Classification of inflammatory arthritis

Abstract

In their hypothesis, Dennis McGonagle and colleagues (Oct 3, p 1137)1McGonagle D Gibbon W Emery P Classification of inflammatory arthritis by enthesitis.Lancet. 1998; 352: 1137-1140Summary Full Text Full Text PDF PubMed Scopus (391) Google Scholar report that with magnetic resonance imaging (MRI), the first abnormality to appear in early knee spondyloarthropathy synovitis, but not knee rheumatoid arthritis, is an enthesitis. They postulate that the synovitis of spondyloarthropathy is secondary to liberation of proinflammatory mediators from the enthesis, whereas the synovitis of rheumatoid arthritis is primary. They suggest classification of the arthritis as primary synovial (rheumatoid like) or entheseal (spondyloarthropathy like). However, the patients with polymyalgia rheumatica and remitting seronegative arthritis with pitting oedema (RS3PE) were not clearly classified.In a case-control study with shoulder MRI, we showed that subacromial and subdeltoid bursitis was the predominant lesion that occurred in all 13 patients with active polymyalgia rheumatica.2Salvarani C Cantini F Olivieri I et al.Proximal bursitis in active polymyalgia rheumatica.Ann Intern Med. 1997; 127: 27-31Crossref PubMed Scopus (137) Google Scholar In patients with early elderly-onset rheumatoid arthritis (controls) with clinical evidence of shoulder involvement this lesion occurred in only two (22%) patients (p<0·001). The frequency of joint synovitis and biceps tenosynovitis did not differ significantly between the two groups (54% vs 33% and 77% vs 55% respectively).2Salvarani C Cantini F Olivieri I et al.Proximal bursitis in active polymyalgia rheumatica.Ann Intern Med. 1997; 127: 27-31Crossref PubMed Scopus (137) Google ScholarInflammatory involvement of distal articular, tenosynovial structures, or both occurs in about half of the cases of polymalgia rheumatica.3Salvarani C Cantini F Macchioni L et al.Distal musculoskeletal manifestations in polymyalgia rheumatica: a prospective followup study.Arthritis Rheum. 1998; 41: 1221-1226Crossref PubMed Scopus (86) Google Scholar A non-erosive, self-limiting, and usually asymmetric arthritis has been reported in about a third of patients. We previously reported an acute carpal tunnel syndrome, and swelling of the distal extremity with pitting oedema in 14% and 12% of patients with polymyalgia rheumatica, respectively.3Salvarani C Cantini F Macchioni L et al.Distal musculoskeletal manifestations in polymyalgia rheumatica: a prospective followup study.Arthritis Rheum. 1998; 41: 1221-1226Crossref PubMed Scopus (86) Google Scholar Similar swelling and oedema also occurs in patients with RS3PE syndrome. The distribution of oedema is mostly along the course of tenosynovial structures, and hand and foot MRI showed predominant distal tenosynovial involvement. In a 5-year prospective follow-up study, we compared 177 patients with polymyalgia rheumatica with 23 patients with pure RS3PE syndrome.4Cantini F Salvarani C Olivieri I et al.Remitting seronegative symmetrical synovitis with pitting edema syndrome: prospective follow-up and magnetic resonance imaging study.Arthritis Rheum. 1998; 41: S118Google Scholar In both clinical groups, the disease frequency increased significantly with age, and was most common in patients aged 70-79 years. Clinical symptoms responded promptly to corticosteroids and no patient developed radiological evidence of erosions or deformities during the follow-up. Furthermore, we found distal pitting oedema manifestations in 13 (10%) of 128 patients with giant-cell arteritis identified over 42 years.5Salvarani C Gabriel SE Hunder GG Musculoskeletal manifestations in giant cell arteritis.Arthritis Rheum. 1998; 41: S119Crossref Scopus (131) Google Scholar These data suggest that these two conditions may be part of the clinical spectrum of the same disease and that the diagnostic labels of polymalgia and RS3PE syndrome may not indicate a real difference.In MRI studies, extra-articular synovial structures are the main site of lesions in polymyalgia rheumatica and RS3PE syndrome. Joint synovitis could be secondary to liberation of proinflammatory mediators of extrasynovial membranes. We suggest a third type of inflammatory arthritis should be classified as primary extra-articular synovial (polymyalgia like) which is common among older people. In their hypothesis, Dennis McGonagle and colleagues (Oct 3, p 1137)1McGonagle D Gibbon W Emery P Classification of inflammatory arthritis by enthesitis.Lancet. 