Chronic pain lasts for more than 6 months. Chronic pain is caused by prolonged irritation of peripheral pain receptor or nerve. Pain receptors are irritated by wide spread scar tissue, which is observed following healing of superficial and deep burn. Nerve irritation or pinched nerve causes severe dermatomal pain, which spreads along the peripheral nerve.
Characteristics of Chronic Pain
- More common pain than acute pain
- Pain often begin as severe to very severe pain and later become mild to moderate pain
- In few cases, mild pain becomes severe pain if not treated.
- Pain is moderate to severe in intensity
- Pain is felt as burning, shooting or stabbing pain
- Severity of pain decreases with time. Initial severe pain later become mild to moderate.
Causes of Chronic Pain
Chronic Pain Due to Headache-
- Headache Disorder– Tension headache, Migraine and cluster headache.
- Intracranial space occupying lesion-Caused by brain tumor, abscess and hematoma.
Facial Chronic Pain-
- Trigeminal Neuralgia– Facial pain over ophthalmic, maxillary or mandibular dermatome of the face.
- Tooth Pain– Caused by dental cavity or abscess
- Eye Pain– Caused by Optic neuritis
Chronic Pain Due to Ear Pain or Earache-
- Otitis Media– Infection of middle ear
- Furuncle– Infection of hair follicle in external ear or outer ear tube, also known as boil.
Chronic Pain Due to Oral Cavity-
- Oral Ulcer– Multiple ulcer in oral cavity secondary to vitamin deficiency causes severe continuous chronic pain if continues more than 6 months.
- Pharyngitis or Tonsillitis– Inflammatory disease of oral cavity mostly causes acute pain. Rarely septic and purulent pharyngitis or tonsillitis causes moderate to severe chronic pain lasting over 6 months.
- Cancer of Oral Cavity– Cancer of pharynx, larynx and tonsil can cause severe chronic pain lasting more than 6 months.
Chronic Pain of Skull-
- Fracture– Fracture of skull, mandible, maxilla or orbital fossa causes severe chronic pain over facial bones and skull.
- Dislocation– Temporomandibular joint (TMJ) rarely causes chronic pain secondary to dislocation. TMJ pain is also observed following joint inflammation or patient grinding teeth.
- Osteomyelitis of Mandible– Infection of mandible secondary to tooth abscess or trauma results in osteomyelitis. Osteomyelitis causes severe chronic pain spread around the infected section of the bone.
Chronic Pain of Neck-
- Cancer Pain– Cancer of larynx, trachea and thyroid causes severe chronic pain in neck. The pain is mostly observed in anterior and lateral section of the neck. Pain is never referred to upper arm.
- Fracture– Fracture of body of vertebra and facet joint causes severe pain over back of the neck.
- Facet Joint Inflammation– Facet joint arthritis or facet joint trauma causes chronic pain lasting over 6 months.
Chronic Pain of Chest
- Cancer Pain– Cancer of lungs, esophagus, bronchi and bones causes severe chronic shooting pain in chest. Pain is intermittent in initial stage and continuous in later stage associated with loss of weight. Metastatic cancer of vertebral column causes severe pain resulting in osseous mid back pain, facet pain or chest wall radicular pain.
- Fracture– Fractured rib following auto or work accident causes severe chest wall pain lasting more than 6 months.
- Nerve Pain– Intercostal neuralgia secondary to shingles infection or post herpetic neuralgia causes severe pain along the rib and often follows blister and rash along the nerve. Pain is observed along 1 to 3 intercostal nerves.
- Radicular Pain– Radicular pain is caused by pinch or irritation of the thoracic spinal nerve. Pain is often spread over multiple chest wall segments. Thoracic spinal nerve is irritated or pinched by disc herniation, bulge disc, prolapse nucleus pulposus, disc protrusions, spinals stenosis, foraminal stenosis and spinal osteophytes.
- Osteomyelitis– Infection of ribs or body of the thoracic vertebrae causes severe pain over the chest wall or mid back.
- Facet Joint Inflammation– Facet joint arthritis or facet joint trauma causes chronic pain lasting over 6 months.
Chronic Pain of Abdomen
- Cancer Pain– Cancer of abdominal viscera causes chronic squeezing or colicky abdominal pain. Abdomen viscera is classified into has multiple organ system as follows-
- Gastrointestinal (GI) system, which includes stomach, pancrease, intestine, appendix and colon.
- Urinary system includes kidney, bladder and ureter.
- Vascular system includes aorta, mesenteric arteries and mesenteric veins.
- Liver and spleen
- Fracture– Fracture of body of vertebrae causes severe pain mostly localized in lower back.
