Disclosures. Outline of Session 5/18/12. Chronic Pain in Children: Pharmacologic and Other Interventions. Pain: Increasing Awareness

Transcription

1 5/18/12 Disclosures Chronic Pain in Children: Pharmacologic and Other Interventions I have nothing to disclose Maurice S Zwass, MD Professor of Anesthesia and Pediatrics, UCSF Outline of Session Pain: Increasing Awareness Quick Overview of Chronic Pain in Children Definitions and Assessment Types Characteristics Treatment Techniques Goals and Approaches Medications Regional Block Options A Case Hospital Based Program For all personnel Patients 1

2 5/18/12 Pain Transduction What is pain? According to the International Association for the Study of Pain, pain is defined as an unpleasant sensory and emotional experience arising from actual or potential tissue damage. Pain is therefore subjective and as reported by the patient. Nociceptive Pain Related to ongoing activation of primary afferent neurons in response to noxious stimuli Pain Terminology Acute Pain is usually consistent with the degree of tissue injury Subtypes Somatic: well localized, described as sharp, aching, throbbing (trigeminal & dorsal root ganglion) Visceral: more diffuse, described as gnawing or cramping (vagal ganglion, DRG) Nociception : The detection of impending or actual tissue damage by specialized sensory nerve terminals derived from A-delta and Cfibers (nociceptors). Proportionate to the stimulation of the nociceptor under normal conditions. When acute - Physiologic pain (protective function) When chronic - Pathologic Allodynia: pain elicited by a non-noxious stimulus (clothing, air movement, touch) Mechanical (induced by light pressure) Thermal (induced by a nonpainful cold or warm stimulus) Hyperalgesia: exaggerated pain response to a mildly noxious (mechanical or thermal) stimulus Hyperpathia: delayed and explosive pain response to a noxious stimulus 2

3 5/18/12 Pain Assessment Differences Between Acute and Chronic Pain! Pain Rating Scales For Children Numerical Rating Scale (NRS) (0-10) Self report, cognitively capable of understanding and abstracting, >6 yrs Wong-Baker Faces Scale (Faces with concurrent numerical ratings of Self report through pictures, 3 years and up FLACC (0-10) Faces-Legs-Activity-Cry-Consolability Behavior observation, birth-3 yrs, uncooperative, too much pain or anxiety to respond, developmentally delayed children, intubated and sedated children Acute " Self-limiting" Warning system " Anxiety" Controlled by analgesics" More easily scored" NIPS, PIPP & CRIES for premature infants and infants up to 3 months of age Chronic pain May not have a defined temporal onset May last months to years May have signs of autonomic nervous system hyperactivity Associated with depression Treatment not necessarily directed at underlying cause Chronic " Self-perpetuating" No apparent purpose" Depression" Seldom controlled by analgesics alone" Involvement difficult to assess" Chronic Pain Examples" Cancer" Sickle-Cell Disease" Recurrent Abdominal Pain" Sympathetically-Mediated Pain" Fibromyalgia" RSD, Causalgia, CRPS" Options in Treatment" Importance and Value of Multidisciplinary Approach" Pharmacologic and Therapeutic Strategies " Goals of Therapy" 3

4 5/18/12 Neuropathic Pain: Symptoms Techniques of Chronic Pain Management! Burning, shooting, electrical-quality pain May be aching, throbbing, sharp Neuropathic sensations: dysesthesias, paresthesias Paresthesias: abnormal; spontaneous-evoked, intermittent, painless Dysesthesias: abnormal; spontaneous or touchevoked, unpleasant Pharmacologic " Nonopiates" Opiates" Regional Anesthesia, Blocks" Other Local anesthetic techniques" Non-pharmacological techniques" The World Health Organization Analgesic Ladder Acetaminophen STEP 1: MILD PAIN: 1-3 on pain scale Non narcotic: ASA, Acet., NSAID +/- Adjuvants STEP 2: MODERATE PAIN: 4-6 on pain scale Non narcotic + Weak Narcotic: ASA or Acet. + Codeine, Hydrocodone, Oxycodone, Tramadol +/- Adjuvants STEP 3: SEVERE PAIN: 7-10 Non narcotic + Strong Narcotic Morphine, Hydromorphone, Methadone, Fentanyl + Nonopioid analgesics + Adjuvants Minimal anti-inflammatory action Central analgesia No GI or platelet-aggregation toxicity Serious dose-dependent hepatotoxicity Ceiling dose effect 4

5 5/18/12 NSAID Guidelines Drug selection should be influenced by drug-selective toxicities, prior experience, convenience, cost. Use with caution in patients with renal insufficiency, congestive heart failure, or volume overload Relative cost-benefit of COX-2 selective drugs and nonselective drugs combined with gastro-protective therapy is not known Adverse effects: GI toxicity, renal toxicity, bleeding diathesis GI toxicity reduced by proton pump inhibitors, misoprostol, and possibly high-dose histamine-2 blockers. COX-2 selective inhibitors may have better GI safety profile. Parenteral NSAIDS Ketorolac (Toradol) : Only parenteral NSAID currently approved in USA. Usually for NPO patients. Excellent analgesia (15-30mg ~ 10mg MS)- usually limited to hours to avoid side effects (q 6-8 hour) (Pediatric dosing mg/kg) Parenteral COX-2 selective agents in development. Opioid Approximate Analgesic Equivalence Medications Used for Treatment of Chronic Pain: Examples PO/PR (mg) Analgesic IV/IM/SQ (mg) 30 Morphine Dilaudid Methadone 10 5

