Prolonged muscle weakness following emergency tonsillectomy in a patient with familial periodic paralysis and infectious mononucleosis.

A thirteen-year-old girl with normokalaemic familial periodic paralysis (FPP) suffered life threatening upper airway obstruction secondary to tonsillopharyngitis resulting from infectious mononucleosis (IM). Emergency tonsillectomy was performed, but her postoperative course was complicated by persistent muscle weakness requiring a very prolonged period of artificial ventilation.