Giant Cell Arteritis (GCA) is an inflammatory condition affecting blood vessels, particularly the arteries supplying the eyes. Early recognition and prompt treatment are crucial to prevent severe complications, including permanent vision loss.
What is Giant Cell Arteritis?
Giant Cell Arteritis is a systemic inflammatory disease primarily affecting medium to large arteries. It is also known as temporal arteritis, as it frequently targets the temporal arteries. It is an autoimmune disease where the immune system attacks healthy blood vessels, causing inflammation and narrowing.
GCA affects individuals over 50. Women are affected two to three times more frequently than men. The cause is unknown, but genetic and environmental factors may contribute to its development.
How Giant Cell Arteritis Affects the Eyes
GCA impacts vision through inflammation and narrowing of blood vessels that supply the optic nerve and retina. This reduced blood flow, known as ischemia, can damage the optic nerve. The most common cause of vision loss is arteritic anterior ischemic optic neuropathy (AAION).
AAION occurs when the short posterior ciliary arteries, which provide blood to the optic nerve head, become occluded due to inflammation. This lack of blood supply causes an ischemic injury to the optic nerve, resulting in vision impairment. Vision loss can be sudden and severe, often affecting one eye initially, but it can progress to involve the other eye within days if left untreated.
GCA can also affect the central retinal artery, leading to central retinal artery occlusion.
Recognizing the Eye Symptoms
Individuals may experience sudden, painless vision loss, which can be partial or complete and often affects one eye, though it can impact both eyes simultaneously or sequentially. Double vision (diplopia) and transient visual obscurations, also known as amaurosis fugax, which are temporary episodes of vision loss, can also occur. These visual disturbances are due to reduced blood flow to the optic nerve or eye muscles.
These ocular symptoms often accompany other general signs of GCA. A new onset headache, particularly around the temples, is a common symptom. Scalp tenderness, where brushing hair or touching the scalp causes pain, is another frequent indicator. Jaw pain that worsens with chewing, known as jaw claudication, is also a characteristic symptom.
General systemic symptoms can include fever, overwhelming fatigue, and unexplained weight loss. Some individuals may also experience stiffness and pain in the neck, shoulders, and hips, a condition called polymyalgia rheumatica, which can occur alongside GCA. If any of these symptoms, especially vision changes, are experienced, immediate medical attention is necessary to prevent permanent vision loss.
Diagnosis and Treatment
Diagnosis involves clinical evaluation, laboratory tests, and imaging studies. A physical examination may reveal tenderness or a reduced pulse in the temporal arteries. Blood tests check for inflammation, specifically elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels. While these tests indicate inflammation, they alone do not confirm GCA.
Imaging techniques such as Doppler ultrasound can show inflammation and narrowing of the temporal arteries, and magnetic resonance angiography (MRA) or positron emission tomography (PET) scans can provide detailed images of blood vessels and highlight areas of inflammation. The gold standard for confirming a GCA diagnosis is a temporal artery biopsy, where a small sample of the artery is removed and examined under a microscope for signs of inflammation and abnormally large cells. However, treatment often begins immediately based on strong suspicion, even before biopsy confirmation, to prevent irreversible vision loss.
High-dose corticosteroids, such as prednisone, are the primary and immediate treatment for GCA. These medications work by rapidly reducing inflammation in the blood vessels, which helps to prevent further vision loss and alleviate other symptoms. Patients typically begin to feel better within a few days of starting corticosteroid therapy. While corticosteroids are effective, they can have side effects with long-term use, including bone loss, high blood pressure, and cataracts. Therefore, doctors may monitor bone density and prescribe supplements like calcium and vitamin D. In some cases, other treatments like tocilizumab may be used to help reduce the reliance on corticosteroids or for long-term management. Regular follow-up with healthcare providers is necessary to manage the disease, adjust medication dosages, and monitor for potential relapses or side effects.