Predictors of clinical and endoscopic findings in differentiating Crohn's disease from intestinal tuberculosis

New diagnostic strategies to distinguish Crohn's disease and gastrointestinal tuberculosis

PURPOSE OF REVIEW

Despite advances in our radiological, histological and microbiological armamentarium, distinguishing between Crohn's disease (CD) and intestinal tuberculosis (ITB), especially in a TB endemic country, continues to be a challenging exercise in a significant number of patients. This review aims to summarize current available evidence on novel diagnostic techniques which have a potential to fill the gap in our knowledge of differentiating between ITB and CD.

RECENT FINDINGS

Both ITB and CD are associated with altered host immune responses, and detection of these altered innate and adaptive immune cells has potential to distinguish ITB from CD. ITB and CD have different epigenetic, proteomic and metabolomic signatures, and recent research has focused on detecting these differences. In addition, the gut microbiome, which is involved in mucosal immunity and inflammatory responses, is considerably altered in both ITB and CD, and is another potential frontier, which can be tapped to discriminate between the two diseases. With technological advancements, we have newer radiological modalities including perfusion CT and dual-layer spectral detector CT enterography and evidence is emerging of their role in differentiating ITB from CD. Finally, time will tell whether the advent of artificial intelligence, with rapidly accumulating data in this field, will be the gamechanger in solving this puzzle of diagnostic dilemma between ITB and Crohn's disease.

SUMMARY

Recent advances need to be clinically validated before they can be used as novel diagnostic measures to differentiate Intestinal TB from CD.

Differentiating gastrointestinal tuberculosis and Crohn's disease- a comprehensive review

Gastrointestinal Tuberculosis (GITB) and Crohn's disease (CD) are both chronic granulomatous diseases with a predilection to involve primarily the terminal ileum. GITB is often considered a disease of the developing world, while CD and inflammatory bowel disease are considered a disease of the developed world. But in recent times, the epidemiology of both diseases has changed. Differentiating GITB from CD is of immense clinical importance as the management of both diseases differs. While GITB needs anti-tubercular therapy (ATT), CD needs immunosuppressive therapy. Misdiagnosis or a delay in diagnosis can lead to catastrophic consequences. Most of the clinical features, endoscopic findings, and imaging features are not pathognomonic for either of these two conditions. The definitive diagnosis of GITB can be clinched only in a fraction of cases with microbiological positivity (acid-fast bacilli, mycobacterial culture, or PCR-based tests). In most cases, the diagnosis is often based on consistent clinical, endoscopic, imaging, and histological findings. Similarly, no single finding can conclusively diagnose CD. Multiparametric-based predictive models incorporating clinical, endoscopy findings, histology, radiology, and serology have been used to differentiate GITB from CD with varied results. However, it is limited by the lack of validation studies for most such models. Many patients, especially in TB endemic regions, are initiated on a trial of ATT to see for an objective response to therapy. Early mucosal response assessed at two months is an objective marker of response to ATT. Prolonged ATT in CD is recognized to have a fibrotic effect. Therefore, early discrimination may be vital in preventing the delay in the diagnosis of CD and avoiding a complicated course.

Differential diagnosis of Crohn’s disease and intestinal tuberculosis: development and assessment of a nomogram prediction model

Background

China is a region with a high incidence of tuberculosis, and the incidence of IBD has also been rising rapidly in recent years. Differentiating Crohn’s disease(CD) from intestinal tuberculosis (ITB) has become a very challenging issue. We aimed to develop and assess a diagnostic nomogram to differentiate between CD and ITB to improve the accuracy and practicability of the model.

Methods

A total of 133 patients (CD 90 and ITB 43) were analyzed retrospectively. Univariate and multivariate logistic regression analysis was included to determine the independent predictive factors and establish the regression equation. On this basis, the nomogram prediction model was constructed. The discrimination, calibration and clinical efficiency of the nomogram were assessed using area under the curve(AUC), C-index, calibration curve, decision curve analysis (DCA) and clinical impact curve.

Results

T-SPOT positive, cobblestone appearance, comb sign and granuloma were significant predictors in differentiating CD from ITB. Base on the above independent predictors, a diagnostic nomogram was successfully established. The sensitivity, specificity, accuracy of the prediction model are 94.4%, 93.0%, 94.0% respectively. The AUC and the C-index of the prediction model are both 0.988, which suggest that the model had a good discrimination power. The calibration curve indicated a high calibration degree of the prediction model. The DCA and clinical impact curve indicated a good clinical efficiency of the prediction model which could bring clinical benefits.

Conclusion

A nomogram prediction model for distinguishing CD from ITB was developed and assessed, with high discrimination, calibration and clinical efficiency. It can be used as an accurate and convenient diagnostic tool to distinguish CD from ITB, facilitating clinical decision-making.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02519-z.

A Novel Clinical Radiomics Nomogram to Identify Crohn's Disease from Intestinal Tuberculosis

Purpose

To establish a clinical radiomics nomogram to differentiate Crohn’s disease (CD) from intestinal tuberculosis (ITB).

Patients and Methods

Ninety-three patients with CD and 67 patients with ITB were recruited (111 in training cohort and 49 in test cohort). The region of interest (ROI) for the lesions in the ileocecal region was delineated on computed tomography enterography and radiomics features extracted. Radiomics features were filtered by the gradient boosting decision tree (GBDT), and a radiomics score was calculated by using the radiomics signature-based formula. We constructed a clinical radiomics model and nomogram combining clinical factors and radiomics score through multivariate logistic regression analysis, and the internal validation was undertaken by ten-fold cross validation. Analyses of receiver operating characteristic (ROC) curves and decision curve analysis (DCA) were used to evaluate the prediction performance. DeLong test was applied to evaluate the performance of the clinical, radiomics and combined model.

Results

The clinical radiomics nomogram, which was based on the 9 radiomics signature and two clinical factors, indicated that the clinical radiomics model had an area under the ROC curve (AUC) value of 0.96 (95% confidence interval [CI]: 0.93–0.99) in the training cohort and 0.93 (95% CI: 0.86–1.00) in validation cohort. The clinical radiomics model was superior to the clinical model and radiomics model, and the difference was significant (P = 0.006, 0.004) in the training cohort. DCA confirmed the clinical utility of clinical radiomics nomogram.

Conclusion

CTE-based radiomics model has a good performance in distinguishing CD from ITB. A nomogram constructed by combining radiomics and clinical factors can help clinicians accurately diagnose and select appropriate treatment strategies between CD and ITB.

An outcome-based composite approach for the diagnosis of intestinal tuberculosis: a pilot study from a tertiary care centre in South India

BACKGROUND

The diagnosis of intestinal TB (ITB) is challenging because of its overlapping features with Crohn's disease. This outcome-based study evaluated the combination of colonoscopy, histopathology, Xpert MTB/RIF and TB culture for best sensitivity and specificity.

