Sheltering insights: early recognition and diagnosis of giant cell arteritis: Exploring clinical, imaging and translational facets

Giant cell arteritis (GCA), a vasculitis of the medium to large sized blood vessels, is a medical emergency as severe complications such as irreversible blindness can occur when treatment is delayed. Early recognition and diagnosis are crucial as this leads to timely and correct treatment. Research in this thesis was performed in a fast-track clinic, where priority and efficient care is provided to patients with suspected GCA. First of all, this thesis shows that diagnostic testing is essential to confirm GCA. Delay in diagnosis is not uncommon, and diagnosis and stratification into different GCA subtypes based solely on clinical criteria can possibly result in misclassification. Ultrasound, FDG-PET/CT and MRI can be used to diagnose GCA and each imaging modality has its own limitations. Ultrasound is often rapidly available and relatively cheap and can therefore be used as a first test when GCA is suspected. When ultrasound results are not conclusive, additional testing should be performed. This thesis also shows that the use of pre-test probability tools can be used for risk stratification of GCA suspected patients, which can aid in assessing the urgency of further diagnostic work-up. In addition, easily measurable blood markers could contribute to fast diagnosis of GCA suspected patients. This thesis shows that the marker Interferon type I will not aid in diagnosis of GCA, even though a minor role in pathogenesis is not excluded. In conclusion, this thesis focusses on diverse aspects of early recognition, diagnosis and classification in patients with suspected GCA.