Computed tomography evaluation of the sacroiliac joints in Crohn disease. Radiologic/clinical correlation

Prevalence of undiagnosed axial spondyloarthritis in inflammatory bowel disease patients with chronic back pain: secondary care cross-sectional study

OBJECTIVE

To elucidate the prevalence of undiagnosed rheumatologist-verified diagnosis of axial spondyloarthritis (RVD-axSpA) in patients attending routine secondary care IBD clinics with chronic back pain.

METHODS

Screening questionnaires were sent to consecutive patients attending IBD clinics in a university teaching hospital. Patients fulling the eligibility criteria (gastroenterologist-verified diagnosis, 18-80 years old, biologic therapy naïve, no previous diagnosis of axSpA); and a moderate diagnostic probability of axSpA (self-reported chronic back pain [CBP] > 3 months, onset < 45 years) were invited for rheumatology assessment. This included medical review, physical examination, patient reported outcome measures, human leucocyte antigen B27, C-reactive protein, pelvic radiograph and axSpA protocol magnetic resonance imaging. A diagnosis of RVD-axSpA was made by a panel of rheumatologists.

RESULTS

Of the 470 patients approached, 91 had self-reported CBP > 3 months, onset < 45 years, of whom 82 were eligible for clinical assessment. The prevalence of undiagnosed RVD-axSpA in patients attending IBD clinics in a secondary care setting, with self-reported CBP, onset < 45 years is estimated at 5% (95% CI 1.3,12.0) with a mean symptom duration of 12 (S.D. 12.4) years.

CONCLUSION

There is a significant hidden disease burden of axSpA among IBD patients. Appropriate identification and referral from gastroenterology is needed to potentially shorten the delay to diagnosis and allow access to appropriate therapy.

Imaging in the Assessment of Musculoskeletal Manifestations Associated with Inflammatory Bowel Disease

Extraintestinal manifestations are the cause of morbidity and affect the quality of life of patients with inflammatory bowel diseases (IBDs). Musculoskeletal manifestations, in particular, spondyloarthritis and osteoporosis, are the most frequent extraintestinal manifestation of IBDs. The diagnosis and management of the musculoskeletal manifestation of IBDs relies on imaging. Conventional radiography, magnetic resonance imaging, computed tomography, and ultrasound can help to detect pathological signs of spondyloarthritis, both peripheral and with axial involvement. Dual-energy X-ray absorptiometry is the gold standard for identifying the presence of osteoporosis, whereas conventional radiology and computed tomography can reveal occult vertebral fractures. The aim of this narrative review is to describe the imaging of musculoskeletal manifestations of IBDs.

Prevalence of axial spondyloarthritis in patients with inflammatory bowel disease using cross-sectional imaging: a systematic literature review

BACKGROUND

Patients with inflammatory bowel disease (IBD) have an excess burden of axial spondyloarthritis (axSpA), which, if left untreated, may significantly impact on clinical outcomes. We aimed to estimate the prevalence of axSpA, including previously undiagnosed cases, in IBD patients from studies involving cross-sectional imaging and identify the IBD features potentially associated with axSpA.

METHODS

PubMed, Embase and Cochrane databases were searched systematically between 1990 and 2018. Article reference lists and key conference abstract lists from 2012 to 2018 were also reviewed. All abstracts were reviewed by two authors to determine eligibility for inclusion. The study inclusion criteria were (a) adults aged 18 years or above, (b) a clinical diagnosis of IBD and (c) reporting identification of sacroiliitis using cross-sectional imaging.

RESULTS

A total of 20 observational studies were identified: 12 used CT, 6 used MR and 2 utilised both computed tomography (CT) and magnetic resonance (MR) imaging. Sample sizes ranged from 25 to 1247 (a total of 4096 patients); 31 studies were considered to have low selection bias, 13 included two or more radiology readers, and 3 included rheumatological assessments. The prevalence of sacroiliitis, the most commonly reported axSpA feature, ranged from 2.2% to 68.0% with a pooled prevalence of 21.0% [95% confidence interval (CI) 17-26%]. Associated IBD features include increasing IBD duration, increasing age, male sex, IBD location, inflammatory back pain and peripheral arthritis. No significant difference in the prevalence of sacroiliitis between Crohn's disease and ulcerative colitis was identified. Study limitations include variability in the individual study sample sizes and patient demographics.