- Nerve Pain or Radicular Pain– Lumbar chronic radicular pain along lumbar nerve L1 and L2 is caused by abnormalities of lumbar spinal segment secondary to disc herniation, bulge disc, prolapse nucleus pulposus, disc protrusions, spinals stenosis, foraminal stenosis and spinal osteophytes. Pain is observed over side and back of the lower back and lower extremity.
- Osteomyelitis– Osteomyelitis of lumbar vertebrae vertebra causes chronic pain in lower back, which is referred to back of the thigh.
- Visceral Pain– Inflammation of viscera such as appendicitis or cholecystitis causes severe burning cute pain of abdomen. Crohn’s disease and ulcerative colitis is an inflammatory bowel disease, which causes chronic colicky or squeezing abdominal pain.
- Facet Joint Inflammation– Facet joint arthritis or facet joint trauma of lumbar facet joint causes chronic pain lasting over 6 months.
Chronic Pain of Pelvis
- Cancer Pain– Cancer of pelvic viscera causes chronic squeezing or colicky pain. Pelvic viscera is classified into multiple organ system as follows-
- Gastrointestinal (GI) System- Includes sigmoid colon, rectum and anus.
- Urinary System- Includes bladder, prostate and urethra.
- Vascular System- includes internal and external iliac artery and vein.
- Female Genital System- includes ovary, fallopian tube, uterus and vagina.
- Fracture– Fracture of body of pelvic bones causes severe pain mostly localized in pelvis and buttocks. Pelvic bone includes ilium, ischial bone and pelvis.
- Nerve Pain or Radicular Pain– Pelvic pain is caused by pinched nerve of lumbar 1 to 3 segments. Pain is also caused by irritation or pinch of the peripheral nerve branching to pelvic viscera.
- Osteomyelitis– Osteomyelitis of pelvic bone causes chronic pain in pelvis and lower abdomen. Pain is often referred to lower back and buttocks.
- Visceral Pain– Inflammatory bowel disease like crohn’s disease and ulcerative colitis involving sigmoid colon and rectum causes chronic colicky or squeezing pelvic pain. Obstruction of urinary bladder or urethra by a stone and chronic prostatitis also causes chronic pain lasting more than 6 months.
Chronic Pain of Upper Extremity
- Dislocation– Dislocation of the hip, knee, ankle and joint of foot causes severe stabbing chronic pain, which may last less than 6 months or
- Fracture– Pain caused by fracture immediately following injury is considered acute pain. Pain is considered chronic if pain continues after 6 months following healing of fracture or surgical treatment.
- Tendon Pain– Tendon pain is secondary to inflammation of tendon known as tendonitis or injury of the tendon resulting in partial or complete tear of the tendon. Pain is considered chronic if pain continues beyond 6 months.
- Ligamental Pain– Ligamental pain is observed following inflammation of ligament and ligamental tear. Pain of less than 3 to 6 months duration is considered acute and more than 6 months is considered chronic.
- Muscle Pain– Most of the muscle pain last less than 3 months. Healing of muscle tear results in scarring. Scarring of muscles often causes chronic pain.
- Nerve Pain– Peripheral nerve pain is caused by irritation or pinch of the peripheral pain receptors and nerve endings. Prolonged irritation of pain receptors causes burning pain in extremities. Skin burn causes irritation and destruction of pain receptors resulting in severe acute pain. The healing of burn result in scarring of skin and subcutaneous tissue. Entrapped nerve ending and receptors within scar tissue causes chronic pain lasting more than 6 months.
- Radicular Pain– Radicular pain is the pain that is spread along the nerve in upper extremity. Radicular pain is caused by disc herniation, bulge disc, prolapsed nucleus pulposus, disc protrusions, spinals stenosis, foraminal stenosis and spinal osteophytes.
Chronic Pain of Lower Extremity
- Dislocation– Dislocation of the hip, knee, ankle and joint of foot causes severe stabbing chronic pain, which may last less than 6 months
- Fracture– Pain caused by fracture immediately following injury is considered acute pain. Pain is considered chronic if pain continues after 6 months following healing of fracture or surgical treatment.
- Tendon Pain– Tendon pain is secondary to inflammation of tendon known as tendonitis or injury of the tendon resulting in partial or complete tear of the tendon. Pain is considered chronic if pain continues beyond 6 months.
- Ligamental Pain– Ligamental pain is observed following inflammation of ligament and ligamental tear. Pain less than 3 to 6 months is considered acute and more than 6 months is considered chronic.
