Nasolacrimal obstruction secondary to I131 therapy

Purpose: To report the finding of nasolacrimal drainage system obstruction associated with I-131 therapy for thyroid carcinoma from an updated and expanded cohort. Methods: Patients with a history of epithelial derived thyroid carcinoma who had tearing were offered referral for evaluation by an oculoplastic surgeon. Patients underwent nasolacrimal probing and irrigation procedures with localization of their nasolacrimal obstruction. Therapy for the site of obstruction was instituted. Results: Clinically significant tearing was identified in 26 patients, all of whom had previously undergone I-131 therapy (n = 563). Nineteen patients were evaluated and confirmed to have nasolacrimal drainage system obstruction; 7 have yet to be formally evaluated. Areas of obstruction included nasolacrimal duct, common canaliculus, and, rarely, distal upper and lower canaliculi. Patients were treated with a variety of modalities including silicone intubation, balloon dacryoplasty, dacryocystorhinostomy, and conjunctival dacryocystorhinostomy. Conclusions: The use of I-131 for thyroid carcinoma is associated with a 3.4% incidence of documented nasolacrimal drainage obstruction and an overall 4.6% incidence of documented or suspected obstruction. The true incidence may be higher, since-I-131. treated individuals were neither systematically evaluated nor questioned about tearing. It has yet to be established if the obstructions result from local toxicity caused by the passive flow of radioactive iodine containing tears through these tissues or the active uptake and concentration of I-131 in lacrimal drainage system tissues through the sodium/iodide supporter.