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Flashcards in Topic 21 Deck (20):
1

What is Malignant Hyperthermia?

an autosomally dominant disorder of skeletal muscles.
--Calcium that’s stored in skeletal muscle is released inappropriately causing muscles to contract & stiffen simultaneously

2

Malignant Hyperthermia causes what effects? (8)

dangerous hyperthermia
skeletal muscle breakdown (rhabodmyolysis)
run-away hypermetabolism
acidosis
flushed skin
myoglobinuria
hypotension
death

3

do most cases occur in adults or children?

Most cases occur in children and young adults <30 years old
--Occurs in all races & ethnicities

4

how long before symptoms appear?

appear within one hour (but can be delayed up to ~12 hours)

5

name some known chemical triggers of MH? (4)

Forane
Sevoflurane
Suprane
Anectine

6

name some things that are NOT triggers of MH? (5)

-Intravenous anesthetics (including Propofol)
-Opiates
-Non-depolarizing muscle relaxants
-Ketamine
-Sedatives and Tranquilizers.

7

International mortality data on MH ranges from 1.4%-20.0% which appears to be based entirely on what?

the speed of MH diagnosis and therapy initiation!

8

name 4 SPECIFIC signs of MH

Muscle Rigidity
Dramatically increase CO2 production
Rhabdomyolysis
Profound hyperthermia

9

name 4 NON-SPECIFIC signs of MH

Tachycardia
Tachypnea
Acidosis (both respiratory & metabolic)
Hyperkalemia

10

what are the 3 MH Clinical presentations?

Fulminant MH
Masseter Muscle Rigidity (MMR)
Late Onset MH

11

Fulminant MH=

(most common): muscular rigidity, extreme hyperthermia, tachycardia. Typically occurs shortly after anesthetic induction

12

Masseter Muscle Rigidity (MMR)=

profound jaw muscle rigidity after succinylcholine administration; may be an early sign of MH

13

Late Onset MH=

(uncommon): Occurs within the first hour of anesthetic termination

14

why is MMR a prognostic indicator? *KNOW*

Patients with a history of MMR post-anesthetic induction have a 25-30% chance of having Fulminant MH during their next anesthetic!

15

Why does MH occur? *KNOW*

A mutation in the ryanodine receptor gene (RYR1) in skeletal muscles affects the muscles’ ability to properly utilize calcium

16

Treatment of acute MH (7 steps) *KNOW COLD*

1. Immediately discontinue volatile gas anesthetics and succinylcholine administration
2. Hyperventilate with 100% oxygen
3. Give 1-2 mg/kg bicarbonate
4. Give Dantrolene at a dose of 2.5mg/kg IV push and repeat PRN
5. Cool patient
6. Treat arrhythmias but DO NOT GIVE CALCIUM CHANNEL BLOCKERS!!!
7. Monitor coagulation and electrolytes

17

how much dantrolene do you give to treat

2.5mg/kg IV push and repeat PRN

18

when you treat the arrhythmia's- what are you careful not to give?

DO NOT GIVE CALCIUM CHANNEL BLOCKERS!!!

19

Dantrolene

(Dantrium)

20

how does Dantrolene work?

blocks the release of calcium from skeletal muscle’s
sarcoplasmic reticulum which prevents the pathologically massive, prolonged release of calcium through the RYR1 channels which is the etiology of Fulminant MH