Enthesitis in seronegative spondyloarthropathies with special attention to the knee joint by MRI: a step forward toward understanding disease pathogenesis

The value of different involvement patterns of the knee "synovio-entheseal complex" in the differential diagnosis of spondyloarthritis, rheumatoid arthritis, and osteoarthritis: an MRI-based study

OBJECTIVES

To explore the different involvement patterns of the knee "synovio-entheseal complex (SEC)" on MRI in patients with spondyloarthritis (SPA), rheumatoid arthritis (RA), and osteoarthritis (OA).

METHODS

This study retrospectively included 120 patients (male:female, 55:65) with a mean age of 39.20 years diagnosed with SPA (n = 40), RA (n = 40), and OA (n = 40) at the First Central Hospital of Tianjin between January 2020 and May 2022. Six knee entheses were assessed by two musculoskeletal radiologists according to the SEC definition. Bone marrow lesions associated with entheses include bone marrow edema (BME) and bone erosion (BE), which were classified as entheseal or peri-entheseal based on their relationship to the entheses. Three groups (OA, RA, and SPA) were established to characterize the location of enthesitis and the different SEC involvement patterns. Inter-group and intra-group differences were analyzed using the ANOVA or chi-square tests, and the inter-class correlation coefficient (ICC) test was used to determine inter-reader agreement.

RESULTS

The study contained a total of 720 entheses. The SEC-based analysis revealed different involvement patterns in three groups. The OA group had the most abnormal signals in tendons/ligaments (p = 0.002). The RA group had considerably greater synovitis (p = 0.002). The majority of peri-entheseal BE was identified in the OA and RA groups (p = 0.003). Furthermore, entheseal BME in the SPA group was significantly different from those in the other two groups (p < 0.001).

CONCLUSIONS

SEC involvement patterns differed in SPA, RA, and OA, which is important for differential diagnosis. SEC should be used as a whole evaluation method in clinical practice.

KEY POINTS

• The "synovio-entheseal complex (SEC)" explained differences and characteristic alterations in the knee joint in patients with spondyloarthritis (SPA), rheumatoid arthritis (RA), and osteoarthritis (OA). • The various SEC involvement patterns are crucial for differentiating SPA, RA, and OA. • When "knee pain" is the only symptom, a detailed identification of characteristic alterations in the knee joint of SPA patients may help timely treatment and delay the structural damage.

Peripheral enthesitis assessed by whole-body MRI in axial spondyloarthritis: Distribution and diagnostic value

Objective

To determine the distribution and diagnostic value of peripheral enthesitis detected by whole-body MRI (WBMRI) in axial spondyloarthritis (axSpA) diagnosis, and to determine the value of the peripheral enthesitis score in axSpA assessment.

Methods

Sixty axSpA patients [mean age of 33.2 (24.8–40.6) years] and 50 controls with chronic low back pain (LBP) [mean age of 34.7 (28.3–41.1) years] were enrolled. The gold standard was physician’s comprehensive diagnosis based on current classification criteria and physical examination. All subjects underwent WBMRI, and 47 peripheral entheses were assessed for each patient with scores of 0–188.

Results

WBMRI identified 155 enthesitis sites in 78.3% (n = 47) patients with axSpA. Meanwhile, 23 enthesitis sites were identified in 32% (n = 16) controls. The pelvis had the maximum number of enthesitis sites (52, 33.5%) in axSpA patients. Pelvic and anterior chest wall enthesitis had the highest sensitivity (51.67%) and specificity (100%) in axSpA diagnosis, respectively. There were different manifestations of enthesitis subtypes between axSpA patients and the control group. Osteitis was more present than soft-tissue inflammation in axSpA patients. The AUC for the number of enthesitis sites was 0.819 (95% CI 0.739–0.899), and that for the enthesitis score was 0.833 (95% CI 0.755–0.910), indicating statistically significant differences (P = 0.025). Based on the Youden index and clinical need, three enthesitis sites (sensitivity of 53.33, specificity of 98, and Youden index of 0.51) and enthesitis score (sensitivity of 58.33, specificity of 98, and Youden index of 0.56) may have the greatest value for axSpA diagnosis.

Conclusion

The distribution of peripheral enthesitis can be adequately assessed by whole-body MRI, which could help diagnose axial spondyloarthritis. The enthesitis score may provide a more accurate assessment and diagnostic tool in axSpA compared with enthesitis site counting.

The clinical utility of faecal calprotectin in patients with differentiated and undifferentiated spondyloarthritis: Relevance and clinical implications

OBJECTIVES

There is cumulative evidence in the literature supporting a potential role of faecal calprotectin (FCP) as a biomarker for gut inflammation in spondyloarthritis (SpA). However its relevance in undifferentiated SpA (USpA) is still uncertain. The aim of the current study is to assess the diagnostic significance of FCP levels in patients with differentiated and undifferentiated SpA.

