Clinical and laboratory features of intestinal tuberculosis

Demographic, Clinical, Radiological, and Surgical Outcome of Patients with Intestinal Tuberculosis: A Single-Center Retrospective Study

Background

Intestinal tuberculosis (iTB) represents a potentially underrecognized clinical entity with limited clinical and radiological differentiating features. This study aims to assess the patterns of iTB clinical and radiological findings, along with the treatment approaches and the overall outcome.

Methods

This retrospective cross-sectional study included patients with histopathologically confirmed iTB who presented with acute abdomen and were surgically managed between September 2005 and October 2023. Clinical and sociodemographic variables, imaging features, surgical treatments, and overall outcomes were retrospectively analyzed.

Results

96 patients with iTB were included, with a mean age of 36.1 ± 11.5 years and a relatively proportionate gender distribution. Abdominal pain was the most common presenting symptom (45.8%). The radiological features varied by the modality. Plain imaging showed non-specific findings, while ultrasonography showed loculated ascites (25%), and lymphadenopathy (22%). In computed tomography scans, multi-segmental symmetric intestinal thickening (53.1%) was the most prevalent finding. The most commonly performed surgical procedure was adhesiolysis (29.2%), with the ileocecal junction being the most commonly involved structure (39.6%). Histopathological examination of all the tissue biopsies revealed epithelioid granulomas. Postoperative complications occurred in 19 patients (19.8%), with surgical site infection being the most common complication (10.4%).

Conclusion

Intestinal obstruction is an underrecognized manifestation of tuberculosis, particularly in endemic regions. The non-specific clinical presentation, coupled with the limited utility of laboratory and radiological tests, often leads to delayed recognition and treatment. Maintaining a high index of suspicion is essential, especially in younger patients, inhabitants of endemic areas, or those with laboratory findings indicative of chronic inflammation. Prompt recognition is crucial to ensure the timely initiation of anti-tuberculosis therapy and to optimize patient outcomes through appropriate follow-up.

Asymptomatic intestinal tuberculosis of the terminal ileum diagnosed on colonoscopy: a case report and literature review

Objective

Colonoscopy is useful in diagnosing intestinal tuberculosis. However, the terminal ileum is generally not examined during routine colonoscopy. Therefore, even with colonoscopy, the diagnosis can be missed in patients with lesions confined to the terminal ileum. Herein, we report the case of an asymptomatic patient with intestinal tuberculosis, in whom a colonoscope insertion into the terminal ileum led to the diagnosis.

Patient

An asymptomatic 71-year-old man visited our hospital for a colonoscopy after a positive fecal occult blood test.

Results

Colonoscopy revealed diffuse edematous and erosive mucosa in the terminal ileum. Mycobacterium tuberculosis was detected by polymerase chain reaction and culture of biopsy specimens from the erosions, leading to the diagnosis of intestinal tuberculosis. The patient was treated with antitubercular agents for 6 months, and a follow-up colonoscopy revealed healing of the lesions.

Conclusion

Asymptomatic intestinal tuberculosis may occasionally be detected on colonoscopy following a positive fecal occult blood test and is sometimes confined to the terminal ileum. Therefore, clinicians should consider intestinal tuberculosis in the differential diagnosis of the causes of positive fecal occult blood test results and perform colonoscopies, including observation of the terminal ileum.

Intestinal tuberculosis with small bowel stricture and hemorrhage as the predominant manifestation: Three case reports

BACKGROUND

Intestinal tuberculosis is a chronic disease caused by Mycobacterium tuberculosis that mainly affects the ileum and cecum. Small bowel tuberculosis, characterized by predominant involvement of the small intestine, is an extremely rare condition with highly atypical clinical presentations, making diagnosis even more challenging.

CASE SUMMARY

We report three cases of small intestinal tuberculosis, two of the patients presented primarily with abdominal pain, and one presented with gastrointestinal bleeding. All patients underwent blood tests and imaging examinations. Small bowel endoscopy (SBE) revealed that the main lesions in these patients were intestinal stenosis or gastrointestinal bleeding caused by small intestinal ulcers. One patient ultimately underwent surgical treatment. Following a complex diagnostic process and comprehensive analysis, all patients were confirmed to have small intestinal tuberculosis and received standard antituberculosis treatment, leading to an improvement in their condition.

