Endocrine Abstracts

Case History with Investigations: A 65-year-old female, with no previous thyroid abnormalities, was originally referred to ENT with goitre. She was clinically and biochemically euthyroid, and following ultrasound with fine needle aspiration for right-sided nodules with benign cytology, was discharged. She was subsequently referred to Endocrinology with persistent lethargy and hair loss despite normal thyroid function. She described gritty eyes and swollen eyelids for 2 years, with mild proptosis for 5 years. She was noted to have evidence of thyroid eye disease (TED) with slight left eye exophthalmos, bilateral eyelid inflammation and mild injection of the sclera. There was no ophthalmoplegia and visual acuity was normal. TSH receptor antibody (TRAB) was positive at 2.2 IU/l. Prompt review in the Thyroid Eye Disease multi-disciplinary clinic (oxTED) confirmed mildly active and mildly severe TED (CAS 1, VISA 2). Orbital MRI confirmed bilateral thyroid eye disease. At TED 4-month clinic follow up, left exophthalmos was more pronounced, and she reported new intermittent diplopia with left ocular pain. CAS score was 4, VISA score 3, and TRAB increased to 3.6 IU/l with persistently normal thyroid profile.

Results and Treatment: She received treatment for thyroid eye disease with low dose Rituximab (100 mg) infusion and single dose iv methylprednisolone (100 mg). Symptomatic improvement was noted at 6-month review, with fall in TRAB (2.5 IU/l) as well as CAS score 1 and VISA score 1. To date, she remains biochemically euthyroid.

Discussion: Euthyroid Graves’ Disease is a challenging diagnosis, due to its atypical clinical manifestations and absence of abnormal thyroid function. Typically, thyroid ophthalmopathy is associated with thyrotoxicosis and positive thyrotropin receptor antibodies (TRAB). However, minority of patients remain euthyroid^[1], presenting with milder ophthalmopathy. The above case highlights the importance of remaining vigilant for screening for thyroid eye disease in Graves’ disease even if patients remain biochemically euthyroid. A recent systematic review reported that the global prevalence of TED in euthyroid patients 7.9% ^[1]. Whilst most of historical reports suggest mild disease, the reported case above demonstrates TED may be active and warrant immunotherapy. Although it is usual to note a dysthyroid lab profile prior to ophthalmopathy (80% of cases) or follow it within 2 years of presentation (20%) ^[2], this patient has remained biochemically euthyroid for almost 9 years from first description of symptoms. This emphasizes the importance of long-term follow-up in the management of euthyroid Graves’ patients and signposting TED symptoms.