MATERIAL AND METHODS

A total of 52 differentiated SpA, 33 USpA and 50 controls could be included. For all patients, clinical evaluation, routine laboratory investigations, FCP levels, and occult blood in stool were performed. When indicated imaging and/or endoscopies were performed.

RESULTS

The differentiated SpA patients were 12 (23.1%) with ankylosing spondylitis, 21 (40.4%) with psoriatic arthritis, 13 (25%) with ulcerative colitis, 5 (9.6%) with Crohn's disease (CD) and one (1.9%) with reactive arthritis. The mean FCP level in 85 patients correlated with CRP and ESR. Within the SpA group ulcerative colitis and Crohn's disease patients had increased FCP levels compared to other SpA subgroups and USpA patients (p<0.001). The mean FCP levelwas significantly higher in the SpA patients compared to USpA and controls (p<0.001).

CONCLUSIONS

Elevated FCP levels may identify patients who are most likely to have SpA already in the unclassified phase of the disease. Further studies in different series of patients are needed to evaluate the potential diagnostic and prognostic roles of FCP in both differentiated and undifferentiated phases of the disease.

The Clinical Utility of Faecal Calprotectin in Patients with Differentiated and Undifferentiated Spondyloarthritis: Relevance and Clinical Implications

OBJECTIVES

There is cumulative evidence in the literature supporting a potential role of faecal calprotectin (FCP) as a biomarker for gut inflammation in spondyloarthritis (SpA). However its relevance in undifferentiated SpA (USpA) is still uncertain. The aim of the current study is to assess the diagnostic significance of FCP levels in patients with differentiated and undifferentiated SpA.

MATERIAL AND METHODS

A total of 52 differentiated SpA, 33 USpA and 50 controls could be included. For all patients, clinical evaluation, routine laboratory investigations, FCP levels, and occult blood in stool were performed. When indicated imaging and/or endoscopies were performed.

RESULTS

The differentiated SpA patients were 12 (23.1%) with ankylosing spondylitis, 21 (40.4%) with psoriatic arthritis, 13 (25%) with ulcerative colitis, 5 (9.6%) with Crohn's disease (CD) and one (1.9%) with reactive arthritis. The mean FCP level in 85 patients correlated with CRP and ESR. Within the SpA group ulcerative colitis and Crohn's disease patients had increased FCP levels compared to other SpA subgroups and USpA patients (p<0.001). The mean FCP levelwas significantly higher in the SpA patients compared to USpA and controls (p<0.001).

CONCLUSIONS

Elevated FCP levels may identify patients who are most likely to have SpA already in the unclassified phase of the disease. Further studies in different series of patients are needed to evaluate the potential diagnostic and prognostic roles of FCP in both differentiated and undifferentiated phases of the disease.

ENTHESITIS AND PSORIATIC ONYCHOPATHY AS A FACTOR FOR PREDICTION OF PSORIATIC ARTHRITIS IN PSORIASIS

Psoriatic arthritis is a psoriasis-related spondyloarthropathy that occurs in 20–30 % of patients with psoriasis. Psoriatic arthritis affects the patient’s quality of life indicators and are more often associated with disabilities of working age than psoriasis skin form. Nail psoriasis has been proposed as a predictor for the development of psoriatic arthritis. The inflammation involving the entheses, called enthesitis, is an early inflammatory change seen in psoriatic arthritis, and nail changes appear to result from the close relationship between the nail and the enthesis of the distal interphalangeal extensor tendon, one of the main entheseal compartments affected in psoriatic arthritis. Various imaging studies have demonstrated that there is a considerable proportion of undiagnosed psoriatic arthritis among patients with psoriasis. Since early detection and treatment of psoriatic arthritis could, ultimately, allow the prevention of clinical and radiologic progression of the disease, there is the need to establish clinical indicators to detect this risk.

Exertional leg pain in familial Mediterranean fever: a manifestation of an underlying enthesopathy and a marker of more severe disease

OBJECTIVE

Exertional leg pain is a characteristic musculoskeletal manifestation of familial Mediterranean fever (FMF). We aimed to define the frequency and characteristics of exertional leg pain in a large cohort of FMF patients and to evaluate for additional signs and symptoms of spondyloarthritis (SpA) in this patient population.

METHODS

FMF patients were allocated into study or control groups based on the presence or absence of exertional leg pain. Randomly selected patients underwent magnetic resonance imaging (MRI) of the ankle as well as plain radiography of the sacroiliac joints.

