Distinguishing Gouty Arthritis from Calcium Pyrophosphate Disease and Other Arthritides

Abstract

Objective.Differentiating gout, calcium pyrophosphate deposition disease (CPPD), and non–crystal-related inflammatory arthropathies (non-CRA) is essential but often clinically impossible. The sonographic double contour (DC) sign may have good specificity for gout in highly specialized centers, but it can be challenging to use it to distinguish gout from cartilage hyperenhancements in CPPD. We evaluated the diagnostic value of the DC sign alone and in combination with Doppler signals and uric acid (UA) levels in patients with acute arthritis.Methods.We retrospectively investigated 225 acutely inflamed joints and documented the presence of DC, Doppler hypervascularization, and serum UA (SUA) levels. All patients underwent synovial fluid (SF) analysis. Sensitivity, specificity, and positive predictive values were calculated, and correlation analyses and a binary regression model were used to investigate their diagnostic values.Results.The sensitivity of DC sign for crystalline arthritides was 85% and specificity 80%. Its specificity for gout was 64%, for CPPD 52%. In contrast to non-CRA hypervascularization, degree 2 and 3 Doppler signals were highly associated with gout and less with CPPD (p < 0.01). The combination of DC sign with hypervascularization and elevated UA levels increased specificity for gout to more than 90% and resulted in a 7-fold increase of the likelihood of diagnosis of gout (p < 0.01), but with a loss of sensitivity (42%).Conclusion.The DC sign alone is suitable for predicting crystal-related arthropathies, but it cannot reliably distinguish gout from CPPD in everyday clinical routine. Combining hypervascularization and SUA levels increases the diagnostic value, leading us to propose a diagnostic algorithm.

Is the Double Contour Sign Specific for Gout? Or Only for Crystal Arthritis?

“…In this issue of The Journal, Löffler, et al describes a study assessing the sonographic double contour (DC) sign in gout, calcium pyrophosphate crystal deposition (CPPD), and other arthritides 1 . They investigated the diagnostic value of the DC sign alone and in combination with Doppler signals and serum uric acid (SUA) levels in patients presenting with acute arthritis by examining 225 acutely inflamed joints.…”

Comparative Pathology of Aging Great Apes

“…204 Both conditions are increased in older and elderly humans, with a mean age of 69 y for gout and 73 y for CPPD. 151 Men are more affected than women (82% of gout cases, 63% of CPPD). CPPD can present as a primary acute mono-or pauciarticular IA, but calcium pyrophosphate crystals are also common in joints affected by OA, IA, infections, and joint instability.…”

“…3 Another type of arthritis that occurs in older humans is crystal deposition disease, which includes deposition of uric acid crystals (ie, articular gout) or calcium pyrophosphate deposition (CPPD; pseudogout). 151 Among primates, gout appears to be a uniquely human malady. CPPD, however, has been reported in a variety of nonhuman primates.…”

Overview of the Process of Conducting Meta-analyses of the Diagnostic Test Accuracy

“…The pooled sensitivity and specificity of US were 65.1% (95% confidence interval [CI], 62.0∼68.2) and 89.0% (95% CI, 96.6∼91.1), respectively (Table 1, Figure 1). The PLR, NLR, and DOR were 5.889 (3.365∼10.30), 0.359 (0.266∼ 0.485), and 17.61 (11.11∼17.92), respectively (Table 2) [30][31][32][33][34][35][36][37][38][39][40]. The AUC of US was 0.858 and the Q* index was 0.789, indicating good diagnostic accuracy (Table 1, Figure 2).…”