14 Other Rheumatic Inflammatory Disorders Anne Grethe Jurik Contents 14.1 Introduction ........................................................ 165 14.2 Rheumatoid Arthritis ................................................ 165 14.3 Gout ............................................................... 167 14.4 Pseudogout – Chondrocalcinosis ..................................... 168 14.5 Monarthritis ........................................................ 168 14.6 Other Disorders ..................................................... 171 14.7 Conclusion ......................................................... 172 References .......................................................... 172 14.1 Introduction All rheumatic inflammatory disorders can involve the sternocostoclavicular (SCC) region. The most frequently encountered disorder is osteoarthritis (Chapter 15), but other manifestations of arthritides such as rheumatoid arthritis also occur. Moreover, involvement of SCC joints can occur as the only disease manifestation. 14.2 Rheumatoid Arthritis Rheumatoid arthritis (RA) can involve any of the SCC joints, but especially the sternoclavicular joint [42]. The frequency of SCC involvement in RA is, however, low compared to that of seronegative spondylarthropathies (SpA). Clinical evi- dence of SCC joint involvement in RA occurs in only 10% of patients with RA, al- though symptoms of pain and swelling related to the sternoclavicular, MSJ and Anne Grethe Jurik sternocostal articulations when looked for may be present in more than 70% of patients with erosive RA [28]. The pathoanatomical RA changes in the sternoclavicular joints are similar to those in other joints, including pannus formation and bony erosion [45]. The in- volvement of the MSJ in RA may be related to the occasional occurrence of syno- via in the MSJ [29, 43, 44] or spread of inflammation from the adjacent synovial second sternocostal joints. At autopsy over half of RA patients have been found to have erosion of the MSJ [29]. The symptoms of joint involvement may be overlooked or misinterpreted as caused by shoulder or neck involvement [15]. RA involvement of the SCC joints is therefore seldom obtained at imaging. 14.2.1 Sternoclavicular Joints Clinical signs of sternoclavicular joint involvement consist of pain, tenderness and swelling. It has been reported present in 1–19% of patients with RA [9, 17, 30], but may be more frequent when specially looked for. Radiographic features are like those of other synovial joints involved by RA characterised by subchondral and marginal erosions, and joint space narrowing (Fig. 14.1) [24]. However, involvement of the sternoclavicular joints in RA can manifest as large synovial cysts or a more solid tumour-like mass representing a rheumatoid nodule [1, 11]. Such lesions demands ultrasonography or MRI for ob- taining the diagnosis. 14.2.2 Manubriosternal Joint Clinical signs of MSJ involvement consist of pain, swelling and tenderness. In com- parison with the sternoclavicular joint, clinical involvement of the MSJ is relatively infrequent in RA, occurring in 2–9% of patients [9, 17]. Based on radiographic analysis the joint has been found more frequently involved [29]. The lack of spe- cific symptoms referred to MSJ involvement may be due to symptoms presenting as referred pain or resembling pleuritic pain [10]. Involvement occurs especially in patients with an aggressive and destructive course. There can be complicating MSJ subluxation, described associated with severe cervical spine disease [31] or thoracic kyphosis [28]. Complicating septic arthritis can also occur (Chapter 16; Fig. 16.1). On lateral radiographs the changes consist of diminution in height of the fibro- cartilage with erosion or slight irregularity of the bony ends [10, 41]. The osseous Chapter 14 Other Rheumatic Inflammatory Disorders Fig. 14.1 Rheumatoid arthritis in a 52-year-old woman with known seropositive erosive peripheral RA for 10 years and pain, swelling and tenderness corresponding to the left ster- noclavicular joint during 2 months. a Initial CT, coronal reconstruction shows distension of the left sternoclavicular joint (arrows) and superficial erosion of the lower two thirds of the clavicular joint surface. b Six months later, axial CT slice shows clavicular erosion (arrow) proliferation seen in SpA does not occur, but some of the abnormalities detected have also been observed in healthy persons [41]. Radiographic changes have been reported in 15–71% of RA patients [9, 14, 31, 44]. However, unequivocal radio- graphic abnormalities are also frequent in patients in the same age range, having osteoarthritis, found to occur in 32% of patients compared with 44% of patients with RA [46]. 