CONCLUSION

This review highlights the need for larger, well-designed studies using more sensitive imaging modalities and multivariable modelling to better estimate the prevalence of axSpA in IBD. An improved knowledge of the IBD phenotype(s) associated with axSpA and use of cross-sectional imaging intended for IBD assessment to screen for axSpA may help clinicians identify those patients most at risk.

Inflammatory Bowel Diseases and Coexisting Spondyloarthritis: A Neglected and too Often Under-Reported Association by Radiologists. A Multicenter Study by Italian Research Group of Imaging in Rheumatology

Purpose: The purpose of this study was to evaluate the prevalence and the underreporting rate of sacroiliitis (SI) in a large cohort of patients with biopsy-proved Crohn’s disease (CD) who underwent magnetic resonance enterography (MRE) or computed tomography enterography (CTE). Materials and Methods: Patients with CD were recruited from eight Italian health centers in the period from January 2013 to December 2017. Disease activity was recorded according to the CD activity index (CDAI). The scans were read by two blinded readers who defined the presence of SI according to Assessment of SpondyloArthritis International Society (ASAS) classifications and European League Against Rheumatism (EULAR) recommendations. Moreover, SI was scored using a simplified Spondyloarthritis Research Consortium of Canada (SPARCC) scoring system. Results: Interobserver agreement in diagnosing SI on imaging was good (K = 0.72–0.83). SI was diagnosed in 129 (14.4%, 54 men, 75 women) out of 894 patients; however, sacroiliac joint (SIJ) abnormalities were not mentioned in the radiological reports of 112 patients (86%). Fifty (38.7%) out of 129 patients also underwent a subsequent SIJ evaluation through a dedicated MRI protocol to confirm SI. SI was found in a higher percentage of patients with “active” than “inactive” CD (18% vs. 4%). Conclusion: This study confirms the feasibility of CTE and MRE for the screening of SI in CD patients; however, it also underlines the remarkable problem concerning the underreporting of this entity in radiological practice.

Low Back Pain and Sacroiliitis on Cross-Sectional Abdominal Imaging for Axial Spondyloarthritis Diagnosis in Inflammatory Bowel Diseases

Background

Joint damage is the most frequent extraintestinal manifestation in inflammatory bowel disease (IBD).

Aims

The aim of the study was to assess the value of low back pain (LBP) associated with sacroiliitis on abdominal imaging for the diagnosis of spondyloarthritis (SpA) in IBD.

Methods

We used a questionnaire assessing rheumatological symptoms for all patients with abdominal computed tomography (CT) and magnetic resonance enterography (MRE). Sacroiliitis was assessed on available CT and MRE. Patients were classified as axial SpA according to the Assessment of SpondyloArthritis International Society criteria.

Results

Fifty-one patients completed the questionnaire and performed both exams. LBP was present in 27 patients (52.9%), and 10 (19.6%) had an inflammatory component. Sacroiliitis was reported in 12 patients (23.5%), and 6 of them suffered from LBP. Among the 20 patients referred to the rheumatologist, 11 patients suffered from LBP. One patient was HLA-B27 positive and presented sacroiliitis. For the last 10 patients, none of them had a sacroiliitis, and 2 patients were negative for HLA-B27.

Conclusion

An axial SpA has been diagnosed in 11.8% of IBD patients undergoing cross-sectional imaging, whereas one-fifth had inflammatory LBP, and sacroiliitis was observed in one-quarter of them. To optimize the diagnosis of axial SpA, HLA-B27 testing might be required for patients with both IBD and LBP, but this will require further investigation before its implementation in routine practice.

