Back pain

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Back_pain 

 

Back pain
Different regions (curvatures) of the vertebral column

Back pain (Latin: dorsalgia) is pain felt in the back. It may be classified as neck pain (cervical), middle back pain (thoracic), lower back pain (lumbar) or coccydynia (tailbone or sacral pain) based on the segment affected. The lumbar area is the most common area affected. An episode of back pain may be acute, subacute or chronic depending on the duration. The pain may be characterized as a dull ache, shooting or piercing pain or a burning sensation. Discomfort can radiate to the arms and hands as well as the legs or feet, and may include numbness or weakness in the legs and arms.

The majority of back pain is nonspecific and idiopathic^. Common underlying mechanisms include degenerative or traumatic changes to the discs and facet joints, which can then cause secondary pain in the muscles and nerves and referred pain to the bones, joints and extremities. Diseases and inflammation of the gallbladder, pancreas, aorta and kidneys may also cause referred pain in the back. Tumors of the vertebrae, neural tissues and adjacent structures can also manifest as back pain.

Back pain is common; approximately nine of ten adults experience it at some point in their lives, and five of ten working adults experience back pain each year. Some estimate that as many of 95% of people will experience back pain at some point in their lifetime. It is the most common cause of chronic pain and is a major contributor to missed work and disability. For most individuals, back pain is self-limiting. Most people with back pain do not experience chronic severe pain but rather persistent or intermittent pain that is mild or moderate. In most cases of herniated disks and stenosis, rest, injections or surgery have similar general pain-resolution outcomes on average after one year. In the United States, acute low back pain is the fifth most common reason for physician visits and causes 40% of missed work days. It is the single leading cause of disability worldwide.

Classification

Back pain is classified in terms of duration of symptoms.

1. Acute back pain lasts <6 weeks
2. Subacute back pain lasts between 6 and 12 weeks.
3. Chronic back pain lasts for greater than 12 weeks.

Causes

There are many causes of back pain, including blood vessels, internal organs, infections, mechanical and autoimmune causes. Approximately 90 percent of people with back pain are diagnosed with nonspecific, idiopathic acute pain with no identifiable underlying pathology. In approximately 10 percent of people, a cause can be identified through diagnostic imaging. Fewer than two percent of cases are attributed to secondary factors, with metastatic cancers and serious infections, such as spinal osteomyelitis and epidural abscesses, accounting for approximately one percent.

Common causes

Cause	% of people with back pain
Nonspecific	90%
Vertebral compression fracture	4%
Metastatic cancer	0.7%
Infection	0.01%
Cauda equina	0.04%

Nonspecific

In as many as 90 percent of cases, no physiological causes or abnormalities on diagnostic tests can be found. Nonspecific back pain can result from back strain or sprains, which can cause peripheral injury to muscle or ligaments. Many patients cannot identify the events or activities that may have caused the strain. The pain can present acutely but in some cases can persist, leading to chronic pain.

Chronic back pain in people with otherwise normal scans can result from central sensitization, in which an initial injury causes a longer-lasting state of heightened sensitivity to pain. This persistent state maintains pain even after the initial injury has healed. Treatment of sensitization may involve low doses of antidepressants and directed rehabilitation such as physical therapy.

Spinal disc disease

Spinal disc disease occurs when the nucleus pulposus, a gel-like material in the inner core of the vertebral disc, ruptures. Rupturing of the nucleus pulposus can lead to compression of nerve roots. Symptoms may be unilateral or bilateral, and correlate to the region of the spine affected. The most common region for spinal disk disease is at L4–L5 or L5–S1. The risk for lumbar disc disease is increased in overweight individuals because of the increased compressive force on the nucleus pulposus, and is twice as likely to occur in men. A 2002 study found that lifestyle factors such as night-shift work and lack of physical activity can also increase the risk of lumbar disc disease.

Lumbar disc herniation

Severe spinal-cord compression is considered a surgical emergency and requires decompression to preserve motor and sensory function. Cauda equina syndrome involves severe compression of the cauda equina and presents initially with pain followed by motor and sensory. Bladder incontinence is seen in later stages of cauda equina syndrome.

Degenerative disease

Spondylosis, or degenerative arthritis of the spine, occurs when the intervertebral disc undergoes degenerative changes, causing the disc to fail at cushioning the vertebrae. There is an association between intervertebral disc space narrowing and lumbar spine pain. The space between the vertebrae becomes more narrow, resulting in compression and irritation of the nerves.

Spondylolithesis is the anterior shift of one vertebra compared to the neighboring vertebra. It is associated with age-related degenerative changes as well as trauma and congenital anomalies.

Spinal stenosis can occur in cases of severe spondylosis, spondylotheisis and age-associated thickening of the ligamentum flavum. Spinal stenosis involves narrowing of the spinal canal and typically presents in patients greater than 60 years of age. Neurogenic claudication can occur in cases of severe lumbar spinal stenosis and presents with symptoms of pain in the lower back, buttock or leg that is worsened by standing and relieved by sitting.

Vertebral compression fractures occur in four percent of patients presenting with lower back pain. Risk factors include age, female gender, history of osteoporosis, and chronic glucocorticoid use. Fractures can occur as a result of trauma but in many cases can be asymptomatic.

Infection

Common infectious causes of back pain include osteomyelitis, septic discitis, paraspinal abscess and epidural abscess. Infectious causes that lead to back pain involve various structures surrounding the spine.

Osteomyelitis is the bacterial infection of the bone. Vertebral osteomyelitis is most commonly caused by staphylococci. Risk factors include skin infection, urinary tract infection, IV catheter use, IV drug use, previous endocarditis and lung disease.

Spinal epidural abscess is commonly caused by severe infection with bacteremia. Risk factors include recent administration of epidurals, IV drug use or recent infection.

