[Horner's syndrome after tonsillectomy].

CASE REPORT: A 5-year-old girl underwent a tonsillectomy and developed a right Horner's syndrome after the procedure: we present the clinical findings and the investigations performed.

DISCUSSION: Horner's syndrome is caused by a decrease in sympathetic innervation to the eye, and the defining signs are ptosis and miosis. The reported incidence of Horner's syndrome following tonsillectomy is low, although it is one of the commonest operative procedures performed.