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

Deep Learning Radiomics Analysis of CT Imaging for Differentiating Between Crohn's Disease and Intestinal Tuberculosis

This study aimed to develop and evaluate a CT-based deep learning radiomics model for differentiating between Crohn's disease (CD) and intestinal tuberculosis (ITB). A total of 330 patients with pathologically confirmed as CD or ITB from the First Affiliated Hospital of Zhengzhou University were divided into the validation dataset one (CD: 167; ITB: 57) and validation dataset two (CD: 78; ITB: 28). Based on the validation dataset one, the synthetic minority oversampling technique (SMOTE) was adopted to create balanced dataset as training data for feature selection and model construction. The handcrafted and deep learning (DL) radiomics features were extracted from the arterial and venous phases images, respectively. The interobserver consistency analysis, Spearman's correlation, univariate analysis, and the least absolute shrinkage and selection operator (LASSO) regression were used to select features. Based on extracted multi-phase radiomics features, six logistic regression models were finally constructed. The diagnostic performances of different models were compared using ROC analysis and Delong test. The arterial-venous combined deep learning radiomics model for differentiating between CD and ITB showed a high prediction quality with AUCs of 0.885, 0.877, and 0.800 in SMOTE dataset, validation dataset one, and validation dataset two, respectively. Moreover, the deep learning radiomics model outperformed the handcrafted radiomics model in same phase images. In validation dataset one, the Delong test results indicated that there was a significant difference in the AUC of the arterial models (p = 0.037), while not in venous and arterial-venous combined models (p = 0.398 and p = 0.265) as comparing deep learning radiomics models and handcrafted radiomics models. In our study, the arterial-venous combined model based on deep learning radiomics analysis exhibited good performance in differentiating between CD and ITB.

Differential diagnosis of Crohn's disease and intestinal tuberculosis based on ATR-FTIR spectroscopy combined with machine learning

BACKGROUND

Crohn's disease (CD) is often misdiagnosed as intestinal tuberculosis (ITB). However, the treatment and prognosis of these two diseases are dramatically different. Therefore, it is important to develop a method to identify CD and ITB with high accuracy, specificity, and speed.

AIM

To develop a method to identify CD and ITB with high accuracy, specificity, and speed.

METHODS

A total of 72 paraffin wax-embedded tissue sections were pathologically and clinically diagnosed as CD or ITB. Paraffin wax-embedded tissue sections were attached to a metal coating and measured using attenuated total reflectance fourier transform infrared spectroscopy at mid-infrared wavelengths combined with XGBoost for differential diagnosis.

RESULTS

The results showed that the paraffin wax-embedded specimens of CD and ITB were significantly different in their spectral signals at 1074 cm-1 and 1234 cm-1 bands, and the differential diagnosis model based on spectral characteristics combined with machine learning showed accuracy, specificity, and sensitivity of 91.84%, 92.59%, and 90.90%, respectively, for the differential diagnosis of CD and ITB.

CONCLUSION

Information on the mid-infrared region can reveal the different histological components of CD and ITB at the molecular level, and spectral analysis combined with machine learning to establish a diagnostic model is expected to become a new method for the differential diagnosis of CD and ITB.

ECCO Topical Review on Clinicopathological Spectrum and Differential Diagnosis of Inflammatory Bowel Disease

INTRODUCTION

Many diseases can imitate inflammatory bowel disease [IBD] clinically and pathologically. This review outlines the differential diagnosis of IBD and discusses morphological pointers and ancillary techniques that assist with the distinction between IBD and its mimics.

METHODS

European Crohn's and Colitis Organisation [ECCO] Topical Reviews are the result of an expert consensus. For this review, ECCO announced an open call to its members and formed three working groups [WGs] to study clinical aspects, pathological considerations, and the value of ancillary techniques. All WGs performed a systematic literature search.

