Polymyalgia rheumatica and giant cell arteritis in older patients: diagnosis and pharmacological management

Abstract

Giant cell arteritis (GCA) is an inflammatory vasculopathy that involves large- and medium-sized arteries and can cause vision loss, stroke and aneurysms. GCA occurs in people aged >50 years and is more common in women. A higher incidence of the disease is observed in populations from Northern European countries. Polymyalgia rheumatica (PMR) is a periarticular inflammatory process manifesting as pain and stiffness in the neck, shoulders and pelvic girdle. PMR shares the same pattern of age and sex distribution as GCA. The pathophysiology of PMR and GCA is not completely understood, but the two conditions may be related and often occur concurrently. A delay in the diagnosis should be avoided because of the risk of vascular ischaemic complications due to GCA. The diagnosis should be considered in patients aged >50 years presenting with symptoms such as new headache, visual disturbances, jaw claudication or symptoms of PMR. GCA can also present as a systemic inflammatory syndrome with fever of unknown origin. Marked elevation of acute-phase reactants, recognizable in higher erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels, is often seen in both PMR and GCA. However, some patients can present with a normal ESR. Confirmation of the diagnosis of GCA by temporal artery biopsy is important because clinical findings and laboratory tests are not specific, and because a diagnosis of GCA commits patients to long-term treatment with corticosteroids. The role of imaging techniques for the diagnosis of GCA remains unclear, but these modalities can be helpful in assessing the extent of vascular involvement, especially when extra-cranial disease is present. In PMR, subdeltoid and subacromial bursitis can be identified by imaging techniques, especially ultrasound or MRI. The clinical manifestations of GCA and PMR respond dramatically within 12-48 hours of starting corticosteroid treatment. The initial corticosteroid dosage commonly used in GCA is oral prednisone 40-60 mg/day, and for patients with PMR a dosage of 15-20 mg/day is often sufficient. A prolonged course of treatment is necessary, and corticosteroids are gradually tapered, guided by regular clinical evaluation and ESR (and/or CRP) measurement. Methotrexate is the best studied corticosteroid-sparing agent in GCA, and may be useful for patients with frequent disease relapses and/or corticosteroid-related toxicity. Retrospective studies favour aspirin (acetylsalicylic acid) as an effective adjuvant treatment for reducing the ischaemic complications of GCA. The long-term course of corticosteroid therapy frequently exposes elderly patients with PMR/GCA to various adverse effects, which can be attenuated with appropriate prophylactic measures. Co-morbid diseases and polypharmacy can pose particular challenges in the geriatric population. In general, the life expectancy of patients with GCA does not appear to be shortened, whereas the morbidity associated with the disease and its treatment is well recognized.