Cancer

Spread of cancer to the bone or spinal cord can lead to back pain. Bone is one of the most common sites of metastatic lesions. Patients typically have a history of malignancy. Common types of cancer that present with back pain include multiple myeloma, lymphoma, leukemia, spinal cord tumors, primary vertebral tumors and prostate cancer. Back pain is present in 29% of patients with systemic cancer. Unlike other causes of back pain that commonly affect the lumbar spine, the thoracic spine is most commonly affected. The pain can be associated with systemic symptoms such as weight loss, chills, fever, nausea and vomiting. Unlike other causes of back pain, neoplasm-associated back pain is constant, dull, poorly localized and worsens with rest. Metastasis to the bone also increases the risk of spinal-cord compression or vertebral fractures that require emergency surgical treatment.

Autoimmune

Back pain can be caused by the vertebrae compressing the intervertebral discs.

Inflammatory arthritides such as ankylosing spondylitis, psoriatic arthritis, rheumatoid arthritis and systemic lupus erythematosus can all cause varying levels of joint destruction. Among the inflammatory arthritides, ankylosing spondylitis is most closely associated with back pain because of the inflammatory destruction of the bony components of the spine. Ankylosing spondylitis is common in young men and presents with a range of possible symptoms such as uveitis, psoriasis and inflammatory bowel disease.

Referred pain

Back pain can also be referred from another source. Referred pain occurs when pain is felt at a location different than the source of the pain. Disease processes that can present with back pain include pancreatitis, kidney stones, severe urinary tract infections and abdominal aortic aneurysms.

Risk factors

Heavy lifting, obesity, sedentary lifestyle and lack of exercise can increase the risk of back pain. Cigarette smokers are more likely to experience back pain than are nonsmokers. Weight gain in pregnancy is also a risk factor for back pain. In general, fatigue can worsen pain.

A few studies suggest that psychosocial factors such as work-related stress and dysfunctional family relationships may correlate more closely with back pain than do structural abnormalities revealed in X-rays and other medical imaging scans.

Back pain physical effects can range from muscle aching to a shooting, burning, or stabbing sensation. Pain can radiate down the legs and can be increased by bending, twisting, lifting, standing, or walking. While the physical effects of back pain are always at the forefront, back pain also can have psychological effects. Back pain has been linked to depression, anxiety, stress, and avoidance behaviors due to mentally not being able to cope with the physical pain. Both acute and chronic back pain can be associated with psychological distress in the form of anxiety (worries, stress) or depression (sadness, discouragement). Psychological distress is a common reaction to the suffering aspects of acute back pain, even when symptoms are short-term and not medically serious.

Diagnosis

Diagnostic work-up for acute back pain.

Initial assessment of back pain consists of a history and physical examination. Important characterizing features of back pain include location, duration, severity, history of prior back pain and possible trauma. Other important components of the patient history include age, physical trauma, prior history of cancer, fever, weight loss, urinary incontinence, progressive weakness or expanding sensory changes, which can indicate a medically urgent condition.

Physical examination of the back should assess for posture and deformities. Pain elicited by palpating certain structures may be helpful in localizing the affected area. A neurologic exam is needed to assess for changes in gait, sensation and motor function.

Determining if there are radicular symptoms, such as pain, numbness or weakness that radiate down limbs, is important for differentiating between central and peripheral causes of back pain. The straight leg test is a maneuver used to determine the presence of lumbosacral radiculopathy, which occurs when there is irritation in the nerve root that causes neurologic symptoms such as numbness and tingling. Non-radicular back pain is most commonly caused by injury to the spinal muscles or ligaments, degenerative spinal disease or a herniated disc. Disc herniation and foraminal stenosis are the most common causes of radiculopathy.

Imaging of the spine and laboratory tests is not recommended during the acute phase. This assumes that there is no reason to expect that the patient has an underlying problem. In most cases, the pain subsides naturally after several weeks. People who seek diagnosis through imaging are typically less likely to receive a better outcome than are those who wait for the condition to resolve.

Imaging

Magnetic resonance imaging (MRI) is the preferred modality for the evaluation of back pain and visualization of bone, soft tissue, nerves and ligaments. X-rays are a less costly initial option offered to patients with a low clinical suspicion of infection or malignancy, and they are combined with laboratory studies for interpretation.

Imaging is not warranted for most patients with acute back pain. Without signs and symptoms indicating a serious underlying condition, imaging does not improve clinical outcomes in these patients. Four to six weeks of treatment is appropriate before consideration of imaging studies. If a serious condition is suspected, MRI is usually most appropriate. Computed tomography is an alternative if MRI is contraindicated or unavailable. In cases of acute back pain, MRI is recommended for those with major risk factors or clinical suspicion of cancer, spinal infection or severe progressive neurological deficits. For patients with subacute to chronic back pain, MRI is recommended if minor risk factors exist for cancer, ankylosing spondylitis or vertebral compression fracture, or if significant trauma or symptomatic spinal stenosis is present.

Early imaging studies during the acute phase do not improve care or prognosis. Imaging findings are not correlated with severity or outcome.

Laboratory studies

Laboratory studies are employed when there are suspicions of autoimmune causes, infection or malignancy. Laboratory testing may include white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP).

• Elevated ESR could indicate infection, malignancy, chronic disease, inflammation, trauma or tissue ischemia.
• Elevated CRP levels are associated with infection.

CT scan of the spine, showing calcification of the longitudinal posterior ligament.