1998; 352: 1137-1140Summary Full Text Full Text PDF PubMed Scopus (391) Google Scholar report that with magnetic resonance imaging (MRI), the first abnormality to appear in early knee spondyloarthropathy synovitis, but not knee rheumatoid arthritis, is an enthesitis. They postulate that the synovitis of spondyloarthropathy is secondary to liberation of proinflammatory mediators from the enthesis, whereas the synovitis of rheumatoid arthritis is primary. They suggest classification of the arthritis as primary synovial (rheumatoid like) or entheseal (spondyloarthropathy like). However, the patients with polymyalgia rheumatica and remitting seronegative arthritis with pitting oedema (RS3PE) were not clearly classified. In a case-control study with shoulder MRI, we showed that subacromial and subdeltoid bursitis was the predominant lesion that occurred in all 13 patients with active polymyalgia rheumatica.2Salvarani C Cantini F Olivieri I et al.Proximal bursitis in active polymyalgia rheumatica.Ann Intern Med. 1997; 127: 27-31Crossref PubMed Scopus (137) Google Scholar In patients with early elderly-onset rheumatoid arthritis (controls) with clinical evidence of shoulder involvement this lesion occurred in only two (22%) patients (p<0·001). The frequency of joint synovitis and biceps tenosynovitis did not differ significantly between the two groups (54% vs 33% and 77% vs 55% respectively).2Salvarani C Cantini F Olivieri I et al.Proximal bursitis in active polymyalgia rheumatica.Ann Intern Med. 1997; 127: 27-31Crossref PubMed Scopus (137) Google Scholar Inflammatory involvement of distal articular, tenosynovial structures, or both occurs in about half of the cases of polymalgia rheumatica.3Salvarani C Cantini F Macchioni L et al.Distal musculoskeletal manifestations in polymyalgia rheumatica: a prospective followup study.Arthritis Rheum. 1998; 41: 1221-1226Crossref PubMed Scopus (86) Google Scholar A non-erosive, self-limiting, and usually asymmetric arthritis has been reported in about a third of patients. We previously reported an acute carpal tunnel syndrome, and swelling of the distal extremity with pitting oedema in 14% and 12% of patients with polymyalgia rheumatica, respectively.3Salvarani C Cantini F Macchioni L et al.Distal musculoskeletal manifestations in polymyalgia rheumatica: a prospective followup study.Arthritis Rheum. 1998; 41: 1221-1226Crossref PubMed Scopus (86) Google Scholar Similar swelling and oedema also occurs in patients with RS3PE syndrome. The distribution of oedema is mostly along the course of tenosynovial structures, and hand and foot MRI showed predominant distal tenosynovial involvement. In a 5-year prospective follow-up study, we compared 177 patients with polymyalgia rheumatica with 23 patients with pure RS3PE syndrome.4Cantini F Salvarani C Olivieri I et al.Remitting seronegative symmetrical synovitis with pitting edema syndrome: prospective follow-up and magnetic resonance imaging study.Arthritis Rheum. 1998; 41: S118Google Scholar In both clinical groups, the disease frequency increased significantly with age, and was most common in patients aged 70-79 years. Clinical symptoms responded promptly to corticosteroids and no patient developed radiological evidence of erosions or deformities during the follow-up. Furthermore, we found distal pitting oedema manifestations in 13 (10%) of 128 patients with giant-cell arteritis identified over 42 years.5Salvarani C Gabriel SE Hunder GG Musculoskeletal manifestations in giant cell arteritis.Arthritis Rheum. 1998; 41: S119Crossref Scopus (131) Google Scholar These data suggest that these two conditions may be part of the clinical spectrum of the same disease and that the diagnostic labels of polymalgia and RS3PE syndrome may not indicate a real difference. In MRI studies, extra-articular synovial structures are the main site of lesions in polymyalgia rheumatica and RS3PE syndrome. Joint synovitis could be secondary to liberation of proinflammatory mediators of extrasynovial membranes. We suggest a third type of inflammatory arthritis should be classified as primary extra-articular synovial (polymyalgia like) which is common among older people.