Malignant hyperthermia in maxillofacial surgery: Literature review supported by case presentation

OBJECTIVE

Malignant hyperthermia (MH) is characterized by a state of hypermetabolism after exposure to halogenated inhalational anesthetics or succinylcholine. The aims of this study were to carry out an updated review on the subject and report an illustrative case of MH in urgent maxillofacial surgery.

MATERIAL AND METHODS

A search of the PubMed/MEDLINE database using the keyword "malignant hyperthermia" was performed including articles published over the last 11 years in English, Spanish or Portuguese. Exclusion criteria were similar presentations but not associated with MH and cases not related to the use of anesthetic drugs as a trigger of the condition.

CASE REPORT

A 45-year-old man (75 kg, ASA status IE) with a negative family history for neuromuscular diseases, victim of a car accident with a facial fracture, underwent surgery under balanced general anesthesia and developed signs of MH 4 h after anesthesia induction. In our patient, the causative agent was sevoflurane and the diagnosis of MH was confirmed, subsequently, by muscle biopsy.

RESULTS/DISCUSSION

Overall, 44 cases of MH were found. According to the recent literature, MH shows a male predilection (3:1) and the mean age of patients is 32.2 ± 22.2 years. The most frequently cited causative agents were sevoflurane (30.5%), isoflurane (22.2%), and sevoflurane + succinylcholine (13.8%). The most common clinical indicators included hypercarbia (88.8%), hyperthermia (86.1%), and tachycardia (63.8%). Dantrolene was administered in 24 cases. The outcome was favorable in 31 cases (86.1%). The in vitro muscle contracture test (IVCT) was performed in only 15 patients and all of them tested positive. In our patient, the causative agent was sevoflurane and the diagnosis of MH was confirmed by muscle biopsy.

CONCLUSION

The mortality from MH is still high and an early clinical diagnosis and specific treatment with dantrolene are necessary for a favorable outcome. A complete understanding will allow better management of patients with MH. At present, the best management is to identify susceptible patients and to avoid triggering agents, combined with vigilant monitoring.

Rapid Dantrolene Administration with Body Temperature Monitoring Is Associated with Decreased Mortality in Japanese Malignant Hyperthermia Events

Purpose

Malignant hyperthermia (MH) is a rare genetic disorder but one of the most severe complications of general anesthesia. The mortality rate of MH has dropped from 70% in the 1960s to 15% because of dantrolene, the only currently accepted specific treatment for MH. In this study, we retrospectively identified the optimal dantrolene administration conditions to reduce MH mortality further.

Methods

Our database performed a retrospective analysis of patients with MH clinical grading scale (CGS) grade 5 (very likely) or 6 (almost certain) between 1995 and 2020. We examined whether dantrolene administration affected mortality and compared the clinical variables associated with improved prognosis. Furthermore, a multivariable logistic regression analysis was used to identify specific variables associated with improved prognosis.

Results

128 patients met the inclusion criteria. 115 patients were administered dantrolene; 104 survived, and 11 died. The mortality rate of patients who were not administered dantrolene was 30.8%, which was significantly higher than those of patients who were administered dantrolene (P = 0.047). Among patients administered dantrolene, the interval from the first sign of MH to the start of dantrolene administration was significantly longer in the deceased than in the survivors (100 min vs. 45.0 min, P < 0.001), and the temperature at the start of dantrolene administration was also significantly higher in the deceased (41.6°C vs. 39.1°C, P < 0.001). There was no significant difference in the rate of increase in temperature between the two, but there was a substantial difference in the maximum temperature (P < 0.001). The multivariable analysis also showed that the patient's temperature at dantrolene administration and interval from the first MH sign to dantrolene administration was significantly associated with improved prognosis.

Conclusions

Dantrolene should be given as rapidly as possible once MH has been diagnosed. Beginning treatment at a more normal body temperature can prevent critical elevations associated with a worse prognosis.

A Case Report of an Incidental Ultrasound Finding in a Suspected Malignant Hyperthermia Patient

Malignant hyperthermia (MH) is a rare but life-threatening genetic disorder of the skeletal muscles triggered by inhalation anesthetics or succinylcholine. A 49-year-old female developed symptoms of MH shortly after a lumbar surgery. Despite being insidious, MH was diagnosed based on the clinical grading scale. We incidentally discovered fine fasciculations in extremities while inserting an ultrasound-guided arterial catheter. On receiving dantrolene, her symptoms improved within 20 minutes; a subsequent ultrasound revealed no fasciculations. Although halothane contracture testing was not available, the fasciculations that resolved with dantrolene administration in a MH suspected patient opens up a new potential avenue of diagnostics.

