Final answer:
Giant cell arteritis (GCA) is an inflammatory condition that affects arteries, mainly the temporal arteries. The criteria for diagnosing GCA include patient age, localized headache, and findings on temporal artery biopsy. Labs such as ESR and CRP levels help in the diagnosis. GCA is associated with polymyalgia rheumatica.
Step-by-step explanation:
Giant cell arteritis (GCA), also known as temporal arteritis, is an inflammatory condition that affects the large and medium-sized arteries, particularly the temporal arteries. The criteria for diagnosing GCA include the age of the patient (typically over 50 years), new-onset localized headache, and characteristic findings on temporal artery biopsy. Labs that can help in the diagnosis of GCA include elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels. GCA is also associated with polymyalgia rheumatica (PMR), which is an inflammatory disorder characterized by pain and stiffness in the shoulders and hips.