Summary
Definition
History and exam
Key diagnostic factors
- presence of risk factors
- 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 anaesthetic and/or succinylcholine (suxamethonium)
- susceptibility to MH
- previous MH episode
- positive family history
- exertional heat illness
Diagnostic investigations
1st investigations to order
- discontinuation of inhalation anaesthetic
- 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
Investigations to consider
- caffeine halothane contracture test (CHCT)
- in vitro contracture test (IVCT)
- genetic testing
- screen for muscle enzyme deficiencies
Treatment algorithm
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 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.
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