Endocrine Abstracts

Thyroid eye disease usually occurs in patients with graves'hyperthyroidism although 5-10% of patients are euthyroid or are hypothyroid with positve TSH receptor binding antibodies. We describe a patient with primary hypothyroidism for 14 years prior to the onset of severe thyroid eye disease.

A 61 year old lady with thyroid opthalmopathy was seen in the eye clinic.Previous history included diet controlled diabetes and primary hypothyroidism, adequately replaced with 75 microgrammes of thyroxine.Visual acuity was 6/6 in both eyes with restricted ocular motility.CT scan of the orbits showed thickening of the extraocular muscles with bilateral optic nerve encroachment.

A month later her vision had deteriorated and she was seen urgently in the diabetes clinic.She had conjunctival chemosis with opthalmoplegia. Visual acuity was 6/9 on the right,counting fingers on the left. Mouritz grading gave her a 'A' score of 8/10, 'B' score of 4 She was euthyroid with no goitre or dermopathy. Thyroid function test was normal with negative TSH receptor antibodies. She was given prednisolone and transferred to the regional eye unit. After an unsuccessful trial on intravenous methylprednisolone, she underwent left orbital decompression. She was subsequently treated with prednisolone and azathioprine for three months. Visual acuity returned to normal.

Primary hypothyroidism may be associated with severe opthalmopathy.The Mouritz classification can be used to assess severity of opthalmopathy and guide treatment. 'A' score records symptoms of disease activity ,'B' score indicates threat to vision. A 'B' score of 2 or more as in our patient should be treated promptly with medical and or surgical decompression.