Malignant hyperthermia MH

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Malignant hyperthermia (MH)

• Reported by Shen, Mei-ling
• 2006-12-12

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Malignant hyperthermia (MH)

• First identified in 1960
• Hyper-metabolic state following the triggering
  agents
• Incidence 1 in 6,000 to 1 in 40,000
• Age 0.5 72 y/o median age 15 y/o
• Sex male female 21

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Triggering agents

• Volatile anesthetics
• Halothane
• Isoflurane
• Enflurane
• Sevoflurane
• Desflurane
• Depolarizing muscle relaxant
• Succinylcholine

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Signs and symptoms (1)

• Increased of end-tidal CO2
• Tachycardia
• Tachypnea
• Temperature elevation
• Jaw muscle rigidity
• Generalized muscle rigidity

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Signs and symptoms (2)

• Acidosis
• Hyperkalemia
• Hyperkalemia
• Rhabdomyolysis
• Myoglobinuria
• Elevated creatine kinase

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Pathophysiology

• Abnormal high rate of calcium releasing
• Reduction in the re-uptake calcium by the
  sarcoplasmic reticulum

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Diagnostic tests

• Muscle biopsy
• Caffeine-Halothane contracture test
• In vitro contracture test
• Gene
• A mutation in the ryanodine receptor type 1
  (RyR1) on 19q13

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• Caffeine-halothane contracture test
• Sensitivity 97
• Specificity 78
• The sensitivity and specificity of the
  caffeine-halothane contracture test a
• report from the North American Malignant
  Hyperthermia Registry.
• Anesthesiology 1998 88579-88

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• Caffeine-halothane contracture test
• Vectus lateralis vectus medialis rectus
  abdominis
• Muscle strip measuring 2-3 cm in length
• Electrically stimulate every 10 s
• Add halothane add caffeine
• Recording results

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• Gene
• 25-50 in MH-susceptible cases
• A mutation detection rate of 86 in 50 Italian MH
  susceptible subjects
• Frequency and localization of mutations in the
  106 exons of the RYR1 gene in
• 50 individuals with malignant hyperthermia
• Human Mutation 27(8)830, 2006 Aug

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• In 58 MHS cases, 33 patients were identified
  pathogenic RYR1 sequence (56.9)
• 7 were previously reported but 26 were unknown
• Distribution and frequency of RYR1 mutations
  differed from those of the North American and
  European MHS population
• Malignant hyperthermia in Japan mutation
  screening of the entire ryanodine
• receptor type 1 gene coding region by direct
  sequencing
• Anesthesiology 104(6)1146-54, 2006 Jun.

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Managing MH (1)

• Pre-operative
• Ask history or anesthesia reaction Aware of
  clinical signs
• Body temperature monitoring
• Capnographic monitoring
• Dantrolene available
• ABCs of Managing Malignant Hyperthermia
• An MHAUS Online brochure (4/1/2006 updated)

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Managing MH (2)

• Intra-operative
• Primary survey
• Awareness of S/S Airway
• Breathing Body rigidity Body temperature
• Capnography Circulation
• Drugs for triggering
• Exposure
• ABCs of Managing Malignant Hyperthermia
• An MHAUS Online brochure (4/1/2006 updated)

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Managing MH (3)

• Emergency treatment
• Ask for help Agents
• Breathing
• Cooling Call MH hotline
• Dantrolene
• Electrolytes
• ABCs of Managing Malignant Hyperthermia
• An MHAUS Online brochure (4/1/2006 updated)

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Managing MH (4)

• Secondary Steps
• Acidosis ?
• Bicarbonate ?
• Circulation monitoring laboratories CK,
  coagulation.
• Dysrhythmias Diuresis
• Electrolytes
• Follow up A, B, C, D, E

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Managing MH (5)

• Post-operative
• Post-Crisis Problems
• ARF
• Beware hypothermia, electrolytes
• Creatine Kinase Compartment syndrome
• DIC
• Elevated liver function
• Follow CNS function
• Good communication

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Managing MH (6)

• Post-Acute phase
• Aware of recrudescence of signs Ask relatives
• Biopsy
• Contact MHAUS
• Dantrolene Documentation
• ABCs of Managing Malignant Hyperthermia
• An MHAUS Online brochure (4/1/2006 updated)

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Late complications

• Coagulopathy
• Acute renal failure
• Hypothermia
• Hyperkalemia
• Pulmonary edema
• Muscle edema and necrosis
• Brain edema
• Recurrence of the syndrome

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Post-anesthestic follow-up

• Cardiovascular and respiratory stability
• Body temperature lt 38 ?
• Urine output
• Coagulation
• Acid-base and electrolytes balance
• Continuous administration of dantrolene

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Thanks for you attention !