Small bowel Crohn's disease: an emerging disease phenotype?

Current Approaches for Monitoring of Patients with Inflammatory Bowel Diseases: A Narrative Review

BACKGROUND

Patients with inflammatory bowel diseases (IBD) require proactive monitoring both during the active phase to evaluate therapeutic response and during the remission phase to evaluate relapse or colorectal cancer surveillance. However, monitoring may vary between patients with ulcerative colitis (UC) and Crohn's disease (CD), with distinct tools and intervals.

METHODS

This narrative review aims to focus on modern approaches to IBD monitoring, considering international guidelines and expert consensus.

RESULTS

The most recent European diagnostic guidelines advocate a combination of clinical, laboratory, endoscopic, and radiological parameters to evaluate the disease course of patients with IBD. Unfortunately, the conventional symptom-based therapeutic approach does not improve long-term outcomes and there is no single ideal biomarker available. Endoscopy plays a key role in evaluating response to therapy as well as monitoring disease activity. Recently, bedside intestinal ultrasound (IUS) has gained increasing interest and diffusion as it appears to offer several advantages including the monitoring of therapeutic response.

CONCLUSION

In light of growing clinical advances, we present a schematic evidence-based monitoring algorithm that can be easily applied in clinical practice which combines all major monitoring modalities, including noninvasive tools such as IUS and video-capsule endoscopy.

Viable Mycobacterium avium subsp. paratuberculosis Colonizes Peripheral Blood of Inflammatory Bowel Disease Patients

Pathobionts, particularly Mycobacterium avium subsp. paratuberculosis (MAP) and Escherichia coli isolates with adherence/invasive ability (AIEC) have been associated with inflammatory bowel disease (IBD), particularly Crohn's disease (CD). This study aimed to evaluate the frequency of viable MAP and AIEC in a cohort of IBD patients. As such, MAP and E. coli cultures were established from faecal and blood samples (with a total n = 62 for each) of patients with CD (n = 18), ulcerative colitis (UC, n = 15), or liver cirrhosis (n = 7), as well as from healthy controls (HC, n = 22). Presumptive positive cultures were tested by polymerase chain reaction (PCR), for a positive confirmation of MAP or E. coli identity. E. coli-confirmed isolates were then tested for AIEC identity using adherence and invasion assays in the epithelial cell line of Caco-2 and survival and replication assays in the macrophage cell line of J774. MAP sub-culture and genome sequencing were also performed. MAP was more frequently cultured from the blood and faecal samples of patients with CD and cirrhosis. E. coli presumptive colonies were isolated from the faecal samples of most individuals, in contrast to what was registered for the blood samples. Additionally, from the confirmed E. coli isolates, only three had an AIEC-like phenotype (i.e., one CD patient and two UC patients). This study confirmed the association between MAP and CD; however, it did not find a strong association between the presence of AIEC and CD. It may be hypothesized that the presence of viable MAP in the bloodstream of CD patients contributes to disease reactivation.

Small-bowel capsule endoscopy and device-assisted enteroscopy for diagnosis and treatment of small-bowel disorders: European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2022

MR1: ESGE recommends small-bowel capsule endoscopy as the first-line examination, before consideration of other endoscopic and radiological diagnostic tests for suspected small-bowel bleeding, given the excellent safety profile of capsule endoscopy, its patient tolerability, and its potential to visualize the entire small-bowel mucosa.Strong recommendation, moderate quality evidence. MR2: ESGE recommends small-bowel capsule endoscopy in patients with overt suspected small-bowel bleeding as soon as possible after the bleeding episode, ideally within 48 hours, to maximize the diagnostic and subsequent therapeutic yield.Strong recommendation, high quality evidence. MR3: ESGE does not recommend routine second-look endoscopy prior to small-bowel capsule endoscopy in patients with suspected small-bowel bleeding or iron-deficiency anemia.Strong recommendation, low quality evidence. MR4: ESGE recommends conservative management in those patients with suspected small-bowel bleeding and high quality negative small-bowel capsule endoscopy.Strong recommendation, moderate quality evidence. MR5: ESGE recommends device-assisted enteroscopy to confirm and possibly treat lesions identified by small-bowel capsule endoscopy.Strong recommendation, high quality evidence. MR6: ESGE recommends the performance of small-bowel capsule endoscopy as a first-line examination in patients with iron-deficiency anemia when small bowel evaluation is indicated.Strong recommendation, high quality evidence. MR7: ESGE recommends small-bowel capsule endoscopy in patients with suspected Crohn's disease and negative ileocolonoscopy findings as the initial diagnostic modality for investigating the small bowel, in the absence of obstructive symptoms or known bowel stenosis.Strong recommendation, high quality evidence. MR8: ESGE recommends, in patients with unremarkable or nondiagnostic findings from dedicated small-bowel cross-sectional imaging, small-bowel capsule endoscopy as a subsequent investigation if deemed likely to influence patient management.Strong recommendation, low quality evidence. MR9: ESGE recommends, in patients with established Crohn's disease, the use of a patency capsule before small-bowel capsule endoscopy to decrease the capsule retention rate.Strong recommendation, moderate quality evidence. MR10: ESGE recommends device-assisted enteroscopy (DAE) as an alternative to surgery for foreign bodies retained in the small bowel requiring retrieval in patients without acute intestinal obstruction.Strong recommendation, moderate quality evidence. MR11: ESGE recommends DAE-endoscopic retrograde cholangiopancreatography (DAE-ERCP) as a first-line endoscopic approach to treat pancreaticobiliary diseases in patients with surgically altered anatomy (except for Billroth II patients).Strong recommendation, moderate quality evidence.