RESULTS

Each WG produced a draft text and drew up provisional Current Practice Position [CPP] statements that highlighted the most important conclusions. Discussions and a preliminary voting round took place, with subsequent revision of CPP statements and text and a further meeting to agree on final statements.

CONCLUSIONS

Clinicians and pathologists encounter a wide variety of mimics of IBD, including infection, drug-induced disease, vascular disorders, diverticular disease, diversion proctocolitis, radiation damage, and immune disorders. Reliable distinction requires a multidisciplinary approach.

Value of Fecal Calprotectin Measurement During the Initial Period of Therapeutic Anti-Tubercular Trial

Background/Aims

The diagnosis of intestinal tuberculosis (ITB) is often challenging. Therapeutic anti-tubercular trial (TATT) is sometimes used for the diagnosis of ITB. We aimed to evaluate the changing pattern of fecal calprotectin (FC) levels during TATT in patients with ITB.

Methods

A retrospective review was performed on the data of 39 patients who underwent TATT between September 2015 and November 2018 in five university hospitals in Daegu, South Korea. The analysis was performed for 33 patients with serial FC measurement reports.

Results

The mean age of the participants was 48.8 years. The final diagnosis of ITB was confirmed in 30 patients based on complete mucosal healing on follow-up colonoscopy performed after 2 months of TATT. Before starting TATT, the mean FC level of the ITB patients was 170.2 μg/g (range, 11.5-646.5). It dropped to 25.4 μg/g (range, 11.5-75.3) and then 23.3 μg/g (range, 11.5-172.2) after one and two months of TATT, respectively. The difference in mean FC before and one month after TATT was statistically significant (p<0.001), and FC levels decreased to below 100 μg/g in all patients after one month of TATT.

Conclusions

All ITB patients showed FC decline after only 1 month of TATT, and this finding correlated with complete mucosal healing in the follow-up colonoscopy after 2 months of TATT.

Gastrointestinal and Abdominal Tuberculosis

Gastrointestinal (GI) tuberculosis (TB) remains a significant problem worldwide, and may involve the luminal GI tract from oral cavity to perianal area in addition to associated viscera and peritoneum. Although GI TB more commonly affects immunocompromised hosts, it can also occur in immunocompetent people. Diagnosis is difficult because it usually mimics a malignancy or inflammatory bowel disease. A high index of clinical suspicion and appropriate use of combined investigative methods help in early diagnosis, and reduce morbidity and mortality. Anti-TB therapy is the same as for pulmonary disease, and invasive and specialized interventions are reserved for selected complications.

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.

Can natural language processing help differentiate inflammatory intestinal diseases in China? Models applying random forest and convolutional neural network approaches

Background

Differentiating between ulcerative colitis (UC), Crohn’s disease (CD) and intestinal tuberculosis (ITB) using endoscopy is challenging. We aimed to realize automatic differential diagnosis among these diseases through machine learning algorithms.

Methods

A total of 6399 consecutive patients (5128 UC, 875 CD and 396 ITB) who had undergone colonoscopy examinations in the Peking Union Medical College Hospital from January 2008 to November 2018 were enrolled. The input was the description of the endoscopic image in the form of free text. Word segmentation and key word filtering were conducted as data preprocessing. Random forest (RF) and convolutional neural network (CNN) approaches were applied to different disease entities. Three two-class classifiers (UC and CD, UC and ITB, and CD and ITB) and a three-class classifier (UC, CD and ITB) were built.

Results

The classifiers built in this research performed well, and the CNN had better performance in general. The RF sensitivities/specificities of UC-CD, UC-ITB, and CD-ITB were 0.89/0.84, 0.83/0.82, and 0.72/0.77, respectively, while the values for the CNN of CD-ITB were 0.90/0.77. The precisions/recalls of UC-CD-ITB when employing RF were 0.97/0.97, 0.65/0.53, and 0.68/0.76, respectively, and when employing the CNN were 0.99/0.97, 0.87/0.83, and 0.52/0.81, respectively.