METHOD

This was a four-year retrospective, observational study of 426 clinically suspected patients who underwent colonoscopy with biopsies for histopathology, Xpert MTB/RIF and TB culture. ITB was diagnosed using the composite reference standard (CRS), which comprised either histological features or culture or Xpert MTB/RIF positivity, and positive response to anti-tuberculous treatment on follow up.

RESULTS

35 (8.2%) patients were diagnosed with ITB. Histopathology had the highest sensitivity (91.4%) and negative predictive value (99.2%), MTB/RIF had the highest specificity (100%) and positive predictive value (100%). A combinatorial approach with Xpert MTB/RIF and histopathology had optimal diagnostic value (97%), approaching 100% sensitivity with culture. 40% of cases were diagnosed within 12 hours with Xpert MTB/RIF and 97% cases within three days.

CONCLUSION

This combinatorial diagnostic model provides rapid and reliable diagnosis of ITB which may be useful in endemic areas.

Gastrointestinal tuberculosis: A systematic review of epidemiology, presentation, diagnosis and treatment

Tuberculosis (TB) once considered a disease of the developing world is infrequent in the developing world too. Its worldwide prevalence with a huge impact on the healthcare system both in economic and health terms has prompted the World Health Organization to make it a top priority infectious disease. Tuberculous infection of the pulmonary system is the most common form of this disease, however, extrapulmonary TB is being increasingly recognized and more often seen in immunocompromised situations. Gastrointestinal TB is a leading extrapulmonary TB manifestation that can defy diagnosis. Overlap of symptoms with other gastrointestinal diseases and limited accuracy of diagnostic tests demands more awareness of this disease. Untreated gastrointestinal TB can cause significant morbidity leading to prolonged hospitalization and surgery. Prompt diagnosis with early initiation of therapy can avoid this. This timely review discusses the epidemiology, risk factors, pathogenesis, clinical presentation, current diagnostic tools and therapy.

A Comprehensive Review of Infectious Granulomatous Diseases of the Gastrointestinal Tract

A granuloma is defined as a localized inflammatory reaction or a hypersensitive response to a nondegradable product leading to an organized collection of epithelioid histiocytes. Etiologies of granulomatous disorders can be divided into two broad categories: infectious and noninfectious (autoimmune conditions, toxins, etc.) causes. The endless list of causalities may prove challenging for gastroenterologists and pathologists to formulate a list of clearly defined differentials. This is true when distinguishing these etiologies based on various clinical presentations and endoscopic and histological findings. We aim to provide a comprehensive review of some of the frequent and rare infectious granulomatous diseases of the gastrointestinal tract documented in the literature to date. We provide an overview of each infectious pathology with an emphasis on epidemiology, clinical presentation, and endoscopic and histologic findings, in addition to treatment.

Intestinal Tuberculosis: A Diagnostic Challenge

Diagnosing intestinal tuberculosis (TB) with uncommon clinical manifestations is often challenging. Here, we report a case of an alcoholic patient who presented with vague symptoms and was later diagnosed with intestinal TB. This patient experienced multiorgan failure causing hemodynamic instability requiring ionotropic support; acute hypoxic respiratory failure managed with non-invasive positive pressure ventilation, hepatic failure, transudative peritoneal effusion, and transudative pleural effusion. These conditions clouded our judgment to pursue colonoscopy for a definite diagnosis and delayed the anti-tuberculosis treatment. When intestinal tuberculosis TB is suspected, the differential diagnosis must be established with other gastrointestinal involving diseases, including mycobacterium avium complex (MAC) and Crohn's disease (CD). MAC can show overlapping features with intestinal TB or coexist with it; Acid-fast stain and tissue culture are the key tests to differentiate these two. In the presence of diagnostic uncertainty between intestinal TB and CD, a therapeutic trial with anti-tuberculous therapy may be warranted.

Validation of models using basic parameters to differentiate intestinal tuberculosis from Crohn's disease: A multicenter study from Asia

BACKGROUND

Data on external validation of models developed to distinguish Crohn's disease (CD) from intestinal tuberculosis (ITB) are limited. This study aimed to validate and compare models using clinical, endoscopic, and/or pathology findings to differentiate CD from ITB.

METHODS

Data from newly diagnosed ITB and CD patients were retrospectively collected from 5 centers located in Thailand or Hong Kong. The data was applied to Lee, et al., Makharia, et al., Jung, et al., and Limsrivilai, et al. model.

RESULTS

Five hundred and thirty patients (383 CD, 147 ITB) with clinical and endoscopic data were included. The area under the receiver operating characteristic curve (AUROC) of Limsrivilai's clinical-endoscopy (CE) model was 0.853, which was comparable to the value of 0.862 in Jung's model (p = 0.52). Both models performed significantly better than Lee's endoscopy model (AUROC: 0.713, p<0.01). Pathology was available for review in 199 patients (116 CD, 83 ITB). When 3 modalities were combined, Limsrivilai's clinical-endoscopy-pathology (CEP) model performed significantly better (AUROC: 0.887) than Limsrivilai's CE model (AUROC: 0.824, p = 0.01), Jung's model (AUROC: 0.798, p = 0.005) and Makharia's model (AUROC: 0.637, p<0.01). In 83 ITB patients, the rate of misdiagnosis with CD when used the proposed cutoff values in each original study was 9.6% for Limsrivilai's CEP, 15.7% for Jung's, and 66.3% for Makharia's model.

CONCLUSIONS

Scoring systems with more parameters and diagnostic modalities performed better; however, application to clinical practice is still limited owing to high rate of misdiagnosis of ITB as CD. Models integrating more modalities such as imaging and serological tests are needed.

Intestinal tuberculosis or Crohn's disease: a review of the diagnostic models designed to differentiate between these two gastrointestinal diseases

Differentiating Crohn’s disease (CD) from intestinal tuberculosis (ITB) is a diagnostic dilemma, particularly in regions where ITB is prevalent and CD incidence is increasing, because both diseases can present quite similarly, and diagnostic tests to identify Mycobacterium tuberculosis in tissue samples have rather poor sensitivity. Studies that were conducted to determine the factors that differentiate CD from ITB identified some significant characteristics, but none of those characteristics are exclusive to either ITB or CD. Many diagnostic models or scoring systems that use one to several diagnostic parameters have been proposed to help distinguish these two intestinal diseases. Early models consisted of parameters common to routine clinical practice, such as clinical features, and endoscopic and pathologic findings. The later models also include more advanced diagnostic parameters like high-resolution imaging and serological testing. However, the number and types of parameters differ among diagnostic models, and the systems used to calculate scoring also vary from model to model. Enhanced awareness and understanding of the currently available diagnostic models will help physicians determine which model(s) is/are most suitable for differentiating CD from ITB in their clinical practice.

