chronic pain management in various conditions

About chronic pain and the management of chronic pain about blocks

1. WHO REGIMEN FOR CHRONIC PAIN MANAGEMENT Moderators: Dr.V.Sreelatha Professor Dr.K.Indira Priyadarshini Assistant Professor Department of ANAESTHESIOLOGY Siddhartha Medical College. Vijayawada Presentors Dr.D.Kartheek Kumar 1 st year PG Resident Dr.Jani Begum 1 st year PG Resident

2. PAIN “An unpleasant sensory and emotional experience associated with actual or potential damage or described in terms of such damage”. VARIOUS DESCRIPTORS OF PAIN: Somatic pain: caused by activation of pain receptors in either the cutaneous(body surface) or deeper tissues(musculoskeletal tissues). Visceral pain: pain that is caused by activation of pain receptors from infiltration,compression,extension or stretching of thoracic,abdominal or pelvic viscera(chest,stomach,pelvic areas). Neuropathic pain: caused by injury to the nervous system either as a result of a tumor compressing nerves or the spinal cord,or cancer actually infiltrating into the nerves or spinal cord.

3. Acute pain: short- lasting and manifesting in objective ways that can be easily described and observed. It may be clinically associated with diaphoresis and tachycardia. It can last for several days, increasing in intensity over time (subacute pain), or ti can occur intermittently (episodic or intermittent pain). Usually related to a discrete event for onset: post op, post- truama, fracture, etc., Chronic pain: Long- term and typically defined if it lasts for > three months. It is more subjective and not as easily clinically characterized as acute pain and is more psychological. This kind of pain usually affects a person's life, changing personality, their ability to function, and their overall lifestyle. Chronic pain has a psycho- social component that must be dealt with before depression becomes a part of the clinical picture. Chronic pain should be recognized as a multifactorial disease state requiring intervention at many levels.

4. Most common forms of chronic pain include those associated with musculoskeletal disorders ,chronic visceral disorders,lesions of peripheral nerves,nerve roots or dorsal root ganglion (including diabetic neuropathy,causalgia,phantom limb pain,post herpetic neuralgia),lesions of CNS(stroke,spinal cord injury,multiple sclerosis), and cancer pain.

5. VARIOUS TERMS IN PAIN

6. WHAT IS CHRONIC PAIN? Chronic pain is pain that : continues a month or more beyond the usual recovery period for an injury or illness or goes on for Months or Years due to a chronic condition. The pain may not be constant but disrupts daily life. It also can interfere with sleep, keeping you awake a night.

7. CHRONIC PAIN CAN BE: Nociceptive, Neuropathic or both . Psychological mechanisms play a major role. Attenuated neuroendocrine stress response and have prominent sleep and affective disturbances. Neuropathic pain : Paroxysmal and lancinating, has a burning quality and is associated with hyperpathia. Deafferentation pain : neuropathic pain associated with loss of sensory input into the CNS. Sympathetically mediated pain :sympathetic system plays a major role.

8. COMMON ETIOLOGIES OF CHRONIC PAIN Episodic Pain Syndromes: Headaches - migraine, tension, cluster.. Ischemic episodes- claudication, angina, sickle cell disease Visceral pain - biliary colic, irritable bowel, Premenstrual Syndrome, Renal Colic Somatic pain - Gout

9. Chronic Pain Syndromes: Somatic - low back pain ,degenerative and inflammatory arthritis, lumbosacral radiculopathy, Failed back surgery, vertebral compression fractures, bony metastases, Myofascial pain syndrome. Visceral - abdominal cancers, chronic pancreatitis. Neuropathic - CRPS,Post herpetic neuralgia, Trigeminal neuralgia,diabetic neuropathy, phantom limb pain, spinal stenosis/sciatica, spinal mets.

10. Neuralgia - an extremely painful condition consisting of recurrent episodes of intense shooting or stabbing pain along the course of the nerve. Causalgia - recurrent episodes of severe burning pain. Phantom limb pain - feeling of pain in a limb that is no longer there and has no functioning nerves.

