Compressive optic neuropathy (CON) in Graves' disease caused by hypertrophy of levator and superior rectus muscles: A case report

Dysthyroid Optic Neuropathy

PURPOSE

Dysthyroid optic neuropathy (DON) is a sight-threatening complication of thyroid eye disease (TED). This review provides an overview of the epidemiology, pathogenesis, diagnosis, and current therapeutic options for DON.

METHODS

A literature review.

RESULTS

DON occurs in about 5% to 8% of TED patients. Compression of the optic nerve at the apex is the most widely accepted pathogenic mechanism. Excessive stretching of the nerve might play a role in a minority of cases. Increasing age, male gender, smoking, and diabetes mellitus have been identified as risk factors. Diagnosis of DON is based on a combination of ≥2 clinical findings, including decreased visual acuity, decreased color vision, relative afferent pupillary defect, visual field defects, or optic disc edema. Orbital imaging supports the diagnosis by confirming apical crowding or optic nerve stretching. DON should be promptly treated with high-dose intravenous glucocorticoids. Decompression surgery should be performed, but the response is incomplete. Radiotherapy might play a role in the prevention of DON development and may delay or avoid the need for surgery. The advent of new biologic-targeted agents provides an exciting new array of therapeutic options, though more research is needed to clarify the role of these medications in the management of DON.

CONCLUSIONS

Even with appropriate management, DON can result in irreversible loss of visual function. Prompt diagnosis and management are pivotal and require a multidisciplinary approach. Methylprednisolone infusions still represent first-line therapy, and surgical decompression is performed in cases of treatment failure. Biologics may play a role in the future.

Atypical Asymmetric Presentation of Severe Graves' Orbitopathy

Graves' disease is a self-limiting autoimmune thyroid disorder caused by stimulating antibodies to the thyroid-stimulating hormone receptor. It usually affects middle-aged females in the fourth to sixth decade of life. It is distinguished by keratopathy, chemosis, proptosis, and eyelid swelling, in addition to ocular discomfort. A total of 3-5% of cases present with a severe form of Graves' orbitopathy, which manifests with diminution of vision, optic nerve compression, optic neuropathy, and exposure keratopathy. We describe a case of a 34-year-old female patient who presented with the chief complaint of rapid deterioration of vision over a period of three months in the right eye. Ocular examination revealed proptosis, widened palpebral aperture, elevation of intra-ocular pressure (IOP) in the upgaze, restricted eye movements, and signs of optic nerve compression. Findings were confirmed on a CT scan of the orbit. The unusual presentation in this case was that she had rapid, significant deterioration of vision in the right eye, with a progression of proptosis more marked in the contralateral eye. This underlies the importance of thoroughly examining for any possible orbital apex syndrome in both eyes, not just the eye with marked proptosis. The patient, being reluctant for orbital decompression, was prescribed IV methylprednisolone 1 g for three consecutive days, which reduced her proptosis and improved her vision. This acted as a temporary measure to increase the duration of the surgical window until the time the patient undergoes the surgery.