Anisocoria after scopolamine transdermal patch contamination: A case report.

Area of Science:

• Ophthalmology
• Clinical Toxicology

Background:

• Anisocoria, characterized by unequal pupil sizes, can present with various etiologies requiring a systematic diagnostic approach.
• Transdermal scopolamine patches, used for motion sickness and postoperative nausea, can cause ocular side effects including mydriasis (pupil dilation).

Observation:

• A 35-year-old woman presented with acute-onset right-sided anisocoria (pupil size 5.0 mm vs 2.0 mm) with normal visual acuity and intraocular pressure.
• Physical examination ruled out ptosis and facial anhidrosis; however, pharmacologic testing with apraclonidine and pilocarpine yielded equivocal results for Horner syndrome and oculomotor nerve palsy.
• Crucially, the patient reported recent application of a scopolamine transdermal patch.

Findings:

• The anisocoria resolved spontaneously over four days with conservative management (artificial tears and observation).
• Pharmacologic pupil testing, while initially inconclusive, aided in excluding other critical neurological and ophthalmological conditions.
• The clinical presentation and subsequent resolution strongly implicated the scopolamine patch as the cause of the unilateral mydriasis.

Implications:

• This case highlights the importance of a thorough medication history, specifically inquiring about scopolamine patch use, in patients presenting with isolated anisocoria.
• The diagnostic utility of apraclonidine and pilocarpine in differentiating causes of anisocoria is reinforced.
• Management of scopolamine-induced mydriasis is primarily supportive, with expected natural resolution.