Because laboratory testing lacks specificity, MRI with and without contrast media and often, biopsy are essential for accurate diagnosis 

Red flags

Imaging is not typically needed in the initial diagnosis or treatment of back pain. However, if there are certain "red flag" symptoms present, plain radiographs (X-ray), CT scan or magnetic resonance imaging may be recommended. These red flags include:

• History of cancer
• Unexplained weight loss
• Immunosuppression
• Urinary infection
• Intravenous drug use
• Prolonged use of corticosteroids
• Back pain not improved with conservative management
• History of significant trauma
• Minor fall or heavy lift in a potentially osteoporotic or elderly individual
• Acute onset of urinary retention, overflow incontinence, loss of anal sphincter tone, or fecal incontinence
• Saddle anesthesia
• Global or progressive motor weakness in the lower limbs

Prevention

Moderate-quality evidence exists that suggests that the combination of education and exercise may reduce an individual's risk of developing an episode of low back pain. Lesser-quality evidence points to exercise alone as a possible deterrent to the risk of the condition.

Management

Nonspecific pain

Patients with uncomplicated back pain should be encouraged to remain active and to return to normal activities.

The management goals when treating back pain are to achieve maximal reduction in pain intensity as rapidly as possible, to restore the individual's ability to function in everyday activities, to help the patient cope with residual pain, to assess for side effects of therapy and to facilitate the patient's passage through the legal and socioeconomic impediments to recovery. For many, the goal is to keep the pain at a manageable level to progress with rehabilitation, which then can lead to long-term pain relief. Also, for some people the goal is to use nonsurgical therapies to manage the pain and avoid major surgery, while for others surgery may represent the quickest path to pain relief.

Not all treatments work for all conditions or for all individuals with the same condition, and many must try several treatment options to determine what works best for them. The present stage of the condition (acute or chronic) is also a determining factor in the choice of treatment. Only a minority of people with back pain (most estimates are 1–10%) require surgery.

Nonmedical

Back pain is generally first treated with nonpharmacological therapy, as it typically resolves without the use of medication. Superficial heat and massage, acupuncture and spinal manipulation therapy may be recommended.

• Heat therapy is useful for back spasms or other conditions. A review concluded that heat therapy can reduce symptoms of acute and subacute low-back pain.
• Regular activity and gentle stretching exercises is encouraged in uncomplicated back pain and is associated with better long-term outcomes. Physical therapy to strengthen the muscles in the abdomen and around the spine may also be recommended. These exercises are associated with better patient satisfaction, although they have not been shown to provide functional improvement. However, one review found that exercise is effective for chronic back pain but not for acute pain. Exercise should be performed under the supervision of a healthcare professional.
• Massage therapy may provide short-term pain relief, but not functional improvement, for those with acute lower back pain. It may also offer short-term pain relief and functional improvement for those with long-term (chronic) and subacute lower pack pain, but this benefit does not appear to be sustained after six months of treatment. There do not appear to be any serious adverse effects associated with massage.
• Acupuncture may provide some relief for back pain. However, further research with stronger evidence is needed.
• Spinal manipulation appears to provide similar effects to other recommended treatments for chronic low back pain. There is no evidence it is more effective than other therapies or sham, or as an adjunct to other treatments, for acute low back pain
• "Back school" is an intervention that consists of both education and physical exercises.There is no strong evidence supporting the use of back school for treating acute, subacute, or chronic non-specific back pain.
• Insoles appear to be an ineffective treatment intervention.
• While traction for back pain is often used in combination with other approaches, there appears to be little or no impact on pain intensity, functional status, global improvement or return to work.

Medication

If nonpharmacological measures are ineffective, medication may be administered.

• Non-steroidal anti-inflammatory drugs (NSAIDs) are typically attempted first. NSAIDs have been proven more effective than placebo, and are usually more effective than paracetamol (acetaminophen).
• Long-term use of opioids has not been tested to determine whether it is effective or safe for treating chronic lower back pain. For severe back pain not relieved by NSAIDs or acetaminophen, opioids may be used. Opioids may not be better than NSAIDs or antidepressants for chronic back pain with regard to pain relief and gain of function.
• Skeletal muscle relaxers may also be used. Their short-term use has been proven effective in the relief of acute back pain. However, the evidence of this effect has been disputed, and these medications do have negative side effects.
• For patients with nerve root pain and acute radiculopathy, there is evidence that a single dose of steroids, such as dexamethasone, may provide pain relief.
• Epidural corticosteroid injection (ESI) is a procedure in which steroid medications are injected into the epidural space. The steroid medications reduce inflammation and thus decrease pain and improve function. ESI has long been used to both diagnose and treat back pain, although recent studies have shown a lack of efficacy in treating low back pain.

Surgery

Surgery for back pain is typically used as a last resort, when serious neurological deficit is evident. A 2009 systematic review of back surgery studies found that, for certain diagnoses, surgery is moderately better than other common treatments, but the benefits of surgery often decline in the long term.

Surgery may sometimes be appropriate for people with severe myelopathy or cauda equina syndrome. Causes of neurological deficits can include spinal disc herniation, spinal stenosis, degenerative disc disease, tumor, infection, and spinal hematomas, all of which can impinge on the nerve roots around the spinal cord. There are multiple surgical options to treat back pain, and these options vary depending on the cause of the pain.

When a herniated disc is compressing the nerve roots, hemi- or partial-laminectomy or discectomy may be performed, in which the material compressing on the nerve is removed. A mutli-level laminectomy can be done to widen the spinal canal in the case of spinal stenosis. A foraminotomy or foraminectomy may also be necessary, if the vertebrae are causing significant nerve root compression. A discectomy is performed when the intervertebral disc has herniated or torn. It involves removing the protruding disc, either a portion of it or all of it, that is placing pressure on the nerve root. Total disc replacement can also be performed, in which the source of the pain (the damaged disc) is removed and replaced, while maintaining spinal mobility. When an entire disc is removed (as in discectomy), or when the vertebrae are unstable, spinal fusion surgery may be performed. Spinal fusion is a procedure in which bone grafts and metal hardware is used to fix together two or more vertebrae, thus preventing the bones of the spinal column from compressing on the spinal cord or nerve roots.

