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We were pleased to read the correspondence of Furuhashi et al1 who highlighted the importance of considering coexisting risk factors when diagnosing axial spondyloArthritis (ax-SpA) in early postpartum women. The authors correctly pointed out that patients with inflammatory bowel disease are more likely to develop ax-SpA due to common pathogenic mechanisms.2 In fact, the presence of Crohn’s disease or ulcerative colitis is part of the Assessment of SpondyloArthritis international Society criteria for the diagnosis of ax-SpA.3
In our study, on the prevalence of bone marrow oedema (BME) at the sacroiliac joint (SIJ) in postpartum women,4 we excluded those with known risk factors for developing ax-SpA, such as family or patient history of inflammatory diseases. The exclusion of women with known risk factors for developing ax-SpA was deemed important to eliminate potential confounding factors, and hence ascertain whether observations of sacroiliitis were triggered by, or related to, pregnancy and childbirth as opposed to other aetiologies.
In our experience, women with inflammatory bowel disease who have low back pain within the first 6 months after delivery should be assessed using MRI to identify the causes of pain, which could include infections or degenerative diseases. However, we believe that BME at the SIJ observed in an MRI taken during the early postpartum period is insufficient to diagnose ax-SpA, since BME at the SIJ may be merely transient and could disappear over time. It is also important to note the limitations of MRI for the diagnosis of ax-SpA, due to limited sensitivity and specificity of detecting ‘suggestive BME’ lesions, and the role/necessity of conventional radiography for the standardisation and contextual evaluation.5 While response to tumour necrosis factor inhibitors, such as adalimumab, can confirm diagnosis and relieve symptoms, immunosuppressive drugs are associated with a number of adverse events. We endeavour to improve the efficacy of clinical and imaging diagnostic tools to prescribe the most appropriate treatment and avoid such adverse events, especially in patients that are unlikely to benefit from immunosuppressive drugs.
Handling editor Josef S Smolen
Contributors All authors contributed to this response letter. The first draft of the letter was written by SRP and MS. All authors approved the final letter.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not required.
Provenance and peer review Commissioned; internally peer reviewed.
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