11. CANCER PAIN SYNDROMES PAIN SYNDROMES ASSOCIATED WITH TUMOR INFILTRATION Metastatic bone pain Retroperitoneal lymphadenopathy pain Liver capsule pain Headache Cranial neuralgias Glossopharyngeal neuralgia Trigeminal neuralgia Perineal pain

12. PAIN SYNDROMES ASSOCIATED WITH CANCER THERAPY POST CHEMOTHERAPY SYNDROMES POST SURGICAL PAIN SYNDROMES POST RADIATION PAIN Myalgias/arthralgias Peripheral neuropathy Steroid pseudorheumatism Aseptic necrosis of bone tumors Post mastectomy pain Post radical neck dissection pain Phantom limb pain and stump pain Radiation fibrosis of brachial plexus and lumbosacral plexus Radiation myelopathy Radiation induced peripheral nerve headache

13. CRPS type Il: also called as causalgia. Burning pain, follows high velocity injuries to large nerves. Pain immediate in onset. Associated with allodynia, hyperpathia, vasomotor and sudomotor dysfunction. Treatment: Sympathetic blocks. Physical therapy plays major role. Cure rate is high if Rx initiated within 1 month ot symptoms and appears to decrease with time.

14. EVALUATION OF CHRONIC PAIN: MEDICAL EVALUATION: Location, onset. Quality, radiation. Response to previous treatments. h/o past, personal,social,economic,psychological and emotional status. Plain radiographs,CT,MRI,bone scans.

15. PSYCHOLOGICAL EVALUATION: . Clinical interview. . A structured pain inventory. A . McGill pain questionnaire. B . Psychosocial pain inventory. C . West haven - Yale multidimensional pain inventory. D . Pain profile.

16. Psychometric testing: A . Minnesota multiphasic pain inventory(MMPI) B . Symptom checklist - 90. C . Million behavioural pain inventory. D . The beck depression inventory. E . The spielberger state- trait anxiety scale.

17. Electromyography And Nerve Conduction Studies: Useful for confirming diagnosis of entrapment syndromes, neural trauma and polyneuropathies,radicular syndromes. Can distinguish b/n neurogenic and myogenic disorders.

18. MEASUREMENT OF PAIN Reliable Quantitation of pain severity helps determine therapeutic interventions and evaluate the efficacy of treatments. PAIN SCALES: Numerical rating scale. Faces rating scale Visual analog scale. McGill pain questionnaire.

19. Pain Scales: Numerical Rating Scale:

20. McGill Pain questionnaire: It is a checklist of words describing symptoms. Attempts to define the pain in 3 major dimensions. Sensory - discriminative. Motivational - affective. 3 . Cognitive - evaluative. Contains 20 sets of words that are divided into 4 groups. i.e., 10 sensory. 5 affective. 1 evaluative. 4 miscellaneous.

21. COMMON CONDITIONS Low Back Pain:

22. Treatment: Bed rest widely recommended but shown to impede recovery. Current Consensus - maintenance of activity and work status. If beyond 4-wks - refer to multidisciplinary pain centre.

23. SPINAL STENOSIS: General term for congenital and acquired disorders of spine. Narrowing of the bony frame surrounding the neural structures. Can affect central spinal canal or lateral intervertebral foramen. Narrowing can be caused by spondylolisthesis,osteoarthritis of spine, degenerative disc disease.

24. FAILED BACK SURGERY Also called as post laminectomy syndrome. One of the most difficult groups of chronic pain patients. Exhibits strong nociceptive and neuropathic characteristics. Pain may be sharp and shooting burning. Iatrogenic and due to development of fibrous scarring.

25. MYOFASCIAL PAIN SYNDROME Soft tissue disorder that creates pain in tender areas within muscle groups. Diagnosis made on clinical trigger points. Trigger points are painful regions in a taut band of muscle that produces referenced pain with application of pressure. Painful area usually feels like a "rope". Created by events like trauma or prolonged tension from poor posture. Local prolonged ischemia may trigger the formation of subsequent fibrosis. Therapeutic modalities - passive stretching, cold spray,compression massage, injection of 0.5% lidocaine at the trigger point, botulinum toxin injection.

