From the Guidelines
The most common cause of monocular optic neuritis in a patient 65 years of age is giant cell arteritis (GCA), also known as temporal arteritis. This inflammatory condition affects medium and large arteries, particularly the branches of the carotid artery, and can cause sudden vision loss in older adults, as noted in the study by 1. Patients typically present with unilateral visual loss, headache, scalp tenderness, jaw claudication, and constitutional symptoms like fever and weight loss. Laboratory findings often include elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), which are necessary tests in patients older than 50 years to screen for inflammation, as suggested by 1.
Immediate treatment is essential to prevent permanent vision loss in the affected eye and potential involvement of the contralateral eye. High-dose corticosteroids (typically prednisone 60-100 mg daily or IV methylprednisolone 1000 mg daily for 3 days followed by oral prednisone) should be initiated immediately, even before confirming the diagnosis with temporal artery biopsy, due to the risk of vision loss and the importance of prompt treatment, as implied by the guidelines in 1 and 1. The pathophysiology involves granulomatous inflammation of the arterial wall, leading to ischemia of the optic nerve. Unlike multiple sclerosis-associated optic neuritis which affects younger patients, GCA-related optic neuritis occurs almost exclusively in patients over 50 years of age, with peak incidence in the seventh and eighth decades of life.
Key considerations in the diagnosis and management of GCA include:
- Urgent systemic corticosteroid therapy to preserve or recover vision in the affected eye and prevent involvement of the contralateral eye, as recommended by 1
- Laboratory tests, such as ESR and CRP, to screen for inflammation, as suggested by 1
- Imaging studies, such as MRI or CT, to evaluate for other potential causes of vision loss, as noted in 1
- Referral to a stroke center or rapid-access TIA clinic for further evaluation and management, as recommended by 1.
From the Research
Monocular Optic Neuritis in a 65-Year-Old Patient
- The most common cause of monocular optic neuritis in a patient 65 years of age is Giant Cell Arteritis (GCA) 2, 3, 4.
- GCA is a granulomatous disease that affects large- and medium-sized vessels, most notably the branches of the internal and external carotid arteries 2.
- Arteritic anterior ischemic optic neuropathy (AAION) is the most common ophthalmic complication of GCA and can cause sudden and irreversible loss of vision with a high risk of involvement of the second eye 5, 2.
Diagnosis of GCA
- Diagnosis of GCA is made using criteria developed by the American College of Rheumatology, which include clinical signs, positive biopsy, and elevated erythrocyte sedimentation rate 2.
- C-reactive protein and platelet counts may be elevated in GCA, and noninvasive imaging modalities such as Doppler ultrasound and magnetic resonance imaging are now being used to aid in diagnosis 2, 6, 4.
- A temporal artery biopsy is often performed to confirm the diagnosis of GCA, but a negative biopsy does not rule out the disease 5.