Aim Osteoporosis in axial spondyloarthropathy (axSpA) is difficult to accurately diagnose due to osteoproliferation of the spine interfering with conventional (anteroposterior, AP) dual‐energy X‐ray absorptiometry (DXA). This study compares AP and lateral projections of DXA when assessing bone mineral density (BMD) of the spine and investigates the impact of osteoproliferation on AP DXA. Method In this cross‐sectional study, structured standardized assessments collected demographic, clinical, laboratory and radiographic data. DXA assessed BMD of the spine using PA and lateral projections. Hip BMD was assessed in the usual manner. World Health Organization (WHO) criteria assessed prevalence of low BMD. Incorporating lateral DXA in the bone health assessment of axSpA was investigated. SPSS was used for statistical analysis. Results A total of 100 patients had paired AP and lateral DXA studies: 78% were male, mean (SD) age 52 (12) years. BMD of the spine measured by AP projection was significantly higher than BMD measured by lateral projection (mean difference 0.34 g/cm2, 95% CI 0.30‐0.37). More patients had low BMD with lateral compared to AP projection (47% vs 16%, P = .01). At the hip, 34% of patients had low BMD. Disease duration, body mass index and radiographic severity independently predicted a difference between AP and lateral measurements of the spine. Conclusion Lateral DXA of the spine is unaffected by osteoproliferation of the spine in axSpA and detects significantly more cases of low BMD than conventional AP DXA. Lateral DXA should be included in BMD assessment of patients with axSpA.

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A 52-year-old man with known hereditary angio-oedema (HAE) presented with a 2-day history of progressive severe abdominal pain, distension, nausea, vomiting and constipation. CT of his abdomen and pelvis showed small-bowel obstruction and ascites. HAE is a rare autosomal dominant disorder caused by a C1 esterase deficiency and involves episodic oedema of subcutaneous and mucosal tissues. It commonly affects the face and limbs, causing deformity; the respiratory tract, causing life-threatening laryngeal swelling; and the gastrointestinal tract, causing small-bowel obstruction. An infusion of a C1 esterase inhibitor was given to the patient. His symptoms resolved within 6 hours, and a repeat CT showed complete resolution 24 hours later. Small-bowel obstruction in HAE is often misdiagnosed, leading to ineffective treatment and unnecessary surgery. Therefore, this should be suspected in patients with HAE presenting with an acute abdomen, and clinicians should understand the unique treatment required.

BackgroundAxial spondyloarthropathy (axSpA) is a chronic inflammatory arthritis affecting the sacroiliac joints and spine. The consequence of inflammation in axSpA is new bone formation, or syndesmophytes, which can result in complete ankylosis of the spine. The pathogenesis of syndesmophyte formation is incompletely understood. It is agreed that presence of baseline syndesmophytes predicts further syndesmophytes, but other predictive factors have been difficult to define. In particular, the impact of extra-articular manifestations (EAMs) on syndesmophyte formation is unclear.Objectives1. To assess the burden of radiographic disease in a well-characterised axSpA cohort.2. To investigate demographic and disease-related variables associated with syndesmophytes (specifically EAMs).MethodsA cross-sectional study of AxSpA patients was performed, comprising standardised clinical assessment and structured interviews. Validated measures of disease severity were used: BASDAI and ASDAS-CRP (disease activity), BASMI (spinal mobility), HAQ (disability), BASFI (function). Lateral x-rays of the lumbar and cervical spine were performed to quantify syndesmophytes using a validated score (mSASSS) ranging from 0–72, with higher numbers indicating a higher burden. BASRI-hip was used to determine hip involvement, assessed on x-ray of pelvis.ResultsOne hundred and four patients with axSpA were included: 78.8% (n=82) male, 98.1% (n=102) Caucasian, average (SD) age 50.8 (12) years and average disease duration 2513 years. Modified New York (mNY) criteria were fulfilled by 84.6% (n=88) of the cohort. An EAM was present in 29.1% (n=30) of patients. Uveitis was the most prevalent EAM (29%), followed by inflammatory bowel disease (IBD) (18.4%) and psoriasis (17.5%). Average (SD) BASDAI was 3.9 (2.2), ASDAS-CRP 2.3 (1), BASMI 4.2 (1.9), indicating a mild to moderate disease burden in the cohort.Median (IQR) mSASSS was 9.5 (33.8), 10.6% (n=11) of patients had an mSASSS of 0% and 7.7% (n=8) had a bamboo spine. There was no significant difference in the median cervical and lumbar spine mSASSS scores (4 v 6, p>0.05). The distribution of mSASSS was similar in males and females. HLA-B27 status had no effect on mSASSS scores.Increasing mSASSS correlated significantly (p<0.05) with increasing age (rho=0.6), longer disease duration (rho=0.5), rising BASMI (rho=0.8), higher BASFI (rho=0.4) and higher HAQ (rho=0.3). Worsening hip disease, as measured by BASRI, also correlated with an increasing mSASSS (rho=0.4, p<0.01). There was also a statistically significant difference between patients who met mNY criteria compared to those that didn’t (median 14.4 v 2.5, p<0.01).Patients with hypertension had a significantly higher median mSASSS score than patients without (25.4 v 7, p<0.01). Smoking status, hypercholesterolaemia, ischaemic heart disease and diabetes had no impact on mSASSS.The presence or absence of uveitis, psoriasis or IBD had no effect on syndesmophyte formation. Equally, peripheral arthritis had no effect. Patients with moderate or severe hip ...