14.3 Gout Acute gout may involve the SCC region although rarely. The sternoclavicular joint [12, 40], the costochondral articulations [12] and the MSJ [27] can be affected. The appearance by radiography is not specific and may simulate degenerative changes [27]. The definite diagnosis is obtained by arthrocentesis followed by Anne Grethe Jurik polarising microscopy showing needle-shaped crystals, or by histology in the rare occurrence of tophus formation [45]. 14.4 Pseudogout – Chondrocalcinosis Calcium pyrophosphate deposition disease (CPPD) mainly occurs in the knees, wrists, hips, glenohumeral and acromioclavicular joints, but can involve the SCC region. Involvement of the sternoclavicular joint predominantly occurs in the polyarticular form of chondrocalcinosis. The radiological changes consist of calcification in the articular disc and usually a gradual development of secondary degenerative changes with marginal osteo- phytes, particular on the clavicles [37, 49]. Involvement of the MSJ may also oc- cur, probably corresponding to the occasional involvement of the pubic symphysis [37]. The rare occurrence of tophaceous CPPD in the soft tissue of the SCC region simulating chondrosarcoma have been described [38]. 14.5 Monarthritis Monarthritis of the SCC region is rare, but can occur corresponding to the ster- noclavicular, manubriosternal and sternocostal joints. Such involvement should always be considered as a differential diagnosis of chest and shoulder pain and/or swelling in the SCC region. Involvement of the SCC joints may manifest as pain referred to areas distant from the joints [15, 21, 22]. Monarthritis of the sternoclavicular joint without evidence of systemic disease and radiography showing erosion of the clavicular end have been reported in post- menopausal women corresponding to the dominant sternoclavicular joint and re- solving within a year [5]. Such changes are usually due to degenerative changes. Consistent with this, self-limited monoarticular subacute arthritis of the sterno- clavicular joint has also been reported on the dominant side in women performing strenuous physical activities [13]. It probably represents post-traumatic arthritis or erosive episodes as part of osteoarthritis. Osteoarthritis presenting as monarthri- tis of the sternoclavicular joint may be more common than is usually recognised (Chapter 15). Monarthritis of the manubriosternal joint is rare [20, 33, 34, 36]. In the early reports it was suggested to be due to trauma [33, 34] or to repeated overexertion by hard manual work [36], which can have elicited osteoarthritis. In later studies Chapter 14 Other Rheumatic Inflammatory Disorders an association with PPP, psoriasis, acne and HLA-B27 was observed [19, 20]. This indicated that MSJ monarthritis sometimes belongs to the group of seronegative arthritides. In accordance with this, MSJ arthritis may occasionally be the first manifestation of a generalised arthritis, and then for a period be monoarticular [18, 20]. However, persistent MSJ monarthritis may occur and can be associated with psoriasis vulgaris or HLA-B27 (Fig. 14.2). The MSJ monarthritis associated with psoriasis, psoriasis in the family or HLA- B27 may be viewed as a variant of psoriatic or reactive arthritis, although trig- gering infection may escape detection [18, 20]. The involvement associated with PPP or acne can be regarded as a sign of a PPP- or acne-associated arthropathy (Chapter 12). The pain of MSJ involvement often radiates to the shoulders, and sometimes also to the arms. If it is precipitated by exertion, it can simulate angina [4, 20]. Monarthritis of the sternocostal joint is also a rare finding. It may occur as a sign of degenerative changes or be the first manifestation of a systemic disease Fig. 14.2 Monarthritis of the MSJ in a 48-year-old woman with psoriasis. Sag- ittal CT reconstruction shows erosion of the joint facets and distension of the capsule posteriorly Anne Grethe Jurik Fig. 14.3 Osteoarthritis of the second right sternocostal joint in a 56-year-old man with synostosis of the MSJ. a Coronal CT reconstruction and b VIP view show broadening of the right second sternocostal joint with osteophyte formation (arrow) (Fig. 14.3) [21]. Such changes have sometimes been termed Tietze’s syndrome. This syndrome was described in 1921 as a benign self-limiting entity characterised by non-suppurative, tender, painful swelling of costal cartilage of unknown aetiol- ogy, and absence of other lesions that could establish a definite diagnosis [25, 32]. Despite the definition several disorders have been described under the term, com- prising sternocostal joint swellings as part of rheumatoid [39] or seronegative ar- thritis [8], rheumatic fever [8] and gout [12]. Patients with idiopathic monarthritis of the sternoclavicular joint have also