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Diagnosis
The diagnosis of GO is usually straightforward, especially when the typical
eye changes occur in the setting of Graves' hyperthyroidism. It must be
realized, however, that none of the eye changes is specific for GO: similiar
manifestations are encountered in a wide variety of other orbital disorders
(like pseudotumor orbitae, orbital myositis, Wegener's granulomatosis,
sarcoidosis, tumors, arteriovenous malformations). The diagnosis might
be difficult in patients with atypical presentations, like in euthyroid
GO or unilateral GO. In euthyroid GO (or "ophthalmic Graves' disease")
the finding of thyroid autoantibodies or an abnormal thyroid regulation
provides circumstantial evidence for GO. Although GO is the most common
cause of unilateral exophthalmos, it is mandatory to perform orbital imaging
in cases of unilateral eye disease to exclude other orbital disorders,
especially tumours. Using CT or MRI the typical enlargement of the belly
of the extra-ocular muscles in GO is nicely visualized. In the absence
of a gold standard or a specific immunologic test GO essentially remains
a clinical diagnosis.
It is recommended that the eye changes of GO are assessed as the following capters. |
