Chronic pain
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Please help improve this article or section by expanding it. Further information might be found on the talk page or at requests for expansion. This article has been tagged since March 2007. |
| ICD-10 | R52.1 - R52.2 |
|---|---|
| ICD-9 | 780.96 |
| MedlinePlus | 002164 |
| eMedicine | topic list |
Chronic pain was originally defined as pain that has lasted 6 months or longer. It is now defined as pain that persists longer than the normal course of time associated with a particular type of injury. However, this is a rather subjective assessment.
This constant or intermittent pain has often outlived its purpose, as it does not help the body to prevent injury. On the other hand, pain does have a purpose. It is a warning to the body that something is wrong. So, even though the preventative nature of pain is absent (withdrawing your hand from a fire, to prevent a burn), pain is indicative of cellular damage. Therefore, the perception of pain, on an acute basis, occurs when heat, or chemical irritation or mechanical pressure, has created disruption of the cells, with release of certain chemical irritants to inform the brain of the tissue damage. Chronic pain, on the other hand, is often the result of ongoing irritation of the nerve fibers that carry the message of pain to the brain.
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[edit] Causes
Chronic pain is transmitted to the brain central nervous system (CNS) by nociceptive impulses, which causes changes in the neural response. A nerve fiber is like an electrical wire, with insulation. The insulating material is called myelin, and it prevent electrical charges from jumping across or "shorting out" one pain nerve from the other. The more the myelin or insulation, the better protected the pain nerve fiber is from chemical, pressure, or electrical injury.
There are three broad types of nerve fibers that carry the message of pain. These are the small, sparsely or totally unmyelinated fibers, called "C fibers," and the A delta and A beta pain fibers, which has more myeline surrounding them. In counter-distinction to acute pain, the chronic pain message reaches multiple areas of the brain, or central nervous system, including the reticular activating system, involved in the control of sleep, the hypothalamus, involved the the control of food intake, and emotions, the thalamus, and the sensory cortex (Hendler, N., The Anatomy and Psychopharmacology of Chronic Pain,The Jounral of Clinical Psychiatry, Vol. 43, No. 8, Sec 2:15-21, August, 1982).
Chronic pain subsequently provokes changes in the behavior of the patient, with depression being one of the most common features after six months (Hendler, N., Depression Caused by Chronic Pain, The Journal of Clinical Psychiatry, Vol. 45, No. 3, Sec 2:30-36, March 1984). As a result, the patient may also become physically atrophied and deconditioned. However, it is important to remember that chronic pain is multifactorial, with the underlying biological changes affecting physical and psychosocial factors.
[edit] Types
This article discusses chronic pain in two categories: malignant and non-malignant.
- Pain associated with malignancy can be caused by the cancer itself or by treatment.
- Non-malignant pain includes a variety of causes: arthritis, neuropathy/neuralgia, back pain from injury or disorders (such as spinal stenosis, degenerative disc disease, spinal disc herniation, etc), migraines and other types of headaches, abdominal pain from chronic pancreatitis, bowel disorders, etc; pelvic pain from various conditions (endometriosis, interstitial cystitis, etc); and also diffuse conditions such as fibromyalgia, reflex sympathetic dystrophy, lupus and other systemic autoimmune/connective tissue conditions, multiple sclerosis and some other neuromuscular conditions.
Chronic pain can occur anywhere in the body; this list includes only a few examples of conditions that can cause chronic pain. However, recent articles have suggested that between 40%-67% of chronic pain patients are misdiagnosed (Hendler, N., Kozikowski, J. Overlooked physical diagnoses in Chronic Pain Patients involved in Litigation, Psychosomatics, Vol. 34, No 6:494-501, November/December, 1993, and Hendler, N., Bergson, C., and Morrison, C. Overlooked Diagnoses in Chronic Pain Patients Involved in Litigation, Vol. 37, No 6:507-517, November/December 1996). Clearly, it is essential to obtain a proper diagnosis, because if a person is misdiagnosed, he or she will not receive the right treatment.
[edit] Post Operative Chronic Pain
Post operative chronic pain is often over looked.[citation needed]. This is distinct from the initial discomfort of the surgery itself or the temporary numbness or tingling around or near where the operation was performed caused by the severing of nerves within the skin. In contrast, Post Operative Chronic Pain occurs when the nerves regenerate, but with the neurones growing back into the wrong myelin sheaths, or do not enter the sheath at all. This condition is called a neuroma. The pain nerve fibres result in messages being crossed over and sent to the wrong part of the brain. Hence a light touch may result in a perceived sense of pain or temperature change. There are no tests or scans to confirm this, as the nerves are tiny and do not show up, but it is a very real problem and can cause a person to be incapacitated with pain for which standard analgesics fail to help.
