P-097 A RARE CASE OF THYROID-ASSOCIATED EYE DISEASE IN A PATIENT WITH HASHIMOTO’S THYROIDITIS HYPOTHYROIDISM AND NEGATIVE TRAB

Abstract Introduction Thyroid-associated eye disease (TAED) is commonly linked to the presence of thyrotropin receptor antibodies (TRAb). However, this case presents an unusual occurrence of TAED in a patient with long-standing Hashimoto’s thyroiditis, demonstrating unilateral orbital involvement despite negative TRAb antibodies. This raises questions about other contributing factors beyond TRAb presence, such as chronic hypothyroidism and poor medication adherence. Rare cases of TAED in hypothyroid patients challenge the conventional understanding of its pathogenesis. This case highlights the possibility of alternative mechanisms influencing orbital involvement. Clinical Case A 48-year-old male, Mr. H.M., with a 25-year history of Hashimoto’s thyroiditis-induced hypothyroidism, was referred by a neurologist in June 2023 for reassessment of thyroid function. He reported experiencing diplopia since early 2022. Orbital imaging—including CT scan and MRI—revealed homogenous enhancement and enlargement of the right inferior rectus muscle, as well as retrobulbar heterogeneous fat enhancement and enlargement. Initially suspected to be an orbital pseudotumor or, less likely, thyroid-associated eye disease (TAED), the patient underwent a comprehensive workup for potential pseudotumor etiologies such as IgG4-related disease, sarcoidosis, and lupus. All investigations returned negative results, leading to the exclusion of pseudotumor and confirming TAED. The patient was subsequently referred to an ophthalmologist, who diagnosed unilateral right proptosis with mild inactive orbitopathy. Conservative management was advised, including artificial lubricants, the use of sunglasses, and optimization of thyroid function through close follow-up. Two months later, the patient returned with improved thyroid function, reflected by a reduction in TSH levels to 13.6 uIU/ml. He reported better vision, though mild diplopia persisted. At the six-month follow-up, the patient demonstrated good adherence to thyroxine therapy, achieving well-controlled thyroid function with normalized TSH levels. Despite overall improvement in his general condition, mild diplopia remained. The ophthalmologist subsequently recommended surgical intervention for further management. The absence of TRAb in a patient with TAED presents an interesting anomaly. This case suggests that poor thyroid control and non-adherence to treatment may contribute to the development of orbital involvement, possibly through inflammatory pathways independent of TRAb. Further research is warranted to understand the potential mechanisms and alternative risk factors influencing TAED. Conclusion This report highlights the importance of considering TAED in hypothyroid patients, especially those with chronic disease and poor compliance. Clinicians should remain vigilant for atypical presentations and explore factors beyond TRAb when diagnosing and managing orbital complications in thyroid disorders.Figure 1:Thyroid eye disease