Imaging in discriminating intestinal tuberculosis and Crohn's disease: past, present and the future

Introduction: Intestinal tuberculosis (ITB) and Crohn's disease (CD) have similar clinical presentation, but require different treatment approaches. Despite advances in various endoscopic, imaging, microbiological, and histological techniques, the differentiation of these two entities is often difficult. Newer radiological and image acquisition modalities have now become indispensable tools for evaluation of these two diseases.Areas covered: This review summarizes the currently available literature on various radiological investigations to differentiate ITB from CD. This review also enumerates the newer modalities in image acquisition techniques and their potential role for differentiating these two diseases. At present abdominal computed tomography (CT) scan is used as a first line investigation for differentiating ITB from CD. Magnetic resonance imaging (MRI) is preferred in pediatric patients and for follow-up studies.Expert opinion: Role of newer modalities like contrast enhanced abdominal ultrasound, perfusion CT, advanced MRI and positron emission tomography (PET) is evolving and requires further exploration. Till further robust studies are available, differentiation between ITB and CD requires use of a combination of clinical, endoscopic, serological, histological, and radiological parameters rather than relying on a single test.

Differentiating Crohn’s disease from intestinal tuberculosis

Differentiating Crohn’s disease (CD) and intestinal tuberculosis (ITB) has remained a dilemma for most of the clinicians in the developing world, which are endemic for ITB, and where the disease burden of inflammatory bowel disease is on the rise. Although, there are certain clinical (diarrhea/hematochezia/perianal disease common in CD; fever/night sweats common in ITB), endoscopic (longitudinal/aphthous ulcers common in CD; transverse ulcers/patulous ileocaecal valve common in ITB), histologic (caseating/confluent/large granuloma common in ITB; microgranuloma common in CD), microbiologic (positive stain/culture for acid fast-bacillus in ITB), radiologic (long segment involvement/comb sign/skip lesions common in CD; necrotic lymph node/contiguous ileocaecal involvement common in ITB), and serologic differences between CD and ITB, the only exclusive features are caseation necrosis on biopsy, positive smear for acid-fast bacillus (AFB) and/or AFB culture, and necrotic lymph node on cross-sectional imaging in ITB. However, these exclusive features are limited by poor sensitivity, and this has led to the development of multiple multi-parametric predictive models. These models are also limited by complex formulae, small sample size and lack of validation across other populations. Several new parameters have come up including the latest Bayesian meta-analysis, enumeration of peripheral blood T-regulatory cells, and updated computed tomography based predictive score. However, therapeutic anti-tubercular therapy (ATT) trial, and subsequent clinical and endoscopic response to ATT is still required in a significant proportion of patients to establish the diagnosis. Therapeutic ATT trial is associated with a delay in the diagnosis of CD, and there is a need for better modalities for improved differentiation and reduction in the need for ATT trial.

Diagnostic Performance of a 5-Marker Predictive Model for Differential Diagnosis Between Intestinal Tuberculosis and Crohn's Disease

BACKGROUND

The differentiation between intestinal tuberculosis (ITB) and Crohn's disease (CD) is a challenge. The aim of this study was to investigate a predictive model for differential diagnosis between ITB and CD.

METHODS

A total of 268 patients who were suspected of having ITB or CD were prospectively recruited between January 2013 and September 2016. The clinical, laboratory, radiological, endoscopic, and histological features were investigated and subjected to univariate and multivariate analyses. The final predictive model was developed based on the regression coefficients of multivariate logistic regression. To validate the model, the same regression equation was tested on the other group.

RESULTS

A total of 239 patients had a final diagnosis, including 86 ITB and 153 CD. Five variables (perianal disease, pulmonary involvement, longitudinal ulcer, left colon, and ratio of tuberculosis-specific antigen to phytohaemagglutinin) were selected for the predictive model to discriminate between ITB and CD. In the predictive model of the training data set, the area under the receiver operating characteristic (ROC) curve, sensitivity, specificity, and accuracy, with a cutoff level of 0.29, were 0.975 (95% confidence interval [CI], 0.939-0.993), 96.7%, 90.7%, and 92.8%, respectively. Application of the predictive model to the validation data set showed similar performance in distinguishing ITB from CD. The area under the ROC curve, sensitivity, specificity, and accuracy were 0.950 (95% CI, 0.871-0.987), 88.5%, 93.5%, and 91.7%, respectively.

CONCLUSIONS

This 5-marker predictive model could be conveniently used by clinicians to draw a reliable differential diagnosis between ITB and CD in clinical practice. 10.1093/ibd/izy154_video1izy154.video15790725497001.

Tuberculosis of the gastrointestinal tract and associated viscera

Tuberculosis involvement of the gastrointestinal tract, peritoneum, and associated viscera is an uncommon but well described entity. While peritoneal tuberculosis and tuberculous enteritis are more common, involvement of the esophagus, stomach, colon, rectum, anus, liver, bile ducts, gallbladder, and pancreas can occur. Diagnosis is challenging as cases often mimic neoplasm or inflammatory bowel disease. In this review we outline the pathogenesis, clinical presentation, diagnostic testing, and treatment strategies pertaining to such cases.

Clinical and laboratory features of intestinal tuberculosis

Background/aims

As increasing numbers of Crohn's disease (CD) cases are being recognized in India, so the differential diagnosis of CD and gastrointestinal tuberculosis (GITB) is becoming increasingly important. If patients are misdiagnosed with GITB, toxicity may result from unnecessary anti-TB therapy and treatment of the primary disease (ie, CD) gets delayed. We therefore aimed to assess the accuracy of various parameters that can be used to predict GITB diagnosis at index evaluation.

Materials and methods

This was a prospective, unicentric, observational study carried out in the gastroenterology department of a tertiary care hospital between August 2011 and January 2013. Patients who presented to our hospital and were suspected of having GITB were included in our study. Patients were then followed up over a 6-month period.

Statistical analysis

Chi-square test was used to analyze the data.

Results

Of the 69 patients with GITB, 49 (71.01%) had thickening of the involved part of the colon and 33 (47.83%) had abdominal lymphadenopathy. The ileocecal valve was involved in 58 patients (84.05%) Histological detection of granulomas had 78.95% specificity, 36.23% sensitivity, and 51.40% accuracy. Tuberculosis polymerase chain reaction was found to have 78.95% specificity, 71.01% sensitivity, and 73.83% accuracy. BACTEC-MGIT culture was found to have 100% specificity, 20.29% sensitivity, and 48.60% accuracy.

Conclusion

Although histology is helpful in ruling out other conditions, TB-specific findings such as caseating granuloma and acid-fast bacilli are rarely seen. Instead, tuberculosis polymerase chain reaction has the highest diagnostic accuracy followed by BACTEC culture.

