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AB0659 Prevalence and clinical features of cranial and extracranial giant cell arteritis

Background Giant cell arteritis (GCA) is the most common systemic vasculitis in adults. Although it typically affects the cranial branches derived from the aortic arch, there is increasing evidence of the damage occurring to large vessel extracranial arteries, which is usually misdiagnosed. This subset of large vessel extracranial GCA may have specific clinical features that could hinder the diagnosis, which highlights the need for a different treatment and follow up. Objectives To analyse the frequency and clinical and analytical features in cranial and extra-cranial GCA. Methods An observational retrospective descriptive study analysing data from patients with GCA was performed in our hospital. Colour duplex sonography (CDS) studies carried out in the last 29 months were revised. Standardised CDS images from the frontal and parietal branches of the temporal superficial artery (TA) and axillary artery (AXE) with GCA compatible image with intra or extra-cranial involvement (hypoechoic, homogeneous and circumferential thickening of the artery wall ≥0.34 mm in TA, and ≥1 mm in AXE, respectively). SPSS version 23 were used to analyse a total of 29 variables. Results Out of the 119 patients that were tested in our fast track GCA clinic, with standardised CDS of TA and AXE, 22 had GCA. All GCA patients was hallo sign in CDS. From them, 7 had large vessel involvement (31.8%), from whom 6 were mixed and 1 had exclusively extra-cranial involvement. Mean age at diagnosis was 76±9.7 SD in the extracranial GCA arteritis and 79±5.7 SD in the cranial GCA. The extracranial subset had a greater number of men than the cranial (28.6% and 26.6%, respectively) and suffered usually more fever (28.5%>6.6%, respectively), constitutional syndrome (85.7%>40%, respectively) or polymyalgia rheumatica (42.8%>40%, respectively). However, they suffered with more frequency from headache (85.7% vs 93.3%) and jaw claudication (28.5% vs 33.3%). None of them suffered from visual impairment or central nervous system involvement; both do appeared in the cranial GCA group in 13.3% and 6.6%. In the blood tests, mean ±standard deviation was: ESR 87.6±36 mm/h in cranial GCA and 89.5±19.5 SD mm/h in extracranial GCA, CRP 65±57.6 and 82.6±48.4 mg/L and Hb 11.4±1.3 and 12.1±1.3 g/dl, respectively. Patients with large vessel involvement met ACR criteria in 80% opposite 92.8% from these with solely cranial GCA. AT biopsy was performed in 7 patients in the cranial subset and 2 in the extra-cranial, testing positive for GCA in 5 (71.4%) in the first group, and none in the second one. CT-PET was performed in 2 patients with cranial GCA with negative results, and in 4 with large vessel involvement, testing positive in 50%. Despite the large differences, the statistical analysis didn’t reach statistical significance due to the small simple size. Conclusions One third of the patients in our study had large vessel involvement, making axillary vessel CDS an important tool for the clinical exam of this disease. These patients tend to be younger and start more often with fever or general syndrome and less with GCA typical symptoms like headache, jaw claudication or visual loss. Disclosure of Interest None declared