Malignant Hyperthermia in PICU—From Diagnosis to Treatment in the Light of Up-to-Date Knowledge

Malignant Hyperthermia (MH) is a rare, hereditary, life-threatening disease triggered by volatile anesthetics and succinylcholine. Rarely, MH can occur after non-pharmacological triggers too. MH was detected more often in children and young adults, which makes this topic very important for every pediatric specialist, both anesthesiologists and intensivists. MH crisis is a life-threatening severe hypermetabolic whole-body reaction. Triggers of MH are used in pediatric intensive care unit (PICU) as well, volatile anesthetics in difficult sedation, status asthmaticus or epilepticus, and succinylcholine still sometimes in airway management. Recrudescence or delayed onset of MH crisis hours after anesthesia was previously described. MH can also be a cause of rhabdomyolysis and hyperpyrexia in the PICU. In addition, patients with neuromuscular diseases are often admitted to PICU and they might be at risk for MH. The most typical symptoms of MH are hypercapnia, tachycardia, hyperthermia, and muscle rigidity. Thinking of the MH as the possible cause of deterioration of a patient’s clinical condition is the key to early diagnosis and treatment. The sooner the correct treatment is commenced, the better patient´s outcome. This narrative review article aims to summarize current knowledge and guidelines about recognition, treatment, and further management of MH in PICU.

Pathophysiology and Treatment of Malignant Hyperthermia

Malignant hyperthermia (MH) is caused by a genetic disorder of the skeletal muscle that induces a hypermetabolic response when patients are exposed to a triggering agent such as volatile inhaled anesthetics or depolarizing neuromuscular blockers. Symptoms of MH include increased carbon dioxide production, hyperthermia, muscle rigidity, tachypnea, tachycardia, acidosis, hyperkalemia, and rhabdomyolysis. Common scenarios for triggering agents are those used are during surgery and rapid sequence intubation. Hypermetabolic symptoms have a rapid onset; hence, prompt recognition and treatment are vital to prevent morbidity and mortality. The first-line treatment agent for an MH response is dantrolene. Further treatment includes managing complications related to a hypermetabolic response such as hyperkalemia and arrhythmias. This review is focused on the recognition and treatment considerations of MH in the emergency department to optimize therapy and improve patient morbidity and mortality.

Malignant hyperthermia 2020: Guideline from the Association of Anaesthetists

Malignant hyperthermia is defined in the International Classification of Diseases as a progressive life-threatening hyperthermic reaction occurring during general anaesthesia. Malignant hyperthermia has an underlying genetic basis, and genetically susceptible individuals are at risk of developing malignant hyperthermia if they are exposed to any of the potent inhalational anaesthetics or suxamethonium. It can also be described as a malignant hypermetabolic syndrome. There are no specific clinical features of malignant hyperthermia and the condition may prove fatal unless it is recognised in its early stages and treatment is promptly and aggressively implemented. The Association of Anaesthetists has previously produced crisis management guidelines intended to be displayed in all anaesthetic rooms as an aide memoire should a malignant hyperthermia reaction occur. The last iteration was produced in 2011 and since then there have been some developments requiring an update. In these guidelines we will provide background information that has been used in updating the crisis management recommendations but will also provide more detailed guidance on the clinical diagnosis of malignant hyperthermia. The scope of these guidelines is extended to include practical guidance for anaesthetists dealing with a case of suspected malignant hyperthermia once the acute reaction has been reversed. This includes information on care and monitoring during and after the event; appropriate equipment and resuscitative measures within the operating theatre and ICU; the importance of communication and teamwork; guidance on counselling of the patient and their family; and how to make a referral of the patient for confirmation of the diagnosis. We also review which patients presenting for surgery may be at increased risk of developing malignant hyperthermia under anaesthesia and what precautions should be taken during the peri-operative management of the patients.

The current status of malignant hyperthermia

Malignant hyperthermia (MH) is a rare and life-threatening pharmacogenetic disorder triggered by volatile anesthetics, the depolarizing muscle relaxant succinylcholine, and rarely by strenuous exercise or environmental heat. The exact prevalence of MH is unknown, and it varies from 1:16 000 in Denmark to 1:100 000 in New York State. The underlying mechanism of MH is excessive calcium release from the sarcoplasmic reticulum (SR), leading to uncontrolled skeletal muscle hyper-metabolism. Genetic mutations in ryanodine receptor type 1 ( RYR1) and CACNA1S have been identified in approximately 50% to 86% and 1% of MH-susceptible (MHS) individuals, respectively. Classic clinical symptoms of MH include hypercarbia, sinus tachycardia, masseter spasm, hyperthermia, acidosis, muscle rigidity, hyperkalemia, myoglobinuria, and etc. There are two types of testing for MH: a genetic test and a contracture test. Contracture testing is still being considered as the gold standard for MH diagnosis. Dantrolene is the only available drug approved for the treatment of MH through suppressing the calcium release from SR. Since clinical symptoms of MH are highly variable, it can be difficult to establish a diagnosis of MH. Nevertheless, prompt diagnosis and treatments are crucial to avoid a fatal outcome. Therefore, it is very important for anesthesiologists to raise awareness and understand the characteristics of MH. This review summarizes epidemiology, clinical symptoms, diagnosis and treatments of MH and any new developments.