Red flags for appropriate referral to the gastroenterologist and the rheumatologist of patients with inflammatory bowel disease and spondyloarthritis

Collaboration between gastroenterologists and rheumatologists is recommended for the correct management of patients with associated spondyloarthritis (SpA) and inflammatory bowel disease (IBD). We aimed to establish the appropriateness of several red flags for a prompt specialist referral. A systematic review of the literature was performed using the GRADE method to describe the prevalence of co-existing IBD-SpA and the diagnostic accuracy of red flags proposed by a steering committee. Then, a consensus among expert gastroenterologists and rheumatologists (10 in the steering committee and 13 in the expert panel) was obtained using the RAND method to confirm the appropriateness of each red flag as 'major' (one sufficient for patient referral) or 'minor' (at least three needed for patient referral) criteria for specialist referral. The review of the literature confirmed the high prevalence of co-existing IBD-SpA. Positive and negative predictive values of red flags were not calculated, given the lack of available data. A consensus among gastroenterology and rheumatology specialists was used to confirm the appropriateness of each red flag. Major criteria to refer patients with SpA to the gastroenterologist included: rectal bleeding, chronic abdominal pain, perianal fistula or abscess, chronic diarrhoea and nocturnal symptoms. Major criteria to refer patients with IBD to the rheumatologist included: chronic low back pain, dactylitis, enthesitis and pain/swelling of peripheral joints. Several major and minor red flags have been identified for the diagnosis of co-existing IBD-SpA. The use of red flags in routine clinical practice may avoid diagnostic delay and reduce clinic overload.

Diagnosis and progression of sacroiliitis in repeated sacroiliac joint computed tomography

Objective. To assess the clinical utility of repeat sacroiliac joint computed tomography (CT) in sacroiliitis by assessing the proportion of patients changing from normal to pathologic at CT and to which degree there is progression of established sacroiliitis at repeat CT. Methods. In a retrospective analysis of 334 patients (median age 34 years) with symptoms suggestive of inflammatory back pain, CT had been performed twice, in 47 of these thrice, and in eight patients four times. The studies were scored as normal, equivocal, unilateral sacroiliitis, or bilateral sacroiliitis. Results. There was no change in 331 of 389 repeat examinations. Ten patients (3.0%) had progressed from normal or equivocal to unilateral or bilateral sacroiliitis. Of 43 cases with sacroiliitis on the first study, 36 (83.7%) progressed markedly. Two normal cases had changed to equivocal. Eight equivocal cases were classified as normal on the repeat study. In further two patients, only small changes within the scoring grade equivocal were detected. Conclusions. CT is a valuable examination for diagnosis of sacroiliitis, but a repeated examination detects only a few additional cases of sacroiliitis. Most cases with already established sacroiliitis showed progression of disease.

Epidemiology of spondyloarthritis

Spondyloarthritis (SpA) represents a group of interrelated diseases with common clinical features and a close association with HLA-B27. Reports of incidence and prevalence of diseases vary depending on methodological differences between studies, the case definition used to classify disease, and the prevalence of HLA-B27 in the population studied. Newly proposed criteria for axial SpA and peripheral SpA present a new approach to facilitate classification of the SpA into 2 main subtypes and the criteria allow earlier detection of patents with inflammatory back pain. These criteria were developed for use in a (specialized) clinical setting and not for large epidemiologic studies.

Seronegative spondyloarthritis

Seronegative spondyloarthritis (SpA) is a group of inflammatory rheumatic diseases with common clinical and aetiological features, including axial and peripheral inflammatory arthritis, enthesitis, extra-articular manifestations and a close link to the presence of the human leucocyte antigen (HLA)-B27 epitope. Ankylosing spondylitis is the most common of the SpA diseases, with prevalence in the Caucasian population ranging between 0.15% and 1.8%, generally higher in populations with a higher background prevalence of HLA-B27 positivity. Incidence has been estimated between 0.49 (Japan) and 10 (Norway) per 100,000. The prevalence of psoriatic arthritis ranges from 0.02% to 0.2%, and the incidence in the normal population is 7.2 per 100,000 per year. In patients with existing psoriasis, the prevalence of psoriatic arthritis rises to 6-42%. The prevalence of reactive arthritis is dependent on the background incidence of gastrointestinal or genitourinary infections; incidence has been described as up to 30-40 per 100,000. SpA symptoms are present in up to 50% of patients with inflammatory bowel disease.

Whole-blood gene expression profiling in ankylosing spondylitis shows upregulation of toll-like receptor 4 and 5

OBJECTIVE

to identify differentially expressed genes in peripheral blood cells (PBC) of patients with ankylosing spondylitis (AS) relative to healthy controls and controls with systemic inflammation.

