Diagnostic sensitivity of culture and drug resistance patterns in Korean patients with intestinal tuberculosis

Computed tomography enterography-based multiregional radiomics model for differential diagnosis of Crohn's disease from intestinal tuberculosis

PURPOSE

To build computed tomography enterography (CTE)-based multiregional radiomics model for distinguishing Crohn's disease (CD) from intestinal tuberculosis (ITB).

MATERIALS AND METHODS

A total of 105 patients with CD and ITB who underwent CTE were retrospectively enrolled. Volume of interest segmentation were performed on CTE and radiomic features were obtained separately from the intestinal wall of lesion, the largest lymph node (LN), and region surrounding the lesion in the ileocecal region. The most valuable radiomic features was selected by the selection operator and least absolute shrinkage. We established nomogram combining clinical factors, endoscopy results, CTE features, and radiomic score through multivariate logistic regression analysis. Receiver operating characteristic (ROC) curves and decision curve analysis (DCA) were used to evaluate the prediction performance. DeLong test was applied to compare the performance of the models.

RESULTS

The clinical-radiomic combined model comprised of four variables including one radiomic signature from intestinal wall, one radiomic signature from LN, involved bowel segments on CTE, and longitudinal ulcer on endoscopy. The combined model showed good diagnostic performance with an area under the ROC curve (AUC) of 0.975 (95% CI 0.953-0.998) in the training cohort and 0.958 (95% CI 0.925-0.991) in the validation cohort. The combined model showed higher AUC than that of the clinical model in cross-validation set (0.958 vs. 0.878, P = 0.004). The DCA showed the highest benefit for the combined model.

CONCLUSION

Clinical-radiomic combined model constructed by combining CTE-based radiomics from the intestinal wall of lesion and LN, endoscopy results, and CTE features can accurately distinguish CD from ITB.

Clinical characteristics and diagnosis of intestinal tuberculosis in clinical practice at Thailand's largest national tertiary referral center: An 11-year retrospective review

BACKGROUND

Diagnosing intestinal tuberculosis (ITB) is challenging due to the low diagnostic sensitivity of current methods. This study aimed to assess the clinical characteristics and diagnosis of ITB at our tertiary referral center, and to explore improved methods of ITB diagnosis.

METHODS

This retrospective study included 177 patients diagnosed with ITB at Siriraj Hospital (Bangkok, Thailand) during 2009-2020.

RESULTS

The mean age was 49 years, 55.4% were male, and 42.9% were immunocompromised. Most diagnoses (108/177) were made via colonoscopy; 12 patients required more than one colonoscopy. Among those, the sensitivity of tissue acid-fast bacilli (AFB), presence of caseous necrosis, polymerase chain reaction (PCR), and culture was 40.7%, 13.9%, 25.7%, and 53.4%, respectively. Among patients with negative tissue histopathology, 4 (3.7%) and 13 (12.0%) were ITB positive on tissue PCR and culture, respectively. The overall sensitivity when all diagnostic methods were used was 63%. Seventy-six patients had stool tests for mycobacteria. The overall sensitivity of stool tests was 75.0%. However, when analyzing the 31 patients who underwent both endoscopy and stool testing, the sensitivity of stool testing when using tissue biopsy as a reference was 45.8%. Combining stool testing and tissue biopsy did not significantly increase the sensitivity compared to tissue biopsy alone (83.9% vs. 77.4%, respectively).

CONCLUSION

Despite the availability of PCR and culture for TB, the overall diagnostic sensitivity was found to be low. The sensitivity increased when the tests were used in combination. Repeated colonoscopy may be beneficial. Adding stool mycobacteria tests did not significantly increase the diagnostic yield if endoscopy was performed, but it could be beneficial if endoscopy is unfeasible.

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.

