PAIN AND ITS MANAGEMENT

1
PAIN AND ITS MANAGEMENT

• D. C. MIKULECKY
• PROFESSOR OF PHYSIOLOGY

2
(No Transcript)
3
(No Transcript)
4
SOMATOSENSORY CORTEX

• SOMATOTOPIC ORGANIZATION
• MORE AREA TAKEN BY SENSITIVE REGIONS (GREATER
  RECEPTOR DENSITY-SMALLER RECEPTIVE FIELDS)
• CELLS RESPONDING TO ONE TYPE OF SENSATION IN
  VERTICLE COLUMNS(FOR EXAMPLE..PACINIAN CORPUSCLES
  IN A FINGERTIP)

5
THE ANTEROLATERAL PAIN AND TEMPERATURE PATHWAY

• SENSORY NEURONS SYNAPSE IN SUBSTANTIA GELATINOSA
• SECONDARY NEURONS CROSS MIDLINE AND ASCEND IN
  ATEROLATERAL COLUMN
• BRANCHES GO TO THE RETICULAR FORMATION
• TERMINATE IN VENTROBASAL NUCLEUS OF THALMUS
• TERTIARY NEURONS GO TO SENSORY CORTEX

6
THE ANTEROLATERAL PATHWAY
SUBSTANTIA GELITANOSA
7
(No Transcript)
8
THE SENSATION OF PAIN

• FAST PAIN
• SLOW PAIN
• MECHANICAL PAIN
• CHEMICAL PAIN
• THERMAL PAIN

9
PAIN NERVES
10
FAST PAIN

• OCCURS IN ABOUT 0.1 SECONDS
• SUBJECTIVE DESCRIPTIONSHARP, ACUTE, ELECTRIC OR
  PRICKING
• A? FIBERS SYNAPSE ON CELLS IN LAMINA I (LAMINA
  MARGINALIS) IN THE DORSAL HORNS
• SECONDARY NEURONS CROSS AND TRAVEL THROUGH THE
  ANTEROLATERAL PATHWAY TO THE VENTROBASAL COMPLEX
  OF THE THALAMUS
• TERTIARY NEURONS GO TO THE PRIMARY SENSORY CORTEX

11
FAST PAIN PATHWAY
VENTROBASAL NUCLEUS
LAMINA MARGINALIS
I
II
IV
III
VI
V
VII
SUBSTANTIA GELITANOSA
ANTEROLATERAL PATHWAY
IX
VIII
12
SLOW PAIN

• OCCURS AFTER A SECOND OR MORE
• OFTEN ASSOCIATED WITH TISSUE DESTRUCTION
• SUBJECTIVELY DESCRIBED AS BURNING,
  ACHING,THROBBING, NAUSEOUS, OR CHRONIC
• C FIBERS WHICH SYNAPSE IN THE SUBSTANTIA
  GELITANOSA
• FINAL PROJECTION IS THE FRONTAL CORTEX

13
SLOW PAIN PATHWAY
VENTROBASAL NUCLEUS
LAMINA MARGINALIS
I
II
IV
III
VI
V
VII
SUBSTANTIA GELITANOSA
ANTEROLATERAL PATHWAY
IX
VIII
14
MECHANICAL, CHEMICAL AND THERMAL PAIN

• FAST PAIN IS GENERALLY MECHANICAL OR THERMAL
• SLOW PAIN CAN BE ALL THREE
• CHEMICAL PAIN RECEPTORS BRADYKININ, SEROTONIN,
  HISTAMINE, POTASSIUM IONS, ACIDS, ACETYL CHOLINE
  AND PROTEOLYTIC ENZYMES
• PROSTAGLANDINS ENHANCE PAIN SENSATION

15
BRAIN STRUCTURES AND PAIN

• COMPLETE REMOVAL OF THE SENSORY CORTEX DOES NOT
  DESTROY THE ABILITY TO PERCIEVE PAIN
• STIMULATION OF THE SENSORY CORTEX EVOKES A
  SENSATION OF PAIN

16
PAIN CONTROL (ANALGESIA)

• THE ANALGESIA SYSTEM
• THE BRAINS OPIATE SYSTEM
• INHIBITION OF PAIN BY TACTILE STIMULATION
• TREATMENT OF PAIN BY ELECTRICAL STIMULATION
• REFERED PAIN