Differentiation Between Crohn Disease and Intestinal Tuberculosis in Children

OBJECTIVES

The aim of the study was to evaluate clinical, endoscopic, radiologic, and histopathological features helpful in differentiating Crohn disease (CD) from intestinal tuberculosis (ITB) in children.

METHODS

Patients diagnosed to have CD or ITB based on standard recommended criteria were enrolled. Children with inflammatory bowel disease unclassified or suspected ITB or CD with incomplete work-up or lost to follow-up were excluded. The clinical and laboratory (radiology, endoscopy, and histology) details of children were analyzed.

RESULTS

Twenty cases of ITB (14 [3-17] years) and 23 of CD (11 [1-17] years) were enrolled. Presentation with chronic diarrhea (82% vs 40%; P = 0.006) and blood in stool (74% vs 10%; P = 0.001) favored CD, whereas subacute intestinal obstruction (20% vs 0%; P = 0.04) and ascites (30% vs 0%; P = 0.005) favored ITB. Presence of deep ulcers (61% vs 30%; P = 0.04), longitudinal ulcers (48% vs 15%; P = 0.02), involvement of multiple colonic segments (70% vs 35%; P = 0.02), left-sided colon (87% vs 40%; P = 0.003), extraintestinal manifestations (21.7% vs 0%; P = 0.02), and higher platelet count (3.9 vs 2.6 × 10/mm; P = 0.02) favored CD. Isolated ileocecal involvement (40% vs 8.7%; P = 0.03) was a feature of ITB. TB bacilli were demonstrated in 40% ITB cases (colon-6, ascites-1, abdominal lymph node-1). On multivariate analysis, presence of blood in stool (odds ratio: 37.5 [confidence interval: 3.85-365.72], P = 0.002) and left-sided colonic involvement (odds ratio: 16.2 [confidence interval: 1.63-161.98], P = 0.02) were independent predictors of CD.

CONCLUSIONS

Microbiologic confirmation of tuberculosis is possible in 40% ITB cases. Presence of blood in stool and left-sided colonic involvement are the most important features favoring CD.

Temporal trends in the misdiagnosis rates between Crohn's disease and intestinal tuberculosis

AIM

To investigate the temporal trends in the misdiagnosis rate between Crohn's disease (CD) and intestinal tuberculosis (ITB) in South Korea.

METHODS

We retrospectively reviewed the medical records of patients managed for CD or ITB at Asan Medical Center, a tertiary referral hospital, Seoul, Korea between 1996 and 2014. The temporal trends in the misdiagnosis rates between the two diseases were analyzed. The demographic and clinical characteristics were compared between CD patients who were initially misdiagnosed as ITB (final CD group) and vice versa (final ITB group). Final diagnostic criteria for ITB and medication for CD before definite diagnosis of TB were also analyzed in final ITB group.

RESULTS

In total, 2760 patients were managed for CD and 772 patients for ITB between 1996 and 2014. As well, 494 of the 2760 CD patients (17.9%) were initially misdiagnosed as ITB and 83 of the 772 ITB patients (10.8%) as CD. The temporal trend in misdiagnosing CD as ITB showed a decrease (OR = 0.89, 95%CI: 0.87-0.91, P < 0.001), whereas the temporal trend in misdiagnosing ITB as CD showed an increase (OR = 1.06, 95%CI: 1.01-1.11, P = 0.013). Age at diagnosis, presenting symptoms, and proportion of patients with active/past perianal fistula and active/inactive pulmonary tuberculosis (TB) were significantly different between final CD group and final ITB group. Forty patients (48.2%) in final ITB group were diagnosed by favorable response to empirical anti-TB treatment. Seventeen patients (20.5%) in final ITB group had inappropriately received corticosteroids and/or thiopurines due to misdiagnosis as CD. However, there were no mortalities in both groups.

CONCLUSION

Cases of CD misdiagnosed as ITB have been decreasing, whereas cases of ITB misdiagnosed as CD have been increasing over the past two decades.

Capsule endoscopy in small bowel Crohn’s disease and Tuberculosis

Differentiation of small bowel tuberculosis (SBTB) from Crohn’s disease (CD) is a diagnostic challenge. We studied 52 patients with suspected SBTB or CD with terminal ileal involvement, who were prospectively enrolled. After confirming patency of the gastrointestinal tract, 26 patients underwent capsule endoscopy (CE). A final diagnosis of CD was found in 18 patients and SBTB in eight patients. All SBTB patients had involvment of the ileocecal valve (ICV) with large (n = 6) and aphthous (n = 2) ulcers in the ileal segment. In CD, ICV involvement was seen in five (33%) patients. Large and aphthous ulcers were observed in seven (47%) and 15 (100%) patients, respectively. On comparison with CD, patients with SBTB had increased frequency of ICV involvement ( P = 0.002) and lesser frequency of aphthous ulcers ( P = 0.007). CE can help in differentiating CD from SBTB by the position of its involvement and the type of ulcers present.

Clinical and Laboratory Diagnosis of Intestinal Tuberculosis

Background:

Tuberculosis (TB) remains a worldwide problem. Intestinal TB (ITB) constitutes a major public health problem in developing countries and has been associated with significant morbidity and mortality. The aim of this study was to characterize the clinical, radiological, endoscopic, and pathological features of ITB and to define the strategy for establishing the diagnosis.

Methods:

A retrospective study (from January 2000 to June 2015) was carried out in Peking Union Medical College Hospital and all hospitalized cases were diagnosed as ITB during the study period were included. The relevant clinical information, laboratory results, microbiological, and radiological investigations were recorded.

Results:

Of the 85 cases, 61 cases (71.8%) were ranged from 20 to 50 years. The ileocecal region was involved in about 83.5% (71/85) of patients. About 41.2% (35/85) of patients had co-existing extra ITB, especially active pulmonary TB. Abdominal pain (82.4%) was the most common presenting symptom followed by weight loss (72.9%) and fever (64.7%). Both T-cell spot of TB test (T-SPOT.TB) and purified protein derivatives (PPD) tests were performed in 26 patients: 20 (76.9%) positive T-SPOT.TB and 13 (50.0%) positive PPD were detected, with a statistical significant difference (P = 0.046). Twenty cases (23.5%) were histopathology and/or pathogen confirmed TB; 27 cases (31.8%) were diagnosed by clinical manifestation consistent with ITB and evidence of active extra ITB; 38 cases (44.7%) were diagnosed by good response to diagnostic anti-TB therapy.

Conclusions:

ITB is difficult to diagnose even with modern medical techniques due to its nonspecific clinical and laboratory features. At present, combination of clinical, endoscopic, radiological, and pathological features continues to be the key to the diagnosis of ITB.

