What is pain?
The International Association for the Study of Pain (IASP) says that pain is "an unpleasant sensory and emotional experience associated with actual or potential tissue damage." Pain is very personal and subjective. Unlike a fever, where a thermometer can show if you have a high temperature, there is no objective way to measure how much pain you are feeling.
How do we feel pain?
Have you ever wondered why you feel pain? Usually, pain is your body's warning system. It alerts you that something is wrong.
Nerve cells, also called neurons, transmit signals from your five senses to your brain. There are certain neurons, called nociceptors, that specialize in sending pain signals. These pain neurons are found throughout your skin and other body tissues. When the pain neurons are stimulated, they send electrical and chemical signals through nerves in your spinal cord to your brain and are interpreted as pain.
What are the different types of pain?
Everyone has experienced pain. It could be acute pain, like that from a needle or a cut. Or it could be chronic pain due to something more long-lasting like arthritis.
Acute pain is called ordinary or nociceptive pain. It is what you feel when normal nerves send messages from the injured body tissues. Everyone has experienced acute pain. This is the type of pain you feel from a needle poke for blood work, or a sprained ankle. This pain is temporary, lasting minutes to several weeks. Acute pain goes away when healing occurs and is usually easily treated. It can often be treated with a single approach using medications, physical (heat, cold, rest) or psychological therapies (distraction, deep breathing).
Acute pain is useful because it protects you from hurting yourself. Acute pain alerts you to actual or impending damage. For example, if you were to step barefoot onto a piece of glass, your brain would quickly recognize the pain and tell you to move your foot. You would also know that you might need to seek medical attention. In this way, acute pain can help protect you against harmful situations.
Chronic pain is pain that has lasted for at least three months. Chronic pain may also be any recurrent pain that occurs at least three times within three months. Chronic pain can be:
- Persistent: continuous pain, or
- Recurrent: frequent episodes of pain such as headaches
Unlike acute pain, chronic pain does not serve a useful purpose. Chronic pain is a prolonged, abnormal response to injury. You can think of it as a malfunction in your body's alarm system in which it sends off danger signals for no good reason.
Chronic pain can be associated with diseases like arthritis and cancer or can occur for no known reason (idiopathic). Unlike acute pain, chronic pain serves very little purpose other than to remind a person that their disease is ongoing and requires continued treatment. Chronic pain is what most people with pain suffer from. It requires careful management in order to treat the pain and improve functioning. It is generally harder to treat than acute pain and requires a multi-modal approach. A multi-modal treatment approach uses a combination of medication as well as physical and psychological therapies. There are also specialized chronic pain teams that use an interdisciplinary approach (medicine, nursing, physical therapists, psychologists etc) to treat pain.
There are two types of chronic pain: nociceptive pain and neuropathic pain.
Nociceptive pain is the most common type of chronic pain. It is what you feel when normal nerves send messages from the injured or inflamed body tissues. This can be caused by pressure, extreme hot or cold temperatures, or chemical signals sent out by certain tissues in response to injury. Examples would include joints that are damaged by arthritis, or muscles that are painful because of chronic tension.
The other type of chronic pain is neuropathic pain. This type of chronic pain is not caused by normal nerves telling the brain that tissues are injured or inflamed. Instead, neuropathic pain is caused by damage to a nerve or a problem with the nervous system. The damaged nerves send abnormal pain messages to the brain.
Neuropathic pain is difficult to diagnose since there are often no obvious signs of disease. The problem originates in the nerve itself or in the brain. This type of pain is also more difficult to treat than nociceptive pain. Examples might be the burning pain that comes from shingles (an infection that affects pain nerves), or phantom limb pain (in which a limb that has been amputated still hurts).
Some people with chronic pain can have both nociceptive and neuropathic pain. This is also called mixed pain.
Your pain can be changed
Pain can be changed by stopping pain signals from reaching your brain. These pain signals can be reduced or blocked anywhere along the pain pathway. It may not be possible to eliminate all pain due to your chronic pain condition. However, there are things you can do to reduce your pain.
Pain can be changed using:
- Pharmacological strategies or pain medications
- Physical methods such as heat, cold, massage, and exercise
- Psychological strategies such as relaxation, distraction (engaging in pleasurable activities) and changing the way you think