Ipratropium-bromide-induced acute anisocoria

Key words: Anisocoria, Child, Ipratropium bromide, Pharmacological mydriasis

The article reports the case of a 9-year-old boy who presented with fixed dilated pupil secondary to areosol inhalation of nebulised ipratropium bromide. While a fixed dilated pupil is an alarming sign, if it is caused by inhalation of ipratropium bromide the condition will resolve, although it may take up to 24 hours. The differential diagnosis of anisocoria includes partial third nerve palsy, tonic pupil, direct trauma to the eye and pharmacological mydriasis. In some cases the diagnosis can be determined by using pilocarpine eye drops. A unilateral dilated pupil can be a worrying sign that requiries thorough investigation. This could occasionally be avoided if the benign differential diagnosis described is considered.