Fecal calprotectin predicts endoscopic activity and mucosal healing of small bowel Crohn's disease evaluated by double-balloon endoscopy

PURPOSE

Fecal calprotectin (FC) levels can reflect the level of intestinal inflammation. Crohn's disease (CD), which affects the small bowel, has not been linked to FC levels. We determined if FC levels and endoscopic activity were related by performing double-balloon endoscopy (DBE).

METHODS

Herein, patients with small bowel CD diagnosed by DBE between January 2020 and January 2022 were prospectively observed. Feces and blood samples of patients were collected before performing DBE and checked for the levels of FC and serological biomarkers. The endoscopic activity and mucosal healing (MH) were evaluated using the partial simple endoscopic score (pSES-CD).

RESULTS

In all 254 CD patients, FC levels were correlated with pSES-CD (r = 0.775, P < 0.001). Even in patients with isolated small bowel CD, FC levels were strongly correlated with pSES-CD (r = 0.753, P < 0.001). In all patients, FC as an endoscopic remission indicator was found to have an area under the curve (AUC) of 0.872, with a cut-off value of 156.09 µg/g. In patients with isolated small bowel CD, FC yielded a high AUC of 0.865 for predicting endoscopic remission, with a cut-off value of 211.48 µg/g, sensitivity of 73.95%, and specificity of 91.30%. FC was optimally cut-off at 76.99 µg/g to predict MH in accordance with the AUC of 0.877.

CONCLUSIONS

Using DBE findings, FC was found to be significantly correlated with pSES-CD. Even in isolated small bowel CD, FC may be a more reliable marker of accurately predicting endoscopic remission and MH.

Differentiation of Isolated Small Bowel Crohn’s Disease from Other Small Bowel Ulcerative Diseases: Clinical Features and Double-Balloon Enteroscopy Characteristics

Background. The diagnosis of isolated small bowel Crohn’s disease (ISBCD) has always been challenging. Aims. This study is aimed at comparing the clinical features and double-balloon enteroscopy (DBE) characteristics of ISBCD with those of other small bowel ulcerative diseases (OSBUD). Methods. Patients with coexisting colonic and/or ileal valve lesions ( $n=45$ ) or whose final diagnosis was not determined ( $n=29$ ) were excluded. One hundred thirty-nine patients with ISBCD and 62 patients with OSBUD found by DBE were retrospectively analyzed. Results. The age of ISBCD onset was lower than that of OSBUD (OR 0.957, 95% CI 0.938-0.977, $p<0.001$ ). Abdominal pain was more common in ISBCD (OR 4.986, 95% CI 2.539-9.792, $p<0.001$ ). Elevated fibrinogen levels (OR 1.431, 95% CI 1.022-2.003, $p=0.037$ ) and lower levels of D-dimer (OR 0.999, 95% CI 0.999-1.000, $p=0.017$ ) were also more supportive of the diagnosis of ISBCD. Nonsteroidal anti-inflammatory drugs (NSAIDs) used for more than two weeks decreased the probability of a diagnosis of ISBCD (OR 0.173, 95% CI 0.043-0.695, $p=0.013$ ). Abdominal computed tomography revealed a higher proportion of skip lesions in ISBCD than in OSBUD (OR 9.728, 95% CI 3.676-25.742, $p<0.001$ ). The ulcers of ISBCD were more distributed in the ileum (111 (79.9%) vs. 29 (46.8%), $p<0.001$ ), and their main morphology differed in different intestinal segments. Longitudinal ulcers (OR 14.293, 95% CI 4.920-41.518, $p<0.001$ ) and large ulcer (OR 0.128, 95% CI 0.044-0.374, $p<0.001$ ) contributed to the differentiation of ISBCD from OSBUD. We constructed a diagnostic model, ISBCD index ( $\text{AUROC}=0.877$ , 95% CI: 0.830-0.925), using multifactorial binary logistic regression to help distinguish between these two groups of diseases. Conclusion. Clinical features, laboratory tests, abdominal computed tomography, DBE characteristics, and pathology help to distinguish ISBCD from OSBUD.