METHODS

we investigated PBC samples of 16 patients with AS and 14 matched controls, in addition to systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) samples utilizing Illumina Human Ref-8 BeadChips. Candidate genes were confirmed using quantitative PCR. Subsequently, these genes were also validated in a separate sample of 27 patients with AS [before and after anti-tumor necrosis factor (anti-TNF) treatment] and 27 matched controls.

RESULTS

we identified 83 differentially expressed transcripts between AS patients and controls. This gene list was filtered through the lists of differentially expressed transcripts in SLE and SSc, which resulted in identification of 52 uniquely dysregulated transcripts in AS. Many of the differentially expressed genes belonged to Toll-like receptor (TLR) and related pathways. TLR4 and TLR5 were the only dysregulated TLR subtypes among AS patients. We confirmed the overexpression of TLR4 and TLR5 in AS patients in comparison to controls (p = 0.012 and p = 0.006, respectively) and SLE (p = 0.002, p = 0.008) using quantitative PCR in the same sample. Similarly, TLR4 (p = 0.007) and TLR5 (p = 0.012) were significantly upregulated among the AS patients before anti-TNF treatment in the confirmatory sample. TLR4 (p = 0.002) and TLR5 (p = 0.025) decreased significantly after anti-TNF treatment.

CONCLUSION

PBC gene expression profiling in AS shows an upregulation of TLR4 and TLR5. This supports the importance of TLR subtypes in the pathogenesis of AS that are responsible for the immune response to Gram-negative bacteria.

Spondyloarthritis in a patient with unilateral buttock pain and history of Crohn disease

BACKGROUND AND PURPOSE

Patients with inflammatory spinal conditions related to spondyloarthritis are rarely seen by primary care practitioners. However, patients with a history of inflammatory bowel disease and chronic low back or buttock pain should be examined carefully for the presence of spondyloarthritis, as proper management may include referral to a rheumatologist and appropriate medical intervention.

CASE DESCRIPTION

A 27-year-old woman with a 6-month history of posterior buttock pain was referred for physical therapy with a diagnosis of piriformis syndrome. During the second physical therapy visit, a nonmechanical source of lumbopelvic pain was suspected, and the patient was referred for medical consultation. The patient underwent evaluation by a rheumatologist and was eventually diagnosed with spondyloarthritis associated with inflammatory bowel disease.

OUTCOMES

The patient initiated treatment with anti-tumor necrosis factor medication to address the spondyloarthritis. Medical management resulted in significant improvement in all outcome measures.

DISCUSSION

Clinical suspicion of spondyloarthritis is raised when specific historical, examination, and imaging findings are present. The posttest probability of spondyloarthritis is increased with the presence of inflammatory back pain and specific spondyloarthritic features, such as a positive history of inflammatory bowel disease, radiographic evidence of sacroiliitis, and improvement with anti-inflammatory medication. Referral of patients with these findings for a rheumatological evaluation is warranted, as these diseases are managed effectively with specific treatment.

Joint involvement in inflammatory bowel disease: managing inflammation outside the digestive system

Joint inflammation is present in approximately 30% of patients with inflammatory bowel disease. Peripheral arthritis can frequently be controlled by an optimal treatment of the gut inflammation in association with short-term use of NSAIDs. Recurrent inflammation requires the use of sulfasalazine. More therapy-resistant forms and axial arthropathy can be treated with anti-TNF drugs, predominantly infliximab and adalimumab. An intensified multidisciplinary approach in research and in the clinic may help to unravel the question of why common etiopathogenic mechanisms ultimately lead to different disease phenotypes. Animal models may help to identify the most promising therapeutic strategies including in the near future modulation of adhesion molecules, costimulatory molecules and the Th17 pathway.

