Application of ultrasound in diagnosing and follow-up of endocrine orbitopathy.

Endocrine orbitopathy or ophthalmopathy is an organ-specific, genetically conditioned autoimmune disease, resulting from a thyroid disorder. It is the most common cause of unilateral and bilateral proptosis in adults. Endocrine orbitopathy occurs most frequently in women aged 30 to 50 years. Ultrasound diagnostic is of primary importance in orbital pathology because of its safety, non-invasiveness, rapid application, and no need for preparation of the patient. The A scan in endocrine orbitopathy shows the echographical widening of the peripheral orbital space, a widening of the muscle echo, and the B scan shows a high internal echo of the connective tissue septa, increased reflection of the muscle belly, and distension of the retrobulbar optic nerve sheaths, enlargement of lacrimal gland and dilatation of the superior ophthalmic vein. All ultrasound features of the endocrine orbitopathy can be explained by immunological abnormalities and histological changes in orbital adipose tissue and extraocular muscles.