Study of the Association Between Sacroiliitis/Axial Spondylarthritis and Giant Cell Arteritis/ Polymyalgia Rheumatica

The purpose of the study is to recruit as many patients as possible presenting with sacroiliitis or authentic axial spondylarthritis and giant cell arteritis. The investigators will also be interested in the association of spondylarthritis and polymyalgia rheumatica given the continuum between these two pathologies. The aim is to investigate whether there is an association between giant cell arteritis and spondylarthritis or polymyalgia rheumatica and spondylarthritis.