Meta-Analytic Bayesian Model For Differentiating Intestinal Tuberculosis from Crohn's Disease

OBJECTIVES

Distinguishing intestinal tuberculosis (ITB) from Crohn's disease (CD) is difficult, although studies have reported clinical, endoscopic, imaging, and laboratory findings that help to differentiate these two diseases. We aimed to produce estimates of the predictive power of these findings and construct a comprehensive model to predict the probability of ITB vs. CD.

METHODS

A systematic literature search for studies differentiating ITB from CD was conducted in MEDLINE, PUBMED, and EMBASE from inception until September 2015. Fifty-five distinct meta-analyses were performed to estimate the odds ratio of each predictive finding. Estimates with a significant difference between CD and ITB and low to moderate heterogeneity (I²<50%) were incorporated into a Bayesian prediction model incorporating the local pretest probability.

RESULTS

Thirty-eight studies comprising 2,117 CD and 1,589 ITB patients were included in the analyses. Findings in the model that significantly favored CD included male gender, hematochezia, perianal disease, intestinal obstruction, and extraintestinal manifestations; endoscopic findings of longitudinal ulcers, cobblestone appearance, luminal stricture, mucosal bridge, and rectal involvement; pathological findings of focally enhanced colitis; and computed tomographic enterography (CTE) findings of asymmetrical wall thickening, intestinal wall stratification, comb sign, and fibrofatty proliferation. Findings that significantly favored ITB included fever, night sweats, lung involvement, and ascites; endoscopic findings of transverse ulcers, patulous ileocecal valve, and cecal involvement; pathological findings of confluent or submucosal granulomas, lymphocyte cuffing, and ulcers lined by histiocytes; a CTE finding of short segmental involvement; and a positive interferon-γ release assay. The model was validated by gender, clinical manifestations, endoscopic, and pathological findings in 49 patients (27 CD, 22 ITB). The sensitivity, specificity, and accuracy for diagnosis of ITB were 90.9%, 92.6%, and 91.8%, respectively.

CONCLUSIONS

A Bayesian model based on the meta-analytic results is presented to estimate the probability of ITB and CD calibrated to local prevalence. This model can be applied to patients using a publicly available web application.

Endoscopic and clinical responses to anti-tubercular therapy can differentiate intestinal tuberculosis from Crohn's disease

BACKGROUND

Differentiation between intestinal tuberculosis and Crohn's disease is difficult and may require therapeutic trial with anti-tubercular therapy in tuberculosis-endemic regions.

AIM

To evaluate the role of therapeutic trial with anti-tubercular therapy in patients with diagnostic confusion between intestinal tuberculosis and Crohn's disease.

METHODS

We performed retrospective-comparative (n = 288: 131 patients who received anti-tubercular therapy before being diagnosed as Crohn's disease and 157 intestinal tuberculosis patients) and prospective-validation study (n = 55 patients with diagnostic confusion of intestinal tuberculosis/Crohn's disease). Outcomes assessed were global symptomatic response and endoscopic mucosal healing.

RESULTS

In the derivation cohort, among those eventually diagnosed as Crohn's disease, global symptomatic response with anti-tubercular therapy was seen in 38% at 3 months and in 37% who completed 6 months of anti-tubercular therapy. Ninety-four per cent of intestinal tuberculosis patients showed global symptomatic response by 3 months. Endoscopic mucosal healing was seen in only 5% of patients with Crohn's disease compared with 100% of intestinal tuberculosis patients. In the validation cohort, all the patients with intestinal tuberculosis had symptomatic response and endoscopic mucosal healing after 6 months of anti-tubercular therapy. Among the patients with an eventual diagnosis of Crohn's disease, symptomatic response was seen in 64% at 2 months and in 31% who completed 6 months of anti-tubercular therapy, none had mucosal healing.

CONCLUSIONS

Disproportionately lower mucosal healing rate despite an overall symptom response with 6 months of anti-tubercular therapy in patients with Crohn's disease suggests a need for repeat colonoscopy for diagnosing Crohn's disease. Patients with intestinal tuberculosis showing significant symptomatic response after 2-3 months of anti-tubercular therapy, suggest that symptom persistence after a therapeutic trial of 3 months of anti-tubercular therapy may indicate the diagnosis of Crohn's disease.

The Challenge of Inflammatory Bowel Disease Diagnosis in Asia

Background

The current major clinical challenge relates to the accurate diagnosis of inflammatory bowel disease (IBD) in Asian countries with a high background prevalence of infections.

Summary

The diagnosis of Crohn's disease in geographical areas where tuberculosis is endemic poses a major diagnostic challenge.

Key Messages

Infections can mimic IBD and complicate the course of existing IBD. Limited availability of diagnostic modalities and health service may delay diagnosis. A multidisciplinary approach, continuous medical education, and academic activities may warrant an accurate diagnosis of IBD.

Predictive Factors for Differentiating Between Crohn's Disease and Intestinal Tuberculosis in Koreans

OBJECTIVES

A differential diagnosis between intestinal tuberculosis (ITB) and Crohn's disease (CD) is challenging. The aim of this study was to investigate the clinical, endoscopic, and histological features and to create a predictive score model for differentiating CD and ITB.

METHODS

In total, 261 patients, 99 with ITB and 162 with CD, were recruited from seven tertiary centers from 2005 to 2013 and reviewed retrospectively. For the creation of a validated model, parameters were selected by univariate logistic regression and receiver operating characteristic curve analyses. Then, the prediction model was established on the basis of β-coefficients of the multivariate logistic regression. For the validation of the model, the same regression equation was tested on the other group.

RESULTS

Age, diarrhea, ring-shaped ulcer, longitudinal ulcer, sigmoid involvement, suspicious radiological pulmonary tuberculosis, and gender were selected as the factors for a seven-marker model. In the seven-marker model of the validation data set, the sensitivity, specificity, positive predictive value, and negative predictive value with a cutoff level of 0.35 were 98.0, 92.4, 88.9, and 98.6, respectively.

CONCLUSIONS

The seven-marker model seems to be highly reliable for differentiating between ITB and CD and could be conveniently used by clinicians to obtain results.

Proteome analysis of the macroscopically affected colonic mucosa of Crohn's disease and intestinal tuberculosis

Differentiation between intestinal tuberculosis (ITB) and Crohn’s disease (CD) is challenging in geographical regions where both these diseases are prevalent. There is a need of biomarkers for differentiation between these two disorders. Colonic biopsies from inflamed mucosa of treatment-naive patients with ITB, CD and controls were used for analysis. Protein extracted from biopsies was digested with trypsin and resulting peptides were labeled with iTRAQ reagents. The peptides were subsequently analyzed using LC-MS/MS for identification and quantification. Gene ontology annotation for proteins was analyzed in PANTHER. Validation experiments were done for six differentially expressed proteins using immunohistochemistry. 533 proteins were identified and 241 proteins were quantified from 5 sets of iTRAQ experiments. While 63 were differentially expressed in colonic mucosa of patients with CD and ITB in at least one set of iTRAQ experiment, 11 proteins were differentially expressed in more than one set of experiments. Six proteins used for validation using immunohistochemistry in a larger cohort of patients; none of them however was differentially expressed in patients with ITB and CD. There are differentially expressed proteins in tissue proteome of CD and ITB. Further experiments are required using a larger cohort of homogeneous tissue samples.

