State-dependent laryngomalacia.

We have observed 5 infants who demonstrate normal breathing when awake, but develop stridor while asleep. Flexible laryngoscopy in the awake state reveals either a normal larynx or redundancy of the aryepiglottic folds or arytenoid soft tissue without prolapse into the laryngeal inlet. When these children are sedated, however, the classic signs of laryngomalacia appear. Wet inspiratory stridor with concomitant supraglottic prolapse can be demonstrated by flexible videolaryngoscopy in this state. As these findings vary with level of consciousness, we have dubbed this condition "state-dependent" laryngomalacia. We believe the appearance and disappearance of classic laryngomalacia with changes in level of consciousness adds credence to the neurogenic theory of laryngomalacia.