Does scorpion bite lead to resistance to action of local anaesthetic agentsby dr. minnu m. panditrao
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Does scorpion bite lead to resistance to action of local anaesthetic agentsby dr. minnu m. panditrao



Professor Minnu M. Panditrao gives her award winning (SAARC Bengaluru 2011) and recently published paper in Inidan Journal of Anaesthesia 56, 6 Nov.dec 2012, 575-78, paper where she explains the ...

Professor Minnu M. Panditrao gives her award winning (SAARC Bengaluru 2011) and recently published paper in Inidan Journal of Anaesthesia 56, 6 Nov.dec 2012, 575-78, paper where she explains the peculear responswe seen by herself and her team, about the developement of resistance to the local anaesthetic agents given via various routes, inpatients who give history of old single/ or usually multiple scorpion bites.



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Does scorpion bite lead to resistance to action of local anaesthetic agentsby dr. minnu m. panditrao Presentation Transcript

  • 1. Does Scorpion Bite Lead toDevelopment of Resistance toEffect of Local Anaesthetics? : A Case Report
  • 4. THIS CASE REPORT HAS BEEN RECENTLY PUBLISHED IN:INDIAN JOURNAL OF ANAESTHESIA,issue 56, volume 6, Nov-Dec 2012, page no.s 575-578.
  • 5. Introduction• Failure of Local Anesthetic Block” : via various routes isa rare but a known phenomenon !• Various factors/causes have been considered to beresponsible for this i. e. technical difficulties, drugerrors etc.• Even genetic factors like being a Redhead, i.e. carrying avariants of the melanocortin-1 receptor (MC1R) gene, maylead to resistance to not only local anaesthetics likenovocaine, lidocaine, but may make them resistant toeffects of inhalational anaesthetic agents like desflurane
  • 6. • Can happen even in „ expert/ skillful‟ hands• May be misinterpreted as a “technical or Skill‟s failure”, causing embarrassment, Low morale, wastage of time and resources (needing G.A.)• Unexplainable factors responsible for this failure
  • 7. Case Report• 65 years old multi-para female• Grade IV procedentia, cystocele, rectocele and enterocele• Posted for vaginal hysterectomy and pelvic floor repair
  • 8. Case Report ( contd.)• Pre-op. evaluation: H/O Hypertension, controlled with Amlodipine 2.5 mg o.d. G. P. E. Normal M. P. C. grade II Lab. Inv., X-ray, E.C.G., ECHO, were W. N. L.• A.S.A. Grade II.• Planned subarachnoid Block
  • 9. Case Report ( contd.)• Operative Procedure :Infusion of D.N.S. with 20 Gz. I.V. cannulaMonitoring of E.C.G., SPO2 and NIBPAseptic Precautions , Lumbar Puncture26 Gz. Quincke‟s needle at L3-L4 interspaceSitting position3.5 ml of 0.5% hyperbaric Bupivacaine injected after free flow of CSFPatient turned supine, with head down tilt 10o
  • 10. Case Report ( contd.)• No „Sensory or Motor Blockade‟ observed• Waited for 10 minutes• Increased Head down Tilt• Waited another 10 minutes• Still „No effect‟• No changes in the vitals (PR, BP) observed
  • 11. Case Report ( contd.)• Decision to repeat „Spinal Block‟• Performed by a Sr. Consultant at L2-3 Interspace• Again 3.5 ml 0.5% Hyperbaric Bupivacaine of different batch/ brand administered• Patient made supine and 20o Head down tilt• „ No Sensory/ Motor Block even after 30 min.• No signs of „autonomic block‟ seen
  • 12. Case Report ( contd.)• On specific inquiry into past history• Gave history of “Scorpion Bite” Two times• First at 17 years on right foot• Second time, 8 months back on face, right arm and forearm• Decided to abandon the spinal block and to give G.A.
  • 13. Case Report ( contd.)• Standard balanced G.A.• Injs. Glycopyrrolate, Butorphanol• Injs. Propofol, Rocuronium• Intubation, O2, N2O and Isoflurane, IPPV• Surgery lasted 105 min., uneventful• Reversed with glycopyrrolate + neostigmine, extubated• After recovery no signs of residual/delayed spinal block• Follow up for 48 hours, uneventful.