26. HEADACHES: Common Complaint:

27. COMPLEX REGIONAL PAIN SYNDROME(CRPS) Neuropathic pain that involves upper and lower extremities. Reflex sympathetic dystrophy and causalgia are replaced by CRPS I,CRPS II. CRPS type I: Follows minor trauma.Also known as reflex sympathetic dystrophy(RSD).Preceding events are trauma,surgery,sprain,fracture, dislocation.No direct damage to the nerves in the affected limb.About 90% of people with CRPS have type 1.

28. 3 PHASES:

29. CRPS type II: also called as causalgia. Burning pain, follows high velocity injuries to large nerves. Pain immediate in onset. Associated with allodynia, hyperpathia, vasomotor and sudomotor dysfunction.

30. IASP Clinical Budapest Criteria in diagnosing CRPS Continuing pain that is disproportionate to any inciting event At least one symptom reported in at least three of the following categories: Sensory Hyperesthesia or allodynia Vasomotor Temperature asymmetry, skin color changes, skin color asymmetry Sudomotor Edema, sweating changes, sweating asymmetry Decreased range of motion, motor dysfunction (weakness, tremor, dystonia), trophic changes (hair, nail, skin) Motor/trophic 3. At least one sign at time of evaluation in at least two of the following categories: Sensory Evidence of hyperalgesia (to pinprick), allodynia (to light touch, temperature sensation, deep somatic pressure or joint movement) Evidence of temperature asymmetry (>1 C°), skin color changes or asymmetry Evidence of edema, sweating changes or sweating asymmetry Evidence of decreased range of motion, motor dysfunction (weakness, tremor, dystonia), trophic changes (hair, nail, skin) Vasomotor Sudomotor Motor/trophic 4. No other diagnosis can better explain the symptoms and signs

31. Treatment: Sympathetic blocks. Physical therapy plays major role. Cure rate is high if Rx initiated within 1 month of symptoms and appears to decrease with time.

32. POST HERPETIC NEURALGIA(PHN) Intractable pain that develops as a sequel of acute herpes zoster infection.(AHZ) Pain from AHZ resolves usually within 3- 4 weeks and if pain lasts longer than 4- 6wks PHN should be suspected. In AHZ large myelinated fibers are destroyed whereas in PHN pain processing by small fibers is compromised. Typically presents with unilateral pain in dermatomal distribution. Treatment : Sympathetic blockade during attack Antidepressants, anticonvulsants, opioids. TENS

33. TRIGEMINAL NEURALGIA TIC DOULOUREUX classically presents as a painful, unilateral affliction of the face, characterized by brief electric- shock- like pain, limited to the distribution of one or more divisions of the trigeminal nerve. Pain is commonly evoked by trivial stimuli, including washing, shaving, smoking, talking and brushing the teeth, but may also occur spontaneously. The pain is abrupt in onset and termination may remit for varying periods.

34. Treatment : Carbamazepine. Invasive treatment- Glycerol injection Radiofrequency ablation of gasserian ganglion Microsurgical decompression of trigeminal nerve.

35. MANAGEMENT THERAPEUTIC MODALITIES PHARMACOLOGICAL. PHYSICAL MEASURES/NON PHARMACOLOGICAL. PSYCHOLOGICAL MEASURES. INVASIVE TECHNIQUES.

36. NON STEROIDAL ANTI INFLAMMATORY DRUGS Mechanism Of Action: - Inhibit both peripheral and central cyclo - oxygenase, reducing prostaglandin formation.Traditional NSAIDs are effective in the treatment of mild to moderate pain, but their use is limited by potentially serious adverse effects. Ketorolac: indicated only in the management of moderately severe acute pain that requires opioid level analgesics; not more than 5 days. COX- 2 selective inhibitors [celecoxib (Celebrex), rofecoxib (Vioxx) and valdecoxib (Bextra)] have better GI safety profile;no change in platelet function.

37. OPIOIDS Codeine Methadone Fentanyl Morphine Hydrocodone Oxycodone Hydromorphone Oxymorphone

38. PRINCIPLES OF OPIOID ANALGESIC USE IN CHRONIC PAIN Individualize route, dosage, and schedule Administer analgesics regularly if pain is present most of day Become familiar with dose / time course of several strong opioids Give infants / children adequate opioid dose Follow patients closely, particularly when beginning or changing analgesic Regimens when changing to a new opioid or different route.

