Pain: Nociceptive, Neuropathic, Acute, Chronic, Visceral, Cutaneous, Somatic
What are the different types of Pain?
Pain is either acute or chronic. acute pain last less than 3 to 6 months and chronic pain last more than 6 months.
Pain is also classified as Nociceptive, Neuropathic and Mixed pain. Nociceptive pain is mostly acute in character, while neuropathic and mix pain are chronic in nature.
What is Nociceptive Pain?
Nociceptive pain is instantaneous aching occurs after tissue damage. Nociceptive pain disappears as the tissue damages heal. Nociceptive pain is provoked by several nerve irritating chemicals released after tissue trauma. These chemicals irritate nociceptor receptors and produce pain impulses. Pain impulses are carried by nerve fibers to spinal cord. Nociceptive receptors are in the soft tissue such as skin, subcutaneous tissue, muscles and viscera (internal organs).
What is Neuropathic Pain?
Neuropathic pain is cause by malfunction of pain receptors and nerve fibers carrying pain impulses after injury to soft tissue or skeletal system. In later stages tissue injury follows impairment of pain receptors, abnormal function of nerve fibers carrying pain impulses to spinal cord and irregularities within neurons responsible to modulate pain impulses in central nervous system. Neuropathic pain is chronic, continuous, intractable and intense.
What are the causes of acute pain?
Cutaneous (skin) acute pain- Confined within skin and subcutaneous tissue.
- skin - Laceration, abrasion, burn, bumps, bruises and inflammation
- Repeat injury - increases intensity of and duration (chronic)
- Non-healing skin ulcers
Somatic (muscle) Acute Pain- observed in muscles, tendons and skeletal system (bones)
- Inflammation - Myalgia (muscles) and tendinitis (ligaments and tendon)
- Infection and abscess - Muscles and tendons
- Inflammation of joint and bone - Rheumatoid arthritis and osteoarthritis
- Sprains - Ligaments, muscles and tendon
- Trauma soft tissue - Muscle tear or injury and tendon rupture
- Laceration of periosteum
- Trauma bones and joint - Fracture, joint dislocation and blunt trauma
- Disease of Muscle and Tendon - Fibromyalgia, myofascial pain and myofascitis.
Visceral Acute pain- Pain is caused by injury, inflammation or trauma to the internal organs. Visceral pain is also caused by obstruction of visceral tubes and lack of blood supply (ischemic) to viscera. Visceral tissues are stomach, intestine, appendix, gall bladder, ureter, kidney, urinary bladder, uterus and pancreas.
- Obstructions - stricture, adhesions, volvulus or impacted stones causing obstruction of Gall Bladder, Bile Duct, Ureter, Urethra and Urinary Bladder
- Inflammation - causing Peritonitis, Appendicitis, Gastric Ulcer, Cholecystitis (Gall Bladder Inflammation)
- Ischemic - Myocardial Infarction (heart attack), Non Healing Ulcers and Ischemic Colitis
What are the causes of Chronic Pain?
Causes of Non-cancer Chronic Pain
- Failed back syndrome
- Pain after surgery in scar tissue or healing tissue
- Peripheral neuropathy- induced by medications, chemotherapy, radiation treatment, vitamin deficiency, alcohol, AIDS and HIV
- Diabetic neuropathy
- Inflammatory - Joint Pain, Arthritis, injury
- Pinch Nerve - Scar tissue, Disk Herniation, Disk Fragments
- Amputation - Phantom Pain
- Trigeminal Neuralgia
- Multiple Sclerosis
- Shingles - Postherpatic Neuralgia
- Complex Regional Pain Syndrome
- Entrap Neuropathy
- Toxicity following chemotherapy
- Multiple Sclerosis
Causes of Chronic Cancer Pain
- Pain cause by cancer of external Organ - Skin, Bones, Muscles, and Breast.
- Pain cause by cancer of internal Organs - Esophagus, Stomach, Intestine, Liver, Pancreas, Gall Bladder, Kidney, Bladder, Uterus, Vagina
- Pain cause by Metastasis of cancer - Spread of cancer to adjacent tissue or distant tissue
- Local - Around primary cancer
- Distal - Location away from primary e.g. Brain, Lungs, Bone
What are the Symptoms & Signs of "Acute Cutaneous and Somatic Pain"?
Symptoms (Cutaneous and Somatic) acute pain
- Pain less than 3 months duration
- Pain at rest- Mild to moderate
- Pain with activities - Moderate to very severe
- Character of Pain - Sharp, well localized, aching or throbbing pain
- Episode of pain - Constant or intermittent
- Duration Pain - Pain resolves with healing of tissue damage
Signs (Cutaneous and Somatic) acute pain
- Joint examination - passive or active restricted joint activities
- Muscles and ligament- tender, painful to touch
- Hematoma - swelling and subcutaneous hematoma may be observed
- Muscle contraction - painful and patient prefers to restrict muscle contractions
- Arthritis - joint swelling and restricted joint movements
- Pain is limited to area of injury or inflammation
- Nociceptive pain tends to respond well to treatment with NSAIDS (non steroidal anti inflammatory drugs) or opioids
What Are The Symptoms And Signs Of "Acute Visceral Pain"?
Symptoms (Visceral) Pain
- Dull and Aching
- Throbbing and colicky pain at time
- Difficult to localize
- Episodic and poorly localized
- Pain is referred to adjacent or distal part of the body e.g. gallbladder pain is referred to the scapula
- Duration of pain- short or prolong
Signs (Visceral Pain)
- Localized in the internal organs
- Poorly localized
- Tenderness on palpation
- Pain is severe on deep pressure over involved organ
- skin over the inflame organ may be warm
What are the Symptoms and Signs of "Chronic Pain"?
Symptoms of Chronic Pain
- Character of Pain - Burning, Lancinating, or Electric shock type of pain
- Quality of Pain - Shooting Pain associated with Tingling and Numbness
- Sweating - Increase sweating
- Tingling And Numbness associated with Pain in few cases
- Pain associated with muscle spasm
- Allodynia - Pain with light touch (non painful stimulus), severe amplified response to a stimulus, which is normally just painful
- Hyperalgesia an exaggerated sense of Pain at the site of injury and surrounding tissue disproportionate to the provocative stimulus
- Hyperpathia - A painful stimulus induces extreme level of Pain unlike allodynia where a non-painful stimulus induces exaggerated Pain
Signs of Chronic Pain
- Severe pain observed on examination by palpation of painful inflame area
- Muscle spasms felt on examination
- Muscle atrophy seen on examination
- Joint stiffness observed on examination
- Edema - local swelling
- Sweating - Increased sweating
- Skin temperature - usually hot but sometimes cold
- Skin color - Bright red or a reddish violet
- Vasospasm - Pale skin because of constriction of blood vessels
- Bones - examination and X-ray indicates softening and thinning
- Joint - tender, stiff, restricted or painful movement, thickening of synovial membrane and joint
- Hair - Rapid hair growth
- Nail - Growth rapid, nails become cracked, brittle, grooved, and spotty
- Osteoporosis becomes severe and diffuse, confirm by X-ray, CAT Scan or MRI