Clinical management for small bowel of Crohn's disease in the treat-to-target era: now is the time to optimize treatment based on the dominant lesion

A treat-to-target strategy, in which treatment is continuously adjusted according to the results of scheduled objective monitoring, is optimal for patients with Crohn's disease (CD) in the era of biologics. The small bowel is a common site of intractable CD, which may result from multiple strictures or expanding lesions. To improve the prognosis of patients with small bowel CD, lesions should be proactively monitored within the subclinical phase. Objective assessment of small bowel lesions is technically difficult, however, due to the relatively poor correlation between endoscopic activity and clinical symptoms or biomarker titers. The presence of proximal small bowel lesions and asymptomatic "Real Silent CD" must be considered. Endoscopy remains the gold standard to assess these lesions. In clinical practice, the advantages and disadvantages of each imaging modality and biomarker must be carefully weighed for appropriate application and reliable monitoring. The prevalence of small bowel lesions depends on the precision of the imaging modality used for detection. Clinical management should be based on the dominant location of the intestinal lesions rather than classical classification. Optimal strategies for detecting and treating small bowel lesions in patients with CD must be developed utilizing reliable, precise, and objective monitoring.

Enteroscopy in children and adults with inflammatory bowel disease

Inflammatory bowel disease (IBD) includes Crohn’s disease (CD), ulcerative colitis and unclassified entities. CD commonly involves the terminal ileum and colon but at the time of diagnosis it can be confined to the small bowel (SB) in about 30% of the patients, especially in the young ones. Management of isolated SB-CD can be challenging and objective evaluation of the SB mucosa is essential in differentiating CD from other enteropathies to achieve therapeutic decisions and to plan the follow-up. The introduction of cross-sectional imaging techniques and capsule endoscopy (CE) have significantly expanded the ability to diagnose SB diseases providing a non-invasive test for the visualization of the entire SB mucosa. The main CE limitations are the low specificity, the lack of therapeutic capabilities and the impossibility to take biopsies. Device assisted enteroscopy (DAE) enables histological confirmation when traditional endoscopy, capsule endoscopy and cross-sectional imaging are inconclusive and also allows therapeutic interventions such as balloon stricture dilation, intralesional steroid injection, capsule retrieval and more recently stent insertion. In the current review we will discuss technical aspect, indications and safety profile of DAE in children and adults with IBD.

Retrospective study of the differential diagnosis between cryptogenic multifocal ulcerous stenosing enteritis and small bowel Crohn's disease

BACKGROUND

Being a rare disease, cryptogenic multifocal ulcerous stenosing enteritis (CMUSE) is easily misdiagnosed as small bowel Crohn's disease (SBCD).

AIMS

This study was aimed to compare clinical features of CMUSE to SBCD.

METHODS

Fourteen patients with CMUSE and 61 patients with SBCD were retrospectively analyzed.

RESULTS

Hematochezia was more frequent in CMUSE patients (10, 71.4% vs 23, 37.7%, P = 0.022), while diarrhea was more common in SBCD patients (23, 37.7% vs 0, 0.0%, P = 0.015). More patients with CMUSE developed intestinal stenosis than with SBCD (14, 100% vs 37, 60.7%, P = 0.011). 30 (50.0%) SBCD patients and none CMUSE patients had an elevated erythrocyte sedimentation rate level (P = 0.001). Extra-enteric findings found by computed tomography enterography were significantly more prevalent in SBCD patients than in CMUSE patients (25,71.4% vs 3,25%, P = 0.013). Longitudinal ulcers found by endoscopy were more common in SBCD patients (16, 37.2% vs 0, 0.0%, P = 0.041), while circumferential ulcers were more common in CMUSE patients (6, 54.6% vs 8, 18.6%, P = 0.041). All ulcers observed in CMUSE patients were within mucosal and submucosal layers, but 8 (44.4%) SBCD patients had deep ulcers that reached beyond submucosal layers (P = 0.003). Ulcers were located at strictures in 9 (90.0%) CMUSE patients but only in 1 (5.6%) SBCD patient (P = 0.000).

