Endocrine Abstracts

Background: Hyperthyroidismcan be associated withorbitopathy that manifests as exophtalmos due to orbital tissue inflammation. Usually the diagnosis is straight forward when an autoimmune thyroid disorder is present, but conditions mimicking Graves orbitopathy can pose a diagnostic challenge.

Case report: We report the case of a 51 year old caucasian woman who was referred to our clinic with asymmetrical exophtalmos in november 2019. The patient stated that she first experienced the right eyeball protrusion after a difficult labour in 1999 but with no ophthalmologic examination until 2019 when she noticed a sudden decrease in the right eye visual acuity following, probably coincidental, blunt ocular trauma. Ophthalmological exam and visual field testing showed almost complete loss of vision in the right eye. She was reffered for endocrinological exam with asymmetrical exophtalmos (ocular protrusion of 24 mm in the right eye and 18 mm in the left eye), upper lid retraction, fine tremor of the hands and a history of palpitations and heat intolerance. Lab results revealed mild hyperthyroidism: TSH < 0.004 µIU/ml (0.4–4.0), FT₄ = 1.79 ng/dl (0.89–1.76), TT₃ = 123 ng/dl (72–179), the lack of thyroid autoimmunity: TPOAb < 10 IU, antithyroglobulin antibodies = 10 IU/ml (10–115), TRAb = 0.765 IU/l (0–1.75).The other blood tests were unremarkable, except an inflammatory syndrome, with a CRP of 34 mg/l (0.2–11). Thyroid ultrasound diagnosed a multinodular goiter. Magnetic resonance imaging and magnetic resonance angiography of the brain and orbital MRI were compatible with optic neuritis of the right eye and showed normal dimensions of the extraocular muscles: right eye – medial rectus = 3.6 mm, lateral rectus = 3.6 mm, superior rectus = 4 mm, inferior rectus = 4.7 mm; left eye – medial rectus = 3.2 mm, lateral rectus = 4.7 mm, superior rectus = 3.3 mm, inferior rectus = 5.3 mm. Moreover, orbital fat was in normal limits. Multidisciplinary team decided rheumatological and neurological check-up for differential diagnosis and a trial of salvage treatment with intravenous methylprednisolone 250 mg weekly for 6 weeks. Interestingly, follow-up perimetry test after 3 weeks showed significant improvement in the visual field of the right eye.

Conclusions: Diagnosis and treatment of orbitopathy in a hyperthyroid patient with no autoimmune thyroid disease proves to be an arduous process. Our patient’s visual field improved dramatically after systemic methylprednisolone administration even though she did not meet the diagnostic criteria for Graves orbitopathy. In such instances a multidisciplinary effort is required in order to identify the underlying cause and provide adequate care.