Malignant Hyperthermia

MALIGNANT HYPERTHERMIA

Q. 1

Agent causing malignant hyperthermia is?

 A Succinylcholine
 B

1120

 C Ether
 D

Verapamil

Q. 1

Agent causing malignant hyperthermia is?

 A Succinylcholine
 B

1120

 C Ether
 D

Verapamil

Ans. A

Explanation:

Succinylcholine REF: Goodman and Gillman p. 152 11th edition

“Succinylcholine is the most common drug used in anesthesia to cause Malignant Hyperthermia”

MALIGNANT HYPERTHERMIA

Malignant hyperthermia is a potentially life-threatening event triggered by certain anesthetics and neuromuscular blocking agents.

Clinical features: contracture, rigidity, and heat production from skeletal muscle resulting in severe hyperthermia, accelerated muscle metabolism, metabolic acidosis, and tachycardia.

Mechanism: Uncontrolled release of Ca2+ from the sarcoplasmic reticulum of skeletal muscle is the initiating event. Although the halogenated hydrocarbon anesthetics (e.g., halothane, isoflurane, and sevoflurane) and succinylcholine alone reportedly precipitate the response, most incidents arise from the combination of depolarizing blocking agent and anesthetic. Susceptibility to malignant hyperthermia, an autosomal dominant trait

Treatment: Intravenous administration of dantrolene (DANTRIUM), which blocks Ca2+release and its sequelae in skeletal muscle. Rapid cooling, inhalation of 100% oxygen, and control of acidosis should be considered adjunct therapy in malignant hyperthermia


Q. 2 All are seen in Malignant hyperthermia except 
 A >Bradycardia
 B >Hyperkalemi a
 C >Metabolic acidosis
 D >Hypertension
Q. 2 All are seen in Malignant hyperthermia except 
 A >Bradycardia
 B >Hyperkalemi a
 C >Metabolic acidosis
 D >Hypertension
Ans. A

Explanation:

Bradycardia [Ref Lee’s Synopsis of Anaesthesia 12th/e p 289]

  • C/f of Malignant Hvperthermia :
  • Heat production exceeds the heat loss in the body to cause a rise of temperature of at least 2° c/h.
  • It is characterized by
  • Hypertension
  • Hypercapnia
  • Hyperkalemia *
  • Metabolic Acidosis *
  • Arrhythmia (Tachycardia)
  • Diffuse intravascular coagulation
  • Pyrexia
  • There is                  – increased hemolysis*

– increase Creatine phosphatase *

– increase Transaminase

  • Management :
  • Early withdrawl of the volatile anaesthetic agent is of utmost importance
  • Cool the patient
  • Acidosis corrected
  • Administer Dantrolene *
  • Correction of Hyperkalenna
  • Promote diuresis
  • Give Dexamethasone

Q. 3

Malignant hyperthermia is most commonly precipitated by:

 A Succinyl choline
 B Dantrolene sodium
 C Gallamine
 D Pancuronium
Q. 3

Malignant hyperthermia is most commonly precipitated by:

 A Succinyl choline
 B Dantrolene sodium
 C Gallamine
 D Pancuronium
Ans. A

Explanation:

Succinyl choline


Q. 4

A 38-year old man presents for ventral hernia repair. He had a malignant hyperthermia crisis during prior surgery.

Assertion: Sevoflurane is contraindicated for induction of anaesthesia in this patient.

Reason: It is found to precipate malignant hyperthermia.

 A

Both Assertion and Reason are true, and Reason is the correct explanation for Assertion

 B

Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion

 C

Assertion is true, but Reason is false

 D

Assertion is false, but Reason is true

Q. 4

A 38-year old man presents for ventral hernia repair. He had a malignant hyperthermia crisis during prior surgery.

Assertion: Sevoflurane is contraindicated for induction of anaesthesia in this patient.

Reason: It is found to precipate malignant hyperthermia.

 A

Both Assertion and Reason are true, and Reason is the correct explanation for Assertion

 B

Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion

 C

Assertion is true, but Reason is false

 D

Assertion is false, but Reason is true

Ans. A

Explanation:

Since this patient gives a history of malignant hyperthermia during previous surgery,

sevoflurane is contraindicated in this patient.

Drugs known to precipitate malignant hyperthermia are succinylcholine, halothane, isoflurane, desflurane and sevoflurane.

Ref : Essentials of Medical Pharmacology By K D Tripathi 5th edn, page 340.


Q. 5

Which of the following type of receptor is involved in malignant hyperthermia ?

 A

Nicotinic receptor

 B

Ryanodine receptor

 C

Muscarinic receptor

 D

None

Q. 5

Which of the following type of receptor is involved in malignant hyperthermia ?

