Lacrimal Drainage System Obstruction Associated to Radioactive Iodine Therapy for Thyroid Carcinoma

The radioactive radioiodine therapy (Na131I) for the treatment of differentiated thyroid carcinoma is a procedure used for ablation of remaining thyroid tissue after thyroidectomy and metastases. Although serious complications are uncommon after treatment, there are well-documented adverse reactions secondary to the involvement of the salivary glands, such as dry mouth, pain in the parotid glands and dysphagia, even after administration of low doses of radioiodine. However, ocular complications of such treatment are scarcely reported in literature. Among them the investigators can mention recurrent and chronic conjunctivitis, keratoconjunctivitis sicca and dry eye, affecting 23% of patients undergoing radioactive iodine therapy. Dysfunction of the lacrimal gland is described in recent studies, especially after high cumulative dose of the drug. Likewise, epiphora and nasolacrimal duct obstruction have been reported as complications associated with the use of radioiodine, although studies are not available to assess its true incidence through the systematic evaluation of patients. It can be seen in routine practice that these patients would normally be referred for ophthalmological examination only if a complaint, what happens in the process of OVL already installed after the use of high doses of radioiodine. With the early evaluation of these patients, the investigators focused on detecting the process of ongoing obstruction in order to study interventions that prevent its final installation.