dr. Henny Anggraini Sadeli SpS(K) Patomechanism of Pain dr. Henny Anggraini Sadeli SpS(K)

Definition of PAIN Pain is unpleasent sensory and emotional experience associated with actual or potential tissue damage, or discribe in term of such damage ( IASP, 1986 ) HAS/Neuro/2007

Types of Pain Nociceptive Pain Inflammatory Pain Neuropathic Pain Transient pain in response to a noxious stimulus Spontaneous pain and hypersensitivity to pain in response to tissue damage and inflammation Spontaneous pain and hypersensitivity to pain in association with damage to or a lesion of the nervous system -survival -protecting from injury -promoting healing -maladaptive pain -pain as disease HAS/RSHS/FKUP07

Types of Pain Somatic Pain Neurophatic Pain Visceral Pain Mixed Pain Pain from nerve endings in tissues/bones Aching, gnawing Well localised Pain from nerve irritation/damage Sharp, electrick shock, burning, tingling Often follow nerve pathway Deep,squeesing,pressure Poorly localized Sometimes referred Eg. Heart, lung, liver, pancreas,etc Eg. Bone metastases, bone fracture Myofacial pain Peripheral NeP Central NeP Eg. Polineuropathy Mononeuropathy Radicular Pain Trigeminal neuralgia Post herpetic neuralgia Eg.Post stroke pain Spinal cord pain Mixed Pain Low Back pain Henny’s

Spontaneous Pain aauuuw aauuuw Stimulus Evoked Pain/ hypersensitivity to pain Spontaneous Pain aauuuw allodynia aauuuw HAS/Neuro/RSHS-FKUP hyperalgesia

Hypersensitivity to pain HAS/neuro

PAIN BEHAVIOUR AFFECTIVE COGNITIVE SENSORY Waddel G, 1992 Biopsychosocial & chronic pain disability model HAS/Neuro/RSHS-FKUP

Henny’s

Henny’s

Henny’s

Pain Mechanism Nociception : transduction-conduction-transmission-perception Phenotypic switches Peripheral sensitization Ectopic exitability Central sensitization Decreased inhibition Structural reorganization HAS/neuro

Excitability in dorsal horn neurons is determined by balance between exitatory inputs from primary afferents and inhibitory inputs (local and descending) Henny’s

HAS/Neuro/2006

Henny’s

Henny’s

Henny’s

Central Sensitization interneuron microglia Descendens Descendens inhibitory 5HT, NE BDNF TNFα IL-1 Descendens exitatory COX2 PGE2 Primary afferent nociceptor P2X4 opioid Central Sensitization CB1 gly Glutamate GABA inhibitory excitatory NMDA Ca++ AMPA/kainate SP CGRP Somatostatin(-) mGluR NK1 COX2 PGE2 VGCC EP GABA Dorsal horn neuron α2δCC apoptosis HAS/RSHS/FKUP07 interneuron

Henny’s

Central Sensitization A reduction in activation threshold An increased responsiveness An expansion of receptive field in dorsal horn neurons Henny/neuro

Henny’s

Henny’s

Structural reorganization henny’s

henny’s

Thank you