Exclusion of dysthyroid eye disease as a cause of unilateral proptosis.

In many patients with unilateral proptosis dysthyroid disease can be excluded on clinical grounds. The primary purpose of the CT scan is to exclude a mass lesion but the appearances must be correlated with biochemical tests of thyroid function. Confirmation of dysthyroid disease is provided by an abnormal thyrotrophin releasing hormone (TRH) test in the great majority of patients whose proptosis is increasing or is of recent origin.