Chronic Pain Syndrome

Chronic pain syndrome (CPS) is a common problem that presents a major challenge to healthcare 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 reasonable expected healing time for the involved tissues should be considered chronic pain.

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 pathophysiology of 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.

United States

Pain is the most common complaint that leads patients to seek medical care. Chronic pain is not uncommon. Approximately 35% of Americans have some element of chronic pain, and approximately 50 million Americans are disabled partially or totally due to chronic pain. Various neuromuscular, reproductive, gastrointestinal, and urologic disorders may cause or contribute to chronic pain. Sometimes multiple contributing factors may be present in a single patient.

  1. Musculoskeletal disorders
    1. Osteoarthritis/degenerative joint disease/spondylosis
    2. Rheumatoid arthritis
    3. Lyme disease
    4. Reiter syndrome
    5. Disk herniation/facet osteoarthropathy
    6. Fractures/compression fracture of lumbar vertebrae
    7. Faulty or poor posture
    8. Fibromyalgia
    9. Polymyalgia rheumatica
    10. Mechanical low back pain
    11. Chronic coccygeal pain
    12. Muscular strains and sprains
    13. Pelvic floor myalgia (levator ani spasm)
    14. Piriformis syndrome
    15. Rectus tendon strain
    16. Hernias (eg, obturator, sciatic, inguinal, femoral, spigelian, perineal, umbilical)
    17. Abdominal wall myofascial pain (trigger points)
    18. Chronic overuse syndromes (eg, tendinitis, bursitis)
  2. Neurological disorders
    1. Brachial plexus traction injury
    2. Cervical radiculopathy
    3. Thoracic outlet syndrome
    4. Spinal stenosis
    5. Arachnoiditis
    6. Metabolic deficiency myalgias
    7. Polymyositis
    8. Neoplasia of spinal cord or sacral nerve
    9. Cutaneous nerve entrapment in surgical scar
    10. Postherpetic neuralgia (shingles)
    11. Neuralgia (eg, iliohypogastric, ilioinguinal, or genitofemoral nerves)
    12. Polyneuropathies
    13. Polyradiculoneuropathies
    14. Mononeuritis multiplex
    15. Chronic daily headaches
    16. Muscle tension headaches
    17. Migraine headaches
    18. Temporomandibular joint dysfunction
    19. Temporalis tendonitis
    20. Sinusitis
    21. Atypical facial pain
    22. Trigeminal neuralgia
    23. Glossopharyngeal neuralgia
    24. Nervus intermedius neuralgia
    25. Sphenopalatine neuralgia
    26. Referred dental or temporomandibular joint pain
    27. Abdominal epilepsy
    28. Abdominal migraine
  3. Urologic disorders
    1. Bladder neoplasm
    2. Chronic urinary tract infection
    3. Interstitial cystitis
    4. Radiation cystitis
    5. Recurrent cystitis
    6. Recurrent urethritis
    7. Urolithiasis
    8. Uninhibited bladder contractions (detrusor-sphincter dyssynergia)
    9. Urethral diverticulum
    10. Chronic urethral syndrome
    11. Urethral carbuncle
    12. Prostatitis
    13. Urethral stricture
    14. Testicular torsion
    15. Peyronie disease
  4. Gastrointestinal disorders
    1. Chronic visceral pain syndrome
    2. Gastroesophageal reflux
    3. Peptic ulcer disease
    4. Pancreatitis
    5. Chronic intermittent bowel obstruction
    6. Colitis
    7. Chronic constipation
    8. Diverticular disease
    9. Inflammatory bowel disease
    10. Irritable bowel syndrome
  5. Reproductive disorders (extrauterine)
    1. Endometriosis
    2. Adhesions
    3. Adnexal cysts
    4. Chronic ectopic pregnancy
    5. Chlamydial endometritis or salpingitis
    6. Endosalpingiosis
    7. Ovarian retention syndrome (residual ovary syndrome)
    8. Ovarian remnant syndrome
    9. Ovarian dystrophy or ovulatory pain
    10. Pelvic congestion syndrome
    11. Postoperative peritoneal cysts
    12. Residual accessory ovary
    13. Subacute salpingo-oophoritis
    14. Tuberculous salpingitis
  6. Reproductive disorders (uterine)
    1. Adenomyosis
    2. Chronic endometritis
    3. Atypical dysmenorrhea or ovulatory pain
    4. Cervical stenosis
    5. Endometrial or cervical polyps
    6. Leiomyomata
    7. Symptomatic pelvic relaxation (genital prolapse)
    8. Intrauterine contraceptive device
  7. Psychological disorders
    1. Bipolar personality disorders
    2. Depression
    3. Porphyria
    4. Sleep disturbances