Conclusions

Classifiers built by RF and CNN approaches had excellent performance when classifying UC with CD or ITB. For the differentiation of CD and ITB, high specificity and sensitivity were achieved as well. Artificial intelligence through machine learning is very promising in helping unexperienced endoscopists differentiate inflammatory intestinal diseases.

Conference

The abstract of this article has won the first prize of the Young Investigator Award during the Asian Pacific Digestive Week (APDW) 2019 held in Kolkata, India.

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.

Intestinal tuberculosis and Crohn's disease: the importance and difficulty of a differential diagnosis

Tuberculosis (TB) is the most prevalent infection worldwide and affects one third of the population, predominantly in developing countries. Intestinal TB (ITB) is the sixth most frequent extra-pulmonary TB infection. Crohn's disease (CD) is a chronic inflammatory bowel disease that arises from the interaction of immunological, environmental and genetic factors. Due to changes in the epidemiology of both diseases, distinguishing CD from ITB is a challenge, particularly in immunocompromised patients and those from areas where TB is endemic. Furthermore, both TB and CD have a predilection for the ileocecal area. In addition, they share very similar clinical, radiological and endoscopic findings. An incorrect diagnosis and treatment may increase morbidity and mortality. Thus, a great degree of caution is required as well as a familiarity with certain characteristics of the diseases, which will aid the differentiation between the two diseases.

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.

Altered monocyte phenotypes but not impaired peripheral T cell immunity may explain susceptibility of the elderly to develop tuberculosis

Tuberculosis (TB) is the leading killer due to a single infectious disease worldwide. With the aging of the global population, the case rate and deaths due to TB are highest in the elderly population. While general immunosenescence associated with old age is thought to contribute to the susceptibility of the elderly to develop active TB disease, very few studies of immune function in elderly individuals with Mycobacterium tuberculosis (M.tb) infection or disease have been performed. In particular, impaired adaptive T cell immunity to M.tb is one proposed mechanism for the elderly's increased susceptibility primarily on the basis of the decreased delayed type hypersensitivity response to tuberculin-purified protein derivative in the skin of elderly individuals. To investigate immunological reasons why the elderly are susceptible to develop active TB disease, we performed a cross-sectional observational study over a five year period (2012-2016) enrolling participants from 2 age groups (adults: 25-44 years; elderly: 65 and older) and 3 M.tb infection statuses (active TB, latent TB infection, and healthy controls without history of M.tb infection). We hypothesized that impaired peripheral T cell immunity plays a role in the biological susceptibility of the elderly to TB. Contrary to our hypothesis, we observed no evidence of impaired M.tb specific T cell frequency or altered production of cytokines implicated in M.tb control (IFN-γ, IL-10) in peripheral blood in the elderly. Instead, we observed alterations in monocyte proportion and phenotype with age and M.tb infection that suggest their potential role in the susceptibility of the elderly to develop active TB. Our results suggest a potential link between the known widespread low-grade systemic inflammation of old age, termed "inflammaging," with the elderly's specific susceptibility to developing active TB. Moreover, our results highlight the need for further research into the biological reasons why the elderly are more susceptible to disease and death from TB, so that public health systems can be better equipped to face the present and future problem of TB in an aging global population.

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.

Retrospective evaluation of the clinical utility of serological biomarkers in Chinese patients with inflammatory bowel disease: 2-year clinical experience

BACKGROUND

Antibodies to saccharomyces cerevisiae (ASCA), antibodies to perinuclear anti-neutrophil cytoplasmic (pANCA), pancreatic autoantibodies (PAB) and antibodies against intestinal goblet cells (GAB) are important in diagnosing Crohn's disease (CD) and ulcerative colitis (UC). However, little is known about their diagnostic value in real clinical practice in China. This retrospective study aimed to present our 2-year clinical experience with those biomarkers in diagnosis of CD and UC.

