Last reviewed: February 2020
Last updated: January  2020

Summary

Definition

History and exam

Key diagnostic factors

  • exposure to potent inhalation anesthetic and/or succinylcholine
  • susceptibility to MH
  • previous MH episode
  • positive family history
  • increased minute ventilation
  • elevated core temperature
  • muscle rigidity

Other diagnostic factors

  • tachycardia
  • decreased urine output
  • excessive sweating with exercise
  • muscle cramps
  • spontaneous episodes of severe muscle stiffness

Risk factors

  • exposure to potent inhalation anesthetic and/or succinylcholine
  • susceptibility to MH
  • previous MH episode
  • positive family history
  • exertional heat illness

Diagnostic investigations

1st investigations to order

  • discontinuation of inhalation anesthetic
  • exhaled carbon dioxide, oxygen consumption (inspired-expired oxygen concentration difference)
  • venous blood gases
  • serum electrolytes
  • serum creatinine
  • therapeutic trial of intravenous dantrolene
  • creatine kinase
  • urinalysis
  • urine myoglobin
  • platelets
  • prothrombin time
More 1st investigations to order

Investigations to consider

  • caffeine halothane contracture test (CHCT)
  • in vitro contracture test (IVCT)
  • genetic testing
  • screen for muscle enzyme deficiencies
More investigations to consider

Treatment algorithm

Contributors

Assistant Professor

Department of Anesthesiology

University of Florida College of Medicine

Gainesville

FL 

Disclosures

CME volunteers for the Malignant Hyperthermia Association of the United States (MHAUS), including as a consultant for the malignant hyperthermia hotline. CME is co-author of a chapter on malignant hyperthermia in Fuhrman & Zimmerman’s Pediatric Critical Care, 6th ed., Elsevier.

Professor

Department of Anesthesiology

University of Florida College of Medicine

Gainesville

FL

Disclosures

NG is Medical Director of the North American Malignant Hyperthermia Registry. 

Christopher M Edwards and Nikolaus Gravenstein would like to gratefully acknowledge Dr Barbara W. Brandom and Dr Lena Mayes, the previous contributors to this topic.

Peer reviewersVIEW ALL

Director

Department of Medical Education and Clinical Research

Saint Barnabas Medical Center

Livingstone

NJ

Disclosures

HR declares that he has no competing interests.

Professor of Anesthesia

University of Leeds

Academic Unit of Anesthesia

St James's University Hospital

Leeds

UK

Disclosures

PH is an author of a number of references cited in this topic.

Associate Professor

Perioperative Patient Safety

Department of Biomedicine

University Hospital Basel

Basel

Switzerland

Disclosures

TG declares that he has no competing interests.

Professor and Chairman

Department of Anesthesiology

Wake Forest University School of Medicine

Winston-Salem

NC

Disclosures

JT is an author of a number of references cited in this topic.

Use of this content is subject to our disclaimer