Clinical features and epidemiology of spondyloarthritides associated with inflammatory bowel disease

Inflammation of axial and/or peripheral joints is one of the most frequent extra-intestinal manifestations complicating the clinical course and therapeutic approach in inflammatory bowel diseases (IBD). The frequency of these complications seems to be similar for both diseases, Crohn's disease and ulcerative colitis. Arthritis associated with IBD belongs to the category of spondyloarthropathies. Axial involvement ranges from isolated inflammatory back pain to ankylosing spondylitis, whereas peripheral arthritis is noted in pauciarticular and in polyarticular disease. Asymptomatic radiological involvement of the sacroiliac joints is reported to occur in up to 50% of patients. Other musculoskeletal manifestations such as buttock pain, dactylitis, calcaneal enthesitis, and thoracic pain are frequently underdiagnosed and, consequently, are not treated appropriately. Several diagnostic approaches and criteria have been proposed over the past 40 years in an attempt to correctly classify and diagnose such manifestations. The correct recognition of spondylarthropathies needs an integrated multidisciplinary approach in order to identify common therapeutic strategies, especially in the era of the new biologic therapies.

Clinical features and epidemiology of spondyloarthritides associated with inflammatory bowel disease

Inflammation of axial and/or peripheral joints is one of the most frequent extra-intestinal manifestations complicating the clinical course and therapeutic approach in inflammatory bowel diseases (IBD). The frequency of these complications seems to be similar for both diseases, Crohn’s disease and ulcerative colitis. Arthritis associated with IBD belongs to the category of spondyloarthropathies. Axial involvement ranges from isolated inflammatory back pain to ankylosing spondylitis, whereas peripheral arthritis is noted in pauciarticular and in polyarticular disease. Asymptomatic radiological involvement of the sacroiliac joints is reported to occur in up to 50% of patients. Other musculoskeletal manifestations such as buttock pain, dactylitis, calcaneal enthesitis, and thoracic pain are frequently underdiagnosed and, consequently, are not treated appropriately. Several diagnostic approaches and criteria have been proposed over the past 40 years in an attempt to correctly classify and diagnose such manifestations. The correct recognition of spondylarthropathies needs an integrated multidisciplinary approach in order to identify common therapeutic strategies, especially in the era of the new biologic therapies.

The prevalence, clinical features and association of HLA-B27 in sacroiliitis associated with established Crohn's disease

BACKGROUND

Sacroiliitis is a recognized complication of Crohn's disease and may occur distinct from progressive ankylosing spondylitis (AS).

AIM

To estimate prospectively the prevalence of sacroiliitis in patients with established Crohn's disease, to characterize the clinical features and to correlate these with the presence of HLA-B27.

METHODS

All Crohn's disease patients under active follow-up of between 5 and 12 years duration were invited to participate. Patients underwent a clinical evaluation including symptom questionnaire, rheumatological examination and underwent HLA genotyping. Patients then underwent magnetic resonance imaging (MRI) of the sacroiliac joints. The clinical and radiological factors were correlated with HLA-B27 status.

RESULTS

56 patients underwent initial assessment and 44 had MRI scans. Seventeen of 44 (39%) patients had MRI evidence of sacroiliitis, of whom 5 fulfilled the criteria for AS. Symptoms of low back pain were elicited in a majority of these patients--11/17 (65%) compared to 3 of 27 (11%) patients with normal scans (P = 0.003). There were no differences in functional indices with the exception of patients with AS. HLA-B27 was present in seven patients, and all seven had MRI evidence of sacroiliitis, five had AS.

CONCLUSIONS

Sacroiliitis is common in patients with established Crohn's disease and in the majority of cases, patients have symptoms of inflammatory low back pain if questioned carefully. HLA-B27 is not associated with isolated sacroiliitis, but is associated with AS. However, possession of HLA-B27 appears to convey a very high risk of developing axial inflammation in Crohn's disease.

Extraintestinal manifestations of inflammatory bowel diseases

Inflammatory bowel diseases are associated with extraintestinal manifestations involving almost every organ system in the body. They occur in approximately 20% to 40% of patients with inflammatory bowel diseases. Immune-related and genetic mechanisms play an important role in the pathogenesis of these complications. Peripheral arthritis, erythema nodosum, and episcleritis respond to the treatment of the underlying intestinal inflammation, whereas axial arthropathy, pyoderma gangrenosum, and uveitis do not. Immunomodulator therapy, particularly with biologic agents has been shown to be effective in treating some of the extraintestinal manifestations. Early recognition and treatment are crucial in preventing major morbidity.

