28-10: Thyroid Eye Disease

GENERAL CONSIDERATIONS

Thyroid eye disease (TED, Graves orbitopathy) is a syndrome of clinical and orbital imaging abnormalities caused by deposition of mucopolysaccharides and infiltration with chronic inflammatory cells of the orbital tissues, particularly the extraocular muscles. In patients with Graves disease, 20–40% have clinically apparent eye disease; about 5–10% of patients experience severe exophthalmos, with the eye being pushed forward by increased retro-orbital fat and eye muscles that have been thickened by lymphocytic infiltration. Eye involvement is frequently assymetric. The severity of eye disease is not correlated with the severity of thyrotoxicosis. In fact, about 10% of patients with thyroid eye disease have no clinical or laboratory evidence of Graves disease at presentation or on long-term follow-up, the absence of laboratory evidence requires consideration of other diagnoses.

Thyroid eye disease has an early inflammatory stage, typically lasting 18–36 months, where there is active lymphocytic infiltration into retrobulbar tissues. The active inflammatory stage then tends to evolve to a chronic, fibrotic, “burned out” stage in which treatment of the exophthalmos is medically resistant to glucocorticoid treatment. Aggravation of thyroid eye disease has occurred after ¹³¹I treatment or during therapy with thiazolidinediones (eg, pioglitazone); the presence of thyroid eye disease is a relative contraindication to ¹³¹I treatment. Cigarette smoking increases the severity of thyroid eye disease, and ethanol injection of thyroid nodules have been reported to be followed by severe disease.

CLINICAL FINDINGS

The primary clinical features of thyroid eye disease of any etiology include upper eyelid retraction (Dalrymple sign), lid lag with downward gaze (von Graefe sign), and a staring appearance (Kocher sign) (eFigure 28–7). There can be proptosis, conjunctival chemosis, episcleral inflammation, and weakness of upward gaze (Stellwag sign) (eFigure 28–8) (eFigure 28–9). Corneal drying may occur with inadequate lid closure. Eye changes may sometimes be asymmetric or unilateral. Resulting symptoms are cosmetic abnormalities and surface irritation. Patients with severe exophthalmos can experience diplopia from extraocular muscle entrapment and optic nerve compression, causing progressive loss of color vision, visual acuity, and visual fields (inferior especially).