Background/Purpose: In parallel to the improvements in imaging, increasing data is accumulated regarding phenotypes of primary vasculitides. Giant cell arteritis (GCA) is a large vessel vasculitis encompassing cranial and extracranial arterial involvements and as well as polymyalgia rheumatica (PMR). Clinical manifestations and treatment responses may be different in the course of GCA. In this survey, we purpose to investigate the phenotypic overlap between the different vascular GCA subtypes and PMR.

Methods: We retrospectively analyzed the 55 GCA patients of the Hacettepe University Vasculitis Center (HUVAC). All clinical, laboratory, imaging and histopathological features were analyzed. The revised 2016 ACR and ACR 1990 GCA classification criteria were applied to patients diagnosed GCA according to the multidisciplinary expert group. Patients were grouped according to cranial, extracranial and PMR symptoms. Cranial GCA group comprised new headache, clinical temporal artery abnormality, visual disturbance, and jaw claudication; extracranial GCA group, limb claudication, bruits and Raynaud’s phenomenon; Polymyalgic+GCA group, bilateral shoulder/hip pain, morning stiffness and peripheral arthritis(1). Some patients had characteristics of more than one group, so the key phenotypic features of GCA were evaluated in 87 cases. Two patients were not included in any group because they did not have any symptoms according to this classification. Subgroup comparisons were done in terms of clinical features.

Results: A total of 55 GCA patients (Female/Male: 40/15) with a mean age and mean age of diagnosis patients were 73.0±9.7 and 67.7±9.2 years, respectively. Of the 43 patients (%78) met ACR 1990 classification criteria and 44 patients (%80) the revised 2016 ACR in our cohort. Temporal artery Doppler ultrasonography was applied to 36 patients and 10 (28%) of them were compatible with GCA and temporal artery biopsy was compatible in 26/36 (72%) of the patients. According to this classification 50 patients had cranial, 11 patients extracranial and 26 patients polymyagic symptoms. Of the 21 patients had characteristics features of both cranial and PMR group, 6 patients both cranial and extracranial group, and 3 patients all 3 groups. In comparison with extracranial GCA (9%) and polymyagic+GCA group (3%), cranial GCA group (40%) tends to occur more isolated. The phenotypic overlap between these groups was also illustrated in the Figure. The most common clinical signs and symptoms observed in GCA groups were shown in Table. Limb claudication (p=0.019), arterial bruits (p=0.018) and Raynaud’s phenomenon (p=0.028) were significantly higher in extracranial GCA group than other 2 groups.

Conclusion: Most of the phenotypic features were similar among GCA groups except for limb claudication, arterial bruits and Raynaud’s phenomenon in extracranial GCA group. Although there was a relationship between all groups, the cranial GCA group may exist with less clinical features.

References

1. Dejaco C, et al. Rheumatology (Oxford). 2017

Table GCA cluster ACR 2019

Figure GCA Cluster ACR 2019

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/are-there-phenotypic-overlaps-between-giant-cell-arteritis-subgroups/