The role of sonography in diagnosing SLE-related diseases

Background: Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple systems in the body. Musculoskeletal system involvement is common, and patients may develop underlying conditions, such as rheumatoid arthritis (RA) and myositis, which ultimately complicate treatment plans and outcomes. Objective: The goal of this literature review is to understand how sonography can inform treatment planning for patients with SLE when the disease presents concurrently with RA and myositis. Methods: PubMed was used to identify relevant literature on the topic. The search strategy employed a mix of relevant free-text keywords and Medical Subject Headings (MeSH). To ensure relevance and current clinical practices, articles published within 5 years of writing this article (between 2019 and 2024) were prioritized. In order to support core concepts, foundational textbooks and pivotal/landmark studies were included. Results: When SLE impacts joints, commonly observed characteristics on ultrasound are tendinitis and tenosynovitis. If SLE patients develop RA (“Rhupus syndrome”), the primary sonographic features are synovitis and synovial hypertrophy. For SLE patients with concern for myositis, an ultrasound to assess muscle echotexture can be done using qualitative analysis, the Heckmatt grading system, and quantitative grayscale analysis. On ultrasound, chronic myositis is observed as increased muscle echogenicity and atrophy in affected muscles, while acute forms may demonstrate edema and mildly increased echogenicity. Ultrasound may show high sensitivity and specificity for soft tissue abnormalities but variable sensitivity for bone erosion. Conclusion: Throughout the literature review, ultrasound demonstrated the ability to identify sonographic signs of SLE, RA and myositis such as tenosynovitis, tendinitis, synovitis, increased muscle echogenicity, atrophy and edema. This may be clinically relevant to treatment planning for SLE when it is concurrent with other disorders, particularly RA and myositis, as certain therapies used to treat SLE and RA overlap. Both RA and SLE may be treated with corticosteroids and hydroxychloroquine (HCQ), while myositis has been reported as a potential side effect of HCQ. Ultimately, ultrasound may influence treatment planning through diagnostic guidance when SLE is concurrent with RA and/or myositis.