Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology > Malignant Hyperthermia > Flashcards

Malignant Hyperthermia Flashcards

1
Q

MH is transmitted by

A

Autosomal Dominance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where is the genetic defect located chromosomally

A

Long arm of chromosome 19

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where is the defect associated with MH

A

Ryanodine receptors

Ry1 (skeletal) only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

True/False

Triggering of MH may not occur with a SINGLE anesthetic exposure

A

True- may trigger after several exposures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

True/False

MH is a malignancy

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

True/False

MH causes hyperthermia

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is MH

A

A fulminant HYPERMETABOLIC state of skeletal muscle induced by VOLATILE inhalational anesthetics, succinylcholine, and perhaps by stress/excercise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

** What is the MOA of MH

A

Release of substantial amounts of calcium into sarcoplasm caused by defective Ryd1 receptors, with reversal of usual gradients into the SR, mitochondria, and/or sarcolemma into extracellular fluid.

As a result, calcium pump requires excessive amounts of ATP leading to heat, acid, and C02 production which alters the energy supply and demand and causes cell breakdown, release of intracellular contents, and ischemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does Dantrolene stop MH

A

by stopping the loss of calcium from SR, but not interfering with calcium uptake. This allows the calcium pumps to catch-up with calcium demands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name the triggering agents for MH

A

All halogenated agents including: Methoxyflurane, Cyclopropane, ether, and the rest

Succinylcholine
Decamethonium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

List the Main clinical presentations of MH

A 
SNS stimulation secondary to hypermetabolism
TACHYCARDIA
MASSETER MUSCLE RIGIDITY and generalized muscle rigidity 
HYPERCAPNIA
INCREASED TEMP (1-2 degrees/5 min)
hyperKalemia
hyperCacemia
myoglobinuria
CPK > 20K 
Lactidemia r/t hypermetabolism
Ventricular dysrhythmias
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

MMR occurs more commonly in

A

children

young adults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Most MMR occurs after which inhalation/muscle blockers

A

Halothane, Sevoflurane following succs administration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Will repeat doses of succs or NDMR relieve MMR

A

NO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What will the peripheral nerve stimulator reveal with MMR

A

flaccid paralysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

List the differential diagnosis for MMR

A 
Myotonic syndrome
TMJ dysfunction
Underdosing with succs
Not allow succs to work
Increased resting tone after succ with fever or elevated epi levels

MH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

List management strategies with MMR

A

DC anesthesia and postpone case if possible
continue anesthesia with non-triggering agent
give dantrolene, only if generalized rigidity/hypermetabolism noted
admit for 12-24 hours after episode
serial CKs, at 6,12,24 hours
* contracture test- only definitive diagnosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Identify other dx’s associated with MH

A 
King-denborough syndrome
Duchenne muscular dystrophy
Becker dystrophy
Myopathies
Myotonias
Periodic paralysis
Osteogenesis imperfecta
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

List syndromes with clinical resemblances to MH

A 
Pheochromocytoma
Thyrotoxicosis
Sepis
Hypoxic encephalopathy
Mitochondrial myopathies
NMS
Serotonin Syndrome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Differences between pheochromocytoma and MH

A

Highest BP/ Tachy with pheo
No rigidity with pheo
CO2 less with pheo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Differences between Thyrotoxicosis and MH

A

Second highest BP ever seen/Tachy

CO2 less with thyrotox

22
Q

Hypoxic encephalopathy and MH

A

Patient doesnt wake up, posturing, stiff neck with HE

23
Q

NMS and MH

A

In NMS, symptoms occur in severly ill patients treated with antipyschotics, or dopamine antagonists with symptoms resembling MH such as: muscle rigidity, and hyperpyrexia

NMS:

  • Severe muscle rigidity
  • Slow onset (1-3 days)
24
Q

Treatment of NMS include

A

temperature, acid-base, fluid status

Benzo, Bromocriptine (dopamine agonist), Dantrolene

25
Q

Serotonin Syndrome

A

Occurs within hours vs. MH which occurs within minutes, Hypercapnia within minutes

26
Q

Differential Diagnosis r/t ETCO2 > 5mmHg above steady state

A

**Increased CO2 production is most sensitive and specific for MH
r/o fever, light anesthesia
Decreased ventilation- r/o spont. breathing, ventilator issues, breathing circuit, pulmonary issues, extrathoracic issues
Monitoring error-r/o technical problems

27
Q

Differential Diagnosis r/t Tachycardia and Fever

A

Too much covers or ambient temp
equipment problems
Increased heat production-r/o infection,pheo, etc
CNS-r/o hypothalamus injury, serotonin, prostaglandin
Drug reactions-r/o NMS, MAOI, cocaine, TCA,ketamine, etc.

