Malignant Hyperthermia


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Malignant Hyperthermia

  1. 1. MALIGNANT HYPERTHERMIA Dr. Shailendra.V.L. Specialist in Anesthesia, Al Bukariya general hospital
  2. 2. CASE HISTORY <ul><li>A 5 year old boy for tonsillectomy & adenoidectomy was induced with halothane by mask. Three minutes later, succinylcholine is given. Mild muscle rigidity of the jaw is noted, but intubation is accomplished. The child </li></ul><ul><li>is noted to develop a bradycardiac cardiac arrest. ( asystole ) </li></ul>
  3. 3. CASE HISTORY <ul><li>A 9 year old girl develops masseter muscle rigidity after propofol induction and succinylcholine administration. Rigidity of the </li></ul><ul><li>arms is also noted. But end - tidal </li></ul><ul><li>CO2 is normal </li></ul>
  4. 4. CASE HISTORY <ul><li>A 16 year old patient was maintained on isoflurane and vecuronium. At the end of the surgery, she is breathing 20 times per minute and her end-tidal CO2 is 65mm Hg. She suddenly develops ventricular premature contractions. Her forehead skin temperature is 99 F. </li></ul>
  5. 5. DEFINITION OF M H <ul><li>It is charecterised by hyper metabolic response to potent inhalation agents and succinylcholine resulting in increased CO2 production, oxygen consumption, fever, tachycardia, tachypnoea, acidosis, hyperkalemia, myoglobinuria, increased CPK, </li></ul><ul><li>cyanosis & death </li></ul>
  6. 6. HISTORY OF M H <ul><li>1960: Critical worldwide insight into MH began when Denborough & Lovell described </li></ul><ul><li>a 21 year Australian, with an open leg # who was more anxious about anaesthesia, because 10 of his relatives had died during anaesthesia . </li></ul><ul><li>1966: Hall reported on MH induced by halothane & succinylcholine in swines. The human & porcine forms are virtually identical. </li></ul><ul><li>1975: Harrison described efficacy of Dantrolene in preventing & treating porcine MH, which was confirmed in humans. </li></ul>
  7. 7. INCIDENCE OF M H <ul><li>1 in 12,000 pediatric anesthetics </li></ul><ul><li>1 in 40,000 adult anesthetics </li></ul><ul><li>Incidence has an apparent geographic variation – more prevalent in US </li></ul><ul><li>2/3 of susceptible patients manifest this syndrome during their first anesthetic </li></ul>
  8. 8. GENETICS OF M H <ul><li>Three modes of inheritance : </li></ul><ul><ul><li>Autosomal dominant </li></ul></ul><ul><ul><li>Autosomal recessive </li></ul></ul><ul><ul><li>Unclassified </li></ul></ul><ul><li>The Gene for MH is located </li></ul><ul><li>on Chromosome 19, which is also </li></ul><ul><li>the genetic coding site for Ryanodine </li></ul><ul><li>receptors ( Calcium release channel) </li></ul><ul><li>of skeletal muscle sarcoplasmic reticulum </li></ul>
  9. 9. PATHOPHYSIOLOGY OF MH <ul><li>Defect in excitation—contraction coupling of calcium in the sarcolemma in the muscle </li></ul><ul><li>The basic defect lies in the muscle fiber involving cellular membrane permeability of the sarcoplasmic reticulum, which results in an inability to control calcium concentrations within the fiber. </li></ul><ul><li>The resultant events are heat production & muscle contracture secondary to enhanced glycolysis, uncoupling of oxidative phosphorylation, & activation of actin-myosin filaments. </li></ul>