CONCLUSIONS

Gastrointestinal symptoms, erythrocyte sedimentation rate levels, radiologic, endoscopic and pathologic features help to distinguish CMUSE from SBCD.

Monocytes from infliximab-resistant patients with Crohn's disease exhibit a disordered cytokine profile

Crohn's disease (CD) is a chronic inflammatory disorder characterized by immune response dysregulation. Tumor necrosis factor-α (TNFα) is a key cytokine in the pathogenesis of CD, as indicated by the efficacy of anti-TNF-α therapy with infliximab (IFX). However, approximately 30-40% of CD patients fail to respond to IFX with still unclear underlying mechanisms. This study compares the inflammatory phenotype of monocytes from CD patients, who respond or non-respond to IFX. Under basal conditions, the mRNA for the cytokines TNFα, IL-23, IL-1β and the chemokines CXCL8/IL-8, CCL5/RANTES and CCL2/MCP-1 was up-regulated in monocytes from non-responders than responders. The expression of the same cytokines and CCL2/MCP-1 was higher in non-responders also upon LPS treatment. Moreover, higher secretion of TNFα, IL-1β, IFNγ and IL-2 proteins occurred in the supernatants of LPS-treated non-responders cells. Resistance to IFX in CD may result from a transcriptional dysregulation of circulating monocytes, leading to hyperactivation of pro-inflammatory pathways. Monocytes' cytokine profile may thus represent a predictive marker of response to IFX. Monocytes were isolated from blood samples of 19 CD patients (11 responders, 8 non-responders) and incubated with or without LPS. Cytokine profiles were assessed by RT-qPCR and, in the supernatants, by ELISA assay.

Diagnostic efficacy of double-balloon enteroscopy in patients with suspected isolated small bowel Crohn's disease

BACKGROUND

Owing to the development of double-balloon enteroscopy (DBE) and video capsule endoscopy (VCE) in recent years, direct visualization of the entire small intestinal mucosa has become possible. Because of the nonspecific symptoms and the anatomic location of the small bowel, diagnosis of isolated small bowel Crohn's disease (CD) remains a challenge. The aim of this research was to explore the value of DBE for isolated small bowel CD in situations where routine tests cannot confirm the diagnosis.

METHODS

This study included patients with suspected isolated small bowel CD who were hospitalized in Shengjing Hospital from April 2014 to June 2018. We included patients presenting with chronic diarrhea, abdominal pain, abdominal mass, perianal lesions, and systemic symptoms including weight loss, fever, and anemia after excluding infection factors. Patients with purely colonic CD were excluded from this cohort. Patients with suspected isolated small bowel CD underwent DBE.

RESULTS

In 16/18 patients, pathological findings were detected by DBE. In 12 of the cases, small bowel CD was confirmed. The remaining four patients were diagnosed with small bowel inflammation, duodenal carcinoma, ileum inflammation and small bowel ulcers. However, the diagnosis of CD was confirmed in 14/18 (78%) patients by taking into account the clinical presentation, endoscopic and histological results as well as the experimental treatment. DBE assisted in the diagnosis in 86% (12/14) of the patients.

CONCLUSIONS

In the diagnosis of small bowel CD, DBE is a helpful tool. Before assessment with DBE, clinical features, colonoscopy, and CT were used to initially assess the intestine. According to the lesions indicated by CT, we chose the most appropriate endoscope insertion route, and combined the endoscopic characteristics and pathological results of DBE to confirm the diagnosis.

Small bowel strictures

PURPOSE OF REVIEW

Strictures of the small bowel are an underdiagnosed entity with significant morbidity because of obstruction and risk of perforation and penetrating disease.

RECENT FINDINGS

Recent advances in imaging, enteroscopy, and therapeutic advances particularly in Crohn's disease have enabled gastroenterologists to target and individualize management of small bowel strictures, preventing untimely surgery and complications.

SUMMARY

All patients with obstructive symptoms, suspected small bowel disease, and negative panendoscopy should be evaluated for small intestinal strictures with cross-sectional imaging and considered for capsule endoscopy. Furthermore, the role of device-assisted enteroscopy, initially employed as a diagnostic tool, has evolved into triaging and delivering further medical and interventional treatments.

