1 / 50

PAIN!!

PAIN!! . RAJESH MENON 04/09/2013. PAIN. Acute pain Definition Measurement of Pain Pain pathway Gate control theory Management of acute Pain . PAIN. Chronic pain Types: Nocieceptive Neuropathic Pathophysiology

leala
Download Presentation

PAIN!!

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PAIN!! RAJESH MENON 04/09/2013

  2. PAIN • Acute pain Definition Measurement of Pain Pain pathway Gate control theory Management of acute Pain

  3. PAIN • Chronic pain Types: Nocieceptive Neuropathic Pathophysiology Assessment of Chronic Pain Management of Chronic Pain What is useful for exam

  4. Definition of pain “An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage”International Association for the Study of Pain

  5. Assessment • An objective estimate of a subjective perception (i.e. it’s difficult!) • Clouded by personality and culture • Scales • Pictures for children • Numerical for adults

  6. Pain Pathways

  7. Gate control theory

  8. BEFORE PAIN!!

  9. POSTOPERATIVE PAINWhy bother? • CVS • Tachycardia • Hypertension • Increased myocardial O2 demand • GI • Nausea and vomiting • Ileus • RS • ↓ Vital Capacity • ↓ FRC • Basal atelectasis • Respiratory infection • Other • Urinary retention • DVT + PE PAIN

  10. Chronic pain as a disease Definitions • “Pain extending for a long period of time, represents low levels of underlying pathology that does not explain the presence and extent of pain, or both” Turk in: Bonica’s Management of Pain 3rd Ed. • “Pain without apparent biological value that persists beyond normal tissue healing (usually taken to be 3 months)” IASP 1986

  11. Chronic Pain Pathophysiology • Chronic pain is not prolonged acute pain

  12. Chronic Pain-central mechanisms

  13. Chronic Pain Pathophysiology is different from acute pain • Sensitization • Reduced pain threshold (hyperalgesia) • Non-painful stimulus (allodynia)

  14. Chronic Pain • Pathophysiology is different from acute pain • Nociceptive Pain • Neuropathic pain Site Character Timing

  15. Chronic Pain • Often neuropathic in origin • 2 characteristic types of pain • Sharp, shooting • Burning • Examples • Nerve root compression, pancreatitis, ischaemic pain • Pain experienced beyond area of original injury (neural plasticity)

  16. ASSESSMENT OF CHRONIC PAIN HISTORY • Site • Nature • Character • Alleviating and exacerbating factors PHYSICAL • Examination • MSK • Limb • Back • Neck • Visceral PSYCHOSOCIAL • Sensation of Pain • Subjective experience of Pain • Attitudes and Beliefs • Suffering and Distress • Illness Behaviour

  17. Case 1 A man with fracture forearm, compartment syndrome Fracture fixed, fasciotomy healed Neurovascular integrity OK But he has pain and other things

  18. Case 1 • A man with fracture forearm, compartment syndrome • What else do you noticed?

  19. Case 1 • A man with fracture forearm, compartment syndrome • He wants to chop his forearm off. Useful?

  20. Case 2 • A lady with difficulty in dressing • Diagnosis?

  21. Case 2 • A lady with difficulty in dressing • Does topical therapy help? • Do NSAIDs help? • Do Opioids help?

  22. Ms. Unhappy Why can’t you fix my neck and fxxk off

  23. Ms. Unhappy • 33 year old woman, traffic accident • “whiplash injury” • MRI: unremarkable Nociception

  24. Ms. Unhappy • She felt so bad that she cannot sleep, eat and became irritable Affect

  25. Ms. Unhappy • She cannot work, go out, do housework, cannot…. Social

  26. Ms. Unhappy • She insisted to use a neck collar, visited 4 doctors for the “right diagnosis”, alcohol to “knock me off the pain” Behavior

  27. Remarks from Case 3 Multi-faceted problems of chronic pain • Nociception is different • Mood is altered • Behavior and thoughts are changed • Function is impaired • They are a different person altogether • Chronic pain is a disease of its own • Pain Management is a specialty of its own

  28. Management MULTIMODAL THERAPY • PHARMACOLOGICAL • ANALGESICS • ADJUVANTS • INTERVENTIONS • NONPHARMACOLOGICAL • TENS • PHYSIOTHERAPY • OCCUPATIONAL THERAPY • ACUPUNTURE • COGNITIVE BEHAVIOYRAL THERAPY • SELF MANAGEMENT PROGRAMME • EDUCATION • COPING STRATEGIES • RELAXATION TECHNIQUE • EXCERCISE( GRADED) • PHASING

  29. Treatment implications? Nociception or neuropathy Pain-free Normal activity & mood restored (e.g. Bogduk N. Management of chronic low back pain. Med J Aust 2004; 180 (2): 79-83)

