Polymyalgia rheumatica and its links with giant cell arteritis.

Polymyalgia rheumatica (PMR) was defined in 1957 and is linked with giant cell arteritis (GCA) in approximately 25% of cases. The peak incidence is between 60 and 75 years old and is increasing with the ageing population. Polymyalgia rheumatica is a clinical diagnosis without a 'gold standard' serological or histological test and there are other conditions that may mimic PMR. Treatment with a dose of 10-20 mg daily of prednisolone is suggested or 40-60 mg daily if GCA is also suspected. There are no absolute guidelines to the dose or its duration. The rate of reduction should be adjusted depending on the individual's response. Where temporal arteritis is suspected, this manifestation of GCA is a treatable medical emergency to prevent possible blindness, and steroids should be commenced immediately. There remain many unknowns in the cause, diagnosis and treatment of PMR and its overlap with GCA, and it is an ongoing challenge requiring further research.