PICU Management of Malignant Hyperthermia

Apr 14, 2024

Explore a case of Malignant Hyperthermia in a 23-month-old premature boy during surgery, discussing pathophysiology, clinical signs, symptoms, and management. Learn about Dantraline's role in inhibiting calcium release, clinical features of MH crisis, triggers, and potential complications. Understand differential diagnoses like Neuroleptic Malignant Syndrome and Serotonin Syndrome. Gain insights into managing MH crisis in pediatric patients, emphasizing the need for a coordinated team and pharmacist collaboration.

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ANECDOTE

OR Case: Rapid MH Presentation

A 23-month-old ex-28-week preemie developed rising ETCO2, tachycardia and fever near end of hernia repair after sevoflurane exposure.
The child arrived to PICU chemically paralyzed with rigidity, high lactate, metabolic acidosis and myoglobinuria suggesting malignant hyperthermia.

INSIGHT

Jaw Rigidity And Rising ETCO2 Are Early Clues

Early anesthetic signs are a tight clenched jaw and a rising end-tidal CO2 despite increased ventilation.
These signs often precede marked hyperthermia and should trigger immediate MH evaluation.

INSIGHT

RYR1 Defect Explains the Whole Cascade

MH results from defective RYR1 causing uncontrolled calcium release from the sarcoplasmic reticulum and sustained muscle contraction.
The hypermetabolic state raises CO2 and heat while consuming ATP, producing lactic acidosis and risking rhabdomyolysis and organ injury.

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Welcome to PICU Doc On Call, A Podcast Dedicated to Current and Aspiring Intensivists.

Hosts:
Dr. Pradip Kamat: Children’s Healthcare of Atlanta/Emory University School of Medicine
Dr. Rahul Damania: Cleveland Clinic Children’s Hospital

Introduction:

Pediatric Intensive Care Unit (PICU) physicians passionate about medical education in the acute care pediatric setting
Episode focus: A case of a 23-month-old ex-28 week premie presenting with sudden high fever and rapidly rising ETCO2 during surgery

Case Presentation:

Presented by Dr. Rahul Damania
23-month-old ex-28 week premie intubated during hernia repair surgery
Noticed rapidly rising ETCO2, unprovoked tachycardia, and elevated temperature
Transferred to PICU, exhibiting rigidity, clenched jaw, metabolic acidosis, and elevated lactate.
Consideration of Malignant Hyperthermia (MH) crisis

Key Points:

Elevated temperature, hypercapnia, metabolic acidosis, and unprovoked tachycardia raise concern for MH
Organized discussion on pathophysiology, clinical signs, symptoms, and management

Multiple Choice Question:

Diagnosis of MH crisis during scoliosis repair
Correct Answer: D) Sarcoplasmic reticulum
Dantrolene acts on the sarcoplasmic reticulum to inhibit calcium release, crucial in MH management

Clinical Presentation of MH Crisis:

Tachycardia, acidosis, muscle stiffness, and hyperthermia are hallmark features
Potential life-threatening complications underscore the urgency of recognition and treatment

Triggers and Pathophysiology of MH Crisis:

Triggered by inhalational agents and depolarizing neuromuscular blocking agents
Pathophysiology involves defective Ryanodine receptor leading to uncontrolled calcium release

Differential Diagnosis:

Includes sepsis, thyroid storm, pheochromocytoma, and neuroleptic malignant syndrome
Differentiation from similar conditions crucial for accurate management

Diagnostic Approach:

High clinical suspicion
Genetic testing (ryanodine receptor gene sequencing) and Caffeine Halothane Contracture Test (CHCT) for diagnosis
Immediate workup during crisis includes blood gas, lactate, CPK, CMP, and urine analysis

General Management Framework:

MH crisis is a medical emergency requiring rapid intervention
Dantrolene Na administration, supportive measures, and continuous monitoring in PICU
Utilization of Malignant Hyperthermia carts and involvement of specialized hotlines

Clinical Pearls and Pitfalls:

Early recognition is crucial.
Proper administration of Dantrolene Na without delay
Extended monitoring period in PICU to ensure stability

Conclusion:

Importance of recognizing and managing MH crisis
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Website picudoconcall.org for additional resources

References:

Fuhrman & Zimmerman - Textbook of Pediatric Critical Care Chapter
Malignant Hyperthermia Association of the United States
What is MH?
[Managing a crisis](https://www.mhaus.org/ healthcare-professionals/managing-a-crisis/)
Rosenbaum HK, Rosenberg H. UpToDate: Malignant hyperthermia: diagnosis and management of acute crisis.