  30. Neuro Ablation Implantable Therapy (Spinal Cord Stimulator) Implantable Therapy (Intrathecal Pump) Long Term Oral Narcotics Behavioural Programs Cognitive & Behavioural Therapies Nerve Blocks NSAID’s (& over the counter drugs) Meditation and Relaxation Physical Therapy (TENS) Traditional “Pain Treatment Ladder” Krames E.S J Pain Symptom Manage; 1996: 333 - 352 Basic rule: “failure” of earlier treatments leads to consideration of next in ladder

  31. Neuro Ablation Implantable Therapy (Spinal Cord Stim) Implantable Therapy (Intrathecal Pump) Long Term Oral Narcotics Behavioural Programs Cognitive & Behavioural Therapies Nerve Blocks NSAID’s (& OTC drugs) Meditation and Relaxation Physical Therapy (TENS) Traditional “Pain Treatment Ladder” Krames E.S J Pain Symptom Manage; 1996: 333 - 352 Suggests that “failure” of earlier treatments is indication for next in line.

  32. Better to assess the whole situation and plan treatment from there EXCESSIVE SUFFERING & DISABILITY REDUCED ACTIVITY PHYSICAL DETERIORATION (eg. muscle wasting, joint stiffness) UNHELPFUL BELIEFS & THOUGHTS PAIN PERSISTING FEELINGS OF DEPRESSION, HELPLESSNESS, IRRITABILITY, SLEEP LOSS REPEATED TREATMENT FAILURES LONG-TERM USE OF ANALGESIC, SEDATIVE DRUGS SIDE EFFECTS (eg. stomach problems lethargy, constipation) WORKPLACE, FINANCIAL DIFFICULTIES, FAMILY STRESS • M K Nicholas PhD • Pain Management & Research Centre • Royal North Shore Hospital • St Leonards NSW 2065 • AUSTRALIA A BIOPSYCHOSOCIAL PERSPECTIVE Influence of workplace, home, treatment providers

  33. Some conclusions • Chronic pain is common (1 in 5 people) • It is a risk factor for disability • The presence of mental disorders increases risk of disability in those with chronic pain • Curative treatment is unlikely (no magic bullet) • Interventions need to be targeted against identified risk factors (bio – psycho – social) • Challenge: Collaborative approach offers best chance of success • All stakeholders must play active, informed roles

  34. APPLY THIS KNOWLEDGE

  35. Opioids • Describe the classification of opioid receptors. • Draw the structure of morphine. • Compare the characteristics of morphine, fentanyl, alfentanil and pethidine • What are the 2 main potentially serious side effects of opioids? • What are the main routes of giving opioids? Discuss the advantages and disadvantages of each route. • Is morphine more or less efficacious in neonates compared with older children? Does that mean you need more or less of it?

  36. Opioids induced hyperalgesia • Desensitization of antinociceptive mechanisms(Tolerance) • Sensitization of pronociceptive mechanisms • Abnormal activation of NMDA receptors in CNS • Long-term potentiation of synapses between nociceptive C fibres and neurons in the spinal cord horn.

  37. NSAIDS • Discuss the uses, presentation and mode of action of non-steroidal anti-inflammatory drugs (NSAIDs). • What is the difference between COX-1 and COX-2 inhibition, and the respective side-effects? • Discuss prostaglandins, thromboxanes, prostacyclin and leukotrienes. • In what situations should you be cautious about using NSAID’s? • By what routes may NSAID’s be given?

  38. Paracetamol • How does paracetamol work? • By what routes may paracetamol be given? • What is the oral loading dose of paracetamol? • Paracetamol may be used to treat: a. mild pain? b. moderate pain? c. severe pain? • How does paracetamol cause liver toxicity?

  39. ORAL ANALGESIA • Paracetamol • Side-effects extremely rare unless taken in overdose • 1% is metabolised to toxic metabolite and normally inactivated by conjugation • In overdose glutathione groups depleted • Excess metabolite binds to SH groups on liver macromolecules –hepatic necrosis • Rx N-acetylcysteine (-SH donor) PAIN

  40. Paracetamol • Inhibits prostaglandin production • Central action – ?COX 3 not active in humans(cox,canabinoids,TPRV1,5HT3) • Dose = 10-20mg/kg up to 1g • Repeat 4 times a day (max 4g/day) • Good opioid sparing effect if given regularly • Good antipyretic • Poor anti-inflammatory PAIN

  41. Misc • Name the 4 main classes of analgesic drugs. • What are ‘adjuvant analgesics’? • What is the mechanism of action of TENS? • What are the benefits of PCA?

  42. QUESTIONS

More Related