Intestinal tuberculosis and Crohn's disease: challenging differential diagnosis

Along with epidemiological changes in tuberculosis (TB) and an increased incidence of Crohn's disease (CD), the differential diagnosis of intestinal TB (ITB) and CD is of vital importance and has become a clinical challenge because treatment based on misdiagnosis may lead to fatal outcomes. In this study, we reviewed the similarities and differences in clinical, endoscopic, radiological and histological features of these two diseases. Concomitant pulmonary TB, ascites, night sweats, involvement of fewer than four segments of the bowel, patulous ileocecal valve, transverse ulcers, scars or pseudopolyps strongly indicate ITB. Bloody stools, perianal signs, chronic diarrhea, extraintestinal manifestations, anorectal lesions, longitudinal ulcers and a cobblestone appearance are all suggestive of CD. Significant differences in the size, number, location and patterns of granulomas in ITB and CD with regard to their histopathologic features have been noted. Immune stain of cell surface markers is also helpful. Interferon-γ release assay and polymerase chain reaction analysis have achieved satisfactory sensitivity and specificity in the diagnosis of ITB. Computed tomography enterographic findings of segmental small bowel or left colon involvement, mural stratification, the comb sign and fibrofatty proliferation are significantly more common in CD, whereas mesenteric lymph node changes (calcification or central necrosis) and focal ileocecal lesions are more frequently seen in ITB. A diagnosis should be carefully established before the initiation of the therapy. In suspicious cases, short-term empirical anti-TB therapy is quite efficient to further confirm the diagnosis.

Asia Pacific Consensus Statements on Crohn's disease. Part 1: Definition, diagnosis, and epidemiology: (Asia Pacific Crohn's Disease Consensus--Part 1)

Inflammatory bowel disease (IBD) was previously thought to be rare in Asia, but emerging data indicate rising incidence and prevalence of IBD in the region. The Asia Pacific Working Group on Inflammatory Bowel Disease was established in Cebu, Philippines, at the Asia Pacific Digestive Week conference in 2006 under the auspices of the Asian Pacific Association of Gastroenterology with the goal of developing best management practices, coordinating research, and raising awareness of IBD in the region. The consensus group previously published recommendations for the diagnosis and management of ulcerative colitis with specific relevance to the Asia-Pacific region. The present consensus statements were developed following a similar process to address the epidemiology, diagnosis, and management of Crohn's disease. The goals of these statements are to pool the pertinent literature specifically highlighting relevant data and conditions in the Asia-Pacific region relating to the economy, health systems, background infectious diseases, differential diagnoses, and treatment availability. It does not intend to be all comprehensive and future revisions are likely to be required in this ever-changing field.

Genome-wide gene expression analysis for target genes to differentiate patients with intestinal tuberculosis and Crohn's disease and discriminative value of FOXP3 mRNA expression

BACKGROUND AND AIMS

Crohn's disease (CD) and intestinal tuberculosis (ITB) are both chronic granulomatous conditions with similar phenotypic presentations. Hence, there is need for a biomarker to differentiate between both these two diseases. This study aimed at genome-wide gene expression analysis of colonic biopsies from confirmed cases of ITB and CD in comparison with controls. To evaluate the role of T regulatory cells, forkhead box P3 (FOXP3) mRNA expression was quantified in serum as well as in colonic biopsies from patients with ITB and with the controls.

METHODS

Paired samples, including serum and colonic biopsies, were taken from 33 study subjects (CD, ITB and controls), and total RNA was extracted. Human whole genome gene expression microarray analysis was performed using the Illumina HumanWG-6 BeadChip Kit with six total RNA samples of the three groups in duplicates. Real-time PCR for FOXP3 mRNA expression was analyzed in serum samples and colonic biopsy samples (4-CD, 5-ITB, 4-controls).

RESULTS

In CD and ITB there was 1.5-fold upregulation of 92 and 382 genes and 1.5-fold downregulation of 91 and 256 genes, respectively. Peroxisome proliferators via the PPARγ pathway were most significantly downregulated (P < 0.005) in CD. Additionally, the IL4/5/6 signaling pathways and Toll-like receptor signaling pathway were identified as significantly differentially regulated (P < 0.005) at > 2-fold change. In ITB, the complement activation pathway, specifically the classical pathway, was the most significantly upregulated. FOXP3 mRNA expression was significantly elevated in colonic biopsies obtained from ITB patients as compared with CD cases (4.70 ± 2.21 vs 1.48 ± 0.31, P = 0.016).

CONCLUSIONS

FOXP3 mRNA expression in colonic mucosa could be a discriminatory marker between ITB and CD. Upregulation of the complement activation pathway in ITB suggests that pathogenetic mechanisms for ITB are similar to those of pulmonary tuberculosis. In CD, downregulation of PPARγ was seen in colonic tissue, suggesting that restoration of PPARγ-dependent anti-microbial barrier function may be a therapeutic target.

Faecal calprotectin levels differentiate intestinal from pulmonary tuberculosis: An observational study from Southern India

BACKGROUND

Current methods to establish the diagnosis of intestinal tuberculosis are inadequate.

OBJECTIVES

We aimed to determine the clinical features of intestinal tuberculosis and evaluate inflammatory biomarkers in intestinal as well as pulmonary tuberculosis.

METHODS

We recruited 38 intestinal tuberculosis patients, 119 pulmonary tuberculosis patients and 91 controls with functional gastrointestinal disorders between October 2009 and July 2012 for the investigation of clinical features, C-reactive protein (CRP), faecal and serum calprotectin. Faecal calprotectin ≥200 µg/g was used as a cut-off to determine intestinal inflammation of clinical significance. Three patient categories were established: (a) pulmonary tuberculosis and faecal calprotectin <200 µg/g (isolated pulmonary tuberculosis); (b) pulmonary tuberculosis and faecal calprotectin ≥200 µg/g (combined pulmonary and intestinal tuberculosis); (c) isolated intestinal tuberculosis.

