Diagnosis and management of malignant hyperthermia Pawan K Gupta 1 and Philip M Hopkins 2, * 1 Consultant Anaesthetist, Leeds Teaching Hospitals NHS Trust, Leeds, UK and Honorary Clinical Associate Professor, University of Leeds, Leeds, UK and 2 Professor of Anaesthesia, University of Leeds, Leeds, UK and Honorary Consultant Anaesthetist, Leeds Teaching Hospitals NHS Trust, Leeds, UK *To whom correspondence should be addressed. Tel: 0113 2065274; Fax: 0113 2064140; E-mail: [email protected] In this article, we will first describe the epidemiology, patho- physiology, diagnosis, and differential diagnosis of malignant hyperthermia (MH). We will then discuss the perioperative management, referral, and diagnosis of suspected MH. In order to set the scene and focus of the article it is useful to initially provide some definitions. Definitions MH is a progressive, life-threatening hyperthermic reaction occurring during general anaesthesia. A separate identity, with specific International Classification of Disease (ICD) codes, for a hyperthermic reaction occurring during general anaesthesia is required because other categories of heat illness require an assessment of cerebral function for their differential diagnosis. MH susceptibility. This describes the genetic predisposition to develop MH under anaesthesia. Epidemiology of MH The occurrence of MH in Japan, China, Australia, America, and Europe is well established. However, some communities still believe that MH does not affect their race. This is ascribed to anecdotal evi- dence, i.e. presumed genetic isolation. The UK is a cosmopolitan country with immigrants from all over the world. Data from our na- tional UK unit confirms the presence of MH susceptibility in individ- uals from Asia, 1 Europe, the Middle East, and Africa. The first patient in a family to have an MH reaction is known as the index case or proband. Audit of the probands referred to the MH unit in Leeds (1990–2010) shows that MH reactions are more common in males (62%) than females (38%). Testing is offered to all family members of probands in whom MH suscep- tibility is confirmed. Of all patients tested for MH susceptibility at Leeds up to December 2014, 4085 were males and 4040 fe- males. The incidence of a positive test result was slightly higher in males (42%) than females (37%). The male preponderance of MH probands could be incidental as a consequence of more males requiring surgery than females or it may be that the clin- ical condition has higher clinical penetrance in males who are MH susceptible than females. An MH reaction can occur at any age but the age distribution of probands is positively skewed with most reactions occurring in children or young adults. This may explain why the Key points • A previous apparently uneventful general anaes- thetic does not exclude the possibility of a malig- nant hyperthermia (MH) reaction on subsequent exposure to MH triggering drugs. • The time course of the clinical presentation of MH under anaesthesia is highly variable: hyper- metabolic features may recur up to 14 h after ini- tial resolution. • Early diagnosis is the key to successful manage- ment of an MH crisis. • Activated charcoal filters are an efficient way to reduce the concentration of volatile agents in inspired gases during an MH reaction. • Genetic testing alone cannot currently exclude susceptibility to MH. Editorial decision: December 8, 2016; Accepted: January 1, 2017 V C The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: [email protected] 249 BJA Education, 17 (7): 249–254 (2017) doi: 10.1093/bjaed/mkw079 Advance Access Publication Date: 24 April 2017 Matrix reference 1A01, 2A06, 3I00
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