If infection, such as a spinal epidural abscess, is the source of the back pain, surgery may be indicated when a trial of antibiotics is ineffective. Surgical evacuation of spinal hematoma can also be attempted, if the blood products fail to break down on their own.

Pregnancy

About 50% of women experience low back pain during pregnancy. Some studies have suggested that women who have experienced back pain before pregnancy are at a higher risk of experiencing back pain during pregnancy. It may be severe enough to cause significant pain and disability in as many as one third of pregnant women. Back pain typically begins at approximately 18 weeks of gestation and peaks between 24 and 36 weeks. Approximately 16% of women who experience back pain during pregnancy report continued back pain years after pregnancy, indicating that those with significant back pain are at greater risk of back pain following pregnancy.

Biomechanical factors of pregnancy shown to be associated with back pain include increased curvature of the lower back, or lumbar lordosis, to support the added weight on the abdomen. Also, the hormone relaxin is released during pregnancy, which softens the structural tissues in the pelvis and lower back to prepare for vaginal delivery. This softening and increased flexibility of the ligaments and joints in the lower back can result in pain. Back pain in pregnancy is often accompanied by radicular symptoms, suggested to be caused by the baby pressing on the sacral plexus and lumbar plexus in the pelvis.

Typical factors aggravating the back pain of pregnancy include standing, sitting, forward bending, lifting and walking. Back pain in pregnancy may also be characterized by pain radiating into the thigh and buttocks, nighttime pain severe enough to wake the patient, pain that is increased at night or pain that is increased during the daytime.

Local heat, acetaminophen (paracetamol) and massage can be used to help relieve pain. Avoiding standing for prolonged periods of time is also suggested.

Economics

Although back pain does not typically cause permanent disability, it is a significant contributor to physician visits and missed work days in the United States, and is the single leading cause of disability worldwide. The American Academy of Orthopaedic Surgeons report approximately 12 million visits to doctor's offices each year are due to back pain. Missed work and disability related to low back pain costs over $50 billion each year in the United States. In the United Kingdom in 1998, approximately £1.6 billion per year was spent on expenses related to disability from back pain.

Chronic pain

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Chronic_pain 

 

Chronic Pain
Other names	Burning pain, dull pain, throbbing pain
Heavy and irregular sports, in a long term, can be the basis of joint or bone injuries and as a result chronic pain.
Specialty	Specialist in pain, neurology and psychology
Symptoms	Pain lasts longer than the expected period of recovery.
Usual onset	All age groups
Duration	From three months to several years
Causes	high blood sugar, cancer, genetic disorder in neural differentiation, tissue damage, neurological disorder and viral diseases
Risk factors	diabetes, cancer and heart diseases
Diagnostic method	Based on medical history, clinical examination, questionnaire and neuroimaging
Differential diagnosis	gastric ulcer, bone fracture, hernia and neoplasia of the spinal cord
Medication	Non-opioid: ibuprofen, acetaminophen, naproxen, NSAIDs and olanzapine Opioid: morphine, codeine, endorphins and buprenorphine
Frequency	8% to 55.2% in different countries

Chronic pain or chronic pain syndrome is a type of pain that is also known by other titles such as gradual burning pain, electrical pain, throbbing pain, and nauseating pain. This type of pain is sometimes confused with acute pain and can last from three months to several years; Various diagnostic manuals such as DSM-5 and ICD-11 have proposed several definitions of chronic pain, but the accepted definition is that it is "pain that lasts longer than the expected period of recovery."

Creating a pain mechanism prevents possible damage to the body, but chronic pain is a pain without biological value (doesn't have a positive effect). This pain has different divisions; Cancer, post-traumatic or surgery, musculoskeletal and visceral are the most important of these divisions. Various factors cause the formation of chronic pain, which can be neurogenic (gene-dependent), nociceptive, neuropathic, psychological or unknown. Some diseases such as diabetes (high blood sugar), shingles (some viral diseases), phantom limb pain, hypertension and stroke also play a role in the formation of chronic pain. The most common types of chronic pain are back pain, severe headache, migraine, and facial pain.

Chronic pain can cause very severe psychological and physical effects that sometimes continue until the end of life. Analysis of the grey matter (damage to brain neurons), insomnia and sleep deprivation, metabolic problems, chronic stress, obesity and heart attack are examples of physical disorder; And depression, cognitive disorders, perceived injustice (PI) and neurosis are examples of mental disorder.

A wide range of treatments are performed for this disease; Drug therapy (types of opioid and non-opioid drugs), cognitive behavioral therapy and physical therapy are the most significant of them. Medicines are usually associated with side effects and are prescribed when the effects of pain become severe. Medicines such as aspirin and ibuprofen are used for milder pain and morphine and codeine for severe pain. Other treatment methods, such as behavioral therapy and physiotherapy, are often used as a supplement along with drugs due to their low effectiveness. There is currently no definitive cure for any of these methods, and research continues into a wide variety of new management and therapeutic interventions, such as nerve block and radiation therapy.

Chronic pain is considered a kind of disease, this type of pain has affected the people of the world more than diabetes, cancer and heart diseases. During several epidemiological studies conducted in different countries, wide differences in the prevalence rate of chronic pain have been reported from 8% to 55.2% in countries; For example, studies evaluate the incidence in Iran and Canada between 10% and 20% and in the United States between 30% and 40%. The results show that an average of 8% to 11.2% of people in different countries have severe chronic pain, and its epidemic is higher in industrialized countries than in other countries. According to the estimates of the American Medical Association, the costs related to this disease in this country are about 560 to 635 billion dollars.

