A RARE CASE OF UNILATERAL TRANSIENT MYDRIASIS AFTER BOTULINUM TOXIN INJECTION FOR COSMETIC PROCEDURE

Introduction: Botulinum toxin A (BTX-A) was first used for the aesthetic purposes in 1990 to reduce wrinkles caused by facial muscle. Its effect starts 3 to 4 days after application and lasts for 4 to 6 months. All the medical doctors, from plastic surgeons to dermatologists can administer botulinum toxin A injection effectively and safely. Ophthalmologists are also performing this procedure for blepharospasm. Case Report: A 35 year old female present to emergency department with complain of sudden onset of right eye blurred vision with tingling sensation of the right side of the face. Patient has been injected with BTX-A for a cosmetic procedure about a 2 weeks ago. On presentation, her right pupil measured 9 mm and was fixed, with no direct or consensual response to light, and her left pupil was 3 mm and had a normal light response. CT brain and cranial MRI revealed no optic nerve or cerebral dysfunction. Patient was counselled that the mydriasis would not be permanent. In follow up after 10 days her mydriasis was improved. Discussion: Botulinum neurotoxins inhibit the release of acetylcholine and act primarily at the peripheral cholinergic synapses. These agents act at the neuromuscular junction in skeletal muscle, causing transient muscle paresis. Botulinum toxins could therefore cause pupil dilatation by uptake into the parasympathetic neurons at the level of the ciliary ganglion or the parasympathetic neuromuscular junctions in the sphincter pupillae of the iris. Conclusion: Before botulinum injection for cosmetic purposes or to treat blepharospasm, patients should be warned about the possibility of developing toxin-induced ptosis and mydriasis.