Update on juvenile spondyloarthritis

Spondyloarthritis (SpA) encompasses a group of disorders linked by overlapping clinical manifestations and genetic predisposition. Newer classification systems developed for adults with SpA focus on identifying individuals with axial or predominantly peripheral involvement. All forms of SpA can begin during childhood, and can be considered on a continuum with adult disease. Nevertheless, there are important differences in presentation and outcome that depend on age at onset. This article highlights these differences, what has been learned about genetics and pathogenesis of SpA, and important unmet needs for future studies.

Axial involvement in patients with early peripheral spondyloarthritis: a prospective MRI study of sacroiliac joints and spine

OBJECTIVES

To assess axial involvement on MRI in early peripheral spondyloarthritis (pSpA) and to evaluate whether axial inflammation predicts relapse on treatment withdrawal.

METHODS

Fifty-six patients with early, active, newly diagnosed pSpA underwent MRI of the sacroiliac joints (SIJs) and spine prior to golimumab initiation. At sustained clinical remission of pSpA, treatment was withdrawn and a second MRI was performed. Bone marrow oedema (BME) was scored by three readers according to the Spondyloarthritis Research Consortium of Canada (SPARCC) method. Scores were compared with an axial spondyloarthritis cohort (Belgian Arthritis and Spondylitis cohort). Structural lesions were assessed using a similar method. Furthermore, fulfilment of the Assessment of Spondyloarthritis International Society (ASAS) definition of a positive MRI for sacroiliitis was assessed. Spinal images were evaluated for BME and structural lesions using the Canada-Denmark MRI spine scoring system by two readers.

RESULTS

Thirty-six per cent showed SIJ BME at baseline, all fulfilling the ASAS definition of sacroiliitis. No association with back pain was found. Twenty-one per cent displayed SIJ structural lesions. Spinal BME was limited: the median inflammation scores were low and no patients had ≥5 inflammatory corner lesions. On clinical remission, a significant decrease in SIJ SPARCC scores was detected. On clinical remission, no significant differences in SIJ SPARCC scores were noted between patients relapsing and those maintaining remission after treatment discontinuation.

CONCLUSION

In patients with early pSpA, a surprisingly high prevalence of sacroiliitis on MRI was observed; SPARCC scores decreased significantly on tumour necrosis factor inhibition. Residual inflammation on MRI was not predictive of relapse of peripheral manifestations. No relevant inflammatory spinal involvement was detected. Collectively, our findings suggest a higher inflammatory burden in patients with early pSpA than anticipated.

Association between inflammatory back pain features, acute and structural sacroiliitis on MRI, and the diagnosis of spondyloarthritis

OBJECTIVES

To evaluate the association between inflammatory back pain (IBP) features, acute and structural MRI findings suggestive of sacroiliitis, and diagnosis of spondyloarthritis (SpA).

METHODS

Data from 224 patients who underwent MRI for suspected sacroiliitis (2005-2015) was retrospectively reviewed by an expert rheumatologist for the presence of IBP features and for clinical standard of reference diagnosis. A telephone questionnaire was performed in cases of missing data. Acute and structural MRI parameters were scored by an experienced radiologist for the presence of sacroiliitis using the Assessment of Spondyloarthritis International Society (ASAS) criteria, Berlin score, and observer's global impression (GI) scores. Association between IBP features and MRI scores, and odds ratio for SpA diagnosis, were calculated.

RESULTS

One hundred ninety-three subjects were included (119 F:74 M, mean age 39.7 ± 15.6, mean follow-up 49 ± 18 months). Fifty-two (26.9%) subjects were diagnosed with SpA. IBP scores were significantly higher in SpA patients (p < 0.001). IBP, ASAS, and GI MRI scores were significantly associated with the SpA diagnosis (p < 0.001 for all). The presence of night pain and morning stiffness was significantly associated with sacroiliac-joints' bone marrow edema (BME, p < 0.05). Sensitivity for diagnosis of SpA was high for IBP (96%) and low for the MRI parameters (26.9-57.4%), and specificity was low for IBP (32%) and high for the MRI parameters (88.3-94.3%).

CONCLUSIONS

The presence of IBP features is highly associated with diagnosis of SpA and correlates with MRI BME, all probably reflect inflammation. The combination of IBP and MRI should be the cornerstone in the clinician's final diagnosis of SpA.

A young female presenting with unilateral sacroiliitis following dengue virus infection: a case report

BACKGROUND

Dengue is a common arthropod-borne viral infection in Sri Lanka which is spread by the mosquitos of the genus Aedes. The clinical features of dengue include high-grade fever associated with arthralgia and myalgia. However, dengue virus is not considered an arthritogenic virus. We report a case of a previously healthy young female who presented with imaging-confirmed right-sided sacroiliitis 10 days after developing dengue fever. This is the first reported case that shows a possible link between dengue infection and development of arthritis.

CASE PRESENTATION

A 14-year-old Sri Lankan female presented to our medical unit with right buttock and hip pain of 3 weeks' duration. She had serologically confirmed dengue infection 10 days prior to the onset of buttock pain. A clinical examination revealed features of right sacroiliitis. An X-ray of her sacroiliac joint showed joint space widening and reactive bone changes. Magnetic resonance imaging of her pelvis and sacroiliac joint confirmed the diagnosis of acute sacroiliitis. She had an erythrocyte sedimentation rate of 110 mm first hour with a normal C-reactive protein. Her human leukocyte antigen-B27, rheumatoid factor, antinuclear antibody, chikungunya antibody, hepatitis serology, Brucella serology, and tuberculin skin test were negative. She was treated with nonsteroidal anti-inflammatory drugs and showed gradual improvement.