Classification

Main article: Pain § Classification

The International Association for the Study of Pain (IASP) defines chronic pain as a general pain without biological value that sometimes continues even after the healing of the affected area; A type of pain that cannot be classified as acute pain and lasts longer than expected to heal, or typically, pain that has been experienced on most days or daily for the past six months, is considered chronic pain. According to the DSM-5 index, a complication is "chronic" when the resulting complication (pain, disorder, and illness) lasts for a period of more than six months (this type of classification does not have any prerequisites such as physical or mental injury). The classification of chronic pain is not only limited to pains that arise in the presence of real tissue damage (secondary pains resulting from a primary event); The title "nociplastic pain" or primary pain is related to the pains that occur in the absence of a health-threatening factor, such as disease or damage to the body's somatosensory system, and as a result of permanent nerve stimulation.

The International Statistical Classification of Diseases, in its 11th edition (ICD-11), proposed a seven-category classification for chronic pain:

1. Primary chronic pain: Defined by 3 months of continuous pain in one or more areas of the body, the origin of which is not understood.
2. Chronic cancer pain: pain in one of the body's organs caused by cancer damage (in internal organs, bone or skeletal muscular) is formed.
3. Chronic pain post-traumatic or surgery: Pain that occurs 3 months after an injury or surgery, without taking into account infectious conditions and the severity of tissue damage; Also, the person's past pain is not important in this classification.
4. Chronic neuropathic pain: pain caused by damage to the somatosensory nervous system.
5. Chronic headache and orofacial pain: pain that originates in the head or face, and occurs for 50% or more days over a 3 months period.
6. Chronic visceral pain: pain originating in an internal organ.
7. Chronic musculoskeletal pain: pain originating in the bones, muscles, joints or connective tissue.

Also, the World Health Organization (WHO) states that optional criteria or codes can be used in the classification of chronic pain for each of the seven categories of chronic pain (for example, "diabetic neuropathic" pain).

Another classification for chronic pain is "nociceptive" (caused by inflamed or damaged tissue that activates special pain sensors called nociceptors) and "neuropathic" (caused by damage or malfunction of the nervous system). The type of "nociceptive" itself is divided into two parts: "superficial" and "deep"; also, deep pains are divided into two parts: "deep physical" and "deep visceral" pain. "neuropathic" pains are also divided into "peripheral" (source The peripheral nervous system) and "central" (Central nervous system from the brain or spinal cord) are divided. Peripheral neuropathic pain is often described as "burning", "tingling", "electrical", "stabbing", or "pins and needles".

"Superficial pain" is the result of the activation of pain receptors in the skin or superficial tissues; "Deep somatic pain" is caused by stimulation of pain receptors in ligaments, tendons, bones, blood vessels, fascia, and muscles. (this type of pain is constant but weak) and "deep visceral pain" is pain that originates from one of the body's organs. Deep pain is often very difficult to localize and occurs in multiple areas of the body when injured or inflamed. In the "deep visceral" type, the feeling of pain exists in a place far from the injury, for this reason it is also called vague pain.

Etiology

Chronic pain has many pathophysiological and environmental causes and can occur in cases such as neuropathy of the central nervous system, after cerebral hemorrhage, tissue damage such as extensive burns, inflammation, autoimmune disorders such as rheumatoid arthritis, psychological stress such as headache, migraine or abdominal pain (caused by emotional, psychological or behavioral) and mechanical pain caused by tissue wear and tear such as arthritis. In some cases, chronic pain can be caused by genetic factors which interfere with neuronal differentiation, leading to a permanently lowered threshold for pain.

The pathophysiology of chronic pain remains unclear. Many theories of chronic pain fail to clearly explain why the same pathological conditions do not invariably result in chronic pain. Patients' anatomical predisposition to proximal neural compression (in particular of peripheral nerves) may be the answer to this conundrum. Difficulties in diagnosing proximal neural lesion may account for the theoretical perplexity of chronic pain.

Pathophysiology

Continuous pressure on the spine can destroy the intervertebral disc and cause the sciatic nerve to actively produce pain.

The mechanism of continuous activation and transmission of pain messages, leads the body to an activity to relieve pain (a mechanism to prevent damage in the body), this action causes the release of prostaglandin and increase the sensitivity of that part to stimulation; Prostaglandin secretion causes unbearable and chronic pain. Under persistent activation, the transmission of pain signals to the dorsal horn may produce a pain wind-up phenomenon. This triggers changes that lower the threshold for pain signals to be transmitted. In addition, it may cause non-nociceptive nerve fibers to respond to, generate, and transmit pain signals. Researchers believe that the nerve fibers that cause this type of pain are group C nerve fibers; These fibers are not myelinated (have low transmission speed) and cause long-term pain.

These changes in neural structure can be explained by neuroplasticity. When there is chronic pain, the somatotopic arrangement of the body (the distribution view of nerve cells) is abnormally changed due to continuous stimulation and can cause allodynia or hyperalgesia. In chronic pain, this process is difficult to reverse or stop once established. EEG of people with chronic pain showed that brain activity and synaptic plasticity change as a result of pain, and specifically, the relative activity of beta wave increases and alpha and theta waves decrease.

Inefficient management of dopamine secretion in the brain can act as a common mechanism between chronic pain, insomnia and major depressive disorder and cause its unpleasant side effects. Astrocytes, microglia and satellite glial cells also lose their effective function in chronic pain. Increasing the activity of microglia, changing microglia networks, and increasing the production of chemokines and cytokines by microglia may exacerbate chronic pain. It has also been observed that astrocytes lose their ability to regulate the excitability of neurons and increase the spontaneous activity of neurons in pain circuits.