28
Q

List treatment measures for MH

A 
STOP triggering agent-start propofol infusion
Hyperventilate with 100% oxygen
Administer Dantrolene
Initiate cooling measures
Correct dysrhythmias
Correct hyperKalemia
Secure monitoring lines
Maintain urine output
Follow postop
Call MHAUS
29
Q

Dantrolene administration

A

IV STAT- 2.5 mg/kg with repeated doses until MH reversed. Dose can be as high as 10mg/kg, but should be less than 30 mg/kg

30
Q

Metabolic acidosis correction

A

Correct metabolic acidosis with Sodium Bicarbonate per ABGs (1-2 mEq/kg)

31
Q

Cooling measures

A

IV iced SALINE SOLUTION with 15 cc/kg/10 minutes for 30 minutes
Surface cooling with ice, hypothermia blanket
Lavage: stomach, bladder, rectum, peritoneal, thoracic cavities with NS

*Stop cooling when temp < or equal to 38 C

32
Q

Dysrhythmias correction

A

Correct hyperKalemia and acidosis

Don’t give CCB- will cause hyperKalemia or cardiac arrest in presence of dantrolene

33
Q

HyperKalemia correction

A 
Hyperventilation
Bicarbonate
Glucose/Insulin- 10 Units with D50 50 mL
Check glucose levels hourly
Frequent ABGs
34
Q

Monitoring lines

A

CORE temp
Foley catheter
art-line

35
Q

Urine output

A

at least 2cc/kg/hr

give mannitol 1.25 gm/kg IV and Lasix 1 mg/kg up to 4 doses

36
Q

Post incident monitoring and therapy

A

until episodes subsides
put in ICU at least 24 hours
PO dantrolene 1 mg/kg q 4-6 hours or 0.25 mg/kg/hr IV
*titrate to muscle rigidity, tachycardia, and acidosis

37
Q

For MH susceptible patients

A 
Choose regional anesthetic 
prep anesthesia machine-remove vaporizers, change CO2 absorbent, 02 flow in circuit for 20 min at 10LPM
Get preop CBC/CPK
Cooling Blankets on OR table
art-line/CVP

*Preop admin of dantrolene not recommended

38
Q

Dantrolene is classified as a

A

skeletal muscle relaxant

39
Q

Dantrolene works by

A

inhibiting the release of calcium from SR

40
Q

Dantrolene is caustic to

A

tissues- prevent extravasation

41
Q

Caution patients of —–, —-, —- after dantrolene administration

A

decreased muscle strength (ambulation), light headness, and swallowing difficulties

42
Q

What two drugs displace Dantrolene from plasma proteins, and thus increases risk for toxicity

A

Warfarin

Clofibrate

43
Q

What drug increases plasma binding of Dantrolene, and thus decreases bioavailability

A

Tolbutamide

44
Q

List the AE of dantrolene

A

Pulmonary edema r/t mannitol
Thrombophlebitis r/t extravasation
Urticaria/Erythema
Hepatitis, seizure, pleural effusion, pericarditis with long term exposure

45
Q

How is dantrolend prepared

A

dilute each vial with 60 cc Sterile water without BACTERIOSTATIC agent
gently shake until clear
Each vial contains 20 mg Dantrolene, 3 g Mannitol, and Sodium hydroxide
pH is 9.5
Once mixed, must be used within 6 hours

46
Q

what is a contracture test

A

A muscle biopsy is carried out at an approved research center, under local anesthesia. The fresh biopsy is bathed in solutions containing caffeine or halothane and observed for contraction; under good conditions

47
Q

what is the sensitivity for the contracture test

A

100%- identifies those with dx

48
Q

what is the specificity for the contracture test

A

78%- identifies who doesn’t have dx

49
Q

List the four basis for litigation r/t MH

A

failure to obtain a thorough personal hx
failure to monitor temperature
failure to have adequae supplies of dantrolene
failure to investigate increase in temp, skeletal muscle tone when assoc. with incr. HR and dysrhythmias

50
Q

What should you ask every patient preop r/t MH

A

“Have you or any family members ever had problems with anesthesia such as fever, or death”

Pharmacology (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions