This patient has Giant Cell Arteritis(GCA) or Temporal Arteritis. GCA is an inflammatory vasculitis that affects medium and large sized arteries. Vertebral arteries, superficial temporal arteries, posterior ciliary arteries, and ophthalmic arteries are the most commonly involved arteries. It is a disease of the elderly and can result in a wide range of systemic, neurologic and ophthalmologic complications. Visual loss is the most common cause of morbidity in GCA. Early diagnosis and emergent treatment are necessary to prevent blindness.
Patients usually present with sudden, painless visual loss. In this case, the patient was experiencing intermittent loss of vision (known as amaurosis fugax). Patients may also have antecedent or simultaneous headache, jaw claudication, tenderness over superficial temporal arteries, proximal muscle and joint aches, anorexia and weight loss. Patients may present with minimal findings, may have an afferent pupillary defect and/or the optic nerve may be swollen with flame-shaped hemorrhages. As the disease progresses, optic atrophy and optic nerve cupping can occur. Patients may also have a palpable, tender, and possibly nonpulsatile temporal artery. In patients with temporal arteritis, elevated ESR, CRP and platelets are supportive of the diagnosis. Definitive diagnosis is confirmed by a temporal artery biopsy showing giant cells invading the walls of the temporal artery, indicating inflammation
Differential diagnosis for GCA includes nonarteritic ischemic optic neuropathy, inflammatory optic neuritis, compressive optic nerve tumor, impending central retinal vein occlusion, and central retinal artery occlusion.
Work-up for GCA includes a detailed history, complete ocular examination, measurement of ESR, CRP, and platelets, and a temporal artery biopsy for definitive diagnosis.
Once GCA is suspected, systemic corticosteroids should be given immediately to prevent irreversible blindness secondary to ophthalmic artery occlusion. These should be started as soon as possible and can be given before a temporal artery biopsy is done. If the patient does present with acute vision loss, IV corticosteroids can be administered. Once the vision has been down for several hours in an eye, it is unlikely that vision recovery will occur. However, steroid treatment should be given to minimize the loss of vision in the affected eye and to prevent involvement in the other eye. If temporal artery biopsy is positive for GCA and/or clinical suspicion is high for GCA, patient must be maintained on oral corticosteroids until the symptoms resolve and ESR normalizes. Treatment should last at least 6 to 12 months.