 A

Nicotinic receptor

 B

Ryanodine receptor

 C

Muscarinic receptor

 D

None

Ans. B

Explanation:

Malignant hyperthermia (MH) is inherited as an autosomal dominant trait with reduced penetrance.

It is associated with mutations in 2 genes: RyR1 (ryanodine receptor type 1), which encodes the skeletal muscle isoform of the calcium release channel of the sarcoplasmic reticulum, and CACNA1S, which encodes the alpha subunit of the L-type calcium channel isoform of the sarcolemma (dihydropyridine receptor). The RyR1 gene is located on chromosome 19. 

Malignant hyperthermia (MH) is a subclinical myopathy that allows large quantities of calcium to be released from the sarcoplasmic reticulum (SR) of skeletal muscle and cause a hypermetabolic state after exposure to triggering agents. Altered calcium channel gating kinetics in the SR is the underlying cause. The sustained elevation of calcium allows excessive stimulation of aerobic and anaerobic glycolytic metabolism, which accounts for respiratory and metabolic acidosis, rigidity, altered cell permeability, and hyperkalemia.


Q. 6

During a surgery a patient developed muscle rigidity, increased heart rate and hypercarbia. Emergence of malignant hyperthermia is suspected. The agent which precipitates this condition most commonly is:

 A

Succinyl choline

 B

Dantrolene sodium

 C

Gallamine

 D

Pancuronium

Q. 6

During a surgery a patient developed muscle rigidity, increased heart rate and hypercarbia. Emergence of malignant hyperthermia is suspected. The agent which precipitates this condition most commonly is:

 A

Succinyl choline

 B

Dantrolene sodium

 C

Gallamine

 D

Pancuronium

Ans. A

Explanation:

Malignant hyperthermia (MH) is commonly triggered by the administration of anesthetic agents; the commonest trigger is the depolarizing muscle relaxant succinylcholine alone or in conjunction with a volatile agent such as halothane.
The earliest signs of MH during anesthesia are succinylcholine-induced masseter muscle rigidity (MMR) or other muscle rigidity, tachycardia, and hypercarbia (due to increased CO2 production).
Hyperthermia may be a late sign, but when it occurs, core temperature can rise as much as 1°C every 5 min.
The treatment of choice is intravenous dantrolene. 
 
  • Drugs known to trigger malignant hyperthermia:
  • Inhaled general anesthetics
  • Ether
  • Halothane
  • Methoxyflurane
  • Enflurane
  • Isoflurane
  • Desflurane
  • Sevoflurane
  • Nondepolarizing muscle relaxants
  • Succinylcholine
Ref: Butterworth IV J.F., Butterworth IV J.F., Mackey D.C., Wasnick J.D., Mackey D.C., Wasnick J.D. (2013). Chapter 11. Neuromuscular Blocking Agents. In J.F. Butterworth IV, J.F. Butterworth IV, D.C. Mackey, J.D. Wasnick, D.C. Mackey, J.D. Wasnick (Eds), Morgan & Mikhail’s Clinical Anesthesiology, 5e.Ether

 


Q. 7

Which of the following drugs can cause malignant hyperthermia?

 A

Succinyl choline

 B

Halothane

 C

Lidocaine

 D

All the above

Q. 7

Which of the following drugs can cause malignant hyperthermia?

 A

Succinyl choline

 B

Halothane

 C

Lidocaine

 D

All the above

Ans. D

Explanation:

Mepivacaine, Gallamine, Methoxy flurane, Ethyl chlonde etc also cause malignant hyperthermia.


Q. 8

There is mutation of gene coding for the ryanodine receptors in malignant hyperthermia. Which of the following statements best explains the increased heat production in malignant hyperthermia?

 A

Increased muscle metabolism by excess of calcium ions

 B

Thermic effect of blood

 C

Increased sympathetic discharge

 D

Mitochondria thermogenesis

Q. 8

There is mutation of gene coding for the ryanodine receptors in malignant hyperthermia. Which of the following statements best explains the increased heat production in malignant hyperthermia?

 A

Increased muscle metabolism by excess of calcium ions

 B

Thermic effect of blood

 C

Increased sympathetic discharge

 D

Mitochondria thermogenesis

Ans. A

Explanation:

A i.e. Increased muscle metabolism by excess of Ca2+ ions


Q. 9

Malignant hyperthermia is best treated with ‑

 A

Dantrolene sodium

 B

Potassium chloride

 C

Atropine

 D

Corticosteroids

Q. 9

Malignant hyperthermia is best treated with ‑

 A

Dantrolene sodium

 B

Potassium chloride

 C

Atropine

 D

Corticosteroids

Ans. A

Explanation:

Ans. is ‘a’ i.e., Dantrolene sodium

o I. V dantroline is the DOC, it acts by preventing the release of calcium from sarcoplasmic reticulum.

o Others are for supportive treatment –> oxygen, cooling, and insulin & dextrose are given for hyperkalemia due to potassium release from contracted muscle.