17
THE ANALGESIA SYSTEM

• PREAQUEDUCTAL GRAY
• RAPHE MAGNUS NUCLEUS
• PAIN INHIBITORY COMPLEX IN DORSAL HORNS

18
PAIN INHIBITORY COMPLEX PRESYNAPTIC INHIBITION
BRAIN STEM.NEURON
ANTEROLATERAL PATHWAY
INHIBITORY NEURON
-
PAIN RECEPTOR

DORSAL HORN OF SPINAL CORD
19
PAIN TRANSMISSION AND INHIBITION

• SUBSTANCE P IS THE NEUROTRANSMITTER BUILDS UP
  SLOWLY IN THE JUNCTION AND IS SLOWLY DESTROYED
• PRESYNAPTIC INHIBITION BY INHIBITORY NEURON
  BLOCKS THE RELEASE OF SUBSTANCE P (ENKEPHALIN)

20
THE BRAINS OPIATE SYSTEM

• OPIATE RECEPTORS EXIST IN MANY CENTERS OF THE
  BRAIN, ESPECIALLY IN THE ANALGESIA SYSTEM
• AMONG THE NATURAL SUBSTANCES WHICH ACTIVATE THESE
  RECEPTORS ARE ENDORPHINS, ENKEPHALINS, AND
  MORPHINE

21
INHIBITION OF PAIN BY TACTILE STIMULATION

• STIMULATION OF LARGE SENSORY FIBERS FOR TACTILE
  SENSATION INHIBITS PAIN TRANSMISSION FOR SAME
  REGION
• RUBBING OFTEN EASES PAIN
• LINAMENTS, OIL OF CLOVE, ETC.
• POSSIBLE EXPLANATION FOR ACUPUNCTURE?

22
TREATMENT OF PAIN BY ELECTRICAL STIMULATION

• STIMULATION OF LARGE SENSORY NERVES
• ELECTRODES IN SKIN OR SPINAL IMPLANTS
• INTRALAMINAR NUCLEUS OF THALAMUS

23
REFERED PAIN

• VISCERAL PAIN FIBERS SYNAPSE ON SAME SECONDARY
  NEURONS AS RECEIVE PAIN FIBERS FROM SKIN

24
CLINICAL ASPECTS OF PAIN

• HYPERALGESIA
• THE THALAMIC SYNDROME
• HERPES ZOSTER (SHINGLES)
• TIC DOULOUREUX
• THE BROWN-SEQUARD SYNDROME
• HEADACHE

25
HYPERALGESIA

• ENHANCED SENSITIVITY AROUND DAMAGED TISSUE
• SENSITIZATION OF NOCICEPTORS BY SUBSTANCES
  RELEASED WHEN TISSUE IS DAMAGED

26
THE THALAMIC SYNDROME

• LESION OF SOMATOSENSORY THALMUS
• USUALLY A DISTORTED AND EXAGERATED SUBJECTIVE
  QUALITY
• MAY CUT OFF PAIN TRASMISSION FROM PERIPHERY

27
HERPES ZOSTER (SHINGLES)

• USUALLY AFFECTS THE DORSAL ROOT
• ONE DERMATOME AND ONE SIDE

28
TIC DOULOUREUX

• CHRONIC NEURALGIA OF TRIGEMINAL NERVE
• SOMETIMES DUE TO INFLAMMATION (NEURITIS)
• SOMETIMES TREATED SURGICALLY, BUT OFTEN RETURNS

29
THE BROWN-SEQUARD SYNDROME

• CHARACTERISTIC PATTERN OF SENSORY LOSS DUE TO
  LOCALIZED DAMAGE ON ONE SIDE OF SPINE
• USUALLY ACCOMPANIED BY MOTOR LOSS AS WELL

30
LESION ON RIGHT HALF OF SPINAL CORD

• LOSS OF PAIN SENSATION ON LEFT SIDE BELOW LESION
• LOSS OF TOUCH AND VIBRATION ON RIGHT SIDE BELOW
  LESION
• LOSS OF BOTH ON RIGHT SIDE AT SAME LEVEL
• NO LOSS ABOVE LESION

31
HEADACHE

• SELDOM DUE TO BRAIN DAMAGE
• NO SENSORY NERVES IN BRAIN LIKE THERE ARE IN
  PERIPHERY
• TENSION INDUCED MUSCLE TIGHTNESS
• SWELLING OF THE MUCOUS MEMBRANES
• EYE DISORDERS
• DILATION OF CEREBRAL BLOOD VESSELS
• INCREASED INTERCRANIAL PRESSURE
• INFLAMMATION AND SWELLING