RESULTS

Common clinical features of intestinal tuberculosis were abdominal pain, fatigue, weight loss and watery diarrhoea. Intestinal tuberculosis patients had elevated median CRP (10.7 mg/l), faecal calprotectin (320 µg/g) and serum calprotectin (5.7 µg/ml). Complete normalisation of CRP (1.0 mg/L), faecal calprotectin (16 µg/g) and serum calprotectin (1.4 µg/ml)) was seen upon clinical remission. Patients with combined pulmonary and intestinal tuberculosis had the highest levels of CRP (53.8 mg/l) and serum calprotectin (6.5 µg/ml) and presented with signs of more severe disease.

CONCLUSION

Calprotectin analysis reveals intestinal tuberculosis in patients with pulmonary tuberculosis and pinpoints those in need of rigorous follow-up.

Confluent granulomas and ulcers lined by epithelioid histiocytes: new ideal method for differentiation of ITB and CD? A meta analysis

BACKGROUND

There are few widely accepted criteria other than caseation, which has low sensitivity, for differentiating intestinal tuberculosis (ITB) and Crohn's disease (CD).

OBJECTIVE

We performed a meta-analysis to evaluate the use of confluent granulomas and ulcers lined by epithelioid histiocytes as histological methods for differentiating ITB and CD, compared with that of caseation.

METHODS

We searched PubMed, Medline, Embase, Web of Science, the Cochrane Library and Chinese Biomedicine Database for all relevant studies on the histological differentiation of ITB and CD. Sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated for each study. Study quality and heterogeneity were assessed. Meta-regression analysis and sensitivity analyses were performed.

RESULTS

Ten randomized trials involving 316 ITB and 376 CD patients were included. The results showed that analysis of caseation showed an overall weighted area under the curve (AUC) of 0.9966, overall sensitivity and specificity were 0.21 and 1.00, respectively, with a positive likelihood ratio (+LR) of 10.79, negative likelihood ratio(-LR) of 0.82 and DOR of 13.74. Confluent granulomas had a lower overall weighted AUC of 0.9381, sensitivity and specificity were 0.38 and 0.99, respectively, with a +LR of 16.29, -LR of 0.65 and DOR of 26.52. Overall weighted AUC for ulcers lined by epithelioid histiocytes was 0.9017, sensitivity and specificity were 0.41 and 0.94, respectively, with a +LR of 6.46, -LR of 0.54 and DOR of 13.17. Significant heterogeneity was noted for the studies. Meta-regression analysis showed that study source, publication year, size, design and quality did not affect heterogeneity.

CONCLUSION

Confluent granulomas and ulcers lined by epithelioid histiocytes are helpful in distinguishing ITB from CD, which may provide a new method, other than caseating granulomas and acid-fast bacilli, to differentiate ITB and CD in mucosal biopsies.

Routine diagnosis of intestinal tuberculosis and Crohn's disease in Southern India

AIM: To investigate whether routinely measured clinical variables could aid in differentiating intestinal tuberculosis (ITB) from Crohn’s disease (CD).

METHODS: ITB and CD patients were prospectively included at four South Indian medical centres from October 2009 to July 2012. Routine investigations included case history, physical examination, blood biochemistry, ileocolonoscopy and histopathological examination of biopsies. Patients were followed-up after 2 and 6 mo of treatment. The diagnosis of ITB or CD was re-evaluated after 2 mo of antituberculous chemotherapy or immune suppressive therapy respectively, based on improvement in signs, symptoms and laboratory variables. This study was considered to be an exploratory analysis. Clinical, endoscopic and histopathological features recorded at the time of inclusion were subject to univariate analyses. Disease variables with sufficient number of recordings and P < 0.05 were entered into logistic regression models, adjusted for known confounders. Finally, we calculated the odds ratios with respective confidence intervals for variables associated with either ITB or CD.

RESULTS: This study included 38 ITB and 37 CD patients. Overall, ITB patients had the lowest body mass index (19.6 vs 22.7, P = 0.01) and more commonly reported weight loss (73% vs 38%, P < 0.01), watery diarrhoea (64% vs 33%, P = 0.01) and rural domicile (58% vs 35%, P < 0.05). Endoscopy typically showed mucosal nodularity (17/31 vs 2/37, P < 0.01) and histopathology more frequently showed granulomas (10/30 vs 2/35, P < 0.01). The CD patients more frequently reported malaise (87% vs 64%, P = 0.03), nausea (84% vs 56%, P = 0.01), pain in the right lower abdominal quadrant on examination (90% vs 54%, P < 0.01) and urban domicile (65% vs 42%, P < 0.05). In CD, endoscopy typically showed involvement of multiple intestinal segments (27/37 vs 9/31, P < 0.01). Using logistic regression analysis we found weight loss and nodularity of the mucosa were independently associated with ITB, with adjusted odds ratios of 8.6 (95%CI: 2.1-35.6) and 18.9 (95%CI: 3.5-102.8) respectively. Right lower abdominal quadrant pain on examination and involvement of ≥ 3 intestinal segments were independently associated with CD with adjusted odds ratios of 10.1 (95%CI: 2.0-51.3) and 5.9 (95%CI: 1.7-20.6), respectively.

CONCLUSION: Weight loss and mucosal nodularity were associated with ITB. Abdominal pain and excessive intestinal involvement were associated with CD. ITB and CD were equally common.

Differentiation of Crohn's disease from intestinal tuberculosis by clinical and CT enterographic models

BACKGROUND

Crohn's disease (CD) and intestinal tuberculosis (ITB) have similar clinical, radiological, and endoscopic features. The objective of our study was to investigate the values of clinical features and computed tomographic (CT) enterographic manifestations in the differential diagnosis between CD and ITB.

METHODS

Clinical features and CT enterographic manifestations in a cohort of 141 patients with CD and 47 patients with ITB were reviewed retrospectively. Parameters were screened by logistic regression analysis. Furthermore, the diagnostic efficacy of screened parameters was analyzed by regression equation (mathematical model) and receiver operating characteristic curve.

RESULTS

The clinical features indicative of CD were hematochezia and perianal disease; features indicative of ITB include positive purified protein derivative skin test, occurrence of ascites, pulmonary tuberculosis, and night sweats. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of regression mathematical model established by clinical features were 94.3, 80.4, 91.0, 93.7, and 82.6%, respectively. CT enterographic manifestations indicative of CD were the involvement of the left colon, asymmetric pattern of involvement and abscess, comb sign; manifestations indicative ITB were the distribution of the lymph nodes along the right colic artery, contracture of ileocecal valve, fixed patulous ileocecal valve and lymph nodes with central necrosis The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of regression mathematical model established by CT enterographic parameters were 96.5, 93.6, 95.7, 97.8, and 89.8%, respectively.

CONCLUSIONS

The accuracy of CT enterographic model suggests the possibility of using CT enterography as an alternative to endoscopy in the differentiation between CD and ITB.

