Differential Diagnosis of Inflammatory Arthropathy Accompanying Active Tuberculosis Infection.

Objective: The study aimed to ascertain the clinical manifestations of inflammatory arthritis accompanying tuberculosis (TB) for the differential diagnosis. Methods: We retrospectively reviewed patients with active TB who presented with inflammatory arthropathy at Seoul Medical Center. Among 2,872 patients with active TB infection, 47 had inflammatory arthropathy 14 had crystal-induced arthropathy; 12, TB arthritis; 12, Poncet's disease (PD); 8, Rheumatoid arthritis (RA); and 1, septic arthritis. The clinical characteristics and laboratory and radiographic findings of each group were analyzed. Results: In TB arthritis, weight-bearing joints were more commonly affected than the elbow and wrist joints. When compared to TB arthritis, PD demonstrated a significantly higher proportion of polyarthritis and involved both large and small-to-medium-sized joints. The duration of arthritis symptoms after anti-TB treatment was significantly shorter in patients with PD (56 days vs. 90 days, p=0.028). When compared to PD, RA flares during active TB infection involved only small-to-medium-sized joints rather than a mixed distribution (62.5% vs. 16.7%, p=0.035). Patients with PD more commonly had fever at onset and showed a good response to nonsteroidal anti-inflammatory drugs alone or were in remission within 3 months after anti-TB treatment. The presence of rheumatoid factor or anti-cyclic citrullinated peptide and radiographic progression after 12 months was frequently observed in patients with RA flares. Conclusion: The differential diagnosis of inflammatory arthritis accompanying active tuberculosis infection is challenging. Comprehensive history taking and physical examination, synovial fluid analysis, and a high level of clinical suspicion are essential to avoid delayed diagnosis and to reduce the significant morbidity involved.