Asymptomatic secondary hyperparathyroidism can mimic sacroiliitis on computed tomography.

Secondary hyperparathyroidism (sHPT) as a result of chronic kidney disease (CKD) is a common health problem and has been reported to manifest at the sacroiliac joints (SIJ). The aim of this investigation was to systematically assess sacroiliac joint changes in asymptomatic sHPT as detected by high-resolution CT. Included in this IRB-approved retrospective case-control study were 56 patients with asymptomatic sHPT as well as 259 matched controls without SIJ disease. Demographic data were retrieved from electronic patient records. High-resolution computed tomography datasets of all patients were subjected to a structured scoring, including erosions, sclerosis, osteophytes, joint space alterations and intraarticular calcifications. Chi2 tests were used to compare frequencies of lesions. Erosions were significantly more prevalent in patients with sHPT, and were found mainly in the ventral (28.6% vs. 13.9%; p = 0.016) and middle (17.9% vs. 7.7%; p = 0.040) iliac portions of the SIJ. Partial ankylosis was rare in both cohorts (3.6% vs. 5.0%; p > 0.999); complete ankylosis was not observed. Neither extent not prevalence of sclerosis or calcifications differed significantly between groups. Joint lesions reminiscent of sacroiliitis can be found in a substantial portion of asymptomatic patients with secondary hyperparathyroidism. Further investigations into the clinical significance of these findings are warranted.

Relationship between faecal calprotectin and inflammation in peripheral joints and entheses in axial spondyloarthritis.

Objectives: To compare faecal calprotectin levels according to the type of manifestation and to investigate factors associated with increases in faecal calprotectin in patients with axial spondyloarthritis (axSpA). Method: The study enrolled 190 patients fulfilling the imaging arm of the Assessment of SpondyloArthritis international Society axSpA criteria. Faecal calprotectin levels were measured in an enzyme-linked immunosorbent assay. Systemic inflammatory markers and the Ankylosing Spondylitis Disease Activity Score (ASDAS) were also assessed. Peripheral joint involvement was assessed using the 44-joint examination and Spondyloarthritis Research Consortium of Canada Enthesitis Index. Results: Of 190 patients, 34 (18%) had increased faecal calprotectin levels. These patients were more likely to have ongoing peripheral arthritis and enthesitis (p = 0.016 and 0.001, respectively). A history of psoriasis and uveitis, or current uveitis symptoms, had no bearing on faecal calprotectin levels. Faecal calprotectin levels increased along with ASDAS-C-reactive protein (CRP), and correlated with ASDAS-erythrocyte sedimentation rate (ESR) (r = 0.240, p = 0.001), ASDAS-CRP (r = 0.162, p = 0.025), ESR (r = 0.228, p = 0.002), and CRP levels (0.258, p < 0.001). Tender joint and swollen joint counts also correlated with faecal calprotectin levels (r = 0.252 and 0.205, p < 0.001 and p = 0.005, respectively). Faecal calprotectin levels were higher in patients with current peripheral symptoms (p = 0.003). Peripheral symptoms were independently associated with increased faecal calprotectin levels (odds ratio = 4.083; 95% confidence interval 1.580-10.556). Conclusions: Faecal calprotectin levels in axSpA patients were associated with disease activity. Subclinical gut inflammation (assessed by measuring faecal calprotectin) in axSpA is more closely related to peripheral joint inflammation than to axial joint inflammation.

Role of 99mTc-Methylene Diphosphonate SPECT/CT in the Detection of Sacroiliitis in Patients with Spondyloarthropathy: Comparison with Clinical Markers and MRI.

Our rationale was to evaluate the role of 99mTc-methylene diphosphonate (99mTc-MDP) SPECT/CT for the detection of sacroiliitis in spondyloarthropathies by comparing it with clinical markers and MRI findings. Methods: We prospectively included 155 patients (83 men and 72 women; mean age, 35.80 ± 12.40 y; range, 18-60 y) diagnosed with spondyloarthropathies as per the criteria of the European Spondyloarthropathy Study Group. All patients underwent clinical evaluation (using the Bath ankylosing spondylitis disease activity index [BASDAI]), measurement of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level, planar 99mTc-MDP bone scintigraphy, SPECT/CT, and MRI of the pelvic region. Using MRI as the reference criterion, the diagnostic accuracy of the clinical and scintigraphic parameters was assessed. On planar bone scintigraphy and SPECT, a score of 0, 1, or 2 was assigned when tracer uptake in the sacroiliac joint was less than, equal to, or more than that in the sacrum. A score of 2 was considered positive for the diagnosis of sacroiliitis. Results: The sensitivity, specificity, accuracy, and positive and negative predictive values of 99mTc-MDP SPECT/CT were 90.0%, 80.0%, 87.0%, 92.0%, and 75.0%, respectively. The accuracy of SPECT/CT (87%) was better than that of ESR (58.1%), CRP (32.9%), BASDAI scoring (77%), and planar bone scintigraphy (53%). Similar results were found for sensitivity and negative predictive value. Regarding specificity, SPECT/CT (80%) was lower than BASDAI scoring (88.6%) and equal to planar bone scintigraphy (80%). Regarding positive predictive value, SPECT/CT (92%) was a bit lower than BASDAI scoring (93.6%). κ-values for planar 99mTc-MDP bone scanning and SPECT/CT were 0.167 and 0.673, respectively, indicating poor agreement for planar bone scanning and good agreement for SPECT/CT. A significant (P < 0.001) correlation (r = 0.659) was observed between SPECT/CT and MRI findings. Conclusion:99mTc-MDP SPECT/CT has diagnostic accuracy comparable to that of MRI for the evaluation of sacroiliitis in spondyloarthropathies and can thus be used as an alternative when MRI is contraindicated. SPECT/CT shows better accuracy than planar bone scintigraphy, ESR, CRP, and BASDAI scoring in the diagnosis of sacroiliitis.

Evaluation of the validity of the different arms of the ASAS set of criteria for axial spondyloarthritis and description of the different imaging abnormalities suggestive of spondyloarthritis: data from the DESIR cohort.

BACKGROUND: The Assessment of Spondyloarthritis International Society (ASAS) criteria for axial spondyloarthritis (SpA) allows classification of patients with ('imaging' arm) and without ('clinical' arm) imaging abnormalities of the sacroiliac joints. OBJECTIVE: To compare the phenotype of early axial SpA with regard to the two arms of the ASAS axial SpA criteria. METHODS: Demographics, clinical and biological features of SpA, disease activity, severity parameters, and imaging abnormalities at the sacroiliac and spine levels were compared, in the two arms of the ASAS axial SpA criteria, in the patients of the French cohort of early SpA. RESULTS: Of the 615 patients analysed, 435 (70.7%) met the ASAS criteria (262 (60.2%) and 173 (39.8%) in the imaging and clinical arms, respectively). There were no major differences in the characteristics of the two groups except that those in the imaging arm were more likely to be younger, male and have higher concentrations of C-reactive protein. Imaging abnormalities other than those meeting the ASAS criteria for the imaging arm (ie, x-ray-determined structural damage or MRI-revealed inflammatory changes in the sacroiliac joint (SIJ)) were observed (MRI-SIJ structural damage (55.0% vs 3.5%), MRI-spine inflammatory changes (35.1% vs 12.9%), MRI-spine structural damage (10.3% vs 5.3%) and x-ray-syndesmophytes (11.8% vs 5.3%)) in the imaging versus clinical arm, respectively. CONCLUSIONS: Our study confirms the external validity of the clinical arm of the ASAS criteria. It is notable that many patients in the clinical arm showed other imaging changes in SIJs and spine.