Altered gut transcriptome in spondyloarthropathy

BACKGROUND

Intestinal inflammation is a common feature of spondyloarthropathy (SpA) and Crohn's disease. Inflammation is manifested clinically in Crohn's disease and subclinically in SpA. However, a fraction of patients with SpA develops overt Crohn's disease.

AIMS

To investigate whether subclinical gut lesions in patients with SpA are associated with transcriptome changes comparable to those seen in Crohn's disease and to examine global gene expression in non-inflamed colon biopsy specimens and screen patients for differentially expressed genes.

METHODS

Macroarray analysis was used as an initial genomewide screen for selecting a comprehensive set of genes relevant to Crohn's disease and SpA. This led to the identification of 2625 expressed sequence tags that are differentially expressed in the colon of patients with Crohn's disease or SpA. These clones, with appropriate controls (6779 in total), were used to construct a glass-based microarray, which was then used to analyse colon biopsy specimens from 15 patients with SpA, 11 patients with Crohn's disease and 10 controls.

RESULTS

95 genes were identified as differentially expressed in patients with SpA having a history of subclinical chronic gut inflammation and also in patients with Crohn's disease. Principal component analysis of this filtered set of genes successfully distinguished colon biopsy specimens from the three groups studied. Patients with SpA having subclinical chronic gut inflammation cluster together and are more related to those with Crohn's disease.

CONCLUSION

The transcriptome in the intestine of patients with SpA differs from that of controls. Moreover, these gene changes are comparable to those seen in patients with Crohn's disease, confirming initial clinical observations. On the basis of these findings, new (genetic) markers for detection of early Crohn's disease in patients with SpA can be considered.

The prevalence of extraintestinal manifestations and HLA association in patients with inflammatory bowel disease

To determine the prevalence, clinical and radiological characteristics of spondyloarthropathy (SpA) in patients with inflammatory bowel disease (IBD), to assess the association between HLA B27 and B51 and the extraintestinal symptoms and to evaluate whether IBD is associated with Behçet's disease (BD). One hundred and sixty-two consecutive adult patients with established diagnosis of IBD as either Crohn's disease (CD) or ulcerative colitis (UC) were evaluated. All the patients including those previously diagnosed with or without SpA had a complete rheumatologic examination and they were evaluated according to the European Spondyloarthropathy Study Group (ESSG) criteria for SpA and The International Study Group for Behçet's disease criteria for BD. The demographic and clinical data were recorded on a standardized form. The radiographies were obtained in all the patients and computed tomography (CT) was performed in the patients with suspected pelvic radiographies and/or low back pain in the physical examination. Radiological evaluation was made according to the Modified New York criteria. HLA B27, B51 and anti-neutrophile cytoplasmic antigen (ANCA) were searched in all the patients. Of the 162 patients with IBD (mean age 41.48+/-11.63 years, male 60, female 102), 78 were CD and 84 were UC. The mean of the IBD duration was 54.92+/-50.32 months and SpA duration was 20.63+/-34.37 months. The prevalence of SpA and AS in IBD was 45.7 and 9.9%, respectively. Frequencies of SpA and AS, the difference between UC and CD were not significant. Spondylitis, enthesitis, peripheral arthritis, oral ulcer and uveitis were not different between UC and CD, but erythema nodosum was found significantly more common in the CD patients compared with UC patients (P=0.005). The duration of IBD and SpA was similar in both groups. As the IBD duration increased, the prevalence of SpA development decreased (rr=0.991, P=0.009). Of the IBD patients, 13.6% were asymptomatic for musculoskeletal manifestations of SpA and their sacroiliac radiographies and CTs showed grade 2 sacroiliitis. HLA B27, B51 and ANCA positivities were not different between the patients with UC and CD. HLA B27 was significantly more common in the patients with sacroiliitis, spondylitis, enthesitis, peripheral arthritis, erythema nodosum, uveitis (P<0.001) and oral ulcer (P=0.025). BD was diagnosed in none of the patients. ANCA positivity was found to be related with the presence of erythema nodosum and uveitis (P=0.001 and P=0.005). The prevalence of SpA and AS is higher in the prospectively evaluated patients with radiological studies than those in the previously published studies. There is a high prevalence of asymptomatic sacroiliitis in IBD. An early diagnosis of inflammatory arthritis in IBD patients may prevent a disability due to SpA and AS.