Challenges in the diagnosis and management of inflammatory bowel disease in resource-limited settings in Asia

Inflammatory bowel disease (IBD) is increasing in prevalence in resource-limited settings in Asia. Although the prevalence of IBD is lower in these settings than in high-income countries, the high disease burden due to large population size is projected to overtake that of high-income countries in the near future. Unique challenges exist for diagnosing and managing IBD in Asia. On one hand, the inadequate disease awareness in physicians and the general population, the scarcity of diagnostic services, the infectious mimics of IBD (specifically intestinal tuberculosis), and the widespread use of empirical antibiotics and antitubercular therapy pose diagnostic challenges. On the other hand, the absence of a centralised health-care delivery system or universal health insurance, the high cost of therapy, limited access to biologics, and the high risk of opportunistic infections with immunosuppressive therapy present therapeutic challenges. The high probability of tuberculosis reactivation often precludes biological therapy because Asia is highly endemic for tuberculosis and has a high prevalence of latent tuberculosis. Current screening strategies are often ineffective in ruling out latent tuberculosis. Hence, management strategies are often modified according to these challenges. This Series paper discusses the challenges in the diagnosis and management of IBD in resource-limited settings in Asia.

Diagnostic accuracy of the Xpert MTB/RIF assay for abdominal tuberculosis: a systematic review and meta-analysis

BACKGROUND

We performed a meta-analysis to determine diagnostic accuracy of Xpert MTB/RIF for diagnosis of abdominal (intestinal or peritoneal) tuberculosis (TB) in various tissues (intestinal, omental/peritoneal tissue or ascitic fluid).

METHODS

Electronic databases were searched for observational studies on use of Xpert MTB/RIF in ascitic fluid, peritoneal, or omental tissue for diagnosis of peritoneal and intestinal TB. We calculated the pooled sensitivity, specificity and diagnostic odds ratio of Xpert MTB/RIF for diagnosis of peritoneal TB in comparison to composite reference standard (CRS) and culture, and in comparison to CRS for intestinal TB.

RESULTS

Twenty-five observational studies were included. The pooled sensitivity and specificity as assessed with peritoneal culture from ascites as an Index test was 64% (95% Confidence Interval [C.I.] 49-76%) and 97% (95% C.I., 95-99%) respectively and with peritoneal CRS was 30% (95% C.I., 22-40%) and 100% (95% C.I., 98-100%) respectively. In the intestinal group, the pooled sensitivity and specificity of Xpert MTB/RIF was 23% (95% C.I., 16-32%) and 100% (95% C.I., 52-100%). The AUC of peritoneal culture and intestinal tissue was 0.935 and 0.499.

CONCLUSION

Xpert MTB/RIF has modest sensitivity for diagnosis of peritoneal and intestinal tuberculosis but has a good specificity.

PROSPERO REGISTRATION

CRD42020140545.

Is the rise in Crohn's disease in India accompanied by a fall in intestinal tuberculosis? A single-center experience

INTRODUCTION

The relationship between the incidence of intestinal tuberculosis (TB) and Crohn's disease (CD) is interesting, especially considering the striking similarity between the two conditions. Some studies from Asian populations suggested that the incidence of intestinal TB decreases when there is an increase in CD.

AIM

To compare the incidence trend between intestinal TB and CD over 15 years.

METHODS

Medical records of patients seen in the Division of Gastroenterology over 15 years (2005-2019) were reviewed. CD was diagnosed according to the Copenhagen criteria. Intestinal TB was diagnosed in the appropriate clinical situation if any one or more of the following was present: (1) positive TB MGIT culture; (2) positive Gene Xpert for TB; (3) suggestive histologic findings, with positive tissue acid-fast bacillus (AFB) on smear or with sustained response to anti-TB therapy. The incidence time trend of patients with CD and intestinal TB diagnosis was then studied year-wise.