RESULTS

The prevalence of exertional leg pain among the 170 FMF patients included in the study was 58.2%. Patients with exertional leg pain had significantly more joint attacks (74.7% versus 40.8%; P < 0.0001), fever attacks (35.4% versus 15.5%; P = 0.004), and pleuritis attacks (48.5% versus 29.6%; P = 0.013) as well as more attacks per year. Elevations of inflammation markers were significantly more frequent among the study group (for the erythrocyte sedimentation rate, 44.4% of patients versus 21.1% of patients; P = 0.016) (for the C-reactive protein level, 48.4% of patients versus 31.8% of patients; P = 0.013), and M694V homozygosity was more prevalent among the study group (45.5% versus 21.1%; P = 0.001). Signs compatible with enthesopathy on MRI were observed in 73.5% of patients in the study group and in 33.3% of patients in the control group (P = 0.046). Definite SpA was diagnosed in 41.2% of the patients in the study group compared to none of the controls (P = 0.07) (odds ratio 1.7 [95% confidence interval 1.2-2.3]).

CONCLUSION

Exertional leg pain is a common manifestation of FMF and is a marker of a more severe disease phenotype. Additionally, exertional leg pain is frequently associated with sacroiliitis and an underlying ankle enthesopathy and should therefore be considered a new feature of SpA.

Arthritis mimicking sports-related injuries

Arthritis, including inflammatory, crystal deposition, and synovial proliferative disorders, may mimic sports injury. The purpose of this article is to review the clinical and radiologic findings of arthropathies that can present in athletes and be confused with internal derangement.

Knee enthesitis and synovitis on magnetic resonance imaging in patients with psoriasis without arthritic symptoms

OBJECTIVE

This case-control study was designed to evaluate magnetic resonance imaging (MRI) findings of knee joints in patients with psoriasis without clinical peripheral or axial joint involvement, and to correlate MRI findings with disease and demographic variables.

METHODS

In total 48 patients with psoriasis and no clinical evidence of synovitis or enthesitis in any peripheral or axial joints were enrolled. A random sample of 20 healthy subjects without knee or other joint complaints and matched for age and sex served as controls. All patients and controls underwent enhanced MRI studies of both knee joints, and MRI findings were compared.

RESULTS

Among 48 patients (96 knees), a total of 90 entheseal lesions were detected, with no enthesitis in 2 cases (6.3%). Signs of continuing inflammation bilaterally were frequently found: soft tissue edema (STE; n = 52), bone marrow edema (BME; n = 20), perientheseal BME (n = 3), cartilaginous erosions (n = 42), and bone erosions (n = 27). In controls, 2 (10%) subjects had BME and another 5 (25%) showed cartilaginous erosions. None showed evidence of enthesitis. Significant correlations were observed between the number of entheseal lesions of both knees vs STE (present vs absent; r = 0.314, p = 0.030) and STE (number of lesions; r = 0.351, p = 0.014). Enthesitis (unilateral vs bilateral) was significantly and positively correlated with STE (r = 0.304, p = 0.036), cartilaginous erosions (r = 0.304, p = 0.036), and villous projections (r = 0.347, p = 0.016).

CONCLUSION

Subclinical synovitis and enthesitis are frequently found in the knee joint of patients with psoriasis. These may be an early sign of psoriatic arthritis.

Effects of inflammation on bone: an update

PURPOSE OF REVIEW

To present an updated summary of the relationship between inflammation and localized and generalized bone loss in the rheumatic diseases.

RECENT FINDINGS

In addition to the well established role of inflammatory cytokines in promoting enhanced osteoclast function and bone loss, recent work has discovered the cytokine milieu may also inhibit osteoblast function and bone repair. The WNT and bone morphogenetic protein pathways provide molecular links between inflammation and altered bone homeostasis in chronic inflammatory states. These pathways and others have been the targets of emerging therapies for the management of inflammatory bone loss.

SUMMARY

Inflammation and bone loss are linked through a number of molecular pathways. Both of these processes need to be addressed when designing an effective treatment strategy for the rheumatic diseases.

Magnetic resonance imaging of inflammatory arthropathies of peripheral joints

As the treatment of inflammatory arthropathies has advanced with new therapies that can slow or even halt the development of disabling disease, early and accurate diagnosis has become imperative. Magnetic resonance (MR) imaging has proved to be very sensitive in the detection of erosions, but more importantly, it can demonstrate pre-erosive changes. Detection of synovitis and edema-like bone marrow lesions for initial diagnosis and as an indicator of disease progression can provide crucial information leading to therapeutic interventions before permanent joint damage occurs. Understanding the characteristic intra-articular and extra-articular MR imaging findings of the inflammatory arthritides allows the radiologist to provide appropriate consultations in the care of these patients. The MR appearances of both intra-articular and extra-articular findings of inflammatory arthritis are presented. Despite the advances in imaging, however, many of the MR findings remain nonspecific, and radiologists must avoid overdiagnosis by synthesizing all of the clinical information available into their interpretations.