Q. 10

Which one of the following anaesthetic agents does not trigger malignant hyperthermia ?

 A

Halothane

 B

Isotlurane

 C

Suxamethonium

 D

Thiopentone

Q. 10

Which one of the following anaesthetic agents does not trigger malignant hyperthermia ?

 A

Halothane

 B

Isotlurane

 C

Suxamethonium

 D

Thiopentone

Ans. D

Explanation:

Ans. is ‘d’ i.e., Thiopentone

Drugs causing Malignant hyperthermia

  • Succinylcholine                            
  • Enflurane                          
  • Methoxyflurane                             
  • Phenothiazines
  • Halothane                                  
  • Sevoflurane                       
  • MAO inhibitors                                
  • Lignocaine
  • Isoflurane                                 
  • Destlurane                          
  • TCA

o Succinylcholine is the most common cause of MH.

o Amongst anaesthetics, halothane is most common cause.

o Combination of Sch and Halothane has a much higher incidence.


Q. 11

End-tidal CO2 is increased to maximum level in :

 A

Pul. embolism

 B

Malignant hyperthermia

 C

Extubation

 D

Blockage of secretion

Q. 11

End-tidal CO2 is increased to maximum level in :

 A

Pul. embolism

 B

Malignant hyperthermia

 C

Extubation

 D

Blockage of secretion

Ans. B

Explanation:

B i.e. Malignant hyperthermia

Unilateral absence (or decrease) of breath sounds over one lung (especially left) after a speedy intubation suggests a diagnosis of inadvertent endobronchial intubation. End tidal CO2 may be low, normal or raised after an endotracheal intubation. Tlie presence of high end tidal CO2 however excludes a diagnosis of esophageal intubation which is associated with reduced or absent end tidal CO2.

Malignant hyperthermia show marked rise in ETCO2.


Q. 12

Malignant hyperthermia is most common with

 A

Succinyl Choline

 B

Gallamine

 C

Dantrolene

 D

Ketamine

Q. 12

Malignant hyperthermia is most common with

 A

Succinyl Choline

 B

Gallamine

 C

Dantrolene

 D

Ketamine

Ans. A

Explanation:

A i.e. Succinyl choline


Q. 13

All are seen in malignant hyperthermia except:

 A

Bradycardia

 B

Hyperkalemia

 C

Metabolic acidosis

 D

Hypertension

Q. 13

All are seen in malignant hyperthermia except:

 A

Bradycardia

 B

Hyperkalemia

 C

Metabolic acidosis

 D

Hypertension

Ans. A

Explanation:

A i.e. Bradycardia


Q. 14

Which of the following is true about malignant hyperthermia

 A

Hypernatremia

 B

Hypercalcemia

 C

Hyperkalemia

 D

Hypothermia

Q. 14

Which of the following is true about malignant hyperthermia

 A

Hypernatremia

 B

Hypercalcemia

 C

Hyperkalemia

 D

Hypothermia

Ans. C

Explanation:

C i.e. Hyperkalemia


Q. 15

About malignant hyperthermia true:

 A

Succinylcholine & Halothane predisposes

 B

Dantrolene usefull in all cases

 C

Ketanserine can be used as an alternative to Dantrolene

 D

a and b

Q. 15

About malignant hyperthermia true:

 A

Succinylcholine & Halothane predisposes

 B

Dantrolene usefull in all cases

 C

Ketanserine can be used as an alternative to Dantrolene

 D

a and b

Ans. D

Explanation:

A i.e. Succinyl choline & halothane predispose B. i.e. Dantrolene useful in all cases


Q. 16

Treatment of malignant Hyperthermia includes:

 A

Dantrolene

 B

Cooling

 C

Deepening plane of inhalational anaesthesia

 D

a and b

Q. 16

Treatment of malignant Hyperthermia includes:

 A

Dantrolene

 B

Cooling

 C

Deepening plane of inhalational anaesthesia

 D

a and b

Ans. D

Explanation:

A.i.e. Dantrolene; B. i.e. Cooling 


Q. 17

Difference between thyrotoxicosis and malignant hyperthermia is –

 A

Hyperthermia

 B

Tachycardia

 C

Muscle rigidity

 D

Elevated serum CPK level

Q. 17

Difference between thyrotoxicosis and malignant hyperthermia is –

 A

Hyperthermia

 B

Tachycardia

 C

Muscle rigidity

 D

Elevated serum CPK level

Ans. D

Explanation:

Ans. is D ie. Elevated Serum CPK level

  • Both thyrotoxicosis, and malignant hyperthermia can cause myopathy but in hyperthyrodism serum CPK level is often normal (In fact many endocrine disorders can cause myopathy but serum CPK level is normal in all of them except for hypothyroidism in which it is elevated upto 10 times)
  • Increased CPK level is seen in malignant hyperthermia*.