Meckel's Diverticulum Diagnosed in a Child with Suspected Small Bowel Crohn's Disease

We report a rare case of Meckel's diverticulum in a boy who initially presented with chronic iron deficiency anemia (IDA) without any history of gastrointestinal (GI) bleeding at 8 years-old. Isolated small bowel Crohn's disease was suspected based on findings of small bowel ulcers on capsule endoscopy. At four years from initial presentation, he developed massive GI bleeding. Abdominal computed tomographic angiography and small bowel series revealed findings suggestive of Meckel's diverticulum. Meckel's diverticulum should be suspected in children with unexplained chronic IDA even in the absence of prominent GI bleeding and negative findings on repetitive Meckel's scans. Moreover, Meckel's diverticulum should be included in the differential diagnosis of isolated small bowel Crohn's disease when the disease is limited to a short segment of the distal small bowel, as ulcers and inflammation may result as a consequence of acid secreted from adjacent heterotopic gastric mucosa constituting the Meckel's diverticulum.

Balloon-Assisted Enteroscopy and Capsule Endoscopy in Suspected Small Bowel Crohn's Disease

Inflammatory bowel diseases are idiopathic inflammatory diseases of two main types, Crohn’s disease and ulcerative colitis. Crohn’s disease can affect the entire gastrointestinal tract, and the distal ileum is involved in up to 70% of patients. Moreover, Crohn’s disease in one-quarter to one-third of patients involves isolation of the small bowel. Due to the nonspecific symptoms and anatomical location of the disease, small bowel Crohn’s disease is a phenotype that is particularly difficult to manage. Since the introduction of capsule endoscopy in 2000 and balloon-assisted enteroscopy in the 21st century, it is now possible to directly inspect for small bowel Crohn’s disease. However, the new modalities still have limitations, such as capsule retention and invasiveness of balloon-assisted enteroscopy. The diagnostic yields of both capsule endoscopy and balloon-assisted enteroscopy are high for patients with suspected small bowel Crohn’s disease. Therefore, earlier use of capsule endoscopy or balloon-assisted enteroscopy can help with the diagnosis and earlier treatment of these patients to avert possible disastrous outcomes.

Current role of capsule endoscopy in Crohn’s disease

Capsule endoscopy (CE) currently plays an important role in Crohn’s disease (CD). It is a noninvasive technique that has led to a breakthrough in the endoscopic diagnosis of diseases of the small intestine. Its superior diagnostic performance and excellent safety profile lead to its considerable acceptance on the part of the patient. This paper reviews current indications of CE in three stages of clinical practice: Suspected CD, unclassified colitis and its extensive role in diagnosed CD. The diagnostic and therapeutic impact of the results of CE on the monitoring of this disease is also reviewed. Knowledge of its applications, the interpretation of its results in an appropriate context and the existence of a validated endoscopic activity index could change the way in which these patients are managed. The definition of mucosal healing and postoperative recurrence by means of endoscopic scoring systems will endow CE with new applications in the management of CD in the near future.

Clinical Factors and Disease Course Related to Diagnostic Delay in Korean Crohn's Disease Patients: Results from the CONNECT Study

Diagnostic delay frequently occurs in Crohn's disease (CD) patients because of diagnostic limitations. However, diagnostic delay and its related factors remain poorly defined. Therefore, we aimed to identify the predictors associated with diagnostic delay and to evaluate the impact of diagnostic delay on clinical course in a Korean CD patient cohort. We performed a multicenter retrospective analysis of 1,047 CD patients registered in the Crohn's Disease Clinical Network and Cohort study in Korea. The mean interval of diagnostic delay was 16.0 ± 33.1 months. Multivariate analysis showed that older age at diagnosis (≥40 years) (p = 0.014), concomitant upper gastrointestinal (UGI) disease (p = 0.012) and penetrating disease behavior at diagnosis (p = 0.001) were positively associated with long diagnostic delay (≥18 months). During the longitudinal follow-up, long diagnostic delay was independently predictive of further development of intestinal stenosis (hazard ratio [HR], 1.43; 95% confidence interval [CI], 1.07-1.93; p = 0.017), internal fistulas (HR, 1.62; 95% CI, 1.12-2.33; p = 0.011), and perianal fistulas (HR, 1.38; 95% CI, 1.06-1.80; p = 0.016). However, as for the risk of abscess formation, bowel perforation, and CD-related abdominal surgery, no significant association with diagnostic delay was observed. Older age at diagnosis, UGI involvement, and penetrating behavior are associated with long diagnostic delay in Korean CD patients. Moreover, diagnostic delay is associated with an increased risk of CD-related complications such as intestinal stenosis, internal fistulas, and perianal fistulas.