Dwarak S, Kamarthy Prabhakar, Vishwanatha Reddy
Thyroid-associated orbitopathy (TAO) is characterized by immune-mediated inflammation of the extraocular muscles surrounding orbital connective tissue and adipose tissue. It often occurs in patients with Grave's disease, but is rare in patients with Hashimoto's thyroiditis, being reported in only 5% of the patients. We report a 33 year old lady with Type I Diabetes Mellitus, who had incidentally noticed progressive increase in prominence of her eyeballs and increased tearing for 2 years. She denied having clinical symptoms suggestive of thyroid disease in the past. There was no thyroid swelling on clinical examination. Eye examination showed bilateral proptosis with lagophthalmos. Lateral eyeball movements were restricted and other signs consistent with thyroid associated ophthalmopathy were present. MRI scan of orbit revealed generalized prominence of bilateral extraconal and retrobulbar orbital fat with bilateral resultant proptosis and bilateral enlarged extraocular muscles and features suggestive of optic neuropathy. The patient had sufficiently high TSH levels, low Free T4 levels, high thyroglobulin antibody and anti-TPO antibody titers to substantiate a diagnosis of Hashimoto’s thyroiditis. Several studies have noted a strong correlation between the levels of antibodies to Anti-TSH receptor antibodies and TAO in Graves’ disease. But patients with Hashimoto's thyroiditis can test negative for TSH-r antibodies as in our case. So other pathogenetic mechanisms may be responsible for the orbitopathy in Hashimoto’s thyroiditis. We report a case of Hashimoto's disease with TAO being the only clinical manifestation of the disease.