“Malignant hyperthermia is a rare complication. It is due to a genetic defect in calcium metabolism at the sarcoplasnic reticulum level of skeletal muscle. It carries a 30% mortality rate and is seen after administration of some inhalational anesthetics, amides based local anesthetics, or ocassionally muscle relaxants similar to succinilcholine. Muscle biopsy is usually required to confirm the diagnosis, but the majority of pts. will have an elevated serum CPK minutes after the administration of anesthetic agents and includes high fever, tachycardia, rigidity and cyanosis. Hyperkalemia, hypercalcemia and metabolic acidosis are also associated findings.”

” Treatment* includes active cooling of the pt. the administration of dantrolene* to block the release of calcium from the sarcoplasmic reticulum and correction of the noted serum electrolyte and acid base abnormalities.”


Q. 18

Calcium channel ryanodine receptor:disorder is seen in:

 A

Malignant hyperthermia

 B

Duchene Muscular Dystrophy

 C

Tibial muscular dystrophy

 D

Limb girdle muscle dystrophy

Q. 18

Calcium channel ryanodine receptor:disorder is seen in:

 A

Malignant hyperthermia

 B

Duchene Muscular Dystrophy

 C

Tibial muscular dystrophy

 D

Limb girdle muscle dystrophy

Ans. A

Explanation:

Answer is A (Malignant Hyperthermia):

Malignant hyperthermia is associated with mutations within the gene encoding the skeletal muscle ryanodine receptor, the calcium channel that releases calcium from sarcoplasmic reticulum. Disordered muscle calcium regulation is recognized as the underlying disorder in malignant hyperthermia.

Ryanodine receptor is the calcium channel on the sarcoplasmic reticulum which controls the flux of calcium from the sarcoplasmic reticulum into the cytoplasm. It plays an important role in the activation of the contractile mechanism, and its malfunction causes malignant hyperthermia. RYR1 is the receptor type in muscle. The ryanodine receptor interacts with an L-tvpe calcium channel.

Mutations in the ryanodine receptor are associated with central core myopathy and malignant hyperthermia.



Q. 19

A 48 year-old woman underwent the procedure represented in the picture below. She has a vague family history of malignant hyperthermia. She develops agitation, restlessness, fever, tremor, shivering, and tachypnea. Thyrotoxic crises can be best distinguished from malignant hyperthermia by estimating ? 

 A

Temperature variation.

 B

Increased CPK levels.

 C

LDH.

 D

Muscular rigidity.

Q. 19

A 48 year-old woman underwent the procedure represented in the picture below. She has a vague family history of malignant hyperthermia. She develops agitation, restlessness, fever, tremor, shivering, and tachypnea. Thyrotoxic crises can be best distinguished from malignant hyperthermia by estimating ? 

 A

Temperature variation.

 B

Increased CPK levels.

 C

LDH.

 D

Muscular rigidity.

Ans. B

Explanation:

The type of thyroidectomy shovrn in the photograph above represents total thyroidectomy.

Thyrotoxic crises can be best distinguished from malignant hyperthermia by estimating increased CPK levels.


Q. 20

True about malignant hyperthermia is all except

 A

Most common cause is Sch

 B

Dantrolene is the drug of choice

 C

End tidal CO, is increased

 D

Bradycardia occurs

Q. 20

True about malignant hyperthermia is all except

 A

Most common cause is Sch

 B

Dantrolene is the drug of choice

 C

End tidal CO, is increased

 D

Bradycardia occurs

Ans. D

Explanation:

Ans. is ‘d’ i.e., Bradycardia


Q. 21

Malignant hyperthermia is caused by

 A

Succinylcholine + halothane

 B

Propranolol

 C

Lidocaine

 D

Bupivacaine

Q. 21

Malignant hyperthermia is caused by

 A

Succinylcholine + halothane

 B

Propranolol

 C

Lidocaine

 D

Bupivacaine

Ans. A

Explanation:

Ans. is ‘a’ i.e., Succinylcholine + halothane


Q. 22

Malignant hyperthermia is caused due to which of the following mechanism?

 A

Increased intracellular Na

 B

Decreased intracellular chlorine

 C

Increased intracellular Ca

 D

Increased serum K

Q. 22

Malignant hyperthermia is caused due to which of the following mechanism?

 A

Increased intracellular Na

 B

Decreased intracellular chlorine

 C

Increased intracellular Ca

 D

Increased serum K

Ans. C

Explanation:

Ans. is ‘c’ i.e., Increased intracellular Ca



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