Minor increase of endtidal CO2 during sevoflurane-induced malignant hyperthermia

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.

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.

Post-Operative Malignant Hyperthermia in a Child after Colon Interposition

Malignant hyperthermia (MH) is a rare and potentially life threatening fatal complication of anaesthesia. We present a 2-year-old boy with late onset MH after colon interposition to replace the oesophagus under sevoflurane anaesthesia. The patient was treated with intravenous dantrolene sodium as well as cooling and controlled ventilation. Despite treatment, the patient developed cardiopulmonary arrest at 21 hours after the operation and died. It should be kept in mind that post-operative MH may develop during these types of operations with ischaemia-reperfusion injuries.

Malignant hyperthermia, a Scandinavian update

BACKGROUND

Malignant Hyperthermia (MH) is a rare pharmacogenetic disorder, triggered by halogenated anesthetics and/or succinylcholine. In susceptible individuals, these drugs can activate an explosive life threatening clinical reaction. Leading symptoms are hypercarbia, muscle rigidity, and metabolic acidosis. MH is inherited in an autosomal-dominant manner and linked to mutations in the large ryanodine 1 gene (RYR1) gene in the majority of cases. Very few MH patients have been found to carry mutations in the CACNA1S gene.

METHODS

For this review a large litterature search was carried out and the Swedish MH database consisting of 436 probands who have undergone in vitro muscle contraction test (IVCT) during 1984-2014 was analyzed.

RESULTS

Twelve different MH causative mutations have been found in Swedish patients so far. These mutations lead to a disturbed calcium balance in striated muscle tissue. A muscle biopsy for the IVCT or finding of an approved causative mutation are required for the diagnosis.

CONCLUSION

A Malignant Hyperthermia susceptible (MHS) patient should be anesthetized with trigger-free anesthesia. There are a few reports of MH-like reactions in patients unrelated to anesthesia. The outcome is dependent on early recognizing of the reaction and fast disconnection of the trigger agents and administration of dantrolene.

Delayed onset malignant hyperthermia after sevoflurane

Malignant hyperthermia is a hypermetabolic response to inhalation agents (such as halothane, sevoflurane, and desflurane), succinylcholine, vigorous exercise, and heat. Reactions develop more frequently in males than females (2 : 1). The classical signs of malignant hyperthermia are hyperthermia, tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, muscle rigidity and rhabdomyolysis. In this case report, we present a case of delayed onset malignant hyperthermia-like reaction after the second exposure to sevoflurane.

Malignant hyperthermia resolving with discontinuation of sevoflurane alone

An otherwise healthy 13 year old developed hypercarbia and increased temperature during anesthesia with sevoflurane. Discontinuation of sevoflurane, surface cooling, and hyperventilation resulted in prompt resolution. However, hyperkalemia continued to raise the suspicion for malignant hyperthermia, which was ultimately confirmed by ryanodine receptor gene sequencing. The case underlines the importance of intraoperative monitoring of end-tidal CO2 and temperature and the potential benefits of early discontinuation of inhalational anesthetics in the presence of signs and symptoms suspicious for malignant hyperthermia. The severe hyperkalemia suggests that standard guidelines for diagnosis and treatment of malignant hyperthermia, including dantrolene treatment, should be followed whenever malignant hyperthermia is suspected.

Scientific advances in the genetic understanding and diagnosis of malignant hyperthermia

Malignant hyperthermia (MH), a potentially fatal disorder triggered by certain types of general anesthesia, has received much attention in the scientific literature. From the first case report in 1960 until the present, hundreds of studies have been conducted. The diagnosis of MH has evolved from subjective assumptions by family history and clinical diagnosis to more sophisticated laboratory testing. A genetic basis for MH was recognized in the early 1990s and, since then, complex genetic pathways have been demonstrated. The purpose of this paper is to summarize the research literature on what is known scientifically about the diagnosis and genetic basis of MH.

Suspected malignant hyperthermia during sevoflurane anesthesia

Malignant hyperthermia is a rare anesthetic-related disorder. We present a case with unusual presentation. A boy aged 3 years and 9 months who was scheduled for Hotz's operation presented normally before the operation. Anesthesia was induced by atropine, thiopental and sevoflurane. Trachea intubation was facilitated by succinylcholine. Jaw stiffness was first noted although trachea was intubated without difficulty. The following tachycardia, hypercapnia and hyperthermia led to the diagnosis of malignant hyperthermia. Symptoms were relieved dramatically after the discontinuation of sevoflurane. Molecular genetic testing identified a novel ryanodine receptor (RYR1) mutation in exon 39, which confirmed malignant hyperthermia susceptibility in this patient.