METHODS

A total of 140 patients with UC, 128 patients with CD, and 224 patients with intestinal associated diseases as disease controls were included. Serum ASCA were determined by ELISA. Serum pANCA, GAB, and PAB were tested by indirect immunofluorescent assay. Retrospective review of laboratory results and clinical information was performed.

RESULTS

ASCA and ASCA+/pANCA- showed poor abilities in differentiating CD from UC, CD from intestinal Behçet's disease (BD), or CD from intestinal tuberculosis (ITB). In contrast, PAB exhibited good capacities in differentiating CD from UC, CD from intestinal BD, and CD from ITB. IgG pANCA demonstrated a high sensitivity and specificity in differentiating UC from CD. pANCA+/ASCA- or pANCA+/PAB- displayed a high sensitivity and specificity in differentiating UC from CD. GAB showed poor potential in differentiating UC from CD. PAB were positively correlated with early disease onset, ileocolonic disease, and perianal disease in CD patients.

CONCLUSIONS

Our data suggest that pANCA and PAB are helpful in diagnosis of UC and CD, respectively, while ASCA and GAB were not. Our findings indicate a clear need for additional biomarkers for diagnosis of CD in China.

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.

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.

Diagnosis of inflammatory bowel disease in Asia: the results of a multinational web-based survey in the 2(nd) Asian Organization for Crohn's and Colitis (AOCC) meeting in Seoul

Background/Aims

As the number of Asian patients with inflammatory bowel disease (IBD) has increased recently, there is a growing need to improve IBD care in this region. This study is aimed at determining how Asian countries are currently dealing with their IBD patients in terms of diagnosis.

Methods

A questionnaire was designed by the organizing committee of Asian Organization for Crohn's and Colitis, for a multinational web-based survey conducted between March 2014 and May 2014.

Results

A total of 353 Asian medical doctors treating IBD patients responded to the survey (114 in China, 88 in Japan, 116 in Korea, and 35 in other Asian countries). Most of the respondents were gastroenterologists working in an academic teaching hospital. While most of the doctors from China, Japan, and Korea use their own national guidelines for IBD diagnosis, those from other Asian countries most commonly adopt the European Crohn's Colitis Organisation's guideline. Japanese doctors seldom adopt the Montreal classification for IBD. The most commonly used activity scoring system for ulcerative colitis is the Mayo score in all countries except China, whereas that for Crohn's disease (CD) is the Crohn's Disease Activity Index. The most available tool for small-bowel evaluation in CD patients differs across countries. Many physicians administer empirical anti-tuberculous medications before the diagnosis of CD.

Conclusions

The results of this survey demonstrate that Asian medical doctors have different diagnostic approaches for IBD. This knowledge would be important in establishing guidelines for improving the care of IBD patients in this region.

Epidemiology, Diagnosis and Management of Extra-Pulmonary Tuberculosis in a Low-Prevalence Country: A Four Year Retrospective Study in an Australian Tertiary Infectious Diseases Unit

OBJECTIVES

Extra-pulmonary tuberculosis (EPTB) is relatively neglected and increasing in incidence, in comparison to pulmonary tuberculosis (PTB) in low-burden settings. It poses particular diagnostic and management challenges. We aimed to determine the characteristics of EPTB in Western Sydney, Australia, and to conduct a quality assurance investigation of adherence to guidelines among Infectious Diseases (ID) practitioners managing EPTB cases.

METHODS

All adult EPTB cases managed by a large ID service during 01/01/2008-31/12/2011 were eligible for inclusion in the retrospective review. Data were extracted from patient medical records on demographic, diagnostic, clinical and management details, and on clinician adherence to local and international TB guidelines.

