From the Guidelines
Temporal arteritis (giant cell arteritis) and rheumatoid arthritis are distinct autoimmune conditions with limited direct association between them, and the current evidence does not support a strong link between the two conditions 1. The primary difference between the two conditions lies in the areas of the body they affect, with temporal arteritis primarily affecting medium and large arteries, especially those in the head and neck, while rheumatoid arthritis targets the synovial joints. Some key features of temporal arteritis include:
- Involvement of the supra-aortic vessels, especially the extracranial branches of the carotid artery, such as the superficial temporal artery 1
- Requirement for immediate high-dose corticosteroids (typically prednisone 40-60mg daily) to prevent vision loss 1
- Potential for large-vessel involvement, particularly the aorta and its main branches, which is known as large-vessel GCA (LV-GCA) 1 In contrast, rheumatoid arthritis management focuses on disease-modifying antirheumatic drugs (DMARDs) and has a different set of clinical features and treatment approaches. While both conditions share some common features, including increased inflammatory markers (ESR, CRP), systemic symptoms like fatigue and weight loss, and response to corticosteroid therapy, the treatment approaches differ significantly, and a careful coordination of treatment is necessary when both conditions coexist, often requiring rheumatology and ophthalmology involvement 1. Some important considerations in the management of these conditions include:
- The use of methotrexate, in combination with glucocorticoids, as a potential treatment option for patients with GCA and PMR, although the data from clinical trials has shown conflicting results 1
- The approval of tocilizumab for the treatment of GCA, which has demonstrated higher remission rates and better glucocorticoid sparing than placebo 1
- The importance of monitoring for complications from both diseases and their treatments, particularly in patients with coexisting conditions 1
From the Research
Association between Temporal Arteritis and Rheumatoid Arthritis
- Temporal arteritis and rheumatoid arthritis can coexist, as reported in a case study of a 75-year-old male patient who was diagnosed with both conditions, along with interstitial lung disease 2.
- The association between temporal arteritis and rheumatoid arthritis is also supported by a study of a 61-year-old woman with seropositive rheumatoid arthritis who developed temporal arteritis, with HLA-DR typing revealing the presence of DR3 and DR4 antigens 3.
- The pathogenesis of temporal arteritis involves the infiltration of the vessel wall by macrophages, giant cells, and T lymphocytes, with the production of several cytokines, including TNF-alpha, which plays a pivotal role in the acute phase response 4.
- Rheumatoid arthritis treatment with methotrexate, alone or in combination with other conventional synthetic DMARDs, biologic drugs, or tofacitinib, has been studied in several trials, with some treatments showing statistically significant superiority to oral methotrexate for ACR50 response and radiographic progression 5.
- A cohort study of patients with rheumatoid arthritis treated with methotrexate alone or in combination with other non-biological DMARDs under a Treat to Target (T2T) approach showed a decrease in disease activity in 80% of patients, with no differences in the level of severity between the treatment groups 6.
Key Findings
- Temporal arteritis and rheumatoid arthritis can coexist, with a possible common immunogenetic mechanism in their pathogenesis 2, 3.
- TNF-alpha plays a pivotal role in the pathogenesis of temporal arteritis, and its inhibition with biologic drugs such as adalimumab may be effective in treating refractory cases 4.
- Methotrexate-based treatments are effective in controlling disease activity in rheumatoid arthritis, with some combinations showing statistically significant superiority to oral methotrexate 5, 6.