Management

Main article: Pain management

Pain management is a branch of medicine that uses an interdisciplinary approach. The combined knowledge of various medical professions and allied health professions is used to ease pain and improve the quality of life of those living with pain. The typical pain management team includes medical practitioners (particularly anesthesiologists), rehabilitation psychologists, physiotherapists, occupational therapists, physician assistants, and nurse practitioners. Acute pain usually resolves with the efforts of one practitioner; however, the management of chronic pain frequently requires the coordinated efforts of a treatment team. Complete, longterm remission of many types of chronic pain is rare.

Chronic pain may originate in the body, or in the brain or spinal cord. It is often difficult to treat. Epidemiological studies have found that 8–11.2% of people in various countries have chronic widespread pain. Various non-opioid medicines are initially recommended to treat chronic pain, depending on whether the pain is due to tissue damage or is neuropathic. Psychological treatments including cognitive behavioral therapy and acceptance and commitment therapy may be effective for improving quality of life in those with chronic pain. Some people with chronic pain may benefit from opioid treatment while others can be harmed by it. People with non-cancer pain who have not been helped by non-opioid medicines might be recommended to try opioids if there is no history of substance use disorder and no current mental illness.

Nonopioids

Initially recommended efforts are non-opioid based therapies. Non-opioid treatment of chronic pain with pharmaceutical medicines might include acetaminophen (paracetamol) or NSAIDs.

Various other nonopioid medicines can be used, depending on whether the pain is a result of tissue damage or is neuropathic (pain caused by a damaged or dysfunctional nervous system). There is limited evidence that cancer pain or chronic pain from tissue damage as a result of a conditions (e.g. rheumatoid arthritis) is best treated with opioids. For neuropathic pain other drugs may be more effective than opioids, such as tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and anticonvulsants. Some atypical antipsychotics, such as olanzapine, may also be effective, but the evidence to support this is in very early stages. In women with chronic pain, hormonal medications such as oral contraceptive pills ("the pill") might be helpful. When there is no evidence of a single best fit, doctors may need to look for a treatment that works for the individual person. It is difficult for doctors to predict who will use opioids just for pain management and who will go on to develop an addiction. It is also challenging for doctors to know which patients ask for opioids because they are living with an opioid addiction. Withholding, interrupting or withdrawing opioid treatment in people who benefit from it can cause harm.

Interventional pain management may be appropriate, including techniques such as trigger point injections, neurolytic blocks, and radiotherapy. While there is no high quality evidence to support ultrasound, it has been found to have a small effect on improving function in non-specific chronic low back pain.

Psychological treatments, including cognitive behavioral therapy and acceptance and commitment therapy can be helpful for improving quality of life and reducing pain interference. Brief mindfulness-based treatment approaches have been used, but they are not yet recommended as a first-line treatment. The effectiveness of mindfulness-based pain management (MBPM) has been supported by a range of studies.

Among older adults psychological interventions can help reduce pain and improve self-efficacy for pain management. Psychological treatments have also been shown to be effective in children and teens with chronic headache or mixed chronic pain conditions.

While exercise has been offered as a method to lessen chronic pain and there is some evidence of benefit, this evidence is tentative. For people living with chronic pain, exercise results in few side effects.

Opioids

In those who have not benefited from other measures and have no history of either mental illness or substance use disorder treatment with opioids may be tried. If significant benefit does not occur it is recommended that they be stopped. In those on opioids, stopping or decreasing their use may improve outcomes including pain.

Some people with chronic pain benefit from opioid treatment and others do not; some are harmed by the treatment. Possible harms include reduced sex hormone production, hypogonadism, infertility, impaired immune system, falls and fractures in older adults, neonatal abstinence syndrome, heart problems, sleep-disordered breathing, opioid-induced hyperalgesia, physical dependence, addiction, abuse, and overdose.

Alternative medicine

Alternative medicine refers to health practices or products that are used to treat pain or illness that are not necessarily considered a part of conventional medicine. When dealing with chronic pain, these practices generally fall into the following four categories: biological, mind-body, manipulative body, and energy medicine.

Implementing dietary changes, which is considered a biological-based alternative medicine practice, has been shown to help improve symptoms of chronic pain over time. Adding supplements to one's diet is a common dietary change when trying to relieve chronic pain, with some of the most studied supplements being: acetyl-L-carnitine, alpha-lipoic acid, and vitamin E. Vitamin E is perhaps the most studied out of the three, with strong evidence that it helps lower neurotoxicity in those with cancer, multiple sclerosis, and cardiovascular diseases.

Hypnosis, including self-hypnosis, has tentative evidence. Hypnosis, specifically, can offer pain relief for most people and may be a safe alternative to pharmaceutical medication. Evidence does not support hypnosis for chronic pain due to a spinal cord injury.

Preliminary studies have found medical marijuana to be beneficial in treating neuropathic pain, but not other kinds of long term pain. As of 2018, the evidence for its efficacy in treating neuropathic pain or pain associated with rheumatic diseases is not strong for any benefit and further research is needed. For chronic non-cancer pain, a recent study concluded that it is unlikely that cannabinoids are highly effective. However, more rigorous research into cannabis or cannabis-based medicines is needed.

Tai chi has been shown to improve pain, stiffness, and quality of life in chronic conditions such as osteoarthritis, low back pain, and osteoporosis. Acupuncture has also been found to be an effective and safe treatment in reducing pain and improving quality of life in chronic pain including chronic pelvic pain syndrome.

Transcranial magnetic stimulation for reduction of chronic pain is not supported by high quality evidence, and the demonstrated effects are small and short-term.

Spa therapy could potentially improve pain in patients with chronic lower back pain, but more studies are needed to provide stronger evidence of this.