6 5/18/12 Pharamacologic Treatments for Chronic Pain Anticonvulsants membrane stabilizers Gabapentin; Pregabalin Favorable safety profile and positive RCTs in PHN/diabetic neuropathy Usual effective dose: mg/d (gabapentin) and sometimes higher Analgesic effects established for phenytoin, carbamazepine, valproate, clonazepam, and lamotrigine Tricyclics amitryptiline (0.5-2 mg/kg po HS) Limited experience with other drugs Tramadol (0.5 mg/kg -> 2 mg/kg po q6h) Topical treatment: Capsaicin Pediatric Dosing Gabapentin (Neurontin ) oral agent Forms tablets (100, 300, 400, 600, 800); elixir 50 mg/ml) Starting dose: 10 mg/kg-day (divided tid) and titrate upward Adjust with renal dysfunction Taper over ~ 7 days when stopping Pregabalin (Lyrica ) oral agent Form tablet only (25, 50, 75, 100, 150, 200, 225, 300) Not approved for pediatric pts. Starting dose: 1 mg/kg-dose bid-tid, titrate upward Adjust with renal dysfunction Taper over ~ 7 days when stopping Regional Anesthesia: Blocks, etc. Regional Anesthesia Equipment Local Anesthetics Needles Short Bevel Styletted Fine (27 g) Insulated Tuohy Catheters Nerve Stimulators Nerve Mapping Ultrasound 6

7 5/18/12 Paravertebral Block Stellate Ganglion Block Atlas of Regional Anesthesia, 2nd edition 1994 Appleton & Lange 7

8 5/18/12 CRPS Fibromyalgia CRPS-types and diagnosis 8

9 5/18/12 CRPS - Vicious Cycle of Pain CRPS-1/ RSD CRPS - Diagnosis CRPS Pediatric-Adult Comparison 9

10 5/18/12 CRPS Regional Blockade Case 1- Emma 10 year old girl s/p R ankle sprain while competing in a gymnastics meet 9 months ago. c/o sharp, burning pain of her right leg Unable to walk without crutches Has missed many days of school Pain unrelieved by acetaminophen, ibuprofen or acetaminophen/hydrocodone Extensive work-up: blood, X-rays, MRI: all negative Lives with both parents, younger brother. Previously happy child, now having angry outbursts directed towards parents. Case 1- Emma CRPS - RSD PE: Right leg Allodynia, nondermatomal distribution Skin cold, purple discoloration from mid-thigh down Calf muscle wasting No numbness or neurological deficit Pain limits any movement of ankle Normal range of motion knees/hips 10

11 5/18/12 Chronic Pain Management: A Team Approach What are the options for treatment that you would consider offering? PCP, Physicians, Consultants, 1. Oral analgesics; non-opiate and opioids 2. Gabapentin 3. Referral for regional block 4. Complementary treatment modalities 5. Behavioral referral 6. Physical Therapy A - 1, 2, 6 B - 2, 5, 6 C - 3, 6 D Some sequential combination of all above Medications, Blocks Physical Therapy Nurses Patient Complementary treatments Family- Caregivers Behavioral/ Cognitive Treatments Selected References Acute and Chronic Pain in Adults and Children With Cancer. SM Jay, C Elliott, JW Varni. Journal of Consulting and Clinical Psychology; (1986) 54;5, Pain In Infants, Children and Adolescents. NL Schechter, CB Berde, M Yaster, eds., 1993 Williams and Wilkins Analgesics for the Treatment of Pain in Children. CB Berde, NF Sethna. N Engl J Med, Vol. 347, No. 14 October 3, 2002 Physical Therapy and Cognitive-Behavioral Treatment for Complex Regional Pain Syndromes. BH Lee, L Scharff, NF Sethna, et al; J Pediatrics (2002) 141: Selected References (cont) Chronic pain in adolescents: evaluation of a programme of interdisciplinary cognitive behaviour therapy. C Eccleston, P N Malleson, et al. Arch Dis Child 2003;88: IV Regional Anesthesia with Ketorolac and Lidocaine: Is It Effective for the Management of Complex Regional Pain Syndrome 1 in Children and Adolescents? (Case Series) S Suresh, M Wheeler, A Patel. Anesthesia Analgesia (2003) 96: Complex Regional Pain Syndromes in Children and Adolescents. L Kachko, R Efrat, SB Ami, et al; Pediatrics International (2008) 50; Effectiveness of a multimodal inpatient treatment for pediatric chronic pain: A comparison between children and adolescents. Hechler, M Blankenburg, M Dobe,, et al. European Journal of Pain 14 (2010) 97.e1 97.e9 T 11