PAIN MANAGEMENT. It is important to know as much about the man who has pain as it is to know about pain the man has Quote by Macnab et al

PAIN MANAGEMENT It is important to know as much about the man who has pain as it is to know about pain the man has Quote by Macnab et al

DEFINATION OF PAIN International Association for the study of pain (IASP) Unpleasant sensory and emotional experience associated with actual/potential tissue damage Pts subjective experience described but not how pt in pain looks only description of his subjective feeling matters

PAIN Pain is a symptom Is protective in function Occur when tissue injury/damage present May form a disease or syndrome if chronic Initiated peripherally,appreciated centrally and modulated in b/w Pain perception varies from person to person Perception also affected by several factors: physiological,emotional,psychological,environme ntal,cultural,social etc

TYPES OF PAIN ACUTE PAIN -Hours-Several days -less than one months duration -cause known and treatable -treament logical and effective -good results and normal life expectancy Examples: postop pain,mi,colics etc

TYPES OF PAIN (cont) CHRONIC PAIN - Several Months -relatively uncommon -cause uncertain and difficult to treat -treatment at times only empirical with poor results -Can be-neuropathic-from nerve tissues -somatic-nonnerve tissues -psychogenic from thought disorder Examples:malignancy,post-herpertic neuralgia, sudecks atrophy etc

PAIN PATHWAY 3 Neuron pathway 1)Nociceptor-nerve ending Sensory nerve fibre-1 st order neurons Two types-typea fast conducting -type C slow conducting To Spinal cord-dorsal root ganglion-dorsal grey horn- substansia gelatinosa (sorting out centre)- synapse

PAIN PATHWAY (cont) 2) Spinothalamic tract for crossed pain fibres -2 nd order neuron to thalamus ( posterolateral ventral nucleus) -Cross Midline 3) Thalamus to cerebral cortex/higher centres -3 rd order Neuron -pain appreciated at cortical level. Several Modulations occur along the pain pathway

RESPONSE TO PAIN Sensory -pain perception Motor -withdrawal,immobility,involuntary muscle spasm Emotional -anxiety,fear,anger,uncooperative, depression,aggression Autonomic hypertension,tachycardia,diaphoresis, bradycardia Others urine retention,mi,git motility decrease

PAIN MECHANISMS 3 THEORIES 1)specific theory specific stimulus-receptors- -nerve fibres-cns areas 2)Pattern theory -pattern of impulses are programmed in the cord and interpreted in the brain

PAIN MECHANISM (cont) 3)Gate theory by Melzack Wall 1965 -also called Modulation theory -input control in spinal cord operating as gate Explains combat analgesia,pain relief by physical rubbing of skin, topical irritants(liniments),tens, acupuncture

PAIN MEASUREMENT Also Subjective 1)Verbal-pt describes the pain 2)Clinical Observation of the pt 3)Visual Analogue Scale(VAS) - Pain Scale 0-----10 4)Amount of drug delivered eg PCA

PAIN MANAGEMENT 3 ASPECTS INVOLVED 1)PHYSICAL 2) EMOTIONAL 3)RATIONAL

PHYSICAL PAIN Mx 1) Remove painful stimuli 2)Prevent neural integration of pain -natural mechanisms -ANALGESICS 3)Nerve block - use LA - -methods-many eg local infiltration,regional block, IV + TQ (Biers block)sympathetic block etc

PHYSICAL PAIN Mx (cont) 4)Destructive blocks -chemical blocks-intrathecal alcohol or phenol -intrathecal hypertonic saline -physical means- barbotage(repeated x15 aspiration and replacement of CSF) 5)Neurosurgical procedures

PHYSICAL PAIN Mx (cont) 6)Other methods -specific treatment eg tumor resection -DXT eg bone mets -Hormonal eg calcitonin(pagets),ca Breast,CA prostate etc -steroids- act on inflammation,appetite,mood -antibiotics in added infections -CXT eg Hodgkins Lymphoma -etc

ANALGESICS Non narcotics-act peripherally -inhibit PG synthesis via cyclo-oxygenase (COX) blockage -COX-two isoenzmes 1and 2 Narcotics -centrally acting on opiate receptors in the CNS

ANALGESIC WHO analgesic ladder 1) paracetamol 2)NSAIDS 3)Narcotics Co-drugs eg steroids,antidepressants,anxiolytics,etc

EMOTIONAL ASPECT OF PAIN MX Psychological support-gd clinician/pt relationship and explanation Drugs anxiolytics(diazepam) -antidepressants - more in chronic pain Psychosurgery- selective surgery on limbic system(emotion centre) eg cingulotomy

RATIONAL ASPECT PAIN Mx Pt helped to learn to live with pain eg -good pt/clinician relationship -group therapy -mental relaxation

PRE-EMPTIVE ANALGESIA Acute pain-easier to control when treated early than late. Neural basis-in posterior horn of spinal cord -painful stimulation produce activation of spinal neurons that persist and enhence response to repeated painful stimulation. Useful in post-op pain Mx

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