Malignant hyperthermia is a serious, life-threatening condition caused by a genetic defect in the ryanodine receptor or calcium channel that makes individuals susceptible to triggering agents like volatile anesthetics and succinylcholine. When exposed to these agents, calcium is released from the sarcoplasmic reticulum in muscle cells, increasing metabolism and causing symptoms like fever, muscle rigidity, and acidosis. Diagnosis involves testing for genetic mutations or abnormal responses to caffeine and halothane. Treatment requires discontinuing triggers, dantrolene administration, supportive care, and cooling to reduce fever and its complications.

1. Malignant hyperthermia
Dr jameel kifayatullah
jamilkifayatullah@yahoo.com

2. Malignant hyperthermia
• Serious life threatening condition
characterised by a state of hypermetabolism
leading to hyperthermia and massive
rhabdomyolysis

3. RHABDOMYOLYSIS

4. Causes
• Autosomal dominant genetic defect of one of
several receptors within sarcoplasmic
reticulum i.e Mutation in the ryonodine
receptor, CACNA 1S calcium receptor
involvement
• Volatile anaesthetic agents e.g
halothane,sevofluorane and skeletal muscle
relaxant Succinylcholine

5. Ryanodine receptor

7. Volatile anaesthetic agents

8. Pathophysiology
• Triggering agents such as Succinylcholine and
volatile anaesthetic agents in a genetically
predisposed patient release calcium from
sarcoplasmic reticulum leading to elevated
concentrations of calcium in the muscle cells
• This increase metabolism is responsible for
the symptoms of Malignant hyperthermia

9. Pathophysiology

10. Definitive Diagnosis
• History suspicious of Malignant hyperthermia
should undergo the following tests before
anaesthesia
skeletal muscle biopsy
caffeine halothane testing
Genetic susceptibility testing for ryanodine
and CACNA 1S receptor mutations

11. Early signs of Malignant Hyperthermia
• Hypercapnia
• Tachycardia
• Muscle rigidity
• Tachypnea
• Hypoxia
• Arrhythmias
• Unstable Blood pressure
• Flushed cyanotic or ruddy skin

12. Late signs of Malignant Hyperthermia
• Fever/diaphoresis
• Respiratory and metabolic acidosis
• High :
Potassium,calcium,magnesium,glucose,creatin
kinse(CK), LDH,SGOT
• Low
Clotting factors
Myoglobinemia

13. Malignant hytperthermia

14. Steps for treating Malignant
Hyperthermia
• Emergency page to staff anaesthesiologist
• Discontinue the triggering agents
• Discontinue the surgical procedure as quickly
as possible
• Start TIVA(Total Intravenous anaesthetic
agents)
• Hyperventilate with 100% Oxygen at high flow
rate

15. Steps for treating Malignant
Hyperthermia
• Give Dantrolene sodium 2.5 mg/Kg I.V
• Obtain Labs(ABGs,Electrolytes,CK,serum/urine
myoglobin,Coagulation parameters)
• Treat Hyperkalemia :Calcium
chloride,Glucose,Insulin
• Treat Metabolic Acidosis: Bicarbonate:1-2
mEq/kgs

16. Steps for treating Malignant
Hyperthermia
• Incase of hyperthermia: cool patient
cold IV fluids(normal saline),Apply ice packs
to groin ,axilla ,nasogastric lavage with cold
solution
• Foley catheter for urine output
• ICU admission

17. Cooling Techniques for Hyperthermia