  • 14. Case Report ( contd.)• Patient called in the O.T. on 8th post op. day• Condition explained• Informed consent obtained• Peripheral Nerve Blocks of Median, Ulnar and Anterior interosseous br. of Radial nerve given at the level of left wrist with 0.5% bupivacaine• Local infiltration of the skin of the left forearm was done with 3 ml. of 2% xylocaine with adrenaline
  • 15. Case Report ( contd.)• Confirming our suspicion, there was neither any sensory nor motor block observed• Even the local infiltration did not produce any perceptible sensory loss• Patient observed for 2 hours in PACU and then sent back to the ward• Discharged on 10th Post operative day after uneventful stay
  • 16. Discussion• Spinal anesthesia is not a 100% certain successful technique.• Failure rates of 0.72% to 16.0% have been reported• Causes of failed spinal anesthesia can be classified as1. Technical Failure to enter the subarachnoid space: no drug injection2. Successfully injected drug may be maldistributed relative to the need of the planned surgery3. Un-recognized failed injection of the drug: partial or total4. Drug errors : wrong drugs, inappropriate doses/ additives
  • 17. Discussion5. Pseudo block failure: excessive expectation for speed of block onset6. Subdural injection of the spinal dose: possible cause, but never reported7. Central neuroplasticity in Phantom limb pain and Human model of tachyphylaxis8. Local Anaesthetic Resistance: Genetic or acquired; these are mystifying circumstances, as in our case, when there is failure of spinal block, despite apparent technically correct injection of the correct dose of drug
  • 18. Discussion• Mechanism of Local Anaesthetic Resistance: Receptor Mutation with Na+ Channel abnormalities Resulting from variation in the amino acid sequence within the Na+ Channel Na+ Channel consists of α, β1, β2 subunits α subunit has 4 domains (I-IV), each made of 6 segments (S1-S6)• L.A. action is due to their interaction with S6-IV D of α subunit (sites of Ph ala and Tyr A.A.residues)• Variation/alteration at this site, can cause LAA resistance
  • 19. Structure of a Na+ channel α‐subunit
  • 20. Discussion• Scorpion Bites• Common Phenomenon in Tropical/ subtropical Countries• Scorpion venom neurotoxins possess general ability to depolarise the excitable membranes due to an increase in Na+ permeabilty of the resting membrane and reduction in the rate and amount of Na inactivation• It may also modify Na pumping mechanism and passive / active Na permeability systems
  • 21. Discussion• In acute phase : Pain, inflammation, N.M. intoxication is due to venom acting on exposed nerve or muscle fibers or N.M. Junction• Muscular twitching/ fibrillations due to release of neuro-transmitter/neurotoxins.• Not much importance given to the past history of scorpion bite by patients or anaesthesiologists
  • 22. Discussion• We had similar type of presentation- failed spinal in some patients in the past, but did not give significant importance to it• Inability to block the peripheral nerves as well as failure of local infiltration, high lights the possibility of resistance to local anaesthetics as the most plausible explanation in this case• Since the patient was bitten by scorpion twice and at multiple sites, it could have caused development of antibodies against the scorpion venom leading to competitive antagonism at the receptor site ( S6-D IV of α subunit of Na channel) where LAAs are supposed to act
  • 23. Observation With h/o scorpion bite• 2 cases of failed supraclavicular brachial block, where local infiltration was also ineffective• 3 cases of failed spinal• 7 cases of delayed effect of spinal block• We are making it our practice to elicit the history, routinely
  • 24. Conclusion• We are convinced about the hypothesis: ‘Scorpion Bites ( especially repeated bites) may cause development of resistance to the action of local anaesthetics used to achieve blocks by various routes!’