Background
Chronic pain syndrome (CPS) is a common problem that presents a major challenge to health-care providers because of its complex natural history, unclear etiology, and poor response to therapy. CPS is a poorly defined condition. Most authors consider ongoing pain lasting longer than 6 months as diagnostic, and others have used 3 months as the minimum criterion. In chronic pain, the duration parameter is used arbitrarily. Some authors suggest that any pain that persists longer than the reasonably expected healing time for the involved tissues should be considered chronic pain. (See Presentation and Workup.)
CPS is a constellation of syndromes that usually do not respond to the medical model of care. This condition is managed best with a multidisciplinary approach, requiring good integration and knowledge of multiple organ systems. (The images below demonstrate conditions associated with CPS.) (See Treatment and Medication.)
Sagittal magnetic resonance imaging (MRI) scan of the cervical spine in a patient with cervical radiculopathy. This image reveals a C6-C7 herniated nucleus pulposus.
Osteoarthritis of the knee, Kellgren stage III.
Changes in the hand caused by rheumatoid arthritis. Photograph by David Effron MD, FACEP. Approximately 35% of Americans have some element of chronic pain, and approximately 50 million Americans are disabled partially or totally due to chronic pain. Chronic pain is reported more commonly in women.
Complications
CPS can affect patients in various ways. Major effects in the patient's life are depressed mood, fatigue, reduced activity and libido, excessive use of drugs and alcohol, dependent behavior, and disability out of proportion with impairment. (See Presentation.)
Chronic pain may lead to prolonged physical suffering, marital or family problems, loss of employment, and various adverse medical reactions from long-term therapy.
A study by van Tilburg et al indicates that adolescents who have chronic pain and depressive thoughts are at increased risk for suicide ideation and attempt.[1]
Etiology
The pathophysiology of chronic pain syndrome (CPS) is multifactorial and complex and still is poorly understood. Some authors have suggested that CPS might be a learned behavioral syndrome that begins with a noxious stimulus that causes pain. This pain behavior then is rewarded externally or internally. Thus, this pain behavior is reinforced, and then it occurs without any noxious stimulus. Internal reinforcers are relief from personal factors associated with many emotions (eg, guilt, fear of work, sex, responsibilities). External reinforcers include such factors as attention from family members and friends, socialization with the physician, medications, compensation, and time off from work.
Patients with several psychological syndromes (eg, major depression, somatization disorder, hypochondriasis, conversion disorder) are prone to developing CPS.
In a study by Alonso-Blanco, a connection was found in women between the number of active myofascial trigger points (MTrPs) and the intensity of spontaneous pain, as well as widespread mechanical hypersensitivity. Nociceptive inputs from these MTrPs may be linked to central sensitization.[2]
Various neuromuscular, reproductive, gastrointestinal (GI), and urologic disorders may cause or contribute to chronic pain. Sometimes multiple contributing factors may be present in a single patient.
Musculoskeletal disorders
Musculoskeletal disorders associated with chronic pain include the following:
- Rheumatoid arthritis (see the image below)
T1-weighted sagittal magnetic resonance imaging (MRI) scan of the cervical spine in a patient with rheumatoid arthritis shows basilar invagination with cranial migration of an eroded odontoid peg. There is minimal pannus. The tip of the peg indents the medulla, and there is narrowing of the foramen magnum, due to the presence of the peg. Inflammatory fusion of several cervical vertebral bodies is shown. - Lyme disease
- Reiter syndrome
- Disk herniation/facet osteoarthropathy
- Fractures/compression fracture of lumbar vertebrae
- Faulty or poor posture
- Polymyalgia rheumatica
- Mechanical low back pain
- Muscular strains and sprains
- Pelvic floor myalgia (levator ani spasm)
- Rectus tendon strain
- Hernias (eg, obturator, sciatic, inguinal, femoral, spigelian, perineal, umbilical)
- Abdominal wall myofascial pain (trigger points)
- Chronic overuse syndromes (eg, tendonitis, bursitis)
Neurologic disorders
Neurologic disorders associated with chronic pain include the following:
- Brachial plexus traction injury
- Cervical radiculopathy
- Thoracic outlet syndrome
- Spinal stenosis (see the image below)
