PAIN AND ITS MANAGEMENT
D. C. MIKULECKYPROFESSOR OF PHYSIOLOGY
SOMATOSENSORY CORTEX
SOMATOTOPIC ORGANIZATIONMORE 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)
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 FORMATIONTERMINATE IN VENTROBASAL NUCLEUS OF
THALMUSTERTIARY NEURONS GO TO SENSORY CORTEX
THE ANTEROLATERAL PATHWAY
SUBSTANTIAGELITANOSA
THE SENSATION OF PAIN
FAST PAINSLOW PAINMECHANICAL PAINCHEMICAL PAINTHERMAL PAIN
PAIN NERVES:
TYPE DIAMETER(m)
CONDUCTIONVELOCITY(m/s)
SENSORYINFORMATION
III(A) 5 15 LIGHTLYMYELINATED:
TOUCH,PRESSURE, AND
PAINIV(C) 1 2 UNMYELINATED:
PAIN ANDTEMPERATURE
FAST PAIN
OCCURS IN ABOUT 0.1 SECONDS SUBJECTIVE DESCRIPTION:SHARP, 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
FAST PAIN PATHWAY
III
IIIIV
VVI
IX
VII
VIII
SUBSTANTIAGELITANOSA
LAMINAMARGINALIS
VENTROBASALNUCLEUS
ANTEROLATERALPATHWAY
SLOW PAIN
OCCURS AFTER A SECOND OR MOREOFTEN ASSOCIATED WITH TISSUE
DESTRUCTIONSUBJECTIVELY DESCRIBED AS BURNING,
ACHING,THROBBING, NAUSEOUS, OR CHRONIC
C FIBERS WHICH SYNAPSE IN THE SUBSTANTIA GELITANOSA
FINAL PROJECTION IS THE FRONTAL CORTEX
SLOW PAIN PATHWAY
III
IIIIV
VVI
IX
VII
VIII
SUBSTANTIAGELITANOSA
LAMINAMARGINALIS
VENTROBASALNUCLEUS
ANTEROLATERALPATHWAY
MECHANICAL, CHEMICAL AND THERMAL PAIN
FAST PAIN IS GENERALLY MECHANICAL OR THERMAL
SLOW PAIN CAN BE ALL THREECHEMICAL PAIN RECEPTORS: BRADYKININ,
SEROTONIN, HISTAMINE, POTASSIUM IONS, ACIDS, ACETYL CHOLINE AND PROTEOLYTIC ENZYMES
PROSTAGLANDINS ENHANCE PAIN SENSATION
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
PAIN CONTROL (ANALGESIA)
THE ANALGESIA SYSTEMTHE BRAIN’S OPIATE SYSTEMINHIBITION OF PAIN BY TACTILE
STIMULATIONTREATMENT OF PAIN BY ELECTRICAL
STIMULATIONREFERED PAIN
THE ANALGESIA SYSTEM
PREAQUEDUCTAL GRAYRAPHE MAGNUS NUCLEUSPAIN INHIBITORY COMPLEX IN
DORSAL HORNS
PAIN INHIBITORY COMPLEX: PRESYNAPTIC INHIBITION
PAINRECEPTOR
BRAIN STEM.NEURON
INHIBITORY NEURON
ANTEROLATERALPATHWAY
DORSAL HORN OFSPINAL CORD
+
-
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)
THE BRAIN’S 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
INHIBITION OF PAIN BY TACTILE STIMULATION
STIMULATION OF LARGE SENSORY FIBERS FOR TACTILE SENSATION INHIBITS PAIN TRANSMISSION FOR SAME REGION
RUBBING OFTEN EASES PAINLINAMENTS, OIL OF CLOVE, ETC.POSSIBLE EXPLANATION FOR
ACUPUNCTURE?
TREATMENT OF PAIN BY ELECTRICAL STIMULATION
STIMULATION OF LARGE SENSORY NERVES
ELECTRODES IN SKIN OR SPINAL IMPLANTS
INTRALAMINAR NUCLEUS OF THALAMUS
REFERED PAIN
VISCERAL PAIN FIBERS SYNAPSE ON SAME SECONDARY NEURONS AS RECEIVE PAIN FIBERS FROM SKIN
CLINICAL ASPECTS OF PAIN
HYPERALGESIATHE THALAMIC SYNDROMEHERPES ZOSTER (SHINGLES)TIC DOULOUREUXTHE BROWN-SEQUARD
SYNDROMEHEADACHE
HYPERALGESIA
ENHANCED SENSITIVITY AROUND DAMAGED TISSUE
SENSITIZATION OF NOCICEPTORS BY SUBSTANCES RELEASED WHEN TISSUE IS DAMAGED
THE THALAMIC SYNDROME
LESION OF SOMATOSENSORY THALMUS
USUALLY A DISTORTED AND EXAGERATED SUBJECTIVE QUALITY
MAY CUT OFF PAIN TRASMISSION FROM PERIPHERY
HERPES ZOSTER (SHINGLES)
USUALLY AFFECTS THE DORSAL ROOT
ONE DERMATOME AND ONE SIDE
TIC DOULOUREUX
CHRONIC NEURALGIA OF TRIGEMINAL NERVE
SOMETIMES DUE TO INFLAMMATION (NEURITIS)
SOMETIMES TREATED SURGICALLY, BUT OFTEN RETURNS
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
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
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