Fluorescent quantitative PCR of Mycobacterium tuberculosis for differentiating intestinal tuberculosis from Crohn's disease

Intestinal tuberculosis (ITB) and Crohn's disease (CD) are granulomatous disorders with similar clinical manifestations and pathological features that are often difficult to differentiate. This study evaluated the value of fluorescent quantitative polymerase chain reaction (FQ-PCR) for Mycobacterium tuberculosis (MTB) in fecal samples and biopsy specimens to differentiate ITB from CD. From June 2010 to March 2013, 86 consecutive patients (38 females and 48 males, median age 31.3 years) with provisional diagnoses of ITB and CD were recruited for the study. The patients' clinical, endoscopic, and histological features were monitored until the final definite diagnoses were made. DNA was extracted from 250 mg fecal samples and biopsy tissues from each patient. The extracted DNA was amplified using FQ-PCR for the specific MTB sequence. A total of 29 ITB cases and 36 CD cases were included in the analysis. Perianal disease and longitudinal ulcers were significantly more common in the CD patients (P<0.05), whereas night sweats, ascites, and circumferential ulcers were significantly more common in the ITB patients (P<0.05). Fecal FQ-PCR for MTB was positive in 24 (82.8%) ITB patients and 3 (8.3%) CD patients. Tissue PCR was positive for MTB in 16 (55.2%) ITB patients and 2 (5.6%) CD patients. Compared with tissue FQ-PCR, fecal FQ-PCR was more sensitive (X2=5.16, P=0.02). We conclude that FQ-PCR for MTB on fecal and tissue samples is a valuable assay for differentiating ITB from CD, and fecal FQ-PCR has greater sensitivity for ITB than tissue FQ-PCR.

Diagnosis of intestinal tuberculosis using a monoclonal antibody to Mycobacterium tuberculosis

AIM: To investigate the utility of immunohistochemical (IHC) staining with an antibody to Mycobacterium tuberculosis (M. tuberculosis) for the diagnosis of intestinal tuberculosis (TB).

METHODS: We retrospectively identified 10 patients (4 males and 6 females; mean age = 65.1 ± 13.6 years) with intestinal TB. Clinical characteristics, including age, gender, underlying disease, and symptoms were obtained. Chest radiograph and laboratory tests, including sputum Ziehl-Neelsen (ZN) staining, M. tuberculosis culture, and sputum polymerase chain reaction (PCR) for tubercle bacilli DNA, as well as Tuberculin skin test (TST) and QuantiFERON-TB gold test (QFT), were examined. Colonoscopic records recorded on the basis of Sato’s classification were also reviewed, in addition to data from intestinal biopsies examined for histopathological findings, including hematoxylin and eosin staining, and ZN staining, as well as M. tuberculosis culture, and PCR for tubercle bacilli DNA. For the present study, archived formalin-fixed paraffin-embedded (FFPE) intestinal tissue samples were immunohistochemically stained using a commercially available species-specific monoclonal antibody to the 38-kDa antigen of the M. tuberculosis complex. These sections were also stained with the pan-macrophage marker CD68 antibody.

RESULTS: From the clinical data, we found that no patients were immunocompromised, and that the main symptoms were diarrhea and weight loss. Three patients displayed active pulmonary TB, six patients (60%) had a positive TST, and 4 patients (40%) had a positive QFT. Colonoscopic findings revealed that all patients had type 1 findings (linear ulcers in a circumferential arrangement or linear ulcers arranged circumferentially with mucosa showing multiple nodules), all of which were located in the right hemicolon and/or terminal ileum. Seven patients (70%) had concomitant healed lesions in the ileocecal area. No acid-fast bacilli were detected with ZN staining of the intestinal tissue samples, and both M. tuberculosis culture and PCR for tubercle bacilli DNA were negative in all samples. The histopathological data revealed that tuberculous granulomas were present in 4 cases (40%). IHC staining in archived FFPE samples with anti-M. tuberculosis monoclonal antibody revealed positive findings in 4 patients (40%); the same patients in which granulomas were detected by hematoxylin and eosin staining. M. tuberculosis antigens were found to be mostly intracellular, granular in pattern, and primarily located in the CD68⁺ macrophages of the granulomas.

CONCLUSION: IHC staining with a monoclonal antibody to M. tuberculosis may be an efficient and simple diagnostic tool in addition to classic examination methods for the diagnosis of intestinal TB.

Crohn disease: recognition is key

Crohn disease (CD) is an autoimmune disease that affects people across the lifespan. Patients with CD are predisposed to other autoimmune illnesses, such as psoriasis or arthritis, and suffer from complications including infection and malnutrition. This article will focus on the diagnosis and treatment of CD.

Endoscopic assessment of inflammatory bowel disease: colonoscopy/esophagogastroduodenoscopy

Endoscopy plays an important role in the initial diagnosis of IBD, including the evaluation of disease severity, activity, and extent. The implications of complete mucosal healing further confirm the function of endoscopy in the follow-up of IBD patients. The use of therapeutic endoscopy, for example stricture dilatation, can avoid the need for bowel resection. Modalities such as capsule endoscopy, EUS, NBI, CE, and other emerging techniques are likely to have an increasing role in the management of IBD, particularly in the area of dysplasia surveillance and treatment.

The role of in vitro interferonγ-release assay in differentiating intestinal tuberculosis from Crohn's disease in China

AIM

Intestinal tuberculosis (ITB) and Crohn's disease (CD) have overlapping clinical, radiographic, endoscopic and histologic features, which makes the distinction between these two disease entities a great challenge in tuberculosis-endemic countries. The aim of the study was to investigate the value of in vitro interferonγ release assay (T-SPOT.TB) in differentiating ITB from CD.

METHODS

From June 2008 to February 2010, a total of 93 consecutive patients with undetermined ITB or CD were prospectively recruited. Clinical, endoscopic, histologic and therapeutic responses were longitudinally monitored at follow-up evaluation until the final definite diagnosis has been reached.

RESULTS

After a median of 6 months' follow-up (interquartile range [IQR], 3.0 to 7.5 months), definitive diagnosis was achieved in 84 of the 93 patients (90%), with 19 having ITB and 65 having CD. On univariate analysis, a long duration of illness, chronic diarrhea, and anemia were significantly more common in CD (P<0.05). While night sweat, ascites, pulmonary lesions, circumferential ulcer on endoscopy, ileo-cecal valve involvement and epithelioid granulomas were significantly more common in ITB (P<0.05). On multivariate analysis, T-SPOT.TB (Hazard ratio 7.0, 95% confidence interval [CI] 1.9-25.7) was found to be a good predictor for ITB diagnosis. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of T-SPOT.TB were 84.2%, 75.4%, 50.0%, and 94.2%, respectively.

CONCLUSIONS

When differentiating ITB and CD in tuberculosis-endemic regions, T-SPOT.TB blood test may be a helpful and practical diagnostic tool for its high NPV to rule out ITB.