Elizabeth Hazel, MD, FRCPC, PGY6 Rheumatology, McGill University Health Centre, Montreal, QC.
Michael Starr, MD, FRCPC, Director, Rheumatology Program; Assistant Professor, Department of Medicine, McGill University, Montreal, QC.

Giant cell arteritis (GCA) is the most common form of vasculitis in the older adult population. There are variable clinical presentations of this entity and no perfect diagnostic test, often making the diagnosis challenging. Prompt initiation of corticosteroids may prevent visual loss in affected individuals. Temporal artery biopsy remains the gold standard for diagnosing GCA. Patients require an individualized steroid tapering schedule to minimize side effects. Physicians caring for these patients should be aware of the potential for long-term vascular complications of GCA.
Key words: giant cell arteritis, temporal arteritis, vasculitis, ESR, corticosteroids.

D'Arcy Little, MD, CCFP
Director of Medical Education,
York Community Services,
Toronto, ON.

Introduction and Historical Background
Although first described in 1888 as "senile rheumatic gout," it wasn't until the 1950s when more cases were described in the literature that Barber coined the term "Polymyalgia rheumatica" to describe a syndrome of myalgias, stiffness of the shoulder and pelvic girdle muscles, and concomitant constitutional symptoms. A case of Temporal arteritis was first described by Thomas Hutchinson in 1890 when an 80-year-old man presented with a painful, inflamed temporal artery. In 1932, Horton first described the typical histological features of temporal artery from biopsies in patients with this condition, and the term "Giant cell arteritis" was first used.^1,2,3

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are closely related conditions that are almost always seen in patients over the age of 50 years. These conditions are relatively common and may represent a continuum of disease.^3,4 The following review will provide a framework for consideration of these diagnoses, as well as a review of their treatments.

Epidemiology
Once considered uncommon, PMR and GCA are among the most common, chronic inflammatory illnesses affecting the elderly, primarily as a result of raised awareness of the conditions.⁴ PMR has an incidence in North America of 52.