RESULTS

129 cases managed by the ID service were identified, with files available for 117. 98 cases were managed by the Respiratory service and were excluded. 98.2%(112/114) had been born in a country other than Australia. HIV status was tested or previously known in 97 people, and positive in 4 (4%). Microbiological confirmation was obtained in 68/117 (58.1%), an additional 24 had histopathological findings considered confirmatory (92/117, 78.6%), with the remainder diagnosed on clinical and/or radiological grounds. Median time to diagnosis post-migration from a high TB-burden country was 5 years (range 0-41). 95 cases were successfully treated, 11 cases defaulted, refused therapy or transferred, 2 cases relapsed and outcomes unknown or pending in 9 cases. No deaths occurred in the sample analysed. Clinician adherence to guidelines was high, but with scope for improvement in offering testing for co-infections, performing eye checks, monitoring blood glucose in patients receiving adjunctive corticosteroids, and considering drug interactions.

CONCLUSIONS

Despite excellent TB outcomes in this setting, the low proportion of cases with susceptibility data is worrying in this era of increasing drug resistance, and illustrates the diagnostic difficulties faced even in a well-resourced setting. Vigilance for EPTB needs to remain high in those moving from high prevalence countries to Australia, even decades after immigration.

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.

Utility of T-Cell Interferon-γ Release Assays for Etiological Diagnosis of Classic Fever of Unknown Origin in a High Tuberculosis Endemic Area--a pilot prospective cohort

Background

Tuberculosis (TB), especially extrapulmonary TB is still the leading cause of fever of unknown origin (FUO) in China. However, diagnosis of TB still remains a challenge. The aim of this study was to evaluate the diagnostic value of T-SPOT.TB for etiological diagnosis of classic FUO in adult patients in a high TB endemic area.

Methods

We prospectively enrolled patients presenting with classic FUO in a tertiary referral hospital in Beijing, China, to investigate the diagnostic sensitivity, specificity, predictive values and likelihood ratio of T-SPOT.TB. Clinical assessment and T-SPOT.TB were performed. Test results were compared with the final confirmed clinical diagnosis.

Results

387 hospitalized patients (male n = 194, female n = 193; median age 46 (range 29–59) yrs) with classic FUO were prospectively enrolled into this study. These FUOs were caused by infection (n = 158, 40.8%), connective tissue disease (n = 82, 21.2%), malignancy (n = 41, 10.6%) and miscellaneous other causes (n = 31, 8.0%), and no cause was determined in 75 (19.4%) patients. 68 cases were diagnosed as active TB eventually. The sensitivity of T-SPOT.TB for the diagnosis of active TB was 70.6% (95%CI 58.9–80.1%), while specificity was 84.4% (95%CI 79.4–88.4%), positive predictive value was 55.8% (95%CI 45.3–65.8%), negative predictive value was 91.2% (95%CI 86.7–94.2%). Among these 68 active TB patients, 12 cases were culture or histology confirmed (11 cases with positive T-SPOT.TB, sensitivity was 91.7%) and 56 cases were clinically diagnosed (37 cases with positive T-SPOT.TB, sensitivity was 66.1%); 14 cases were pulmonary TB (13 cases with positive T-SPOT.TB, sensitivity was 92.9%) and 54 cases were extrapulmonary TB (35 cases with positive T-SPOT.TB, sensitivity was 64.8%).

Conclusions

For patients presenting with classic FUO in this TB endemic setting, T-SPOT.TB appears valuable for excluding active TB, with a high negative predictive value.

Differences in clinical features of Crohn's disease and intestinal tuberculosis

AIM: To investigate the clinical features of Crohn’s disease (CD) and intestinal tuberculosis (ITB) with a scoring system that we have developed.

METHODS: A total of 25 CD and 40 ITB patients were prospectively enrolled from August 2011 to July 2012. Their characteristics and clinical features were recorded. Laboratory, endoscopic, histologic and radiographic features were determined. The features with a high specificity were selected to establish a scoring system. The features supporting CD scored +1, and those supporting ITB scored -1; each patient received a final total score. A receiver operating characteristic (ROC) curve was used to determine the best cut-off value for distinguishing CD from ITB.

