[A case of an unexpected difficult nasal intubation, caused by hypertrophied lingual tonsil].

We experienced a case of unexpected difficult nasal intubation due to lingual tonsil hyperplasia. A 43-year-old man was scheduled for pharyngoplasty because of sleep apnea syndrome. After induction of general anesthesia, Macintosh laryngoscopy failed to expose his glottis by two experienced anesthesiologists. We also found that the view of his larynx by fiberoptic bronchoscope (FOB) was poor, and nasal intubation guided by FOB was difficult. Finally, we made an oral intubation with Macintosh laryngoscopy under a gum elastic bougie guide. Ventilation and oxygenation were maintained throughout the procedure. A FOB guided intubation under general anesthesia is often difficult, because identification of glottis is interfered by deviated pharyngeal tissue and epiglottis, which are affected by the use of muscle relaxants. At present, a selective relaxant binding agent, sugammadex, is available in anesthesia, to reverse the effect of non-depolarizing muscle relaxant and to restore spontaneous breathing in this situation.