Review article: joint involvement in inflammatory bowel disease

Peripheral involvement of the joints, including pauciarticular, asymmetrical, transitory and migrating synovitis and enthesiopathy, is observed in 10-20% of affected inflammatory bowel disease patients. Recurrence is common and frequently coincides with a flare-up of intestinal disease. The true prevalence of axial involvement is less well established. Sacroiliitis is a hallmark of spondylitis, but is under-reported due to its insidious onset and sometimes asymptomatic nature. Radiographic evidence of sacroiliitis is present in about 20-25% of patients. Ankylosing spondylitis, as defined by the Rome criteria, is present in 3-10% of inflammatory bowel disease patients, and is thought to have a different genetic predisposition in these patients compared with 'classic' ankylosing spondylitis: whereas the human leucocyte antigen B27 phenotype is present in 90% of patients with 'classic' ankylosing spondylitis, the prevalence decreases to only 30% in patients with ankylosing spondylitis secondary to Crohn's disease. Polymorphisms involving CARD15 appear to be a possible genetic trigger: 78% of patients with Crohn's disease and symptomatic or asymptomatic sacroiliitis carry at least one mutation, compared with only 48% of control Crohn's disease patients. Moreover, in other forms of spondyloarthropathy, a similar association has been reported: 42% of patients with spondyloarthropathy and associated asymptomatic chronic gut inflammation, who are considered likely to develop Crohn's disease and ankylosing spondylitis, are carriers of at least one CARD15 mutation, compared with only 7% of patients with normal histology. In addition to genetic markers, clinical features support the relationship between gut and joint pathophysiology. In cases of spondyloarthropathy, a very rapid, substantial and sustained improvement in symptoms has been reported following treatment with infliximab, suggesting an essential role for tumour necrosis factor-alpha in spondyloarthropathy, similar to that observed in Crohn's disease.

Radiological sacroiliitis, a hallmark of spondylitis, is linked with CARD15 gene polymorphisms in patients with Crohn's disease

BACKGROUND

Sacroiliitis is a common extraintestinal manifestation of Crohn's disease but its association with the HLA-B27 phenotype is less evident. Polymorphisms in the CARD15 gene have been linked to higher susceptibility for Crohn's disease. In particular, associations have been found with ileal and fibrostenosing disease, young age at onset of disease, and familial cases.

OBJECTIVES

To investigate whether the presence of sacroiliitis in patients with Crohn's disease is linked to the carriage of CARD15 polymorphisms.

METHODS

102 consecutive patients with Crohn's disease were clinically evaluated by a rheumatologist. Radiographs of the sacroiliac joints were taken and assessed blindly by two investigators. The RFLP-PCR technique was used to genotype all patients for three single nucleotide polymorphisms (SNP) in the CARD15 gene. Every SNP was verified by direct sequencing. The HLA-B27 phenotype was determined.

RESULTS

Radiological evidence of sacroiliitis with or without ankylosing spondylitis was found in 23 patients (23%), of whom only three were HLA-B27 positive. In contrast, 78% of patients with sacroiliitis carried a CARD15 variant v 48% of those without sacroiliitis (p = 0.01; odds ratio 3.8 (95% confidence interval, 1.3 to 11.5)). Multivariate analysis (logistic regression) showed that the association between sacroiliitis and CARD15 polymorphisms was independent of other CARD15 related phenotypes (ileal and fibrostenosing disease, young age at onset of disease, familial Crohn's disease) (p = 0.039).

CONCLUSIONS

CARD15 variants were identified as genetic predictors of Crohn's disease related sacroiliitis. An association was demonstrated between these polymorphisms and an extraintestinal manifestation of Crohn's disease.

Musculoskeletal complications of Crohn's disease: the role of computed tomography in diagnosis and patient management

The delayed diagnosis of musculoskeletal complications of Crohn's disease may produce major morbidity in patients. This study compared abdominal and pelvic computed tomography (CT) with conventional radiography in the diagnosis of musculoskeletal complications in 23 of 552 patients with Crohn's disease examined by CT over a 7-year period. Surgical confirmation was available in 15 of 21 patients. The clinical features of psoas/gluteal abscesses, abdominal wall fistulae, and sacral osteomyelitis are described. Because the clinical manifestations of these musculoskeletal complications are often nonspecific, CT is often useful in diagnosing and directing therapeutic interventions.

