Malignant Hyperthermia - 11
Masseter Muscle Rigidity (Spasm) (MMR, MMS)

• Some slight, subclinical increase in masseter muscle tone may be normal.
• Jaw stiffness that interferes with mouth opening for direct laryngoscopy and orotracheal intubation occurs in about 2% of children. This may include an unknown number at risk for MH.
• "True MMR" occurs when "jaws of steel" make mouth opening impossible. This is relatively rare. In one series of children referred for biospy, 50% proved to be MHS.

• not enough time
• not enough succinylcholine (use a peripheral nerve stimulator to test for block)
• temporomandibular joint dysfunction (Could patient open mouth before induction?)
• amyotonic myotonia

• patient may be MHS
• consideration should be given to canceling an elective case
• emergent case may be continued with nontriggering agents (patient may require flexible fiberoptic nasotracheal intubation)
• observe closely for (additional) signs of MH
• be prepared to treat with dantrolene
• extend postoperative observation period
• consider referral for muscle biopsy after discussion with family

<-Back 1 2 3 4 5 6 7 8 9 10 11 Refs Quiz