While some studies have investigated the efficacy of St John's Wort or nutmeg for treating neuropathic (nerve) pain, their findings have raised serious concerns about the accuracy of their results.

Kinesio tape has not been shown to be effective in managing chronic non-specific low-back pain.

Myofascial release has been used in some cases of fibromyalgia, chronic low back pain, and tennis elbow but there is not enough evidence to support this as method of treatment.

Epidemiology

Chronic pain varies in different countries affecting anywhere from 8% to 55% of the population. It affects women at a higher rate than men, and chronic pain uses a large amount of healthcare resources around the globe.

A large-scale telephone survey of 15 European countries and Israel found that 19% of respondents over 18 years of age had suffered pain for more than 6 months, including the last month, and more than twice in the last week, with pain intensity of 5 or more for the last episode, on a scale of 1 (no pain) to 10 (worst imaginable). 4839 of these respondents with chronic pain were interviewed in-depth. Sixty-six percent scored their pain intensity at moderate (5–7), and 34% at severe (8–10); 46% had constant pain, 56% intermittent; 49% had suffered pain for 2–15 years; and 21% had been diagnosed with depression due to the pain. Sixty-one percent were unable or less able to work outside the home, 19% had lost a job, and 13% had changed jobs due to their pain. Forty percent had inadequate pain management and less than 2% were seeing a pain management specialist.

In the United States, chronic pain has been estimated to occur in approximately 35% of the population, with approximately 50 million Americans experiencing partial or total disability as a consequence.^[91] According to the Institute of Medicine, there are about 116 million Americans living with chronic pain, which suggests that approximately half of American adults have some chronic pain condition.^[92][93] The Mayday Fund estimate of 70 million Americans with chronic pain is slightly more conservative.^[94] In an internet study, the prevalence of chronic pain in the United States was calculated to be 30.7% of the population: 34.3% for women and 26.7% for men.

In Canada it is estimated that approximately 1 in 5 Canadians live with chronic pain and half of those people have lived with chronic pain for 10 years or longer. Chronic pain in Canada also occurs more and is more severe in women and Canada's Indigenous communities.

Outcomes

Sleep disturbance, and insomnia due to medication and illness symptoms are often experienced by those with chronic pain. These conditions can be difficult to treat due to the high potential of medication interactions, especially when the conditions are treated by different doctors.

Severe chronic pain is associated with increased risk of death over a ten-year period, particularly from heart disease and respiratory disease. Several mechanisms have been proposed for this increase, such as an abnormal stress response in the body's endocrine system. Additionally, chronic stress seems to affect risks to heart and lung (cardiovascular) health by increasing how quickly plaque can build up on artery walls (arteriosclerosis). However, further research is needed to clarify the relationship between severe chronic pain, stress and cardiovascular health.

People with chronic pain tend to have higher rates of depression and although the exact connection between the comorbidities is unclear, a 2017 study on neuroplasticity found that "injury sensory pathways of body pains have been shown to share the same brain regions involved in mood management." Chronic pain can contribute to decreased physical activity due to fear of making the pain worse. Pain intensity, pain control, and resilience to pain can be influenced by different levels and types of social support that a person with chronic pain receives, and are also influenced by the person's socioeconomic status.

Chronic pain of different causes has been characterized as a disease that affects brain structure and function. MRI studies have shown abnormal anatomical and functional connectivity, even during rest involving areas related to the processing of pain. Also, persistent pain has been shown to cause grey matter loss, which is reversible once the pain has resolved.

One approach to predicting a person's experience of chronic pain is the biopsychosocial model, according to which an individual's experience of chronic pain may be affected by a complex mixture of their biology, psychology, and their social environment.

Psychology

Personality

Two of the most frequent personality profiles found in people with chronic pain by the Minnesota Multiphasic Personality Inventory (MMPI) are the conversion V and the neurotic triad. The conversion V personality expresses exaggerated concern over body feelings, develops bodily symptoms in response to stress, and often fails to recognize their own emotional state, including depression. The neurotic triad personality also expresses exaggerated concern over body feelings and develops bodily symptoms in response to stress, but is demanding and complaining.

Some investigators have argued that it is this neuroticism that causes acute pain to turn chronic, but clinical evidence points the other way, to chronic pain causing neuroticism. When long term pain is relieved by therapeutic intervention, scores on the neurotic triad and anxiety fall, often to normal levels. Self-esteem, often low in people with chronic pain, also shows improvement once pain has resolved.

It has been suggested that catastrophizing might play a role in the experience of pain. Pain catastrophizing is the tendency to describe a pain experience in more exaggerated terms than the average person, to think a great deal more about the pain when it occurs, or to feel more helpless about the experience. People who score highly on measures of catastrophization are likely to rate a pain experience as more intense than those who score low on such measures. It is often reasoned that the tendency to catastrophize causes the person to experience the pain as more intense. One suggestion is that catastrophizing influences pain perception through altering attention and anticipation, and heightening emotional responses to pain. However, at least some aspects of catastrophization may be the product of an intense pain experience, rather than its cause. That is, the more intense the pain feels to the person, the more likely they are to have thoughts about it that fit the definition of catastrophization.

Comorbidity with trauma

Individuals with post-traumatic stress disorder (PTSD) have a high comorbidity with chronic pain. Patients with both PTSD and chronic pain report higher severity of pain than those who do not have a PTSD comorbidity.

Comorbidity with depression

People with chronic pain may also have symptoms of depression. In 2017, the British Medical Association found that 49% of people with chronic pain had depression.

Effect on cognition

Chronic pain's impact on cognition is an under-researched area, but several tentative conclusions have been published. Most people with chronic pain complain of cognitive impairment, such as forgetfulness, difficulty with attention, and difficulty completing tasks. Objective testing has found that people in chronic pain tend to experience impairment in attention, memory, mental flexibility, verbal ability, speed of response in a cognitive task, and speed in executing structured tasks. A review of studies in 2018 reports a relationship between people in chronic pain and abnormal results in test of memory, attention, and processing speed.

