When viewing this topic in a different language, you may notice some differences in the way the content is structured, but it still reflects the latest evidence-based guidance.

Malignant hyperthermia

Last reviewed: 2 Oct 2024
Last updated: 06 Jan 2022

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
Full details

Other diagnostic factors

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

Risk factors

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

Diagnostic tests

1st tests 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
Full details

Tests to consider

  • caffeine halothane contracture test (CHCT)
  • in vitro contracture test (IVCT)
  • genetic testing
  • screen for muscle enzyme deficiencies
Full details

Treatment algorithm

ACUTE

inhalation anesthetic-induced

exercise- or heat-induced

Contributors

Authors

Christopher M. Edwards, MD

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.

Nikolaus Gravenstein, MD

Professor

Department of Anesthesiology

University of Florida College of Medicine

Gainesville

FL

Disclosures

NG is medical adviser/consultant for LifeFlow (410 Medical) and Teleflex, and has received funding from Merck for delivering education lectures to Merck employees. NG is Medical Director of the North American Malignant Hyperthermia Registry.

Acknowledgements

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.

Disclosures

LM declares that she has no competing interests. BWB has been reimbursed by the not-for-profit sponsor of the North American MH Registry (NAMHR), the Malignant Hyperthermia Association of the United States (MHAUS) for attending meetings related to the management of the NAMHR. For the past 16 years, BWB received grants from MHAUS to maintain the NAMHR. BWB was the unpaid director of the NAMHR, until Jul 2016. BWB has given lectures and prepared educational materials for her previous employer, the Department of Anesthesiology in the University of Pittsburgh. As of 1 July, 2016, BWB retired from that employment. BWB has published papers and prepared educational materials for MHAUS, with the help of other volunteers for MHAUS. BWB sponsored LM for an award granted by the American Society of Anesthesiologists. This award allowed LM to travel to several medical centers that were active in the diagnosis of MH, as well as to the NAMHR to improve her understanding of this syndrome. This is part of BWB's mentoring of younger anesthesiologists. BWB is also an author of a number of references cited in this topic.

Peer reviewers

Henry Rosenberg, MD

Director

Department of Medical Education and Clinical Research

Saint Barnabas Medical Center

Livingstone

NJ

Disclosures

HR declares that he has no competing interests.

Philip Hopkins, MD

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.

Thierry Girard, MD

Associate Professor

Perioperative Patient Safety

Department of Biomedicine

University Hospital Basel

Basel

Switzerland

Disclosures

TG declares that he has no competing interests.

Joseph Tobin, MD, FAAP, FCCM

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.

  • Differentials

    • Non-MH rhabdomyolysis
    • Muscle disuse atrophy
    • Myotonia
    More Differentials
  • Guidelines

    • Malignant hyperthermia 2020
    • Consensus guidelines on perioperative management of malignant hyperthermia suspected or susceptible patients from the European Malignant Hyperthermia Group
    More Guidelines
  • padlock-lockedLog in or subscribe to access all of BMJ Best Practice

Use of this content is subject to our disclaimer