(BMJ)—A 19-mo boy w/ hx of asthma and recent exacerbation was brought in by his mother because of 4 episodes of an enlarged left pupil over the past wk. Meds: ipratropium metered-dose inhaler. Exam: L pupil: 8 mm, nonreactive; R pupil: 5 mm, reactive; otherwise, WNL. What is the dx?
Medication reaction
Third nerve palsy
Cluster headache
Adie's pupil
Benign intermittent mydriasis
You are correct. Further questioning revealed that the child’s mother had struggled to deliver his ipratropium inhaler, on occasions misdirecting it toward his eye. Ipratropium is an antimuscarinic that inhibits the sphincter pupillae, producing a prolonged mydriasis. Failure of pupil constriction w/ pilocarpine suggests pharmacological mydriasis. On f/u, the boy’s pupils had returned to normal, w/ no further episodes.

BMJ 2016;355:i5083