CONCLUSIONS

After excluding possible causes for sacroiliitis, we postulated that sacroiliitis in the index case could have been caused or triggered by dengue virus infection. However there is a possibility that the sacroiliitis merely coincided with the dengue virus infection. This case illustrates the possibility that dengue virus could have a link with the development of arthritis in the same manner as other arthritogenic viruses; possible mechanisms for this include direct invasion of the synovium and the joint tissue by the virus, immune complex formation and deposition in the joint tissue, and immune dysregulation. Further studies are needed in this field to gain more knowledge, as dengue infection is highly prevalent in Sri Lanka.

Gadolinium contrast-enhanced MRI sequence does not have an incremental value in the assessment of sacroiliitis in patients with early inflammatory back pain by using MRI in combination with pelvic radiographs: a 2-year follow-up study

OBJECTIVES

To evaluate the potential incremental value in detecting sacroiliitis of the T1 post-gadolinium diethylenetriaminepenta-acetic acid (Gd-DTPA) MRI sequence of the sacroiliac joints (SIJ) compared with the combination of short tau inversion recovery (STIR) MRI sequence and pelvic radiographs in patients with inflammatory back pain (IBP) suspected for axial spondyloarthritis.

METHODS

A 2-year follow-up study was conducted in patients with IBP of less than 2 years duration. Annual MRI of the SIJ (MRI-SIJ) was performed and scored for bone marrow oedema (BME). Pelvic radiographs were scored according to the modified New York (mNY) criteria. Agreement on the presence of BME detected by the STIR and post-Gd-DTPA sequence and the incremental value of post-Gd-DTPA sequence over STIR plus radiographs was analysed by descriptive methods and kappa statistics.

RESULTS

At baseline, 20 (29%) out of 68 patients (38% male; mean (SD) age 34.9 (10.3) years) enrolled had BME both on the STIR and post-Gd-DTPA sequences; 4 patients (6%) on the STIR sequence only; none on the post-Gd-DTPA sequence only (kappa value: 0.87). Fifteen (22%) patients fulfilled the mNY criteria at baseline. Sixty-two (91%) patients had at least 1 follow-up MRI-SIJ. At 2-year follow-up, 2 patients had BME on the post-Gd-DTPA sequence without BME on the STIR sequence. These 2 patients already fulfilled the mNY criteria at baseline.

CONCLUSIONS

In this cohort of patients with early IBP, the post-Gd-DTPA sequence of the MRI-SIJ did not have an incremental value in the detection of sacroiliitis compared with the STIR sequence plus pelvic radiographs.

[Pelvic bone radionecrosis as a late consequence of short-distance radiation therapy]

The paper deals with the estimation of the capabilities and role of different radiation techniques in the detection of late postradiation therapy local tissue responses that are evident as radionecrosis. To specify the nature of changes, it is necessary to take into account clinicoanamnestic data, results of laboratory and instrumental studies (standard X-ray study, multislice computed tomography, and magnetic resonance imaging) at any examination stage. A set of the studies can provide the means of significantly analyzing the bone structures and soft tissues and the degree of injury and identifying complications.

MRI Findings of the Sacroiliac Joints in Patients with Low Back Pain: Alternative Diagnosis to Inflammatory Sacroiliitis

BACKGROUND

Magnetic resonance imaging (MRI) is the most sensitive imaging modality for the detection of sacroiliitis. Diagnosing sacroiliitis on MRI is not always straightforward and can be challenging in some cases.

OBJECTIVES

To evaluate the prevalence of alternative diagnoses suggested by MRI and characterize the MR appearance of the most common ones.

METHODS

Consecutive MRI examinations of the sacroiliac joints (SIJ) performed between 2005 and 2012 were retrospectively evaluated for the presence of structural and active sacroiliitis findings according to the Assessment of SpondyloArthritis International Society guidelines. Alternative diagnoses, including degenerative changes, diffuse idiopathic skeletal hyperostosis (DISH), Osteitis condensans ilii (OCI), septic sacroiliitis/discitis, stress reaction as well as anatomic variants, were registered.

RESULTS

We evaluated 281 MRI examinations, 116 males, 165 females, average age 44 ± 15 years. Sacroiliitis was found in 71 examinations (25%) and alternative diagnoses were suggested in 87 (31%) (OCI 8.9%, anatomic variants 5.3%, septic sacroiliitis 5.3%, degenerative findings 4.3%, diffuse idiopathic skeletal hyperostosis [DISH] 1.5%, stress reaction 0.7%, tumor 0.3%). A normal examination was found in the remaining 123 examinations. Patients with alternative diagnoses were older than those with sacroiliitis (62 vs. 47 years of age, respectively, P > 0.05). Alternative pathologies in the SIJ were significantly more common in females (66) than males (21), P < 0.05.

CONCLUSIONS

A substantial proportion of patients with suspected sacroiliitis had normal SIJ while the rest were more commonly diagnosed with other pathologies. A referral by an experienced rheumatologist may improve the sensitivity and specificity of this important examination.