Chronic pain is a condition characterized by pain that persists even after the injury is healed, lasting for more than 6 months.
Types Of Chronic Pain
Chronic pain can be defined as recurrent pain lasting more than six months. The classification of pain is usually based on the severity, intensity, pain-related distress, and functional impairment. A 2016 study 1 pointed out that a comprehensive history and physical evaluation are necessary to determine the nature of pain and its impact on the patient’s lives. Some of the specific questions can facilitate the doctor to determine the type of pain are:
- The location of the pain
- The duration of the pain
- Descriptions of the pain such as aching or burning
- The severity of the pain on a scale of 1-10
- Is it constant or intermittent?
- Alleviating and aggravating factors
On the basis of these factors, some of the types of chronic pain are listed below:
1. Primary chronic pain
This type of pain is prevalent in one or more anatomic regions that persist or recur for longer than 3 months. Primary chronic pain is also associated with significant emotional distress or functional disability that interferes with the day-to-day functioning of the individual. According to a National Health Survey conducted in 2016 2 , 1 in 5 adults in the United States has chronic pain. Common conditions related to this form of pain include:
- Back pain not identifiable as musculoskeletal or neuropathic pain
- Irritable bowel syndrome
- Complex regional pain syndrome
Some of the symptoms associated with this type are:
- Joint pain
- Sleep issues
- Burning sensations or pains
- Mood swings or conditions such as depression or anxiety
2. Chronic cancer pain
This pain is usually accompanied by cancer. The ICD task force 3 decided to list this type as a separate entity since there are specific treatment guidelines for this type of chronic pain. Chronic cancer pain is usually caused by cancer i.e the primary tumor or metastases and the pain that is associated with receiving treatment i.e surgical, chemotherapy, radiotherapy, and others. Cancer pain can be either continuous or intermittent if it is associated with physical movement or clinical procedures.
Some of the common symptoms of cancer-related pain are:
- Shortness of breath
- Sleep disturbances
Some of the causes of this form of chronic pain include:
- Cancer tumor
- Radiation therapy
3. Chronic post-surgical and post-traumatic pain
This pain is characterized by pain that develops after a surgical procedure or a tissue injury and persists for at least 3 months. A 2013 study 4 suggested that depending on the type of surgery, chronic post-surgical pain is often related to neuropathic pain in an average of 30% of cases. A 2007 study 5 pointed out that pain that involves a neuropathic component is usually more severe than nociceptive pain and often affects the quality of life more adversely. Some of the ways the doctor can diagnose the pain as a post-surgical chronic pain are:
- The pain occurs after a surgical procedure
- The pain lasts for more than 3 months after the operation
- The pain isn’t originated from other causes such as cancer or infection
- The pain doesn’t feel the same as the original condition
4. Chronic neuropathic pain
Neuropathic pain is caused due to lesion or disease of the somatosensory nervous system. This pain usually feels like:
- Burning or coldness
- Pins and needles sensations
- numbness or tingling
Central neuropathic chronic pain is usually found in a spinal cord injury, multiple sclerosis, and some strokes. On the other hand, peripheral neuropathic pain is commonly caused by :
- Metabolic disorders
- HIV related neuropathies
- Nutritional deficiencies
- Herpes zoster infection
Neuropathic pain is common in cancer patients since it is either a direct result of cancer on peripheral nerves, a side effect of chemotherapy or radiation. This form may be spontaneous, evoked, an increased response to a painful stimulus, or a painful response to a non-painful stimulus.
5. Chronic visceral pain
Visceral derives from the word “viscera” meaning organs that are inside the body cavity. This form of chronic pain is characterized by persistent or recurrent pain that originates from the internal organs of the head, neck, and thoracic, abdominal, and pelvic cavities. A 2006 study 6 pointed out that this pain is usually perceived in the somatic tissues of the body wall such as skin or muscle in areas that receive the same sensory innervation as the internal organ at the origin of the symptom. The symptoms are usually described as :
- Constant or intermittent sensation
- Sharp or dull sensation
- Deep or superficial sensation
This type of pain can be difficult to locate. People can experience visceral pain after healing from surgery. They may periodically experience a pattern of pain due to problems such as a sensitive stomach. A 2007 study 7 pointed out that the intensity of the symptom may have no relationship with the extent of the internal damage or noxious visceral stimulation.