  10. 10. TRIGERING AGENTS FOR MH <ul><li>IN ORDER OR THEIR TRIGERRING POTENTIAL: </li></ul><ul><li>Halothane </li></ul><ul><li>Enflurane </li></ul><ul><li>Isoflurane </li></ul><ul><li>Desflurane </li></ul><ul><li>Sevoflorane </li></ul><ul><li>Ether </li></ul><ul><li>Chloroform </li></ul><ul><li>Suxamethonium </li></ul>
  11. 11. SIGNS OF M H <ul><li>Tachycardia </li></ul><ul><li>Tachypnoea </li></ul><ul><li>Arterial hypoxemia </li></ul><ul><li>Hypercarbia </li></ul><ul><li>Metabolic & Respiratory acidosis </li></ul><ul><li>Hyperkalemia </li></ul><ul><li>Cardiac arrhythmias </li></ul><ul><li>Hypotension </li></ul><ul><li>Skeletal muscle rigidity ( masseter spasm ) </li></ul><ul><li>Increased body temperature </li></ul><ul><li>Increased CPK levels – 20,000 I.U. </li></ul>
  12. 12. EARLY DIAGNOSTIC SIGNS OF MH <ul><li>Rising end-tidal CO2 concentration </li></ul><ul><li>Inappropriate tachycardia </li></ul><ul><li>Hypertension, hypoxemia & acidosis </li></ul>
  13. 13. INVESTIGATIONS <ul><li>Capnograph: </li></ul><ul><ul><li>Rising EtCO2 </li></ul></ul><ul><li>Pulse oximeter: </li></ul><ul><ul><li>Falling saturation </li></ul></ul><ul><li>ECG monitor: </li></ul><ul><ul><li>Tachycardia </li></ul></ul><ul><ul><li>Arrythmias </li></ul></ul><ul><ul><ul><li>- Ventricular bigemeny </li></ul></ul></ul><ul><ul><ul><li>Multifocal premature beats </li></ul></ul></ul><ul><ul><ul><li>Ventricular fibrillation </li></ul></ul></ul><ul><ul><ul><li>Ventricular tachycardia </li></ul></ul></ul>
  14. 14. INVESTIGATIONS <ul><li>ABG: </li></ul><ul><ul><li>Arterial hypoxemia </li></ul></ul><ul><ul><li>Hypercarbia ( 100 to 200 mm of Hg ) </li></ul></ul><ul><ul><li>Respiratory & metabolic acidosis( Ph 7.15 to 6.8) </li></ul></ul><ul><li>Electrolytes: </li></ul><ul><ul><li>Hyperkalemia ( > than 6 mEq ) </li></ul></ul><ul><ul><li>Raised transaminase enzymes </li></ul></ul><ul><ul><li>Markedly elevated CPK ( > 20,000 IU ) </li></ul></ul><ul><ul><ul><li>( peak levels after 12 to 24 hours of the episode ) </li></ul></ul></ul><ul><li>Plasma & urine myoglobin elevated </li></ul>
  15. 15. COMPLICATIONS OF M H <ul><li>DIC </li></ul><ul><li>Pulmonary edema </li></ul><ul><li>Acute renal failure </li></ul><ul><li>CNS damage </li></ul><ul><ul><li>blindness, seizures, coma, paralysis </li></ul></ul><ul><li>CVS manifestations </li></ul><ul><ul><li>arrythmias </li></ul></ul>
  16. 16. Differential diagnosis for MH <ul><li>Neuroleptic malignant syndrome </li></ul><ul><li>Thyrotoxic crisis </li></ul><ul><li>Cocaine toxicity </li></ul><ul><li>Heat stroke </li></ul><ul><li>Serotonin syndrome </li></ul><ul><li>Status epilepticus </li></ul><ul><li>Pheochromocytoma </li></ul>
  17. 17. TREATMENT OF M H <ul><li>Etiologic treatment: </li></ul><ul><ul><li>Dantrolene ( 2 – 3 mg/kg IV) as an initial bolus, followed with repeat doses every 5 – 10 minutes until symptoms are controlled. </li></ul></ul><ul><ul><li>Prevent recurrence (dantrolene 1 mg / kg IV every 6 hours for 72 hours ) </li></ul></ul>
  18. 18. TREATMENT OF M H <ul><li>Symptomatic Treatment: </li></ul><ul><li>Immediately terminate trigger drugs & conclude surgery as soon as possible </li></ul><ul><li>Hyperventilate with 100 % oxygen </li></ul><ul><li>Initiate active cooling </li></ul><ul><ul><li>Iced saline 15 ml / kg every 10 minutes </li></ul></ul><ul><ul><li>Gatric lavage with iced saline </li></ul></ul><ul><ul><li>Surface cooling </li></ul></ul>
