A 40-year-old woman was referred to our clinic in May, 1993 because of diplopia and pain of the right eye. She was euthyroid and showed no symptoms suggestive of hyperthyroidism. Thereafter, she was treated with prednisolone (5-10 mg per day) until July 1993.
Physical examination revealed that her height was 172 cm and weight was 60 kg. Her blood pressure was 110/60 mmHg, and pulse rate 72/min. with regular rhythm. Graefe's sign and lid retraction were observed at the right eye. Right hypotropia at primary position and disturbance of right eyeball movement at upper lateral view were observed. The proptosis was 21 mm for the left eye and 23 mm for the right, with a base line of 104 mm measured with a Hertel's ophthalmometer (normal, less than 18 mm). The thyroid gland was not palpable. No abnormality of the heart, chest or abdomen was detected, and the deep tendon reflexes were normal.
Swelling of both the right lateral and right inferior rectus muscles were detected by magnetic resonance imaging (MRI) (Fig.1). Laboratory studies revealed mild hypercholesterolemia but no abnormality of urinalysis results (data not shown). Thyroid function studies revealed euthyroidism (Table 1). The serum TSH concentration was normal, and anti-thyroid auto-antibodies (McAb, TgAb, and TBII) were all negative. TBII was measured by a commercial kit of radio-receptor assay from Cardiff, UK (TRAb 'Cosmic', Cosmic Co., Tokyo, Japan). Her thyroid uptake of 123I was suppressed after 7-day treatment with 75 microgram of T3 per day. The only positive laboratory test related to the thyroid was TSAb (508%; normal range less than 140%) in serum. Thus, her illness was diagnosed as euthyroid Graves' disease.
To improve the limitation of eye movement, we applied external radiotherapy and intend to perform surgical recession of the extraocular muscle.