BackgroundAxial spondyloarthropathy (axSpA) is an inflammatory arthritis which can lead to new bone formation (syndesmophytes) and ankylosis of the spine. Osteoporosis is a recognised feature of axSpA, but can be challenging to diagnose. Traditional dual-energy x-ray absorptiometry (DXA) in the antero-posterior (AP) projection of the spine can overestimate bone mineral density (BMD) due to the presence of syndesmophytes, potentially under-diagnosing osteoporosis. There is a real need to find an accurate method to assess BMD in axSpA patients. Lateral DXA of the lumbar spine is unaffected by syndesmophyte formation and may be a promising tool.ObjectivesThe aim of this study is to:1. investigate different projections of DXA of the lumbar spine in axSpA patients2. assess the effect of syndesmophytes on spine BMD.MethodsAxSpA patients were assessed with clinical exam, questionnaires and laboratory investigations. The burden of syndesmophytes on lateral x-rays of the lumbar and cervical spine was assessed with the validated modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) score, which ranges from 0–72 (higher scores indicate more severe disease). DXA was performed of the spine in both the AP and lateral projections. SPSS was used for statistical analysis.ResultsOne hundred patients with axSpA were recruited: 78% (n=78) male, mean (SD) age 5212 years, disease duration 2613 years, 85% (n=85) fulfil modified New York criteria. The median (IQR) mSASSS score was 10.33 Lumbar spine BMD was lower when measured by lateral DXA rather than AP (0.76 v 1.11 g/cm2, p<0.01). Lateral DXA detected more cases of spinal osteopenia or osteoporosis than AP (21% v 44%, p<0.01). Lateral spine BMD reduced with longer duration of disease (r=-0.3, p=0.02), whereas AP spine BMD increased with age (r=0.3, p=0.01). Women had significantly more cases of osteoporosis at the lumbar spine than men when measured by lateral DXA (32% v 12%, p=0.02), but not by AP DXA.A higher mSASSS, reflecting more syndesmophytes/new bone formation, was associated with a rising AP spine BMD (r=0.5, p<0.01), but had no effect on lateral spine BMD. The gap between AP and lateral spine BMD, i.e. when AP BMD was higher than lateral BMD, increased significantly (p<0.05) with increasing age (r=0.38), disease duration (r=0.37) and mSASSS (r=0.52). mSASSS was the strongest independent predictor of a difference between AP and lateral BMD measurements, suggesting that syndesmophyte formation interferes with AP DXA assessment of the spine.ConclusionsAP DXA of the spine is affected by a higher burden of syndesmophytes (new bone formation), raising concerns that traditional DXA assessment may miss cases of osteoporosis. We suggest that lateral DXA of the spine may be a more accurate tool to detect osteoporosis in axSpA patients.Disclosure of InterestNone declared