Almost-certain malignant hyperthermia during cardiopulmonary bypass: a case report and literature review

Malignant hyperthermia is a well-known but potentially lethal disorder which is triggered by volatile anesthetics and depolarizing muscle relaxants. Early diagnosis and treatment could save lives. However, during cardiac surgery, hypothermia and cardiopulmonary bypass make the diagnosis of malignant hyperthermia extremely difficult than other surgeries. We report a case of almost-certain malignant hyperthermia, according to the clinical grading scale, in a patient undergoing on-pump coronary artery bypass grafting surgery. The patient underwent difficult weaning from cardiopulmonary bypass until intra-aortic balloon pump and temporary cardiac pacemaker had been implanted. Although dantrolene and corresponding treatments were administered recently, the patient died 12 days after surgery because of acute kidney failure and cardiac arrest. Therefore, it is important for us to previously recognize some specific signs of malignant hyperthermia during cardiopulmonary bypass to avoid severe outcomes.

Evidence of Malignant Hyperthermia in Patients Administered Triggering Agents before Malignant Hyperthermia Susceptibility Identified: Missed Opportunities Prior to Diagnosis

Malignant hyperthermia (MH) is a hypermetabolic disorder of skeletal muscle triggered almost exclusively by potent inhalational agents and suxamethonium. Signs of an MH reaction are non-specific and may be confused with the presentation of other problems such as sepsis and overheating of a patient. A high index of suspicion is needed to be aware of an early presentation of MH. Nine patients are presented who showed abnormal signs with an earlier anaesthetic where the possible diagnosis of an MH reaction was missed. These patients either presented later with an MH reaction, confirmed by DNA analysis and in some cases in vitro contracture testing, or were diagnosed by the identification of a causative mutation confirming MH susceptibility. The MH clinical grading scale is helpful in determining the likelihood that clinical indicators indicate a possible MH reaction. Masseter muscle rigidity is a known sign of MH, confirmed in this report by positive in vitro contracture testing and DNA analysis. Several uncommon muscle disorders have a high association with MH, and postoperative myalgia unrelated to suxamethonium can be a sign which is associated with MH. These reports emphasise the importance of a thorough family history (as the MH status was known by the family in four patients), a high index of suspicion for MH, and documentation of the possibility of MH susceptibility in the anaesthesia record.

Sequencing of genes involved in the movement of calcium across human skeletal muscle sarcoplasmic reticulum: continuing the search for genes associated with malignant hyperthermia

The genetic basis of malignant hyperthermia (MH) is not fully characterised and likely involves more than just the currently classified mutations in the gene encoding the skeletal muscle ryanodine receptor (RYR1) and the gene encoding the α1 subunit of the dihydropyridine receptor (CACNA1S). In this paper we sequence other genes involved in calcium trafficking within skeletal muscle in patients with positive in vitro contracture tests, searching for alternative genes associated with MH. We identified four rare variants in four different genes (CACNB1, CASQ1, SERCA1 and CASQ2) encoding proteins involved in calcium handling in skeletal muscle in a cohort of 30 Australian MH susceptible probands in whom prior complete sequencing of RYR1 and CACNA1S had yielded no rare variants. These four variants have very low minor allele frequencies and while it is tempting to speculate that they have a role in MH, they remain at present variants of unknown significance. Nevertheless they provide the basis for a new set of functional studies, which may indeed identify novel players in MH.

Successful early application of extracorporeal membrane oxygenation to support cardiopulmonary resuscitation for a patient suffering from severe malignant hyperthermia and cardiac arrest: a case report

Malignant hyperthermia (MH) may lead to metabolic crisis of skeletal muscle in susceptible individuals following exposure to triggering agents such as volatile anesthetics or depolarizing muscle relaxants. MH is a rare and a potentially lethal disease, which can lead to cardiac arrest. We report a case of severe MH, in which the rapidly evolving signs of hypermetabolism eventually resulted in cardiac arrest. Despite conventional treatments following cardiopulmonary resuscitation, the patient's vital signs did not improve. Therefore, we applied extracorporeal membrane oxygenation for providing hemodynamic support.