- Muscle Pain– Most of the muscle pain lasts less than 3 months. Healing of muscle tear results in scarring. Scarring of muscles often causes chronic pain.
- Nerve Pain– Nerve pain is observed in peripheral tissue or in entire lower extremity. Peripheral tissue pain is caused by irritation or pinch of the peripheral pain receptors and nerve endings. Prolonged irritation of pain receptors causes burning pain in extremities. Peripheral receptors and nerve ending are irritated following entrap nerve ending in scar tissue of inflammatory disease of skin and subcutaneous tissue.
- Radicular Pain– Radicular pain is the pain spread along the nerve in lower extremity. Radicular pain is caused by lumbar disc herniation, bulged disc, prolapsed nucleus pulposus, disc protrusions, spinal stenosis, foraminal stenosis and spinal osteophytes.
Investigations To Diagnose The Reason For Chronic Pain
X-Ray, MRI and CT Scan To Diagnose The Reason For Chronic Pain
X-Ray, MRI or CT Scan of the Brain Studies-
- Headache- Migraine, cluster and tension headache.
- Intracranial Space occupying lesion- Brain mass or space occupying lesion may cause headache e.g. brain tumor, brain abscess or hematoma.
- Cerebral aneurysm- Brain aneurysm often causes chronic headache.
X-Ray, MRI or CT Scan of Skull
- Trigeminal neuralgia
- Optic nerve pain
- Dental pain
- Mandibular pain
- Skull fracture
X-Ray, MRI or CT Scan of the Vertebrae and Spinal cord
- Disc herniation
- Bulge disc
- Prolapsed nucleus pulposus
- Disc protrusions
- Spinal stenosis
- Foraminal stenosis
- Spinal osteophytes.
X-Ray, MRI or CT Scan of the Joint
- Fracture
- Dislocation
- Joint hematoma (blood clot)
- Joint abscess
- Arthritis- Osteoarthritis, Rheumatoid arthritis, Psoriatic arthritis, gout and pseudogout.
X-Ray, MRI or CT Scan of the Bones
- Fracture
- Osteomyelitis
- Bone tumor or metastasis
X-Ray, MRI or CT Scan of Chest
Inflammatory Diseases-
- Pneumonia
- Bronchitis
- Trachitis
- Esophagitis
Foreign Body-
- Trachea
- Lungs
- Esophagus
Soft tissue cancer of lung, trachea, bronchi and esophagus-
- Benign cancer
- Malignant cancer
- Metastatic cancer
X-Ray, MRI or CT Scan of Abdomen
Inflammatory bowel disease-
- Appendicitis
- Ulcerative colitis and
- Crohn’s disease
Abdominal cancer of abdominal viscera-
- Benign cancer tumor
- Malignant cancer tumor
- Metastasis
X-Ray, MRI or CT Scan of Pelvis
Inflammatory bowel disease-
- Proctitis
- Ulcerative colitis of sigmoid colon and
- Crohn’s disease of sigmoid colon
Pelvic cancer of uterus, vagina, bladder, urethra, ovary and fallopian tube
- Benign cancer tumor
- Malignant cancer tumor
- Metastasis
Blood Examinations To Diagnose The Reason For Chronic Pain
White Blood Cell (WBC) Count Increase-
- Infection
Erythrocyte Sedimentation Rate (ESR) Increase-
- Infection
- Autoimmune Disease
Antinuclear Antibody Increase-
- Osteoarthritis
- Rheumatoid arthritis
Rheumatoid Factor Increase-
Rheumatoid arthritis
Synovial Fluid Study To Diagnose The Reason For Chronic Pain
Aspirated synovial fluid from joint is examined for infection, bleeding and cancer cells.
Electromyogram (EMG) To Diagnose The Reason For Chronic Pain
EMG study is performed to evaluate following diseases-
- Radiculopathy
- Lateral Sclerosis
- Myasthenia Gravis
- Carpal tunnel Syndrome
- Guillain-Barre Syndrome
Nerve Conduction Studies To Diagnose The Reason For Chronic Pain
Nerve conduction study involves X and F wave study of sensory and motor nerve. Study is performed to diagnose following diseases-
- Carpal tunnel syndrome
- Tarsal tunnel syndrome
- Cubital tunnel syndrome
- Guillain-Barre syndrome
- Peripheral neuropathy
- Radiculopathy
- Ulnar neuropathy
- Sciatica
Ultrasound Study To Diagnose The Reason For Chronic Pain
Ultrasound study of chest, abdomen, pelvis and joint is performed to rule out following diseases-
- Hematoma
- Abscess
- Fluid collection.