Faculty Bibliography

PURPOSE: To determine the utility of CT imaging in identifying patients with dysthyroid optic neuropathy. METHODS: Orbital CT scans of 12 randomly selected patients with dysthyroid optic neuropathy and 15 control subjects with Graves orbitopathy were retrospectively reviewed by two investigators blinded to the clinical data. The clinical diagnosis of optic neuropathy was made by one author before obtaining CT images and was based on clinical features. RESULTS: Optic nerve crowding (P<0.001) and intracranial fat prolapse (P<0.05) were the imaging features independently related to optic neuropathy. A muscle index greater than 50% had excellent sensitivity (100%) but did not have high specificity (47%) for dysthyroid optic neuropathy. Superior ophthalmic vein dilation and proptosis did not show significant relations with optic neuropathy. CONCLUSIONS: This study suggests that patients with Graves orbitopathy who have severe optic nerve crowding, intracranial fat prolapse, and/or muscle index greater than 50% present on orbital CT scans are more likely to have coexisting optic neuropathy

BACKGROUND: Orbital signs and symptoms occur in approximately one half of children with Graves disease, but the symptoms are usually minor and limited to the eyelids. Prominent proptosis is uncommon in children with this disorder. METHODS: Review of eight children with prominent proptosis associated with thyroid eye disease. Four patients were treated at the Children's Hospital of Philadelphia, the other four at the Columbia Presbyterian Medical Center. RESULTS: At initial presentation, children ranged in age from 3 to 16 years. There were five girls and three boys. Seven of eight children had hyperthyroidism at ophthalmic presentation. Four patients had restrictive myopathy, and all of the seven patients who underwent neuroimaging had extraocular muscle enlargement. Five patients were treated with lubrication. Two underwent orbital fat decompression. One patient had thyroid eye disease and myasthenia gravis. CONCLUSIONS: Proptosis in childhood thyroid eye disease usually is associated with a hyperthyroid state. The proptosis may be dramatic, but corneal exposure and restrictive myopathy are seen in only some of the patients. Neuroimaging shows enlarged extraocular muscles. Most children with this complication can be treated conservatively with topical lubrication, but orbital fat decompression may be considered in patients with more advanced conditions.