39. - Use equianalgesic dosing table to estimate new dose Modify estimate based on clinical situation Recognize and treat side effects Be aware of potential hazards of meperidine/ mixed agonist- antagonists particularly pentazocine Do not use placebos to assess nature of pain Watch for development of Tolerance- treat appropriately Physical dependance- prevent withdrawal

40. OPIOID SIDE EFFECTS Constipation, no tolerance develops to constipation, use stimulants (Senokot, Bisacodyl, Peri Colace) Nausea/vomiting- tolerance can occur in 2- 5 days. • Sedation - tolerance can occur in 2- 3 days. Clonic jerks - usually high doses, can change drug or diazepam can help Respiratory suppression in toxic doses Can produce Hyperalgesia in certain individuals.

41. PHYSICAL MEASURES Exercises: Graded exercise program prevents joint stiffness, muscle atrophy and contractures. Superficial heating modalities : Conductive - hot packs, paraffin baths, fluid therapy. Convective Radiant.

42. ACUPUNCTURE: Useful adjunct for patients with chronic musculoskeletal disorders and headaches. Technique - insertion of needles in Discrete Anatomically defined points called "MERIDIANS" .

43. TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION (TENS) Used widely in chronic pain. All available trials used “TENS” as an adjuvant to Medication, and it's possible the effects of “TENS” was masked by the Analgesic Effect of Medication . ULTRASOUND: for deep pain

44. Ice Packs, Chiropractic/osteopathic manipulations, Massage, Yoga. Topical agents (Menthol, Salicylates, Capsaicin) Local injections (Steroids, Lidocaine) Glucosamine shown to help with osteoarthritis

45. PSYCHOLOGICAL METHODS Cognitive Methods: Based on assumptions that a Patient’s attitude towards pain can influence the perception of pain. Maladaptive attitudes contribute to suffering and disability. Patient is taught skills for coping with pain either individually or in group therapy.

46. Biofeedback - provides biophysiological feedback to patient about some bodily process the patient is unaware of. (e.g., forehead muscle tension) Relaxation - Hypnosis - systematic relaxation of the large muscle groups. relaxation +suggestion + distraction +altering the meaning of pain. OPERANT / BEHAVIOUR THERAPY: Based on premise that behaviour in patients with chronic pain is determined by consequences of behaviour. Positive reinforcers aggravate the pain, negative reinforcers reduce pain behaviour .

47. INVASIVE TECHNIQUES: SOMATIC NERVE BLOCKS: Trigeminal nerve blocks Cervical, thoracic, lumbar paravertebral blocks Facet blocks Trans sacral nerve blocks etc.

48. SYMPATHETIC BLOCKS: Stellate Ganglion block Celiac Plexus block Thoracic, Lumbar sympathetic chain block etc.,

49. EPIDURAL INJECTIONS: Lumbar interlaminar epidural injections Fluoroscopic injections Transforaminal injections Radiofrequency rhizotomy SPINAL INJECTIONS: Therapeutic effects of spinal injections are a combination of primary physiological changes that result from procedure and the secondary results arising the enhanced pain control that allow other treatments.

50. SPINAL CORD STIMULATION- Also called Dorsal Column Stimulation . Produces analgesia by directly stimulating large A beta fibers in dorsal columns of the Spinal cord. Mechanism - activation of descending modulating systems and inhibition of sympathetic outflow.

51. Indications: Sympathetically mediated pain Spinal cord lesions. Phantom limb pain. Failed back surgery syndrome. Technique: electrodes placed epidurally and connected to an external generator. Complications: infection, lead migration, lead breakage.

52. INTRACEREBRAL STIMULATION Deep brain stimulation may be used for intractable cancer pain and rarely for intractable neuropathic pain of nonmalignant origin. Electrodes are implanted stereotactically into periaqueductal and periventricular grey areas for nociceptive pain. Complications: intracranial hemorrhage and infection

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