Graves’-like orbitopathy: do not forget IgG4-related disease

Excerpt

Graves’ orbitopathy (GO) affects about 25 % of patients with hyperthyroidism due to Graves’ disease [1], is usually mild and infrequently progressive [2, 3], although moderate-to-severe or (rare) sight-threatening forms do exist and require aggressive treatments [1]. In most cases, the onset of GO is temporally related to the onset of hyperthyroidism, but in some instances the orbital disease may precede or follow the onset of hyperthyroidism by months or years [1]. In addition, it is known that GO may less frequently develop in patients with euthyroid or hypothyroid Hashimoto’s thyroiditis [1]. The diagnosis of GO is simple and straightforward in the typical patient who, in addition to signs and symptoms of hyperthyroidism, has positive TSH-receptor antibody tests, bilateral eye symptoms (lacrimation, grittiness, photophobia, diplopia) and signs (exophthalmos, periorbital soft tissue swelling, ocular dysmotility, rarely visual defects). Diagnosis is confirmed by imaging studies showing enlarged extraocular muscles (with tendon sparing) and/or expansion of the orbital fibroadipose tissue [1]. Diagnostic problems arise particularly in those patients who are not hyperthyroid and have asymmetrical or unilateral orbital involvement. The presence of euthyroid/hypothyroid chronic autoimmune thyroiditis does not guarantee that orbital disease be related to GO; the absence of thyroid ultrasonographic and/or serological evidence of autoimmune thyroid disease makes diagnosis of GO even more uncertain. Thus, if in typical cases imaging is confirmatory, then in doubtful circumstances it is mandatory. Many conditions may cause exophthalmos and/or extraocular muscle enlargement mimicking GO. Table 1 offers a list of these conditions, for some of which etiology is uncertain. …