Malignant hyperthermia as a rare complication of local lidocaine injection:A case report

BACKGROUND Malignant hyperthermia(MH)is a hypermetabolic disorder of skeletal muscles triggered by exposure to volatile anesthetics and depolarizing muscular relaxants.It manifests with clinical presentations such as tachycardia,muscle rigidity,hyperpyrexia,and rhabdomyolysis in genetically predisposed individuals with ryanodine receptor or calcium voltage-gated channel subunit alpha1 S mutations.Local anesthetics,such as lidocaine,are generally considered safe;however,complications can arise,albeit rarely.Lidocaine administration has been reported to induce hypermetabolic reactions resembling MH in susceptible individuals.The exact mechanism by which lidocaine might trigger MH is not fully understood.Although some mechanisms are postulated,further research is needed for a better understanding of this.CASE SUMMARY We present the case of MH in a 43-year-old male patient with an unknown genetic predisposition following a lidocaine injection during a dental procedure.This case serves as a reminder that while the occurrence of lidocaine-induced MH is rare,lidocaine can still trigger this life-threatening condition.Therefore,caution should be exercised when administering lidocaine to individuals who may be susceptible to MH.It is important to note that prompt intervention played a crucial role in managing the patient’s symptoms.Upon recognizing the early signs of MH,aggressive measures were initiated,including vigorous intravenous normal saline administration and lorazepam.Due to the effectiveness of these interventions,the administration of dantrolene sodium,a specific antidote for MH,was deferred.CONCLUSION This case highlighted the significance of vigilant monitoring and swift action in mitigating the detrimental effects of lidocaine-induced MH.Caution should be exercised when administering lidocaine to individuals who may be predisposed to MH.It is very important to be aware and vigilant of the signs and symptoms of MH as early recognition and treatment intervention are important to prevent serious complications to decrease mortality.

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 CACNA1 S 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.

Survey of Long-Term Sequelae in Survivors of a Malignant Hyperthermia Reaction

BACKGROUND: Malignant Hyperthermia (MH) is a potentially fatal, autosomal dominant disorder associated with administration of volatile anesthetics and/or the depolarizing paralytic succinylcholine. Symptoms include muscle rigidity, tachycardia, elevated body temperature, and metabolic acidosis, which are secondary to accelerated skeletal muscle metabolism. MH susceptibility can be a chronic condition, and some MH susceptible patients may develop symptoms subsequent to anesthetic exposure. OBJECTIVE: This is the first study examining the sequelae of an MH event after hospital discharge. METHODS: A survey was sent to patients who voluntarily registered with the North American Malignant Hyperthermia Registry, which included questions on severity of symptoms predominating prior to the MH event, one month after the MH event, and presently on a scale of 1 - 10 with a free text option to expound further. Participants were also asked about their opinions on causality between MH and these symptoms. RESULTS: Twenty-three responses were analyzed (34.8% response rate). Participants were categorized by their age at the time of the MH event and years since the event. Most (83%) stayed in the ICU between 1 - 4 days, and 39% experienced the event over 25 years ago. While 43% did not attribute any long-term symptoms to their MH event, all others believed that certain symptoms were linked, including muscle pain (90%), muscle cramps (75%), muscle weakness (100%), back/joint pain (36%) and depression/anxiety (42%). CONCLUSIONS: Our study concluded that long-lasting morbidities may be attributed to an MH event. Chronic musculoskeletal symptoms are experienced by the majority of patients who experience acute MH.

Clinical features and diagnosis for Chinese cases with malignant hyperthermia： a case cluster from 2005 to 2007

Background Malignant hyperthermia （MH）, manifesting as MH crisis during and/or after general anesthesia, is a potentially fatal disorder in response to volatile anesthetics and depolarizing muscle relaxants. Though typical features of MH episode can provide clues for clinical diagnosis, MH susceptibility is confirmed by in vitro caffeine-halothane contracture test （CHCT） in western countries. It is traditionally thought that MH has less incidence and fewer typical characteristics in Chinese population than their western counterparts because of the different genetic background. In this study, we investigated the clinical features of MH in Chinese cases and applied the clinical grading scale and CHCT for diagnosis of MH. Methods A cluster of three patients with MH, from January 2005 to December 2007, were included in the study. Common clinical presentations and the results of some lab examinations were reported in detail. The method of the clinical grading scale of diagnosis of MH was applied to estimate the qualitative likelihood of MH and predict MH susceptibility. Muscle fibers of femoral quadriceps of the patients were collected and CHCT was performed to confirm the diagnosis of MH. Results The clinical grading scales of diagnosis of the disease for these cases were all ranked grade D6, suggesting almost diagnosed ones. And the results of caffeine test were positive correspondingly, indicating that the patients should be diagnosed as MH susceptibility （MHS） according to diagnostic criteria of the North America MH group, which were already confirmed by clinical presentations and biochemical results. Conclusions These Chinese cases manifest as MH crisis. The clinical grading scale of diagnosis of MH may provide clues for clinical diagnosis. CHCT can also be used in confirming diagnosis of MH in Chinese cases though they have different genetic background from their western counterparts.

Malignant hyperthermia in severe COVID-19:2 case reports

Malignant hyperthermia is a rare but potentially fatal condition.We present 2 cases of young patients with coronavirus disease 2019(COVID-19)requiring intubation for hypoxic respiratory failure who both developed significant hyperthermia post intubation and were suspected to have malignant hyperthermia.However,the 2 patients had different responses to conservative management and dantrolene.These cases highlight the increased challenge imposed by intubation complications when managing patients with COVID-19.

A Case Series on Central Core Disease in Pregnancy

Congenital myopathies are a group of minimally progressive or non-progressive neuromuscular conditions which is present from birth. A classical type of congenital myopathy is called central core disease. This condition is often confused with muscular dystrophy. Central core disease can be associated with comorbidities which affect pregnancy and its management. In this case series, we describe two cases, who are siblings affected by the same condition but at varied levels and their management during pregnancy. We also would like to illustrate a management plan for congenital myopathy during pregnancy, for a good maternal and fetal outcome.