Background:
Malignant hyperthermia (MH) is a rare and potentially life-threatening condition of hypermetabolism. Delayed onset in the setting of a complex medical picture can result in a fulminant malignant hyperthermia crisis that can be more difficult to diagnose and treat.
Case report:
A 40-year-old man (BMI 33) with history of hypertension, congestive heart failure, obstructive sleep apnea, and type 2 diabetes suffered an acute intraparenchymal hemorrhage with ventricular extension. On admission, he arrived intubated, hypertensive, and hyperthermic (Tmax 38.7°C) requiring multiple doses of acetaminophen. His pCO2 on arterial blood gas was 86. The fever defervesced after 24 hours and was attributed to his intracranial hemorrhage.
On hospital day 17, he complained of stridor, chest pain, and supraglottic edema. Chest CT showed cervical and mediastinal subcutaneous emphysema. He was taken to the operating room (OR) for airway management and neck exploration. General anesthesia was induced with etomidate and rocuronium and maintained with sevoflurane for 3.5 hours without incident. He was found to have a retropharyngeal necrotizing soft tissue infection (NSTI).
Despite ongoing antibiotics for 9 subsequent days, the retropharyngeal NSTI developed into an abscess with extension along the right posterolateral mediastinum with persistent leukocytosis. He was taken to the OR for thoracotomy. General anesthesia was induced with fentanyl and sevoflurane through his tracheostomy with vecuronium as the paralytic. He remained stable for 6 hours on sevoflurane maintenance before suddenly experiencing dramatic increases in temperature (0.7-0.9°C every 15 minutes) and end tidal CO2 levels (20-30 points every 15 minutes) without tachycardia. Despite maximal efforts to treat with 51 vials (1020 mg) of IV dantrolene, external and internal cooling methods, total intravenous anesthesia with thorough flushing of the anesthesia machine, and symptomatic treatment for hyperkalemia and acidosis, the patient’s temperature reached a maximum of 41.4°C. The end tidal CO2 was so elevated it was not measurable and hyperkalemia continued to increase to 9.2 mEq/L despite ongoing treatment. Within 30 minutes the patient succumbed to death. The patient’s family declined genetic testing for malignant hyperthermia.
Discussion:
Malignant hyperthermia is rare and can be misdiagnosed in the setting of other more likely diagnoses such as septic shock and one-lung ventilation. Appropriate diagnosis and treatment can be further delayed in delayed onset malignant hyperthermia due to its a rare presentation. However, the incidence of delayed onset MH is increasing with increased use of non-halothane inhalational anesthetics. Therefore, a high degree of suspicion is necessary to promptly diagnose delayed onset fulminant malignant hyperthermia.
