Rare postoperative delayed malignant hyperthermia after off-pump coronary bypass surgery and brief review of literature

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.

Postoperative malignant hyperthermia confirmed by calcium-induced calcium release rate after breast cancer surgery, in which prompt recognition and immediate dantrolene administration were life-saving: a case report

Background

Malignant hyperthermia (MH) is a rare genetic disease characterized by the development of very serious symptoms, and hence prompt and appropriate treatment is required. However, postoperative MH is very rare, representing only 1.9% of cases as reported in the North American Malignant Hyperthermia Registry (NAMHR). We report a rare case of a patient who developed sudden postoperative hyperthermia after mastectomy, which was definitively diagnosed as MH by the calcium-induced calcium release rate (CICR) measurement test.

Case presentation

A 61-year-old Japanese woman with a history of stroke was hospitalized for breast cancer surgery. General anesthesia was introduced by propofol, remifentanil, and rocuronium. After intubation, anesthesia was maintained using propofol and remifentanil, and mastectomy and muscle flap reconstruction surgery was performed and completed without any major problems. After confirming her spontaneous breathing, sugammadex was administered and she was extubated. Thereafter, systemic shivering and masseter spasm appeared, and a rapid increase in body temperature (maximum: 38.9 °C) and end-tidal carbon dioxide (ETCO₂) (maximum: 59 mmHg) was noted. We suspected MH and started cooling the body surface of the axilla, cervix, and body trunk, and administered chilled potassium-free fluid and dantrolene. After her body temperature dropped and her shivering improved, dantrolene administration was ended, and finally she was taken to the intensive care unit (ICU). Body cooling was continued within the target range of 36–37 °C in the ICU. No consciousness disorder, hypotension, increased serum potassium level, metabolic acidosis, or cola-colored urine was observed during her ICU stay. Subsequently, her general condition improved and she was discharged on day 12. Muscle biopsy after discharge was performed and provided a definitive diagnosis of MH.

Conclusions

The occurrence of MH can be life-threatening, but its frequency is very low, and genetic testing and muscle biopsy are required to confirm the diagnosis. On retrospective evaluation using the malignant hyperthermia scale, the present case was almost certainly that of a patient with MH. Prompt recognition and immediate treatment with dantrolene administration and body cooling effectively reversed a potentially fatal syndrome. This was hence a valuable case of a patient with postoperative MH that led to a confirmed diagnosis by CICR.

MALIGNANT HYPERTHERMIA IN A CHILD AFTER MAGNETIC RESONANCE IMAGING: A CASE REPORT

OBJECTIVE

To report on a case of malignant hyperthermia in a child after a magnetic resonance imaging of the skull was performed using sevoflurane anesthesia.

CASE DESCRIPTION

A 3-year-old boy admitted to the pediatric intensive care unit after presenting clinical and laboratory findings consistent with unspecified viral meningoencephalitis. While the patient was sedated, a magnetic resonance imaging of the skul was performed using propofol followed by the administration of sevoflurane through a laryngeal mask in order to continue anesthesia. Approximately three hours after the start of the procedure, the patient presented persistent tachycardia, tachypnea, generalized muscular stiffness and hyperthermia. With a diagnostic hypothesis of malignant hyperthermia, dantrolene was then administered, which immediately induced muscle stiffness, tachycardia, tachypnea and reduced body temperature.

COMMENTS

Malignant hyperthermia is a rare pharmacogenetic syndrome characterized by a severe hypermetabolic reaction after the administration of halogenated inhalational anesthetics or depolarizing muscle relaxants such as succinylcholine, or both. Although it is a potentially fatal disease, the rapid administration of continued doses dantrolene has drastically reduced the morbidity and mortality of the disease.

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.