Postoperative Malignant Hyperthermia- A Medical Emergency: A Case Report and Review of Literature

Abstract

A four-year-old female child weighing 15 kg with diagnosis of choledochal cyst was scheduled for cyst excision and Roux-en-Y Hepatico-Jejunostomy under general anaesthesia. Her preoperative routine investigations were within normal limits. Before induction of anaesthesia, her blood pressure was 100/60 mm Hg, heart rate 84 beats/min, body temperature was 36.7°C and respiratory rate was 18 breaths/minutes. Anaesthesia was induced with 20 mcg of fentanyl sevoflurane followed by 2 mg of vecuronium bromide for endotracheal intubation. No abnormal muscular signs were observed during the induction of the anaesthesia.Anaesthesia was maintained with 70% nitrous oxide, 30% oxygen, and isoflurane. After intubation, CVP triple lumen was inserted in right subclavian vein for monitoring of CVP and epidural catheter was inserted into L3-L4 epidural inter space to enable analgesia. Intraoperatively 0.125% bupivacaine 4 ml and morphine 0.5 mg was given. The patient's body temperature ranged between 36.2°C and 36.8°C during the operation. Her blood pressure and SpO 2 was normal and stable intraoperatively but heart rate was 95-120 beats/ min. Her intraoperative End Tidal Carbondioxide (ETCO 2 ) and oxygen saturation were within the normal ranges. Urine output was fair and clear. After surgery, glycopyrrolate 0.3 mg and neostigmine 0.75 mg was given to reverse the muscle relaxant and patient was extubated. At this time, shivering, tremors, muscle rigidity, excitement and other abnormal signs were not visible. The anaesthesia lasted 4 hours and the surgical time was 3 hours 30 minutes. The blood loss was 200 ml, and the total fluid infusion was 500 ml. Immediately after arrival in the postoperative ward, the patient's blood pressure was 90/52 mm Hg, heart rate was 80 beats/min and body temperature was 36.7°C. No abnormal neuromuscular signs were visible. After three hours, the patient's body temperature had increased to 37.2°C. Tachypnea was present. At this time 225 mg of paracetamol was given and surface cooling was started.Despite aggressive measures temperature and heart rate of patient kept on increasing. After eight hours of surgery patient started gasping, oxygen saturation gradually decreased so patient was intubated and put on ventilator. In the absence of dantrolene sodium, we could not administer it. We lost that patient in due course of management. Hence in view of above clinical scenario, dantrolene sodium must be included in the emergency drug list. DISCUSSIONMalignant hyperthermia is an uncommon inherited life threatening pharmacological disorder of muscle catabolism having almost 70% mortality. Diagnosis is difficult due to lack of precise defining characteristics. Known triggering agents of malignant hyperthermia are catabolism, infection, toxicity, drugs etc. Common sign and symptoms of malignant hyperthermia are tachycardia, arrhythmia, elevated systolic blood pressure, tachypnoea, muscle rigidity with elevated body temperature. The important laboratory findings are myoglobinuria, raised serum level of calcium, p...

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