Pain

Pain

1. unpleasant sensory & emotional experience associated with potential tissue damage

2. primarily a protective mechanism

3. subjective sensation

4. Types of Pain

   • Fast Pain (acute)
     • felt after about 0.1sec of the stimulus
     • transmited in Aδ pain fibers
   • Slow Pain (chronic)
     • felt after about 1sec or more of the stimulus & increase over time
     • transmited in C pain fibers

5. Localization of Pain

   • Cutaneous Pain
   • Deep Somatic Pain
   • Visceral Pain
   • Psychogenic Pain

6. Perceiving of pain

   • 1. Transduction
   • 2. Transmission
   • 3. Central processing
   • 4. Modulation
   • Factors affecting pain perception
     • Age, Culture, Attention, Anxiety, Previous experiences, Family and social support

7. Pain receptors - Nociceptors

   • nerve endings with large receptive fields
   • Types
     • Mechanical
     • Thermal
     • Chemical
     • Polymodal nocieptors
     • Silent Nociceptors

8. Pain management

   • 1. Nonopoids - Pain killers
     • 2. Opoids- Pain killers
       • such as: Pethidine
       • mimicking the action of naturally occurring pain-reducing chemicals called endorphins.
     • such as:Voltaren (diclofenac)
   • Pain suppression system
     • The capability of the brain to suppress input of pain signals by activating a pain control system
     • 3 major components
       • The periaqueductal gray and periventricular areas of the mesencephalon and upper pons.
       • the lower pons and upper medulla, and the nucleus reticularis paragigantocellularis, located laterally in the medulla.
       • a pain inhibitory complex located in the dorsal horns of the spinal cord.
     • suppresses the release of neurotransmitter
   • Adequate Clinical History Taking

9. Caused in

   • Shingles
     • caused by varicella-zoster virus
       • PNS infection
       • 1. causes chicken pox
         • IP is 10 to 21 days
       • an enveloped virus
       • Primary target cell: Mucoepitheli al cells & T cells
       • Site of latency : neurones
     • secondary infection after getting chicken pox
       • If the virus gets reactiveted, shingles occur
     • painful, blistering skin rash that affects one side of the body
       • pain and vesicles restricted to one dermatome
         • Dermatome :an area of the skin supplied by nerves from a single spinal root
     • postherpetic neuralgia
       • the result of the shingled virus damaging the nerves of the skin
     • last around 3 to 5 weeks
     • Clinical course:
       • 1.burning or tingling pain
       • 2. after 1-5 days a red rash will appear
       • 3. the rash will turn into fluid-filled blisters
       • 10 days after that, the blisters dry up and crust over .
       • A couple of weeks later, the scabs clear up
     • Transmission: airborne & respiratory, sometimes direct contact
       • mechnism of spread :
     • Laboratory diagnosis
       • Tzanck smear showing multinucleated giant cells & Cowdry type A inclusion bodies
       • CPE - balloning and syncitium formation
     • Treatment
       • acyclovir
         • Inhibit DNA polymerase
         • require phosphorylation by thymidine kinase
       • Vaccines against VZV
         • > 60 yrs of age
         • Two doses, 12 – 15 M, followed by 4 – 6 yrs
         • Live attenauted vaccine – OKA strain
       • Varicella Zoster Immune Globulin (VARIZIG) useful if administered within 96 hours of exposure

10. Psychological management of pain

    • Problem Focused Coping
    • Emotion‐Focused Coping
    • Psychoeducation
    • Relaxation therapy
    • Positive reinforcement
    • 2 factors that affect pain coping
      • 1.living with persistent pain
      • 2. issues that are related to the pain  interfering with one’s life

11. Ascending tracts in the spinal cord

    • Lateral spinothalamic tract in the Lateral White Coulmn
      • Responsible for pain & temperature
      • include 2 pathways
        • Neospinlothalamic tract
          • Glutamate is the neurotransmitter
        • Paleospinlothalamic tract
          • Substance P is the neurotransmitter

12. Inflammatory mediators of pain

    • Cell derived mediators
      • Histamine
      • Arachidonic acid metabolites releases in Cyclo-oxygenase pathway , releases PGE2
      • Neuropeptides
    • Plasma derived mediators
      • The kinin system
        • releases bradykinin

Images and files in the map