Malignant hyperthermia (MH) is a rare medical emergency that can occur during general anesthetics (Hopkins et al 2021). The reaction has genetic basis that can help physicians associate risk factors. MH is an autosomal dominant disorder most commonly associated with a mutation in the RYR1 metabolism gene. Volatile anesthetics such as halothane, isoflurane, sevoflurane, desflurane, and enflurane can elicit a MH response (Rosenberg, MD et al). Triggering substances cause an uncontrollable release of calcium from the sarcoplasmic reticulum. This causes a large entrance of calcium into musculoskeletal structures, inducing contraction, glycogenolysis, and metabolism. The consequences of this mechanism involve the production of heat and excess lactate leading to multiple organ system emergencies.
Clinical Manifestations:
The clinical manifestations involve acidosis, hypercapnia, tachycardia, hyperthermia, and severe medical disorders such as compartment syndrome, rhabdomyolysis, and even cardiac arrest (Hopkins, et al 2021). Almost all cases occur in the operating room, however recent evidence has suspected that individuals with a genetic risk can develop MH with excessive heat exposure during or without exercise.
An increased and unexpected production of carbon dioxide should lead to suspicion of MH. An end-tidal CO2 > 55 mg Hg, PaCO2 > 60 mm Hg during or shortly after general anesthesia is the most important clinical manifestation of the disorder (Hopkins, et al 2021). It is imperative that physicians take a thorough individual and family history to provide information on the genetic basis of the emergency. While MH is extremely difficult to prevent without a known genetic mutation, collaboration between anesthesiologists and nurses can assess risk factors.
Case Study: Susceptibility to Malignant Hyperthermia in an Athlete
Poussel, MD, PhD, et al described the possible association between exertional heat stroke (EHS) and malignant hyperthermia. Research has shown that EHS can manifest in high performance athletes with a known MH mutation in the RYR1 gene. A 30-year old male athlete collapsed while running. The semiprofessional rugby had no previous episodes or medical emergencies before the incident. The patient subsequently suffered from cardiac arrest and multiple organ failure but made a complete recovery. Post-recovery tests confirmed the mutation and abnormal metabolism response in the patient. The is the first description of the MH mutation in the RYR1 gene to be associated with Exertional Heat Stroke.
Reference Links:
https://www.ncbi.nlm.nih.gov/books/NBK1146/https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/10.1111/anae.15317
