MH

Question 1

incidence of malignant hyperthermia

Answer 1

1:8000 or 1:30,000

Question 2

incidence of malignant hyperthermia is higher in

Answer 2

children

Question 3

MH is linked to mutations in

Answer 3

RYR-1 gene mutation.
RYR1 on chromosome 19
CACNA1S - chromosome 1
and STAC3 of chromosome 12

Question 4

all volatile agents (except N2O) can trigger MH via

Answer 4

direct action on RYR-1

Question 5

Depolarizing NMB trigger MH via

Answer 5

over activation of VGCC that lead to opening of RYR-1 ( on the SR) –> indirect

Question 6

early signs of MH

Answer 6

Hypercarbia 
tachypnea 
tachycardia 
MMR
Hyperthermia*

Question 7

MMR is a common SE of

Answer 7

succinylcholine

Question 8

Of the people with MMR

Answer 8

20% will have an MH episode

Question 9

rate of temperature rise in MH

Answer 9

1-2 degrees Celsius ever 5 minutes

Question 10

milder MH triggers =

Answer 10

exercise in hot conditions
neuroleptic drugs
alcohol
infections

Question 11

mild increase in masseter tone + limb flaccidity following succinylcholine =

Answer 11

normal reaction after succinylcholine

Question 12

if MH is suspected immediately draw:

Answer 12

potassium and ABG

Question 13

MH mortality without dantrolene =

Answer 13

70%

Question 14

MH mortality with dantrolene =

Answer 14

5%

Question 15

Dantrolene MOA

Answer 15

reduces muscle tone and metabolism -> stabilizes and restores balance between release and uptake of Ca++

• prevents on going release of calcium from muscle (@SR)
• Blocks external entry of Ca++ into cell
• Hypothesized to inhibit calcium conductance through RYR1

Question 16

half life of dantrolene =

Answer 16

10 to 15 hours

Question 17

calcium channel blockers + dantrolene =

Answer 17

life threatening hyperkalemia and myocardial depression.

avoid calcium channel blockers with history of MH

Question 18

phlebitis often follows

Answer 18

administration of dantrolene

Question 19

traditional minimum and ryanodex minimum

Answer 19

traditional minimum: 36 vials (20 mg/vial)

or 3 vials of (250 mg/vial) of ryanodex must be available

Question 20

h2o mixed with traditional dantrolene =

Answer 20

60 mL sterile H2O PER VIAL.

36 vials = average loading dose

Question 21

dantrolene dosing

Answer 21

2. 5 mg/kg bolus.
   maintenance: 2 mg/KG IV q 5 minutes to a total of 10 mg/kg

then 1 mg/kg q 6 hours for 72 hours

Question 22

goal temperature in cooling for MH

Answer 22

38 degrees C

Question 23

ABG drawn

Answer 23

q 15 min with active MH

Question 24

Iced IV NS bolus =

Answer 24

15 mL/kg q 10 min

Question 25

maintain UO to be

Answer 25

2 ml/kg/hr. ensure adequate urine output by hydration and diuretics

Question 26

treatment of dysthymia =

Answer 26

ensure hyperkalemia is treated. GIC. If needed: lidocaine or procainamide 15 mg.kg IV

Question 27

hyperkalemia tx dosing

Answer 27

1 ml/kg D50 + 0.15 units/kg regular insulin and/or calcium chloride 5-10 mg/kg

Question 28

reoccurrence of MH occurs in

Answer 28

25% of cases

Question 29

Coagulation labs should be drawn for

Answer 29

DIC

Question 30

labs drawn with MH

Answer 30

Asses K and ABG at onset ABG q 15 min during attack? CKs q 6 hours Coags- evaluate for DIC

Question 31

preferred fluids with MH

Answer 31

Normal saline not lactated or anything with potassium

Question 32

halothane-caffeine biopsy has specificity of

Answer 32

80% therefore negative result does not rule out MH susceptibility

Question 33

recrudescence occurs in about

Answer 33

25% of MH cases

Question 34

dantrolene dosing:

Answer 34

onset: 2.5 mg/kg maintenance 2 mg/kg iv Q 5 minutes, not to exceed 10mg/kg for 72 hours, 1 mg/kg q 6 hours

Question 35

hyperkalemia tx:

Answer 35

1 mL/kg D50. 0.15 units/kg regular insulin 5-10 mg/kg calcium chloride