Role of Thrombocytosis in Diagnosis of Giant Cell Arteritis and Differentiation from Nonarteritic Anterior Ischemic Optic Neuropathy

Giant cell arteritis (GCA) can cause devastating vision loss if left undiagnosed. Traditionally, erythrocyte sedimentation rate (ESR), and more recently C-reactive protein (CRP) have been serum acute phase reactants used to make the diagnosis. Thrombocytosis, or elevated platelet count, has also been proposed as a useful hematological marker in the diagnosis of GCA.