RESULTS

632 medical case records were accessed; 60 patients were excluded due to inadequate data or not fulfilling diagnostic criteria. The 572 patients included 224 with intestinal TB (median age 37 years, IQR 22; 125 [56%] females) and 348 with CD (median age 40 years, IQR 25; 159 [46%] females [p < 0.02 as compared to TB]). Thus, more patients with CD were seen during the study period, but there was no correlation between the incidence of the two conditions (r = 0.318; p = 0.25).

CONCLUSION

In Indian patients in a single private-sector center, there was no inverse correlation between the incidence of intestinal TB and CD over 15 years.

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.

Ten Cases of Intestinal Tuberculosis Which Were Initially Misdiagnosed as Inflammatory Bowel Disease

Objective Intestinal tuberculosis (ITB) and inflammatory bowel disease (IBD) frequently present with similar clinical, endoscopic and pathological features, therefore it is difficult to differentiate between them. The aim of this study was to elucidate the diagnostic delay and prognosis of ITB cases, initially misdiagnosed as IBD. Methods ITB cases were selected from the hospitalized patient list between April 2004 and March 2017 in a tuberculosis center in Japan. We retrospectively evaluated the initial diagnosis, clinical characteristics, endoscopic and pathological findings, bacterial examinations, treatment and prognosis. Results Among 66 ITB patients, ten patients were initially misdiagnosed as IBD. Seven patients were male and the median age was 60.5 years (23-74 years). After the diagnosis of IBD, all the patients were treated with mesalazine, in addition to corticosteroids in two patients and sequential azathioprine and infliximab in one. The median duration of diagnostic delay was 5.5 months (range 0.5-17 months). Eight patients had active pulmonary tuberculosis at the diagnosis of ITB. Acid-fast bacilli were confirmed in four of seven patients by reevaluation of the pathological specimens at the IBD diagnosis. Two patients needed intestinal resection and one with erroneous corticosteroid use for IBD died due to respiratory failure in spite of receiving appropriate treatment for tuberculosis. Conclusion ITB patients were frequently misdiagnosed and treated as IBD, thus resulting in a poor clinical outcome even after finally making a correct diagnosis and administering appropriate treatment. On diagnosis of IBD and/or treatment failure, chest radiograph and acid-fast bacilli of the pathological specimens should be carefully evaluated in order to rule out tuberculosis.

Development and Validation of a Novel Diagnostic Nomogram to Differentiate Between Intestinal Tuberculosis and Crohn's Disease: A 6-year Prospective Multicenter Study

OBJECTIVES

Differentiating Crohn's disease (CD) from intestinal tuberculosis (ITB) remains a diagnostic challenge. Misdiagnosis carries potential grave implications. We aimed to develop and validate a novel diagnostic nomogram for differentiating them.

METHODS

In total, 310 eligible patients were recruited from 6 tertiary inflammatory bowel disease centers. Among them, 212 consecutive patients (143 CD and 69 ITB) were used in the derivation cohort for the establishment of diagnostic equation and nomogram; 7 investigative modalities including clinical manifestations, laboratory results, endoscopic findings, computed tomography enterography features, and histology results were used to derive the diagnostic model and nomogram. Ninety-eight consecutive patients (76 CD and 22 ITB) were included for validation of the diagnostic model.

RESULTS

Eight out of total 79 parameters were identified as valuable parameters used for establishing diagnostic equations. Two regression models were built based on 7 differential variables: age, transverse ulcer, rectum involvement, skipped involvement of the small bowel, target sign, comb sign, and interferon-gamma release assays (for model 1) or purified protein derivative (for model 2), respectively. Accordingly, 2 nomograms of the above 2 models were developed for clinical practical use, respectively. Further validation test verified the efficacy of the nomogram 1 with 90.9% specificity, 86.8% sensitivity, 97.1% PPV, 66.7% negative predictive value (NPV), and 87.8% accuracy for identifying CD, and the efficacy of the nomogram 2 with 100% specificity, 84.2% sensitivity, 100% positive predictive value, 64.7% NPV, and 87.8% accuracy for diagnosing CD.

