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.
Pathophysiology
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.
Frequency
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.
- Musculoskeletal disorders
- Osteoarthritis/degenerative joint disease/spondylosis
- Rheumatoid arthritis
- Lyme disease
- Reiter syndrome
- Disk herniation/facet osteoarthropathy
- Fractures/compression fracture of lumbar vertebrae
- Faulty or poor posture
- Fibromyalgia
- Polymyalgia rheumatica
- Mechanical low back pain
- Chronic coccygeal pain
- Muscular strains and sprains
- Pelvic floor myalgia (levator ani spasm)
- Piriformis syndrome
- Rectus tendon strain
- Hernias (eg, obturator, sciatic, inguinal, femoral, spigelian, perineal, umbilical)
- Abdominal wall myofascial pain (trigger points)
- Chronic overuse syndromes (eg, tendinitis, bursitis)
- Neurological disorders
- Brachial plexus traction injury
- Cervical radiculopathy
- Thoracic outlet syndrome
- Spinal stenosis
- Arachnoiditis
- Metabolic deficiency myalgias
- Polymyositis
- Neoplasia of spinal cord or sacral nerve
- Cutaneous nerve entrapment in surgical scar
- Postherpetic neuralgia (shingles)
- 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
- Urologic disorders
- 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
- Chronic visceral pain syndrome
- Gastroesophageal reflux
- Peptic ulcer disease
- Pancreatitis
- Chronic intermittent bowel obstruction
- Colitis
- Chronic constipation
- Diverticular disease
- Inflammatory bowel disease
- Irritable bowel syndrome
- Reproductive disorders (extrauterine)
- Endometriosis
- 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)
- Adenomyosis
- Chronic endometritis
- Atypical dysmenorrhea or ovulatory pain
- Cervical stenosis
- Endometrial or cervical polyps
- Leiomyomata
- Symptomatic pelvic relaxation (genital prolapse)
- Intrauterine contraceptive device
- Psychological disorders
- Bipolar personality disorders
- Depression
- Porphyria
- Sleep disturbances
