Malignant hyperthermia 5 hours into a second general anesthetic for maxillofacial trauma surgery: a case report
Background: Malignant hyperthermia (MH) is a life-threatening autosomal dominant disorder that results in a hypermetabolic syndrome in response to certain anesthetic agents. The triggering agents are typically administered during the induction of anesthesia, which is when most providers expect MH to occur. However, MH can occur at any point in time during anesthesia or even after a history of uneventful anesthetics. Although varying presentations of MH have previously been published, such as after uneventful previous anesthetics or delayed presentations, this presentation is unique as the episode of MH occurred 5 hours into a second general anesthetic with sevoflurane after an uneventful first general anesthetic. Case Description: A male in his 30s with no history of MH experienced maxillofacial trauma due to a low-energy ballistic weapon. On day 4, he was uneventfully taken to the operating room (OR) with general anesthesia for 2 hours and 35 minutes for a tracheostomy and percutaneous gastrostomy tube placement. Medications administered during the first anesthetic event included sevoflurane, rocuronium, dexmedetomidine, fentanyl, midazolam, and phenylephrine. The first surgery and postoperative course were uneventful. Succinylcholine was never used. On day 10, over 5 hours into his second general anesthetic which utilized sevoflurane, propofol, midazolam, fentanyl, remifentanil, ketamine, labetalol, phenylephrine, and dexamethasone, he experienced an episode of MH, which presented in the form of hypercarbia, tachycardia, and hyperthermia. The surgery was aborted, and he was treated with dantrolene 250 mg, calcium gluconate, insulin with glucose, albuterol, as well as intraoperative cooling. He was then transferred to the surgical intensive care unit (SICU) for continued cares. He recovered from the episode and was eventually taken back to the OR for successful treatment of his injuries. Conclusions: Although classically taught that MH occurs soon after induction, this case report shows that it can occur hours into a second general anesthetic, even after an uneventful previous exposure. MH should be considered in patients experiencing refractory hypercarbia, unexplained hyperthermia, or muscle rigidity. This case report adds to the current literature and shows the variability of MH episodes. Appreciating the variability in MH presentations is essential and can prevent a delay in diagnosis which could be life-threatening.
