A solitary tonsil can cause severe obstructive sleep apnea.

Hypertrophy of the tonsils and adenoids is the most common cause of pediatric obstructive sleep apnea. Bilateral tonsillectomy, most commonly performed with adenoidectomy, is the accepted treatment for obstructive sleep apnea. We report the unusual case of a child who underwent unilateral tonsillectomy and adenoidectomy at another institution and subsequently presented to us with persistent severe obstructive sleep apnea and a diagnosis of attention deficit hyperactivity disorder. The adenoids were not obstructing the choanae. The remaining tonsil was removed and the patient's sleep apnea resolved. This is the first objectively documented report of a solitary tonsil causing severe obstructive sleep apnea (using polysomnography) that resolved after removal of the remaining tonsil.