Role of the Underlying Thyroid Disease on the Phenotype of Graves' Orbitopathy in a Tertiary Referral Center

Approximately 35% of patients with Graves' ophthalmopathy do not respond to immunosuppressive treatment. A possible explanation for this finding is that only patients with active ophthalmopathy respond to immunosuppressive treatment, whereas patients with fibrotic end stage disease do not. To distinguish between these two groups and to predict the outcome of immunosuppressive treatment, we developed a clinical activity score (CAS) based on four of the five classical signs of inflammation and tested its efficacy in a double-blind, prospective study. The CAS was determined by an opthalmologist before, on the day of, and after the start of either oral prednisone or retrobulbar irradiation in 43 patients with moderate to severe Graves' ophthalmopathy. The therapeutic outcome was determined by a second ophthalmologist unaware of the CAS stores given. Success of treatment was defined as an improvement in NOSPECS class or grade. Responders (22) and non-responders (21) did not differ in age, sex, duration or severity of their Graves' ophthalmopathy. The pretreatment CAS, however, was significantly higher in responders than in non-responders. Twelve of 22 responders and three of 21 non-responders had a CAS > or = 4 (55% vs 14%; P or = 4 had a similar duration of Graves' ophthalmopathy as patients with a CAS < 4. The clinical activity score has a high predictive value for the outcome of immunosuppressive treatment in Graves' ophthalmopathy. Disease activity, and not disease duration, is the prime determinant of therapeutic outcome.

Graves' orbitopathy (GO), thyroid dermopathy (also called pretibial myxedema) and acropachy are the extrathyroidal manifestations of Graves' disease. They occur in 25, 1.5, and 0.3 % of Graves' patients, respectively. Thus, GO is the main and most common extrathyroidal manifestation. Dermopathy is usually present if the patient is also affected with GO. The very rare acropachy occurs only in patients who also have dermopathy. GO and dermopathy have an autoimmune origin and are probably triggered by autoimmunity to the TSH receptor and, likely, the IGF-1 receptor. Both GO and dermopathy may be mild to severe.