Unilateral ophthalmopathy in a patient with Hashimoto's thyroiditis

Severe thyroid-associated orbitopathy in Hashimoto's thyroiditis. Report of 2 cases

Thyroid-associated orbitopathy (TAO) is characterized by immune-mediated inflammation of the extraocular muscles surrounding orbital connective tissue and adipose tissue. Severe orbitopathy related to autoimmune thyroid disease often occurs in patients with Grave's disease, but it is rare in patients with Hashimoto's thyroiditis. The pathogenesis of TAO is unclear. Several studies have noted a strong correlation between the levels of antibodies to thyrotropin receptor antibody (TRAb) and TAO in Graves' disease. Mild upper eyelid retraction has been reported to be common in Hashimoto's thyroiditis patients, however severe orbitopathy is rare. We report two cases of severe TAO in patients with Hashimoto's thyroiditis who required systemic glucocorticoid therapy and orbital irradiation to treat the TAO. The activity of the TAO was high in both patients, because their clinical activity scores (CAS) for the orbitopathy were high, and magnetic resonance imaging (MRI) showed enlargement of the extraocular muscles and an increase in T2 signal intensity and prolonged T2 relaxation time which indicate an active stage of inflammation. We tested the presence of TRAb by three different assays and were negative in both patients. Since the eye muscle damage cannot be due to TSH receptor antibodies, other pathogenetic mechanisms may be responsible for the orbitopathy in patients with Hashimoto's thyroiditis.

Long-term multidisciplinary follow-up of unilateral thyroid-associated orbitopathy

BACKGROUND

Thyroid-Associated Orbitopathy (TAO) is an autoimmune disease characterized by orbital inflammation involving both adipose tissue and extra-ocular muscles (EOM). Whereas bilateral and possibly asymmetric orbital involvement is commonly found at radiological work-up, mono-orbital involvement is poorly documented, and ascribed to an initial and/or transient stage of subsequent bilateral TAO.

METHODS

From a cohort of two hundred TAO patients, we selected retrospectively fourteen patients with initial clinical unilateral TAO. Five of them were excluded because of clinical bilateralization.

RESULTS

The sex ratio was 0.8 (4M, 5F), and mean age 44.6 years (range: 18-63). All patients were euthyroid when the initial magnetic resonance imaging (MRI) was performed. One patient was treated with Levothyroxine, because of subclinical hypothyroidism. Eight patients (six smokers) suffered from Graves' disease, of 1-4 years duration, for which they were treated with antithyroid drugs. A thyroidectomy was performed in two patients. None of the patients ever received radioiodine. Six patients remained euthyroid after stopping of the antithyroid regimen, and two became hypothyroid. Seven patients had active, and two severe TAO. Four of nine patients exhibited bilateralization of TAO on initial MRI. Clinical status ultimately improved or normalized in all. In two patients, MRI performed after 9 years demonstrated partial shrinkage of previously enlarged EOMs, together with fatty involution of involved muscles.

CONCLUSIONS

Unilateral TAO is not different and just as severe as bilateral TAO. At initial work-up MRI shows signs of bi-laterality in 45% (4/9), with mild involvement of 1 or 2 extra-ocular muscles. The radiological status of affected muscles does not normalize, even in the very long term.

Autoimmune thyroiditis and acquired demyelinating polyradiculoneuropathy

Guillain-Barrè syndrome (GBS) and Miller-Fisher syndrome (MFS) are variant forms of acquired demyelinating polyradiculoneuropathy. Their concurrence with immune disorders of the thyroid is infrequent. We report on a 7.5-year-old girl in whom a subclinical thyroiditis was concurrently detected to GBS and a 70-year-old woman with Hashimoto's thyroiditis (HT) who had recurrent MFS. Even though autoimmune thyroiditis is associated with many autoimmune disorders more often than would be expected by chance alone, its concurrence with immune disorders of the peripheral nerve is less frequently reported. The calculated coincidental concurrence of acquired demyelinating polyradiculoneuropathy (in both variants, MFS and GBS) and autoimmune thyroiditis (as in the present cases) was extremely low (0.0004%), thus suggesting common pathogenic mediators.