A 54-year-old male consulted a local doctor with a chief complaint of systemic convulsions and muscle stiffness and was diagnosed with Isaacs' syndrome based on positive findings for antibodies against voltage-gated potassium channels in 2009. He subsequently experienced repeated hematemesis in 2013, at which time he was taken to our hospital by ambulance. Emergent endoscopy revealed esophageal varices with spurting bleeding. The bleeding was stopped with urgent endoscopic variceal ligation. Three days later, the patient developed sudden dyspnea with stridor during inspiration under sedation with an intravenous injection of low-dose flunitrazepam prior to receiving additional treatment and was aroused with intravenous flumazenil, after which his dyspnea immediately improved. Dyspnea may be induced by muscle cramps associated with Isaacs' syndrome exacerbated by sedation. Endoscopic variceal ligation was performed safely using multiple ligation devices in an awake state following pre-medication with hydroxyzine, without sudden dyspnea. Endoscopists should be cautious of the use of sedatives in patients with diseases associated with muscle twitching or stiffness, as in the current case. In addition, it is necessary to administer endoscopic treatment in an awake state or under conscious sedation in patients with a high risk of dyspnea.
Keywords: Dyspnea; Endoscopic treatment; Isaacs' syndrome; Muscle cramps; Sedation.