Prognosis

Chronic pain leads to a significant decrease in quality of life, decreased productivity, decreased wages, worsening of other chronic diseases, and mental disorders such as depression, anxiety, and substance use disorder. Many drugs that are often used to treat chronic pain have risks and potential side effects and possible complications associated with their use, and the constant use of opioids is associated with decreased life expectancy and increased mortality of patients. Acetaminophen, a standard drug treatment for chronic pain, can cause hepatotoxicity when taken in excess of four grams per day. In addition, therapeutic doses for patients with chronic liver diseases may also cause hepatotoxicity. Long-term risks and side effects of opioids include constipation, drug tolerance or dependence, nausea, indigestion, arrhythmia (QT prolongation of electrocardiography in methadone treatment), and endocrine gland that can lead to amenorrhea, impotence, gynecomastia, and decreased become energy. Also there is a risk of opioid overdose depending on the dose taken by the patient.

Current treatments for chronic pain can reduce pain by 30%. This reduction in pain can significantly improve patients' performance and quality of life. However, the general and long-term prognosis of chronic pain shows decreased function and quality of life. Also, this disease causes many complications and increases the possibility of death of patients and suffering from other chronic diseases and obesity. Similarly, patients with chronic pain who require opioids often develop drug tolerance over time, and this increase in the amount of the dose taken to be effective increases the risk of side effects and death.

Mental disorders can amplify pain signals and make symptoms more severe. In addition, comorbid psychiatric disorders, such as major depressive disorder, can significantly delay the diagnosis of pain disorders. Major depressive disorder and generalized anxiety disorder are the most common comorbidities associated with chronic pain. Patients with underlying pain and comorbid mental disorders receive twice as much medication from doctors annually as compared to patients who do not have such co-morbidities. Studies have shown that when coexisting diseases exist along with chronic pain, the treatment and improvement of one of these disorders can be effective in the improvement of the other. Patients with chronic pain are at higher risk for suicide and suicidal thoughts. Research has shown approximately 20% of people with suicidal thoughts and between 5 and 14% of patients with chronic pain who commit suicide. Of patients who attempted suicide, 53.6% died of gunshot wounds and 16.2% died of opioid overdose. A multimodal treatment approach is important for better pain control and outcomes, as well as minimizing the need for high-risk treatments such as opioid medications. Managing comorbid depression and anxiety is critical in reducing chronic pain. Also, patients with chronic pain should be carefully monitored for severe depression and any suicidal thoughts and plans. Periodic referral of the patient to the doctor for physical examination and to check the effectiveness of treatment 2 is necessary, and the rapid and correct treatment and management of chronic pain can prevent the occurrence of potential negative consequences on the patient's life and increase in healthcare costs.

Social and personal impacts

Social support

Social support has important consequences for individuals with chronic pain. In particular, pain intensity, pain control, and resiliency to pain have been implicated as outcomes influenced by different levels and types of social support. Much of this research has focused on emotional, instrumental, tangible and informational social support. People with persistent pain conditions tend to rely on their social support as a coping mechanism and therefore have better outcomes when they are a part of larger more supportive social networks. Across a majority of studies investigated, there was a direct significant association between social activities or social support and pain. Higher levels of pain were associated with a decrease in social activities, lower levels of social support, and reduced social functioning.

Racial disparities

Evidence exists for unconscious biases and negative stereotyping against racial minorities requesting pain treatment, although clinical decision making was not affected, according to one 2017 review. Minorities may be denied diagnoses for pain and pain medications, and are more likely to go through substance abuse assessment, and are less likely to transfer for pain specialist referral. A 2010 University of Michigan Health study found that black patients in pain clinics received 50% of the amount of drugs that patients who were white received. Preliminary research showed that health providers might have less empathy for black patients and underestimated their pain levels, resulting in treatment delays. Minorities may experience a language barrier, limiting the high level of engagement between the person with pain and health providers for treatment.

Perceptions of injustice

Similar to the damaging effects seen with catastrophizing, perceived injustice is thought to contribute to the severity and duration of chronic pain. Pain-related injustice perception has been conceptualized as a cognitive appraisal reflecting the severity and irreparability of pain- or injury-related loss (e.g., "I just want my life back"), and externalizing blame and unfairness ("I am suffering because of someone else's negligence."). It has been suggested that understanding problems with top down processing/cognitive appraisals can be used to better understand and treat this problem.

Chronic pain and COVID-19

COVID-19 has disrupted the lives of many, leading to major physical, psychological and socioeconomic impacts in the general population. Social distancing practices defining the response to the pandemic alter familiar patterns of social interaction, creating the conditions for what some psychologists are describing as a period of collective grief. Individuals with chronic pain tend to embody an ambiguous status, at times expressing that their type of suffering places them between and outside of conventional medicine. With a large proportion of the global population enduring prolonged periods of social isolation and distress, one study found that people with chronic pain from COVID-19 experienced more empathy towards their suffering during the pandemic.

Effect of chronic pain in the workplace

In the workplace, chronic pain conditions are a significant problem for both the person with the condition and the organization; a problem only expected to increase in many countries due to an aging workforce. In light of this, it may be helpful for organizations to consider the social environment of their workplace, and how it may be working to ease or worsen chronic pain issues for employees. As an example of how the social environment can affect chronic pain, some research has found that high levels of socially prescribed perfectionism (perfectionism induced by external pressure from others, such as a supervisor) can interact with the guilt felt by a person with chronic pain, thereby increasing job tension, and decreasing job satisfaction.