The most common symptoms are a tingling sensation near or around the area where the operation was performed, sharp shooting pains, severe aches after much movement, constant 'low ache' all day and sometimes a general 'weak' feeling.[citation needed]
[edit] Management
Chronic pain is often more difficult to treat than acute pain. Expert physician care is generally necessary to treat any pain that has become chronic and usually involves a multi-disciplinary team which may include a combination of physiotherapists, psychologists, counselors, and specialists, such as cancer or palliative care nurses for cancer or physicians who specialize in spine medicine for back pain. Depression is common for patients with chronic back pain, and it is important to treat both the pain and depression (Depression and chronic back pain). Very often, medications called anti-depressants can help a patient in many ways, by reducing depression and anxiety, helping natural REM sleep, and reducing the perception of pain (Hendler, N, Pharmacotherapy of Chronic Pain, Chapter 9 pages 117-129, in Neurosurgical Management of Pain, (from Johns Hopkins Hospital), Edited by Richard North, MD, Ph.D, and Richard Levy, MD, Springer-Verlag, New York, 1997).
In managing chronic pain (Pain Management of Chronic Pain)and in choosing which pain killers to use, beneficial analgesic effects must be balanced against any suffered drug side-effects if overall quality of life is to be improved. For example, with opioids, patients may need to adjust the dosage to reach a compromise between actual pain-killing effect and an acceptable level of nausea or constipation.
[edit] Opioid analgesia
Opioids are one of the most effective treatments for chronic pain. When opioids (also called a narcotic or painkiller) are used for prolonged periods drug tolerance, chemical dependency and (rarely) psychological addiction may occur. Chemical dependency is somewhat common among opioid users; however, psychological addiction rarely occurs for prescription users. Apparent drug tolerance to the pain-relieving effects of opioids may occur, although tolerance to pain reducing effects usually appears more slowly than tolerance to the euphoric effects of opioids. This may be confused with progression of the underlying disease in cancer patients, back pain patients, and other chronic pain sufferers, rather than an actual decrease in efficacy of the drug. This is normal with opioids but not with many of the other non-opiate drugs. More people die from acetaminophen (Tylenol) a common additive or stand alone pain-killer than from opioids.[citation needed]
[edit] Pain modifiers
Drugs within this class act centrally on the brain to down regulate the perceived painful stimulus. Drugs having this effect were fortuitously identified whilst being used to treat unrelated conditions. The first such group were the tricyclic antidepressants (in particular amitriptyline) and the dose required is far lower than that used to treat depression. Similarly some of the anticonvulsant drugs are used for this (in particular carbamazepine sodium valproate and gabapentin). For most of these drugs, their use in chronic pain management is off-label.
[edit] Trigger Point Injections / Core Blocks
(Excerpt from Chronic Pain written by patient undergoing this treatment) Only recently has research been undertaken to try and find more permanent solutions for these debilitating conditions. One method that has been formulated is Trigger Point Injections which are also sometimes referred to. This involves the injection of a mixture of steroid and anaesthetic into the specific pressure points in the body where the pain is located in an attempt to disburse contracted tissue that could be causing the disturbance.
There has been some success treating cases of migraines, back pain, and other muscular associated situations with this procedure.[citation needed] If they are able to isolate the centers that are the focal points of the pain then a series of treatments are started. In theory as the treatment progresses the nerves are released from the pressure that is causing the continual transmission of the pain signal to the memory centre of the brain. This in turn should allow the brain to forget the pain.
At this time these procedures are starting to become readily available in North America. In the United States these procedures are showing very promising results with patients according to the Chronic Pain Association of America.[citation needed] Insurance companies are gradually starting to cover the costs of the procedures because the government has recognized their validity, based from the outcome of many completed studies and regimens of injections. This also means that the procedures are now regulated so you do have a guarantee that the standards of the Core Block are being maintained.
Although the procedure is covered by provincial health programs in Canada it can only be done by anaesthesiologists in a hospital situation. Since not all doctors in that field even perform this procedure, the wait time to get into a pain clinic in Canada can be as high as sixteen months.
[edit] See also
[edit] External links
- American Chronic Pain Association
- Chronic Pain as a Disease: Why does it still hurt?
- Stress Related Chronic Pain
- American Pain Foundation
- Pain Management Information-Discusses Conventional & Alternative Treatment of Pain
Categories: Articles lacking sources from March 2007 | All articles lacking sources | Articles to be expanded since March 2007 | All articles to be expanded | Medicine articles needing expert attention | Articles with unsourced statements since February 2007 | All articles with unsourced statements | Nociception | Pain
