High prevalence of subclinical extraocular muscles alterations in graves’ disease patients asymptomatic for active graves’orbitopathy

F. Boi;R. Vacca;I. Zucca;A. Cuccu;M. Fossarello;S. Marini;S. Mariotti

2012-01-01

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Abstract

AIM: To evaluate the extraocular muscles involvement in Graves’ disease (GD) patients without signs of active Graves’ orbitopathy (GO). PATIENTS AND METHODS: Fifty three GD patients asymptomatic for active GO and diplopia were studied. All cases were submitted to an ophthalmic visit with 3 ocular tests: the ocular tone measurement in the look-up position, the cover test to evaluated the eyes motility and the red glass test to identify latent diplopia. Orbital ultrasound (US) was employed to measure extraocular muscles thickness (n.v. <4 mm). Thyroid function (serum FT3, FT4 and TSH) and thyroid autoantibodies (TPOAb, TGAb and anti-TSH receptor, TRAb) were also performed. At the time of the enrollment, 6/53 (11%) patients were overt hyperthyroid, 15/53 (28%) were subclinical hyperthyroid and the remaining 32/53 (61%) were euthyroid under anti-thyroid drug therapy or after thyroid definitive cure. RESULTS: Overall, 24/53 (45%) patients displayed both one or more thickened muscles at US and one or more ocular tests alterations; 16/53 (30%) shown ocular tests alterations and 8/53 (15%) displayed only US alterations. The remaining 5/53 (10%) did not display any alteration. The more frequent altered test was increased ocular tone in the look-up position (75%) followed by diplopia with red glass test (55%) and eyes motility alterations at cover test (33%). There were no significant differences between hyperthyroid and euthyroid patients in the prevalence of ocular tests alterations (15/21, 72% vs 25/32, 78%, p=0.7) and US alterations (11/21, 52% vs 21/32, 66%, p=0.3) respectively. An higher prevalence of both US and ocular tests alterations was observed in positive TRAb (33/36, 91%) vs negative TRAb (10/14, 71%, p=0.08) patients. CONCLUSIONS: This preliminary study shows an high prevalence of subclinical extraocular muscles alterations in GD patients asymptomatic for active GO which resulted unrelated to thyroid function. Other investigations are needed to confirm these results.