Sjogren syndrome and fibromyalgia after radioiodine therapy in cancer thyroid patients

ABSTRACT

Salivary and lacrimal gland dysfunction is relatively frequent after radioiodine therapy. An association of Sjogren's syndrome [SS] and other autoimmune rheumatic diseases as fibromyalgia syndrome [FMS] has been reported. Thyroid autoimmunity in FMS patients is higher than normal subjects. To detect the occurrence of Sjogren syndrome [SS] and any rheumatologic association in cancer thyroid patients after radioactive iodine therapy [I -131] and evaluate the salivary and lacrimal glands function. Thirty-one patients with post-surgical differentiated thyroid carcinomas with a mean age 40.13 +/- 9.82 years, were referred for I-131 therapy [mean dose 212.9 +/- 101.63 mCi] and continued the follow-up study. All patients had no symptoms or signs of SS. Thorough rheumatological examination was performed for any musculoskeletal manifestation or associated fibromyalgia syndrome [FMS]. Before and 8-12 months after I-131 therapy, salivary glands function was estimated by sequential scintigraphy, while lacrimal gland function was assessed by Schirmer's test. Antinuclear antibody [ANA], anti-Ro [SS-A], anti-La [SS-B] and rheumatoid factor [RF] were performed. All patients had a normal salivary glands scintigraphy and Schirmer's test before I-131 therapy. On follow up, primary SS occurred in 8 patients [25.81%] while a significant decrease in salivary function occurred in 18 [58.1%] patients and significantly correlated with the I-131 dose. Schirmer's test was significantly abnormal in those with SS. Serum Anti Ro and Anti La levels became significantly higher in SS patients [18.25 +/- 11.61 and 25 +/- 13.06 U/ml] compared to the others [6.57 +/- 1.8 and 7.35 +/- 1.8 U/ml], respectively, [p 0.025 and 0.006]. Fibromyalgia syndrome was present in 12 patients [38.71%] and 6 of them developed SS. Assessment and follow up of salivary and lacrimal glands function is essential in patients receiving radioiodine therapy. Abnormal level of anti-Ro and Anti-La increase the risk for SS that should be closely monitored and fibromyalgia is a common association