What causes pain?
Pain receptors (called nociceptors) are located throughout the human body. During times of injury, a pain receptor is stimulated and transmits a signal to nerve cells within the spinal cord, which send a pain message to the brain. When the brain processes this signal, a person becomes aware of pain. In response, the body releases natural pain killers, called endorphins.
What causes acute pain? - In most cases of acute pain, the initial pain results from disease, inflammation, or injury to tissues. This type of pain generally comes on suddenly after trauma. The cause of acute pain can usually be diagnosed and treated, and the pain can be confined to a given period of time and severity. In some rare instances, acute pain can become chronic. However, acute pain may be accompanied by anxiety or emotional distress. Causes of acute pain include:
- broken bones
- burns or cuts
- dental work
- labor and childbirth
- soft tissue injury
- surgical (post-operative ) pain
What causes chronic pain? – Chronic pain persists over a longer period of time than acute pain and is resistant to most medical treatments. Chronic pain can, and often does, cause severe problems for patients. Although chronic pain often begins with an injury or illness, ongoing pain can become psychological after the original injury or illness heals. Furthermore, chronic pain can be made much worse by environmental and psychological factors. But sometimes, the cause of chronic pain remains unknown (ex. chronic lower back pain).
During experiences of chronic pain, the brain continues to transmit the message of pain long after normal healing time. Doctors have found that severe and constant stimulation of pain receptors may cause changes in the spinal cord. The nerve cells in the spinal cord may actually produce their own pain transmitters completely unrelated to any actual pain signals coming from the body, interrupting the normal pain pathways.
Chronic pain can be caused by many factors, including nerve damage, injuries that fail to heal properly, and conditions that accompany normal aging. The most causes of chronic pain related to disease include:
- chronic pancreatitis
- gallbladder disease
- nerve dysfunction
- soft tissue injury
- spinal disorders
- unresolved disease or injury (psychogenic pain)
What causes different types of pain?
Doctors specify types of pain by location and or cause in the body. Some of the more commonly diagnosed types of pain and their causes include:
Myofascial pain – Myofascial pain is caused by trigger points (sensitive and tender areas) that develop in a muscle or a group of muscles. Myofascial pain may cause 'referred pain' because when a trigger point is pressed the pain may be felt elsewhere. This pain may be chronic and described as nagging, burning, aching or stabbing.
Psychogenic pain – Psychogenic pain manifests as real physical pain caused by a psychological problem such as mental or emotional issues.
Radicular pain – Radicular pain, or radiculitis, is caused by inflammation or compression of a spinal nerve root. Different disorders can cause spinal nerve compression, inflammation and pain such as a spinal tumor or cyst, disc hernia, spinal stenosis and osteoarthritis.
Somatic pain – Somatic pain is caused by injuries affecting the pain receptors in the skin, ligaments, muscles, bones, or joints. This pain may be chronic and is sometimes associated with cancer.
Visceral pain – Visceral pain is caused by internal organs that are damaged or injured.
There are certain risk factors that make it more likely that a person develops or experiences chronic pain. These include previous injury, personal medical history, and degenerative changes related to aging, although psychological and environmental factors are at work as well. The most common factors that can put people at risk for chronic pain include:
Acute pain – People are more likely to develop chronic pain after an injury, illness or disease. The more severe a case of acute pain, the more likely a person is to develop complications such as chronic pain. Risk factors in the development of chronic pain include unrelieved acute post-traumatic and postoperative pains
Age – The older we get, the more likely we are to experience physical pain related to degenerative changes in the body. Validated tools for assessing pain, even in the cognitively impaired, exist and should be used consistently.
Gender – According to the study of the distribution and determinants of disease in human populations, it seems that more women suffer from painful diseases than men (ex. Migraine, fibromyalgia)
Personal medical history - Previous history of diseases, including rheumatoid arthritis and osteoarthritis, cancer, multiple sclerosis (MS), stomach ulcers, AIDS, and gall bladder disease can put people at risk for chronic pain.
Psychology – Doctors believe that some people may be predisposed to experiencing the subjective nature of pain caused by nurtured thoughts, beliefs or perception.
Social and economic status - Disabling chronic pain is relatively common in the working population, among those of lower education who occupy the occupational class.
Pain occurs when injury or illness triggers nerve signals to the brain. During severe pain, the body can sense burning, shooting or stabbing sensations. But how can you be sure that you are experiencing chronic pain that requires medical treatment? Learn to differentiate between the symptoms of acute and chronic pain by reading the next section on Pain Symptoms here. And when should you seek medical help for pain and start a pain management program?