Sensory 5: Pain Flashcards
Pain receptors are called
Noci-ceptors
Duration of adaptation to pain
Slow or Non-adaptive
True or false; pain threshold is the same for everyone
True; but the differece is in the reaction
Enumerate Pain Mediators / Pain Sensitizers
- Bradykinins
- Prostaglandins
- Potassium
- Substance P
- Serotonine
- Histamine
Pain Mediators Sensitize noci-ceptors by
Lowering Pain threshold;
Known As primary Hyperalgesia
Prostaglandin is inhibited by
NSAID (salcynates) such as asprin
Describe Distribution of Pain receptors in the body
- Numerous in superficial layer of skin
- Numerous in Perisoteum, peritoneum, pleura, joints, arterial wall, dura & tentorium
- Not present in Deep tissue/ Deep parts of visceral tissue (Parenchyma)
Definition of Hyperalgesia
Abnormal Increase in sensitivity to pain, leading to exaggerated pain
Importance of Hyperalgesia
Self preservation of Injured tissue, to remind the brain of injured area
Definition of Secondary Hyperalgesia & what accompanies it
- Pain that occurs in uninjured tissue surrounding site of injury
- Accompanied by Allodynia
Compare between Fast pain and Slow Pain in Afferent fiber
- Fast pain: A delta fibers
- Slow Pain: C fibers
Compare between Fast pain and Slow Pain in their tracts
- fast: Neo-spinothalamic
- Slow: Paleo-spinothalamic
Compare between Fast pain and Slow Pain in Examination
- Fast: Moderate compression of Nerve, which leaves only The C fibers (slow Pain)
- Slow: Local Anesthesia (C fibers)
Compare between Fast pain and Slow Pain in Locality
- Fast pain: well localized
- Slow Pain: Poorly localized (diffuse)
Compare between Fast pain and Slow Pain in Neurotransmitters
- Fast pain: Glutamate
- Slow Pain: Substance P
Compare between Fast pain and Slow Pain in Reflexs
- Fast Pain: withdrawl reflex
- Slow Pain: hypertonia of underlying muscle (guarding mechanism)
Compare between Fast pain and Slow Pain in Autonomic response
- Fast: (sympathetic) increase Blood pressure & Heart rate
- Slow: Parasympathetic (Decrease HR & BP) + Nausea and vomiting
Compare between Fast pain and Slow Pain in Emotional Responses
- Fast pain: Anxiety
- Slow Pain: depression
Compare between Fast pain and Slow Pain in description of patient of the pain
- Fast pain: Sharp, pricking, acute
- Slow pain: Dull,Aching, throbbing, burning
Compare between Fast pain and Slow Pain types of noci-ceptors facilitating them
- Slow: Thermal & Mechanical
- Fast: All receptors
Along their way upwards, pain fibers give tributaries to (and name function)
- Anterior horn cells: for Motor reflex
- Reticular formation: for whole cortical Activation (wakening)
- Hypothalamus: for Autonomic reactions
- Limbic System: for Emotional Response
Function of Cortex in Perception of Pain:
- Decoding the pain (Modality, locality, intensity)
- Interpritation of the meaning behind the pain
- Accompanying emotions and behavior to the pain (by prefrontal Lobe)
Cutaneous pain begins as …. and becomes ….
Fast pain, Slow pain
Reasons why cutaneous pain is highly localized
- High receptor density
- Starts as fast pain, which is well localized
- Through Vision (seeing the injury) and touch
Deep pain is always
Slow pain
Causes of deep pain (in muscles, ligaments, tendons, joints)
- Rheumatic Arthritis
- Muscle spasm due to fracture/tendon injury: it causes compression of BV at muscles which causes ischemia
- Ischemia (such as Anginal Pain & Intermittent claudication to lower limb)
Explain why visceral Pain is slow pain
Pain receptors in parenchyma of viceral organs are few, therefore they are scattered (poor localization) and would need large area of injury (dull aching)
Why patient complaining of visceral Pain being poorly localized is better than being well localized
well localized pain would mean that injury/ tumour has spread to through most of the organ and has reaching the covering of the organ (peritoneum, pleura)
Enumerate Causes of Visceral Pain
- Inflammation
- Ischemia
- Spasm of hollow viscus ( obliteration of blood vessels–> further ischemia or Mechanical stimulation of pain receptors themselves (uterus)
- Over-distension
- Tumour
- Chemical stimuli: Peptic ulcer caused by HCL
Description of Neuropathic Pain
Chronic Intractable unresponsive
Neuropathic pain arrives as
Bouts
Neuropathic pain is accompanied by
- Hyperalgesia
- Parasthesia (burning & pricking)
Examples of Neuropathic Pain
- Trigemnal Neuralgia (Tic Douloureux)
- Herpes Zoster
Explain the pathology of Herpes Zoster
- Virus infects DRG
- Leading to Severe pain in dermatomal Segment supplied by infected ganglion
- Virus migrates from ganglion to skin, causing skin rash & pus (Chicken pox)
Cardiac pain is referred at
- retrosternum
- Root of Neck
- Left Arm
- Epigastrum
Gastric Pain is referred at
Between the umbilicus & Zyphoid process
Kidney pain is referred at
- Back
- (male) Testis or (femal) inguinal Region
Appendicitis is referred at
Around the umbilicus