CONCLUSIONS

The derivation and validation cohorts identified and validated 2 highly accurate and practical diagnostic nomograms for differentiating CD from ITB. These diagnostic nomograms can be conveniently used to identify some difficult CD or ITB cases, allowing for decision-making in a clinical setting.

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.

Do additional colonoscopic biopsies increase the yield of Mycobacterium tuberculosis culture in suspected ileo-colonic tuberculosis?

BACKGROUND

Isolation of Mycobacterium tuberculosis on culture is vital for differentiating intestinal tuberculosis (ITB) from Crohn's disease (when histology is not diagnostic) and for diagnosis of multidrug-resistant tuberculosis. The current yield of TB culture (< 50%) from colonoscopic biopsy tissue is not satisfactory.

AIM

To determine whether more colonoscopic biopsies can increase the yield of TB culture in patients with ITB.

METHODS

In this prospective study, in patients who underwent colonoscopy for suspected ITB, four biopsies were taken (container 1) followed by an additional four biopsies (container 2) for TB culture, from involved regions. The culture was done using Mycobacterium Growth Indicator Tube (MGIT) 960. A final diagnosis of ITB was made if TB culture was positive, there was unequivocal histological evidence of TB, or there was unequivocal evidence of TB elsewhere in the body, in the absence of another diagnosis.

RESULTS

Of 182 patients enrolled (mean age 37.5 [SD 17.2] years; 93 [51.5%] women), 70 (38.4%) were finally diagnosed to have ITB. MGIT culture was positive in 29 (41.4%), 27 (38.5%), and 37 (52.8%) of 70 patients from containers 1, container 2, and combined eight biopsies, respectively. The incremental yield of eight biopsies was 11.4% (95% confidence interval [CI] 5.1 to 21.3%) as compared to container 1 and 14.3% (95% CI 7.1 to 24.7%) as compared to container 2.

CONCLUSION

Additional four (total eight) colonoscopic biopsies improved the yield of TB culture positivity over four biopsies by 11.4% to 14.3%, to 52.8%; this increase is clinically useful.

Drug resistance in intestinal tuberculosis: A reason to worry?

Background and Aim

Emergence of drug resistance in intestinal tuberculosis (ITB) makes the treatment of this condition challenging. While there is growing evidence of multiple and extensive drug resistance in pulmonary and glandular tuberculosis (TB), literature regarding susceptibility and resistance patterns in ITB is scarce. The aim of the current paper was to study the prevalence of drug resistance in patients with ITB.

Methods

Among patients presenting to a tertiary care hospital in Mumbai between 2008 and 2016, records of all patients with ITB, whose mucosal biopsy (obtained at ileocolonoscopy) tissue culture was positive for Mycobacterium tuberculosis and in whom drug sensitivity testing was performed, were retrospectively analyzed. Sensitivity and resistance to single or multiple anti-TB drugs were noted.

Results

A total of 43 patients were included, of whom 10 (23.2%) patients were diagnosed to have resistance to at least one first-line anti-TB drug. Resistance to isoniazid was the most common (nine patients), followed by rifampicin (six), pyrazinamide (five), streptomycin and ethionamide (four each), ethambutol, moxifloxacin and ofloxacin (three each), and p-amino salicylic acid (one). Six patients (13.9%) had multidrug-resistant TB and needed second-line anti-TB therapy as per drug sensitivity pattern. There was no patient with extensive drug-resistant TB.

Conclusion

Twenty-three percent of our patients with ITB tested for drug resistance had drug resistance, 13.9% being multidrug resistant and needing second-line anti-TB therapy.

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.

Development and Validation of a Novel Prediction Model for Differential Diagnosis Between Crohn's Disease and Intestinal Tuberculosis

BACKGROUND

Although colonoscopy is useful for differentiating between Crohn's disease (CD) and intestinal tuberculosis (ITB), the technique has limitations. We developed a practical prediction model for differentiating between CD and ITB using laboratory and radiologic parameters and colonoscopic characteristics.

