Chronic Pain

Pain is an uncomfortable feeling that starts in the nervous system. Acute pain lets you know that you may be injured or have a problem you needs to be addressed. Acute pain is a normal sensation triggered in the nervous system to alert you to possible injury and the need to take care of yourself, chronic pain is different. Chronic pain is different than acute pain. In this case, the pain signals last for weeks, months, or even years. The original cause may have been an injury or infection, or a chronic condition or disease, such as arthritis or cancer, may be the source of pain. Problems that cause chronic pain include headache, low back strain, or nerve damage.

Chronic pain usually cannot be cured, but treatments can help. They include medicines, acupuncture, electrical stimulation, and surgery. Other treatments include psychotherapy, relaxation and meditation therapy, biofeedback, and behavior modification.

A person may have 2 or more co-existing chronic pain conditions such as chronic fatigue syndrome, endometriosis, fibromyalgia, inflammatory bowel disease, interstitial cystitis, temporomandibular joint dysfunction, and vulvodynia. It is not known whether these disorders share a common cause.

Chronic pain can affect patients in various ways. Major effects in the patient's life are depressed mood, poor-quality or nonrestorative sleep, fatigue, reduced activity and libido, excessive use of drugs and alcohol, and disability out of proportion with impairment. Chronic pain may lead to prolonged physical suffering, marital or family problems, loss of employment, and various adverse medical reactions from long-term therapy.

The causes of chronic pain are complex and poorly understood. 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 commonly associated with chronic pain include the following:

• 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 (see the image below)
• 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 associated with chronic pain include the following:

• 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
• Stroke (central poststroke pain)

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 associated with chronic pain include the following:

• 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

Female reproductive disorders associated with chronic pain include the following:

• 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
• Adenomyosis
• Chronic endometritis
• Atypical dysmenorrhea or ovulatory pain
• Cervical stenosis
• Endometrial or cervical polyps
• Intrauterine contraceptive devices
• Leiomyomata
• Symptomatic pelvic relaxation (genital prolapse)

Psychological disorders associated with chronic pain include the following:

• Bipolar personality disorders
• Depression
• Porphyria
• Sleep disturbances

The following disorders can also be associated with chronic pain:

• Cardiovascular disease (eg, angina)
• Peripheral vascular disease
• Chemotherapeutic, radiation, or surgical complications

To diagnose chronic pain, your physician will first collect a thorough medical history. A detailed review of the musculoskeletal, reproductive, gastrointestinal, urologic, and neuropsychological systems must be obtained. The physician will focus the history on a characterization of the pain, which includes the following factors:

• Pain location
• Factors that make the pain worse
• Factors that make the pain better
• Quality of pain, which may be described as throbbing, pounding, shooting, pricking, boring, stabbing, lancinating, sharp, cutting, lacerating, pressing, cramping, crushing, pulling, pinching, stinging, burning, splitting, penetrating, piercing, squeezing, and dull aching
• Pain spreading or radiation
• Severity or intensity of pain

The length of time that you have been experiencing pain will also be considered. Generally, chronic pain is pain that lasts at least 3 to 6 months.

A person with chronic pain, and his or her family, should have a good understanding about the many factors that influence chronic pain and the benefits of a multidisciplinary comprehensive management plan.

People with chronic pain should avoid uncomfortable stressful positions and bad posture. In addition, regular exercise, good sleeping habits, and balanced meals are helpful in maintaining good health and relieving symptoms of pain. They may benefit from instruction in biofeedback and relaxation techniques. Massage, acupuncture, and meditation may also provide symptom relief.

Antidepressants are common in the treatment of many chronic pain conditions, even when depression is not a factor. Antidepressants may increase neurotransmitters in the spinal cord that reduce pain signals. But they don't work immediately.

You may feel some relief from an antidepressant after a week or so, but maximum relief may take several weeks. People generally experience moderate pain relief from antidepressants.

Antidepressants seem to work best for pain caused by:

• Arthritis
• Nerve damage from diabetes (diabetic neuropathy)
• Nerve damage from shingles (postherpetic neuralgia)
• Nerve pain from other causes (peripheral neuropathy, spinal cord injury, stroke, radiculopathy)
• Tension headache
• Migraine
• Facial pain
• Fibromyalgia
• Low back pain
• Pelvic pain

Medications from other drug classes with distinct mechanisms of pain relief (such as anticonvulsants) may be used in combination with antidepressant class medications if pain relief with antidepressants is incomplete.

Antidepressants are classified based on their chemical structure and how they work. One of the most effective groups of antidepressants for pain is known as the tricyclics.

Tricyclic antidepressants are the most common type of antidepressant used for pain. They include:

• Amitriptyline
• Imipramine (Tofranil)
• Clomipramine (Anafranil)
• Doxepin
• Nortriptyline (Pamelor)
• Desipramine (Norpramin)

Other classes of antidepressants have become more popular because they have fewer side effects. These drugs may also be used to help relieve chronic pain:

• Serotonin and norepinephrine reuptake inhibitors (SNRIs). Some SNRIs, such as venlafaxine (Effexor), duloxetine (Cymbalta) and milnacipran (Savella), may help relieve chronic pain. People with chronic pain often develop depression along with their chronic pain. Venlafaxine and duloxetine offer the advantage of being effective for depression at the same dosages useful for treating pain.
• Selective serotonin reuptake inhibitors (SSRIs). SSRIs, which include drugs such as paroxetine (Paxil) and fluoxetine (Sarafem, Prozac), are useful for treating depression associated with pain conditions, but do not appear to help relieve pain on their own.