Oblique view of the cervical spine demonstrates 2 levels of foraminal stenosis (white arrows) resulting from facet hypertrophy (yellow arrow) and uncovertebral joint hypertrophy. - Arachnoiditis
- Metabolic deficiency myalgias
- Polymyositis
- Neoplasia of spinal cord or sacral nerve
- Cutaneous nerve entrapment in surgical scar
- Postherpetic neuralgia (shingles)[8, 9]
- Neuralgia (eg, iliohypogastric, ilioinguinal, or genitofemoral nerves)
- Polyneuropathies
- Polyradiculoneuropathies
- Mononeuritis multiplex
- Chronic daily headaches
- Muscle tension headaches
- Migraine headaches
- Temporomandibular joint dysfunction
- Temporalis tendonitis
- Sinusitis
- Atypical facial pain
- Trigeminal neuralgia
- Glossopharyngeal neuralgia
- Nervus intermedius neuralgia
- Sphenopalatine neuralgia
- Referred dental or temporomandibular joint pain
- Abdominal epilepsy
- Abdominal migraine
- Stroke (central poststroke pain)[10]
Urologic disorders
Urologic disorders associated with chronic pain include the following:
- Bladder neoplasm
- Chronic urinary tract infection
- Interstitial cystitis
- Radiation cystitis
- Recurrent cystitis
- Recurrent urethritis
- Urolithiasis
- Uninhibited bladder contractions (detrusor-sphincter dyssynergia)
- Urethral diverticulum
- Chronic urethral syndrome
- Urethral carbuncle
- Prostatitis
- Urethral stricture
- Testicular torsion
- Peyronie disease
Gastrointestinal disorders
GI disorders associated with chronic pain include the following:
- Chronic visceral pain syndrome
- Gastroesophageal reflux
- Peptic ulcer disease
- Pancreatitis
- Chronic intermittent bowel obstruction
- Chronic constipation
- Diverticular disease
- Inflammatory bowel disease
- Irritable bowel syndrome
Reproductive disorders (extrauterine)
Extrauterine reproductive disorders associated with chronic pain include the following:
- Adhesions
- Adnexal cysts
- Chronic ectopic pregnancy
- Chlamydial endometritis or salpingitis
- Endosalpingiosis
- Ovarian retention syndrome (residual ovary syndrome)
- Ovarian remnant syndrome
- Ovarian dystrophy or ovulatory pain
- Pelvic congestion syndrome
- Postoperative peritoneal cysts
- Residual accessory ovary
- Subacute salpingo-oophoritis
- Tuberculous salpingitis
Reproductive disorders (uterine)
Uterine reproductive disorders associated with chronic pain include the following:
- Adenomyosis
- Chronic endometritis
- Atypical dysmenorrhea or ovulatory pain
- Cervical stenosis
- Endometrial or cervical polyps
- Leiomyomata
- Symptomatic pelvic relaxation (genital prolapse)
An intrauterine contraceptive device can also be associated with chronic pain.
Psychological disorders
Psychological disorders associated with chronic pain include the following:
- Bipolar personality disorders
- Depression
- Porphyria
- Sleep disturbances
Other
The following disorders can also be associated with chronic pain:
- Cardiovascular disease (eg, angina)
- Peripheral vascular disease
- Chemotherapeutic, radiation, or surgical complications
Fibromyalgia risk
Results from a study by Mork et al indicated that women who are overweight or obese have a 60-70% greater risk of developing fibromyalgia than do women of normal weight, with body mass index (BMI) being an independent risk factor for the condition. The report looked at whether physical exercise and high BMI influence the occurrence of fibromyalgia. The study included 15,990 women, none of whom at baseline had fibromyalgia or any other physical impairment. By 11-year follow-up, incident fibromyalgia had reportedly occurred in 380 women. The authors noted that only a weak association typically existed between exercise level and fibromyalgia risk.
In overweight or obese women in the study who exercised for at least 1 hour each week, the relative risk (RR) for fibromyalgia (in comparison with women of normal weight and a similar activity level) was 1.72, while in overweight or obese women who did not exercise or who did so for less than an hour per week, the RR was 2.09.[3]
Patient Education
The patient and family should have a good understanding about the multifactorial nature of chronic pain and the benefits of a multidisciplinary comprehensive management plan.[11]
The patient should avoid uncomfortable stressful positions and bad posture. In addition, regular exercise, good sleeping habits, and balanced meals are helpful in maintaining good health. The patient may also benefit from instruction in biofeedback and relaxation techniques.
For excellent patient education information, see the Mental Health Center, as well as Chronic Pain, Fibromyalgia, Chronic Fatigue Syndrome (CFS), and Pain Medications.
van Tilburg MA, Spence NJ, Whitehead WE, Bangdiwala S, Goldston DB. Chronic pain in adolescents is associated with suicidal thoughts and behaviors. J Pain. Oct 2011;12(10):1032-9. [Medline]. [Full Text].