METHODS

We prospectively enrolled 80 patients newly diagnosed with CD (n = 40) and ITB (n = 40). We developed a new prediction score by integrating colonoscopic, laboratory, and radiologic parameters. The score's predictive ability was validated on an additional 37 patients.

RESULTS

The accuracy of colonoscopic scoring for differentiation was 81.2% (65/80), with 65.0% sensitivity for CD and 97.5% for ITB. In multivariate analysis, positive IgA and/or IgG anti-Saccharomyces cerevisiae antibody and involvement of the proximal intestine were the independent laboratory and radiologic parameters for CD, and positive QuantiFERON-TB Gold In-Tube Test and typical pulmonary TB findings were the parameters for ITB. A new prediction scoring combining colonoscopic, laboratory, and radiologic factors increased the accuracy of diagnosis from 81.2% to 96.3% (77/80). The CD prediction score (from -2 to 2) estimated the likelihood of CD, from 0.3% for patients scoring -2 to 100% for patients scoring 2. The area under the receiver operating characteristic curve of the score was 0.990 in the development group and 0.981 in the validation group.

CONCLUSIONS

The new prediction model using a CD prediction score can be useful for calculating the probability of either CD or ITB at initial evaluation (NCT01392365).

Evaluation of Xpert MTB/RIF assay performance in the diagnosis of abdominal tuberculosis

Background/Aims

The use of genetic probes for the diagnosis of pulmonary tuberculosis (TB) has been well described. However, the role of these assays in the diagnosis of intestinal tuberculosis is unclear. We therefore assessed the diagnostic utility of the Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) assay, and estimated the prevalence of multidrug-resistant (MDR) TB in the Indian population.

Methods

Of 99 patients recruited, 37 had intestinal TB; two control groups comprised 43 with Crohn's disease (CD) and 19 with irritable bowel syndrome. Colonoscopy was performed before starting any therapy; mucosal biopsies were subjected to histopathology, acid-fast bacilli staining, Lowenstein-Jensen culture, and nucleic acid amplification testing using the Xpert MTB/RIF assay. Patients were followed up for 6 months to confirm the diagnosis and response to therapy. A composite reference standard was used for diagnosis of TB and assessment of the diagnostic utility of the Xpert MTB/RIF assay.

Results

Of 37 intestinal TB patients, the Xpert MTB/RIF assay was positive in three of 37 (8.1%), but none had MDR-TB. The sensitivity, specificity, positive predictive value, and negative predictive value of the Xpert MTB/RIF assay was 8.1%, 100%, 100%, and, 64.2%, respectively.

Conclusions

The Xpert MTB/RIF assay has low sensitivity but high specificity for intestinal TB, and may be helpful in endemic tuberculosis areas, when clinicians are faced with difficulty differentiating TB and CD. Based on the Xpert MTB/RIF assay, the prevalence of intestinal MDR-TB is low in the Indian population.

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.

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.

Change in the diagnosis of inflammatory bowel disease: a hospital-based cohort study from Korea

BACKGROUND/AIMS

Accurately diagnosing inflammatory bowel disease (IBD) remains a challenge, but is crucial for providing proper management for affected patients. The aim of the present study was to evaluate the frequency of change in diagnosis in Korean patients who were referred to our institution with a diagnosis of IBD.

METHODS

We enrolled 1,444 patients diagnosed with ulcerative colitis (UC) and 1,452 diagnosed with Crohn's disease (CD), who had been referred to the Asan Medical Center between January 2010 and December 2014. These patients were assessed and subsequently classified as having UC, CD, indeterminate colitis, possible IBD, or non-IBD.

