaxation
• Counseling (psychotherapy)
• Transcutaneous electrical nerve stimulation (also known as TENS)

In some cases, treatments stimulate endorphins (natural painkillers created within the body). In other cases, treatments act directly on nerves, creating other messages that interfere with pain messages. However, in many cases, the pain-killing mechanism for nondrug therapies does not have a clear explanation.

Is it better to treat the cause of chronic pain or treat the pain itself?

Whenever possible, the specific cause of pain should be identified and treated. Pain typically ends if its cause is addressed directly. Here are a few examples:

• Chronic pain caused by an infectious disease (such as Lyme disease) may be treated with antibiotics to eradicate the infection.
• Pain associated with cancer may be treated with drugs or with other nondrug approaches. In addition, chemotherapy, surgery or radiation therapy may provide significant pain relief, especially if the cancer can be cured.
• In certain situations, a painful condition may be cured with surgery; for example, a ruptured disk in the lower spine may cause chronic pain until surgery is performed to repair the disk.

Each situation is unique, but for most painful conditions, one or more of these treatment options will produce effective relief without serious side effects. When a specific cause cannot be identified, it is usually appropriate to make pain reduction the focus of therapy, even though it merely masks the pain. Chronic pain may reduce one's quality of life, so it is important to find relief.