6. Chronic musculoskeletal pain
This type of chronic pain refers to the pain located in the muscles, bones, ligaments, tendons, or nerves. Some of the conditions that can cause musculoskeletal chronic pain are:
- Muscle loss
- Issues with bone structure or joints
- Poor posture
- Prolonged bed rest after surgery
- Tumors on tendons or joints
Some of the signs of musculoskeletal pain are as follows:
- Dull or sharp sensations
- Cracking sounds in the joints
- Muscle spasms
7. Nociceptive pain
The receptors in the nervous system, called nociceptors, are activated when the body experiences an injury. Sometimes these receptors malfunction and continue to send pain messages to the brain despite the injury being healed.
Nociceptive pain is caused by pain from physical damage or potential damage to the body. This pain is usually triggered by inflammation, chemicals, or physical injury events such as stubbing your toe in the furniture. This form of pain is usually an acute form of pain that heals after the injury is healed. The most common nociceptive pain people experience is musculoskeletal pain 8 that includes the joints, tendons, ligaments, or bones. This pain can develop anywhere in the body. For instance, an organ in your abdomen can cause back pain. Individuals with Nociceptive chronic pain often feel pain that is sharp, aching or throbbing. Some of the causes of this form of pain include:
- Knee replacement
- Hip replacement
- Injuries from playing a sport
- Damaged nerves
- Inflammatory bowel disease
The Cure To Chronic Pain
Chronic pain isn’t fatal. It is treatable and manageable with therapy and medications. It is essential to keep in mind that chronic pain can interfere with the quality of life of the individual. Hence, it is necessary to seek medical attention if the pain lasts longer than six months.References:
- Walk D, Poliak-Tunis M. Chronic Pain Management: An Overview of Taxonomy, Conditions Commonly Encountered, and Assessment. Med Clin North Am. 2016 Jan;100(1):1-16. doi: 10.1016/j.mcna.2015.09.005. Epub 2015 Oct 28. PMID: 26614715.
- Dahlhamer J, Lucas J, Zelaya C, Nahin R, Mackey S, DeBar L, Kerns R, Von Korff M, Porter L, Helmick C. Prevalence of Chronic Pain and High-Impact Chronic Pain Among Adults – United States, 2016. MMWR Morb Mortal Wkly Rep. 2018 Sep 14;67(36):1001-1006. doi: 10.15585/mmwr.mm6736a2. PMID: 30212442; PMCID: PMC6146950.
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- Jensen MP, Chodroff MJ, Dworkin RH. The impact of neuropathic pain on health-related quality of life: review and implications. Neurology. 2007 Apr 10;68(15):1178-82. doi: 10.1212/01.wnl.0000259085.61898.9e. PMID: 17420400.
- Giamberardino MA, Affaitati G, Costantini R. Chapter 24 Referred pain from internal organs. Handb Clin Neurol. 2006;81:343-61. doi: 10.1016/S0072-9752(06)80028-X. PMID: 18808846.
- Cervero F. Visceral pain-central sensitisation. Gut. 2000 Dec;47 Suppl 4(Suppl 4):iv56-7; discussion iv58. doi: 10.1136/gut.47.suppl_4.iv56. PMID: 11076916; PMCID: PMC1766826.
- Casser HR, Schaible HG. Muskuloskeletaler Schmerz [Musculoskeletal pain]. Schmerz. 2015 Oct;29(5):486-8, 490-5. German. doi: 10.1007/s00482-015-0046-9. PMID: 26351130.