RESULTS: Based on a high specificity of differentiating between CD and ITB, 12 features, including longitudinal ulcers, nodular hyperplasia, cobblestone-like mucosa, intestinal diseases, intestinal fistula, the target sign, the comb sign, night sweats, the purified protein derivative test, the interferon-γ release assay (T-SPOT.TB), ring ulcers and ulcer scars, were selected for the scoring system. The results showed that the average total score of the CD group was 3.12 ± 1.740, the average total score of the ITB group was -2.58 ± 0.984, the best cutoff value for the ROC curve was -0.5, and the diagnostic area under the curve was 0.997, which was statistically significant (P < 0.001). The patients whose total scores were higher than -0.5 were diagnosed with CD; otherwise, patients were diagnosed with ITB. Overall, the diagnostic accuracy rate and misdiagnosis rate of this scoring system were 97% and 3%, respectively.

CONCLUSION: Some clinical features are valuable for CD and ITB diagnosis. The described scoring system is key to differentiating between CD and ITB.

High faecal calprotectin levels in intestinal tuberculosis are associated with granulomas in intestinal biopsies

BACKGROUND

The diagnosis of intestinal tuberculosis (ITB) is sometimes difficult to establish and requires endoscopic investigation with biopsies for histopathological examination. This study aimed to evaluate calprotectin as a marker of inflammation in ITB.

METHODS

Patients with ITB were prospectively recruited in Southern India from October 2009 until July 2012. Demographic, clinical, endoscopic and histological features were examined along with faecal calprotectin (FC), serum calprotectin (SC) and C-reactive protein (CRP).

RESULTS

Thirty patients (median age 34.5 years, 19 men) were included. Clinical features were abdominal pain (97%), weight loss (83%), cachexia (75%), fatigue (63%), watery diarrhoea (62%), nausea (55%) and fever (53%). Endoscopy showed transverse ulcers (61%), nodularity of mucosa (55%), aphthous ulcers (39%), strictures (10%) and fissures (10%). The terminal ileum and right colon harboured 81% of the lesions. Histology revealed granulomas in biopsies from 10 of the patients. FC and CRP levels showed a strong positive correlation (rs = 0.70, p < 0.01). FC, SC and CRP levels were higher in the granulomatous than the non-granulomatous patients, respectively (median FC 988 μg/g, interquartile range (IQR) 940 vs 87 μg/g, IQR 704, p < 0.01; median SC 8.2 μg/ml, IQR 7.3 vs 3.8 μg/ml, IQR 8.9, p = 0.23; median CRP 38.8 mg/L, IQR 42.9 vs 2.3 mg/L, IQR 13.5, p < 0.01). Higher median calprotectin and CRP levels were detected in patients with extensive than localized disease, but the differences did not reach statistical significance.

CONCLUSION

ITB patients with granulomas on histology have high levels of faecal calprotectin and CRP.

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.

Systematic review with meta-analysis: accuracy of interferon-gamma releasing assay and anti-Saccharomyces cerevisiae antibody in differentiating intestinal tuberculosis from Crohn's disease in Asians

BACKGROUND AND AIMS

Distinguishing Crohn's disease (CD) from intestinal tuberculosis (ITB) is a clinical challenge. This meta-analysis assessed the clinical usefulness of Interferon-gamma releasing assay (IGRA) and anti-Saccharomyces cerevisiae antibody (ASCA) in the diagnosis of ITB and CD, respectively.

METHODS

Systematic search without language restriction was conducted in AMED, EBM, MEDLINE, EMBASE, and Google Scholar until September 2013. Studies that have evaluated performance of IGRA (QuantiFERON-TB Gold or T-SPOT.TB) or ASCA in distinguishing ITB from CD were eligible. Main outcome measures included sensitivity and specificity. Random-effects models were used to combine estimates from studies with significant heterogeneity. Area under the curve (AUC) was used to measure accuracy of the tests.

