title: Epiphora after radioactive iodine ablation for thyroid cancer.
abstract: BACKGROUND
  Epiphora is a condition in which an overflow of tears occurs because of excessive lacrimal secretion or insufficient drainage of tears due to obstruction of the nasolacrimal system. This ophthalmic complication can be an intermediate to late sequela of radioactive iodine ((131)I) therapy in thyroid cancer patients.
  
  
  METHODS
  We present a case of a 23-year-old woman with complaints of bilateral excessive tearing 6 months after (131)I therapy for well-differentiated thyroid cancer. She was diagnosed with epiphora secondary to nasolacrimal duct obstruction (NDO) and had bilateral endoscopic dacryocystorhinostomy, which resulted in complete resolution of her symptoms.
  
  
  CONCLUSIONS
  The sodium iodide symporter, present in cells of the lacrimal drainage system, is the potential mechanism by which (131)I therapy can cause inflammation, fibrosis, and ultimate obstruction of tear outflow. Risk factors such as (131)I dose, female sex, older age, and anatomical variations may also play a role in the obstruction. However, the precise pathophysiologic mechanisms remain incompletely understood.
  
  
  CONCLUSIONS
  NDO is an under-recognized complication of (131)I therapy in thyroid cancer patients. Questions regarding eye symptoms should be an integral part of clinical follow-up in management of such patients so that effective intervention may be performed.
authors.affiliation: Endocrinology & Metabolism Section, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA.
authors.forename: Grace E Ching
authors.initials: GE
authors.lastname: Sun
authors.forename: Betul
authors.initials: B
authors.lastname: Hatipoglu
mesh_terms: D000328:Adult; D002277:Carcinoma / Q000532:radiotherapy*; D002291:Carcinoma, Papillary; D003608:Dacryocystorhinostomy; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects / Q000627:therapeutic use; D007766:Lacrimal Apparatus Diseases / Q000209:etiology* / Q000601:surgery; D007767:Lacrimal Duct Obstruction / Q000150:complications / Q000209:etiology; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000532:radiotherapy*
chemical_list: D007457:Iodine Radioisotopes