RESULTS

During a median follow-up of 15.9 months, 400 of the 2,896 patients (13.8%) analyzed in this study experienced a change in diagnosis. A change in diagnosis from UC to CD, or vice-versa, was made in 24 of 1,444 patients (1.7%) and 23 of 1,452 patients (1.6%), respectively. A change to a non-IBD diagnosis was the most common modification; 7.5% (108 of 1444) and 12.7% (184 of 1452) of the patients with a referral diagnosis of UC and CD, respectively, were reclassified as having non-IBD. Among the 292 patients who were ultimately determined not to have IBD, 135 (55 UC and 80 CD cases) had received IBD-related medication.

CONCLUSIONS

There are diagnostic uncertainties and difficulties in relation to IBD. Therefore, precise assessment and systematic follow-up are essential in the management of this condition.

Clinical Features of Tuberculous Versus Crohn's Anal Fistulas, in Korea

BACKGROUND AND AIMS

In Western countries, tuberculous anal fistula may not be an issue because tuberculosis [TB] is not common, and this is a very rare form of extrapulmonary manifestation of TB. However in TB-endemic countries, careful diagnostic differentiation is required because the clinical features of TB anal fistula and Crohn's disease [CD] anal fistula are similar, with distinguishing features remaining unclear. We aimed to analyse the clinical features of TB versus CD anal fistulas.

METHOD

Among 13872 patients who underwent anal fistula surgery from 2003 to 2014, 87 patients with TB fistulas and 116 patients with CD fistulas were included. Data on the annual incidence of TB and CD, as well as the clinical, pathological, ultrasonographic, colonoscopic and surgical data were analysed.

RESULTS

Compared with CD, the TB group was older [median: 37 vs 22 years] and underlying chronic illness was more common [20.3% vs 2.6%]. In the TB group, 46 patients [59.7%] showed active or inactive pulmonary TB, and acid-fast bacilli and caseating granuloma were found in 56.3% and 62.1%, respectively. During colonoscopy, mucosal lesions were observed more frequently in CD [96.9% vs 16.9%].

CONCLUSIONS

TB anal fistula is clinically very similar to CD anal fistula. In Korea, the incidence of CD anal fistula has recently increased in prevalence, whereas the prevalence of TB anal fistula is decreasing but is still persistent. We recommend that clinicians should prepare for a possibility of TB as well as CD anal fistula in TB-endemic countries including Korea.

Differential diagnosis of Crohn's disease versus ileal tuberculosis

Both intestinal tuberculosis and Crohn's disease are chronic granulomatous inflammatory diseases of the bowel having overlap of clinical, endoscopic, radiological, and histological features. Differentiating between the two disorders is relevant not only in Asian countries but also in the West. In spite of diagnostic criteria for both diseases being available, still the dilemma of segregating the two diseases remains. Nearly one third of the patients with Crohn's disease may receive anti-tuberculosis treatment also. Diagnosis should be based on the combination of all disease-specific and corroborative evidences.

[A case of intestinal tuberculosis with perianal fistula diagnosed after 30 years]

Tuberculosis can occur anywhere in the gastrointestinal tract. However, anorectal tuberculosis has rarely been reported. A 46-years-old male presented with abdominal pain and perianal discharge of 30 years' duration. The patient had received operations for anal fistula and inflammation three times. Although he had been taking mesalazine for the past three years after being diagnosed with Crohn's disease, his symptoms persisted. Colonoscopy performed at our hospital revealed cicatricial change of ileocecal valve and diffuse ulcer scar with mild luminal narrowing of the ascending, transverse, and descending colon without active lesions. Multiple large irregular active ulcers were observed in the distal sigmoid and proximal rectum. An anal fistula opening with much yellowish discharge and background ulcer scar was observed in the anal canal. However, cobble-stone appearance and pseudopolyposis were not present. Therefore, we clinically diagnosed him as having intestinal tuberculosis with anal fistula and prescribed antituberculosis medications. Follow-up colonoscopy performed 3 months later showed much improved multiple large irregular ulcers in the distal sigmoid colon and proximal rectum along with completely resolved anal fistula without evidence of pus discharge.