The epidemiology and the pathogenesis of inflammatory bowel disease

The etiology of inflammatory bowel disease (IBD) is still unknown. However, a satisfactory solution cannot be far away. IBD actually encompasses two diseases, i.e. Crohn's disease (CD) and ulcerous colitis (UC). These diseases resemble each other so closely that they cannot be distinguished even pathologically, but differ from each other sufficiently to regard them as independent entities. Epidemiological observations may be helpful in identifying the true causative factors of this evasive disease. Geographically, the prevalence of the disease has a slope from North to South and, to a lesser degree, from West to East. The Western-Eastern discrepancy can be attributed to a difference in Western life styles. The incidence of the disease has been increasing world-wide of late, but its spread has been slowing down in highly affected countries. Racial and ethnic relations in different populations and immigration studies offer interesting data which can reflect genetic, inherited, environmental and behavioural factors. The disease seems to have a characteristic racial-ethnic distribution: the Jewish population is highly susceptible everywhere, but its prevalence in that population nears that of the domestic society in which they live. In Hungary, the Roma (Gypsies) have a considerably lower prevalence than the average population. This can be attributed to a genetic or environmental influence. According to age, the onset of the disease occurs more often in the second or the third decade of life, but there also is another peak in the 60s. Regarding sexual distribution, there is a slight preponderance of colitis ulcerosa in men and of Crohn's disease in women. It may correspond to the stronger auto-immune affection in the process of Crohn's disease. Environmental factors and behavioural influences also are investigated. Diet, the role of the early ages, smoking habits and the influence of hormonal status and drugs are viewed as useful contributing factors in the manifestation of the disease. Genetic studies show that one-fourth of IBD patients have an affected family member. HLAB27 histocombatibility also plays an important, but not determining role in the development of the disease. Genetic factors seem to have a stronger influence in Crohn's disease than ulcerative colitis. The existence of multiple sclerosis-IBD families may reflect the common genetic background or the similar microbial effect as well. A great number of bacterial and viral factors has been suspected of being infectious factors in IBD, mostly in CD. Mycobacteria, Yersinia, Campylobacter, Clostridium, Clamidias, etc. as well as bacteria and some viruses such as herpes and rotavirus and the primary measles virus. None of them has been proven as a real and exclusively pathogenic factor. Immunological background has an important function in the manifestation of the disease. If an individual has a genetic susceptibility to infections, the down regulation of an inflammation in the bowel wall does not occur in a proper way. This initiates the auto-immune process which is a self-increasing cycle. Extra-intestinal manifestations of IBD are of high importance because they can not only follow intestinal symptoms, but precede them by years. Hepatic and biliary disturbances (primary sclerosing cholangitis), are the most serious complications. Mucocutaneous manifestations can be the first appearance of the main disease (in the mouth). Auto-immune consequences (erythema nodosum) or complications caused even by the therapy can occur. Ocular and musculoskeletal manifestations supposedly have the same genetic background and often precede the intestinal symptoms. Considering the epidemiological, genetic and immunological data, we can conclude that ulcerative colitis and Crohn's disease are heterogeneous disorders of mutifactorial etiology in which hereditary (genetic) and environmental (microbial, behaviour) factors interact to produce the disease.

Asymptomatic sacroiliitis in inflammatory bowel disease. Assessment by computed tomography

Plain film radiographs and computed tomography scans of sacroiliac joints in 65 asymptomatic patients with known inflammatory bowel disease were performed and evaluated by two radiologists. Computed tomography revealed the presence of asymptomatic sacroiliitis in 21 (32%) of the 65 patients (New York grades 2 to 4); asymptomatic sacroiliitis was identified by plain film radiography in only 10 (18%) of 57 patients (p < 0.001). No correlation was observed between the presence or absence of sacroiliitis, and the age and sex of patients, disease type, or duration of disease. The prevalence and diagnostic value of computed tomography in the detection of asymptomatic sacroiliitis in patients with inflammatory bowel disease are discussed.