RESULTS

Eleven studies (five IGRA, three ASCA, three IGRA and ASCA) involving 1081 subjects were included. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of IGRA for the diagnosis of ITB was 81% (95% CI, 75-86%), 85% (95% CI, 81-89%), 6.02 (95% CI: 4.62-7.83), and 0.19 (95% CI: 0.10-0.36), respectively. The AUC was 0.92. The pooled sensitivity and specificity of ASCA for the diagnosis of CD was 33% (95% confidence interval [CI], 27%-38%) and 83% (95% CI, 77-88%), respectively with an AUC of 0.58. T-SPOT.TB showed a higher sensitivity than QuantiFERON-TB Gold for the diagnosis of ITB.

CONCLUSIONS

IGRA and ASCA have a high specificity for the diagnosis of ITB. Both IGRA and ASCA may have a supplementary role in the differential diagnosis between ITB and CD when conventional workup is not diagnostic.

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.

Value of interferon-γ release assay and polymerase chain reaction for Mycobacterium tuberculosis in differentiation of intestinal tuberculosis from Crohn's disease

China is one of the countries having the highest burden of tuberculosis. The number of patients with Crohn's disease (CD) is gradually increasing in China. Sometimes intestinal tuberculosis (ITB) and CD are quite similar in clinical manifestations and the findings of radiological and endoscopic examinations, and it is difficult to differentiate the two diseases; however, the treatments and prognosis of the two diseases are completely different. Besides clinical characteristics, radiological examinations, endoscopic examinations, histopathological examinations, acid-fast staining, Mycobacterium tuberculosis culture, serum markers and tuberculin skin test (TST), interferon-γ release assay (IGRA) and polymerase chain reaction for Mycobacterium tuberculosis (TB-PCR) have recently been used to differentiate ITD from CD. Both IGRA and TB-PCR have a high sensitivity and specificity in diagnosis of ITB when differentiating ITB from CD. This review focuses on the value of IGRA and TB-PCR in the differentiation of ITB from CD.

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.

Effectiveness of interferon-gamma release assays for differentiating intestinal tuberculosis from Crohn’s disease: A meta-analysis

AIM: To investigate the clinical usefulness of interferon-gamma release assays (IGRAs) in the differential diagnosis of intestinal tuberculosis (ITB) from Crohn’s disease (CD) by meta-analysis.

METHODS: A systematic search of English language studies was performed. We searched the following databases: Medline, Embase, Web of Science and the Cochrane Library. The Standards for Reporting Diagnostic Accuracy initiative and Quality Assessment for Studies of Diagnostic Accuracy tool were used to assess the methodological quality of the studies. Sensitivity, specificity, and other measures of the accuracy of IGRAs in the differential diagnosis of ITB from CD were pooled and analyzed using random-effects models. Receiver operating characteristic curves were applied to summarize overall test performance. Two reviewers independently judged study eligibility while screening the citations.

RESULTS: Five studies met the inclusion criteria. The average inter-rater agreement between the two reviewers for items in the quality checklist was 0.95. Analysis of IGRAs for the differential diagnosis of ITB from CD produced summary estimates as follows: sensitivity, 0.74 (95%CI: 0.68-0.80); specificity, 0.87 (95%CI: 0.82-0.90); positive likelihood ratio, 5.98 (95%CI: 3.79-9.43); negative likelihood ratio, 0.28 (95%CI: 0.18-0.43); and diagnostic odds ratio, 26.21 (95%CI: 14.15-48.57). The area under the curve was 0.92. The evaluation of publication bias was not significant (P = 0.235).

CONCLUSION: Although IGRAs are not sensitive enough, they provide good specificity for the accurate diagnosis of ITB, which may be helpful in the differential diagnosis of ITB from CD.