Alonso-Blanco C, Fernández-de-Las-Peñas C, Morales-Cabezas M, Zarco-Moreno P, Ge HY, Florez-García M. Multiple active myofascial trigger points reproduce the overall spontaneous pain pattern in women with fibromyalgia and are related to widespread mechanical hypersensitivity. Clin J Pain. Jun 2011;27(5):405-13. [Medline].
Mork PJ, Vasseljen O, Nilsen TI. The association between physical exercise, body mass index, and risk of fibromyalgia: Longitudinal data from the Norwegian HUNT study. Arthritis Care Res (Hoboken). Jan 29 2010;[Medline].
Gusi N, Parraca JA, Olivares PR, et al. Tilt vibratory exercise improves the dynamic balance in fibromyalgia: A randomized controlled trial. Arthritis Care Res (Hoboken). Mar 16 2010;[Medline].
Rehm SE, Koroschetz J, Gockel U, et al. A cross-sectional survey of 3035 patients with fibromyalgia: subgroups of patients with typical comorbidities and sensory symptom profiles. Rheumatology (Oxford). Mar 17 2010;[Medline].
Thomas EN, Blotman F. Aerobic exercise in fibromyalgia: a practical review. Rheumatol Int. Mar 26 2010;[Medline].
Fontaine KR, Conn L, Clauw DJ. Effects of lifestyle physical activity on perceived symptoms and physical function in adults with fibromyalgia: results of a randomized trial. Arthritis Res Ther. Mar 30 2010;12(2):R55. [Medline].
Rowbotham M, Harden N, Stacey B, et al. Gabapentin for the treatment of postherpetic neuralgia: a randomized controlled trial. JAMA. Dec 2 1998;280(21):1837-42. [Medline].
[Best Evidence] Irving G, Jensen M, Cramer M, et al. Efficacy and tolerability of gastric-retentive gabapentin for the treatment of postherpetic neuralgia: results of a double-blind, randomized, placebo-controlled clinical trial. Clin J Pain. Mar-Apr 2009;25(3):185-92. [Medline].
Klit H, Finnerup NB, Andersen G, Jensen TS. Central poststroke pain: A population-based study. Pain. Apr 2011;152(4):818-24. [Medline].
Durosaro O, Davis MD, Hooten WM, et al. Intervention for erythromelalgia, a chronic pain syndrome: comprehensive pain rehabilitation center, Mayo Clinic. Arch Dermatol. Dec 2008;144(12):1578-83. [Medline].
Tang NK, Salkovskis PM, Hodges A, et al. Chronic pain syndrome associated with health anxiety: a qualitative thematic comparison between pain patients with high and low health anxiety. Br J Clin Psychol. Mar 2009;48:1-20. [Medline].
Nijs J, Van Oosterwijck J, De Hertogh W. Rehabilitation of chronic whiplash: treatment of cervical dysfunctions or chronic pain syndrome?. Clin Rheumatol. Mar 2009;28(3):243-51. [Medline].
Wetherell JL, Afari N, Rutledge T, et al. A randomized, controlled trial of acceptance and commitment therapy and cognitive-behavioral therapy for chronic pain. Pain. Sep 2011;152(9):2098-107. [Medline].
[Best Evidence] Ranoux D, Attal N, Morain F, et al. Botulinum toxin type A induces direct analgesic effects in chronic neuropathic pain. Ann Neurol. Sep 2008;64(3):274-83. [Medline].
[Best Evidence] Kroenke K, Bair MJ, Damush TM, et al. Optimized antidepressant therapy and pain self-management in primary care patients with depression and musculoskeletal pain: a randomized controlled trial. JAMA. May 27 2009;301(20):2099-110. [Medline].
Gianni W, Madaio AR, Ceci M, Benincasa E, Conati G, Franchi F, et al. Transdermal buprenorphine for the treatment of chronic noncancer pain in the oldest old. J Pain Symptom Manage. Apr 2011;41(4):707-14. [Medline].
Kanbayashi Y, Hosokawa T, Okamoto K, et al. Factors Predicting Requirement of High-dose Transdermal Fentanyl in Opioid Switching From Oral Morphine or Oxycodone in Patients With Cancer Pain. Clin J Pain. Oct 2011;27(8):664-667. [Medline].
Gilron I, Wajsbrot D, Therrien F, Lemay J. Pregabalin for peripheral neuropathic pain: a multicenter, enriched enrollment randomized withdrawal placebo-controlled trial. Clin J Pain. Mar-Apr 2011;27(3):185-93. [Medline].
Moore RA, Wiffen PJ, Derry S, McQuay HJ. Gabapentin for chronic neuropathic pain and fibromyalgia in adults. Cochrane Database Syst Rev. Mar 16 2011;3:CD007938. [Medline].




