Round Table on Malignant Hyperthermia in Physically Active Populations: Meeting Proceedings

Abstract

Context: Recent case reports on malignant hyperthermia (MH)-like syndrome in physically active populations indicate potential associations among MH, exertional heat stroke (EHS), and exertional rhabdomyolysis (ER). However, an expert consensus for clinicians working with these populations is lacking.Objective: To provide current expert consensus on the (1) definition of MH; (2) history, etiology, and pathophysiology of MH; (3) epidemiology of MH; (4) association of MH with EHS and ER; (5) identification of an MH-like syndrome; (6) recommendations for acute management of an MH-like syndrome; (7) special considerations for physically active populations; and (8) future directions for research. Setting: An interassociation task force was formed by experts in athletic training, exercise science, anesthesiology, and emergency medicine. The ''Round Table on Malignant Hyperthermia in Physically Active Populations'' was convened at the University of Connecticut, Storrs, September 17-18, 2015.Conclusions: Clinicians should consider an MH-like syndrome when a diagnosis of EHS or ER cannot be fully explained by clinical signs and symptoms presented by a patient or when recurrent episodes of EHS or ER (or both) are unexplained. Further research is required to elucidate the genetic and pathophysiological links among MH, EHS, and ER.

Adaptive thermogenesis enhances the life-threatening response to heat in mice with an Ryr1 mutation

“…Exercise, fever 22 and elevated environmental temperatures with high humidity increase the risk of these MH-like episodes 11 . The heat-induced episodes, however, often occur in nonclinical settings where immediate administration of dantrolene is impractical 23 . Both anesthetic MH episodes and non-anesthetic MH-like responses to heat are highly variable with respect to probability of occurrence and disease presentation both for a single patient and among family members with the same mutation 6,19 .…”

Malignant hyperthermia in a regional facility: A case study

“…Mortality rates have decreased since the implementation of broader anaesthetic techniques, improved monitoring, increased awareness 10 and newer generation muscle relaxants that have fewer side effects than suxamethonium 8 . Mortality rates in the 1970s were almost 80 per cent; with the introduction of dantrolene these rates dropped to less than 15 per cent 19 . MH reactions do not always occur on the first exposure to anaesthetic drugs 23 .…”

“…By the 1990s a genetic connection was discovered linking calcium channels in ryanodine receptors of skeletal muscle (RYR1). Up to 70 per cent of MH vulnerable individuals carry a RYR1 mutation 19 . There are many mutations of this receptor with only 50 per cent of patients carrying known MH genes 20 .…”

Anaesthesia and neuromuscular disorders: what a neurologist needs to know

“…31 32 Patients with a history of a non-anaesthesia-related malignant hyperthermia–like illness should therefore be considered on a case-by-case basis, in order to assess the likelihood of malignant hyperthermia susceptibility and the indication for a referral for in vitro contracture test (or caffeine halothane contraction test) or genetic testing. 33 34…”