Malignant Hyperthermia

Question 1

What are triggers for MH?

Answer 1

Inhaled agents and succinylcholine.

Question 2

First and most sensitive sign of MH?

Answer 2

unexplained tachycardia.

Question 3

What is the most specific sign of MH?

Answer 3

Increasing ETCO2=hypercapnia, 2-3x normal

Question 4

What labs might confirm or help treat MH?

Answer 4

Initial Metabolic Acidosis then a combined resp/met acidosis.
Hyperkalemia.
Hypercalcemia.
Hyperphosphatemia.
Elevated CK.
Myoglobinuria.
Hypoxemia/hypercarbia on blood gas.

Question 5

What is the overall mortality of MH?

Answer 5

10% overall.

Up to 70% without dantrolene therapy.

Question 6

What are the first few things to do when MH is suspected?

Answer 6

Stop off triggering agents.

Call for help.

Question 7

What interventions can be done as soon as MH is suspected?

Answer 7

Hyperventilate with 100% FIO2 on BMV.
Dantrolene 2.5mg/kg repeat up to 10mg/kg.
Bicarbonate 1-2mEq/kg.
Cooling measures.

Question 8

What treatment should be done first for hyperkalemia?

Answer 8

Dextrose and Insulin….

…Along with hyperventilation, Bicarb

Question 9

What drug should be used for persistent ventricular arrhythmias?

Answer 9

Procainamide.

Question 10

What medication must be avoided due to potential for life threatening hyperkalemia and myocardial depression?

Answer 10

Calcium Channel Blockers.

Question 11

What can be done to prevent reoccurance of hypermetabolic state after MH?

Answer 11

Continued dantrolene 1mg/kg Q6hrs.

Question 12

How does dantrolene work?

Answer 12

Directly interferes with muscle contraction by inhibiting Ca++ release from the sarcoplasmic reticulum.

Question 13

What receptor does dantrolene work on?

Answer 13

The ryanodine receptor

Question 14

What is the Gold standard preop test for MH?

Answer 14

Muscle biopsy with halothane-caffeine contracture test

Question 15

What diseases are associated with MH?

Answer 15

*Duchenne's Muscular dystrophy*.
King Denborough syndome.
Central-core disease.
Myotonia.
Osteogensis imperfecta.
Fukuyama.
Beckers.

Question 16

Does a prior uneventful general anesthetic rule out possibility for MH?

Answer 16

No it does not.

Question 17

What are some descriptors of King Denborough Syndrome?

Answer 17

Myopathy, short stature, cryptochidism, pectus carinatum, lumbar lordosis, thoracic kyphosis, unusual facial characteristics

Question 18

Boys <9yrs old who experience sudden cardiac arrest after succinylcholine in the absence of hypoxia are like to have what? and how should it be treated?

Answer 18

Subclinical Muscular Dystrophy. Treat the probably hyperkalemia first with CaCl, Bicarb.

Not related to MH, just succinylcholine.

Question 19

When do symptoms of MH typically occur?

Answer 19

Usually develop within one hour after exposure to trigger substance.