  19. 19. TREATMENT OF M H <ul><li>Symptomatic treatment: </li></ul><ul><ul><li>Correct metabolic acidosis ( NaHCO3 1 – 2 m Eq/kg IV based on arterial ph </li></ul></ul><ul><ul><li>Maintain urine output </li></ul></ul><ul><ul><ul><li>Hydration </li></ul></ul></ul><ul><ul><ul><li>Mannitol ( 0.25 g/kg IV ) </li></ul></ul></ul><ul><ul><ul><li>Furosemide ( 1mg/ kg ) </li></ul></ul></ul><ul><ul><li>Treatment of arrythmias </li></ul></ul><ul><ul><ul><li>Xylocaine infusion </li></ul></ul></ul><ul><ul><li>Monitor in ICU </li></ul></ul>
  20. 20. IDENTIFICATION OF SUSECPTIBLE PATIENTS <ul><li>A detailed medical & family history </li></ul><ul><li>Myopathic syndromes </li></ul><ul><ul><li>Duchenne muscular dystrophy </li></ul></ul><ul><ul><li>Myotonia congenita </li></ul></ul><ul><ul><li>Pectus carinatum </li></ul></ul><ul><ul><li>Kyphoscoliosis </li></ul></ul><ul><ul><li>Ostoegenis imperfecta </li></ul></ul>
  21. 21. IDENTIFICATION OF SUSEPTIBLE PATIENTS <ul><li>Laboratory investigations: </li></ul><ul><ul><li>CPK levels ( 70% suseptibles have elevated resting CPK levels ) </li></ul></ul><ul><ul><li>Electromyographic studies ( 50% suseptibles show changes ) </li></ul></ul>
  22. 22. IDENTIFICATION OF SUSEPTIBLE PATIENTS <ul><li>Skeletal muscle biopsy: </li></ul><ul><ul><li>Taken from vastus muscle of thigh under local anaesthesia. </li></ul></ul><ul><ul><li>Muscle is subjected to isometric contracture testing under influence of caffeine or halothane or both. It produces exaggerated contracture in susceptible patients. </li></ul></ul>
  23. 23. MANAGEMENT OFANAESTHESIA <ul><li>“ AVOID ALL TRIGGERING DRUGS ” </li></ul><ul><li>“ Regional blocks are preferred ” </li></ul><ul><li>Premedication: barbiturates or benzodiazepines can safely be used </li></ul><ul><li>Dantrolene prophylaxis adminstration </li></ul><ul><li>is controversial </li></ul>
  24. 24. MANAGEMENT OF ANAESTHESIA <ul><li>Pre-oxygenation for three minutes </li></ul><ul><li>Induction: thiopentone / propofol </li></ul><ul><li>Intubation : non depolarizing relaxants </li></ul><ul><li>Maintainance: oxygen + nitrous oxide </li></ul><ul><li>Reversal: neosigmine + atropine </li></ul>
  25. 25. MANAGEMENT OF ANAESTHESIA <ul><li>Anaesthesia machine without vaporisers </li></ul><ul><li>New face mask and circle absorber </li></ul><ul><li>New breathing circuit & reservoir bag </li></ul><ul><li>Monitors: </li></ul><ul><ul><li>ECG monitor </li></ul></ul><ul><ul><li>NIBP monitor </li></ul></ul><ul><ul><li>Pulse oximeter </li></ul></ul><ul><ul><li>End-tidal CO2 monitor </li></ul></ul><ul><ul><li>Temperature </li></ul></ul>
  26. 26. NON-TRIGGERING AGENTS FOR MH <ul><li>Barbiturates </li></ul><ul><li>Opioids </li></ul><ul><li>Propofol </li></ul><ul><li>Benzodiazepines </li></ul><ul><li>Nitrous oxide </li></ul><ul><li>Anti-cholinergics </li></ul><ul><li>Anti-cholinesterases </li></ul><ul><li>Local anaesthetics </li></ul><ul><li>Sympathominetics </li></ul>
  27. 27. REFERENCES <ul><li> Anaesthesia & co-existing diseases – </li></ul><ul><li>Stoelting. </li></ul><ul><li> Short practice of Anaesthesia – Churchill </li></ul><ul><li>Davidson </li></ul><ul><li> Problem oriented Anaesthesia – Stoelting. </li></ul><ul><li> American Society of Anaesthesia ( ASA ) </li></ul><ul><li>Annual refresher lecture notes – 1998. </li></ul><ul><li> Textbook of Anaesthesia – Ronald Miller. </li></ul>
  28. 28. &quot;Thank you&quot;