CONCLUSION

Patients with SBTs present with nonspecific symptoms such as abdominal pain, weight loss, and occasional gastrointestinal bleeding. Accurate diagnosis requires a thorough evaluation of clinical symptoms and various tests to avoid misdiagnosis and complications.

Clinical manifestations and immune response to tuberculosis

Tuberculosis is a far-reaching, high-impact disease. It is among the top ten causes of death worldwide caused by a single infectious agent; 1.6 million tuberculosis-related deaths were reported in 2021 and it has been estimated that a third of the world's population are carriers of the tuberculosis bacillus but do not develop active disease. Several authors have attributed this to hosts' differential immune response in which cellular and humoral components are involved, along with cytokines and chemokines. Ascertaining the relationship between TB development's clinical manifestations and an immune response should increase understanding of tuberculosis pathophysiological and immunological mechanisms and correlating such material with protection against Mycobacterium tuberculosis. Tuberculosis continues to be a major public health problem globally. Mortality rates have not decreased significantly; rather, they are increasing. This review has thus been aimed at deepening knowledge regarding tuberculosis by examining published material related to an immune response against Mycobacterium tuberculosis, mycobacterial evasion mechanisms regarding such response and the relationship between pulmonary and extrapulmonary clinical manifestations induced by this bacterium which are related to inflammation associated with tuberculosis dissemination through different routes.

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.

Applying logistic LASSO regression for the diagnosis of atypical Crohn's disease

In countries with a high incidence of tuberculosis, the typical clinical features of Crohn's disease (CD) may be covered up after tuberculosis infection, and the identification of atypical Crohn's disease and intestinal tuberculosis (ITB) is still a dilemma for clinicians. Least absolute shrinkage and selection operator (LASSO) regression has been applied to select variables in disease diagnosis. However, its value in discriminating ITB and atypical Crohn's disease remains unknown. A total of 400 patients were enrolled from January 2014 to January 2019 in second Xiangya hospital Central South University.Among them, 57 indicators including clinical manifestations, laboratory results, endoscopic findings, computed tomography enterography features were collected for further analysis. R software version 3.6.1 (glmnet package) was used to perform the LASSO logistic regression analysis. SPSS 20.0 was used to perform Pearson chi-square test and binary logistic regression analysis. In the variable selection step, LASSO regression and Pearson chi-square test were applied to select the most valuable variables as candidates for further logistic regression analysis. Secondly, variables identified from step 1 were applied to construct binary logistic regression analysis. Receiver operating characteristic (ROC) curve analysis was performed on these models to assess the ability and the optimal cutoff value for diagnosis. The area under the ROC curve (AUC), sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy rate, together with their 95% confidence and intervals (CIs) were calculated. MedCalc software (Version 16.8) was applied to analyze the ROC curves of models. 332 patients were eventually enrolled to build a binary logistic regression model to discriminate CD (including comprehensive CD and tuberculosis infected CD) and ITB. However, we did not get a satisfactory diagnostic value via applying the binary logistic regression model of comprehensive CD and ITB to predict tuberculosis infected CD and ITB (accuracy rate:79.2%VS 65.1%). Therefore, we further established a binary logistic regression model to discriminate atypical CD from ITB, based on Pearsonchi-square test (model1) and LASSO regression (model 2). Model 1 showed 89.9% specificity, 65.9% sensitivity, 88.5% PPV, 68.9% NPV, 76.9% diagnostic accuracy, and an AUC value of 0.811, and model 2 showed 80.6% specificity, 84.4% sensitivity, 82.3% PPV, 82.9% NPV, 82.6% diagnostic accuracy, and an AUC value of 0.887. The comparison of AUCs between model1 and model2 was statistically different (P < 0.05). Tuberculosis infection increases the difficulty of discriminating CD from ITB. LASSO regression showed a more efficient ability than Pearson chi-square test based logistic regression on differential diagnosing atypical CD and ITB.

Recent advances in the diagnosis of intestinal tuberculosis

BACKGROUND

Intestinal tuberculosis still has a high incidence, especially in developing countries. The biggest challenge of this disease is the establishment of the diagnosis because the clinical features are not typical. Investigations such as culture, acid-fast bacilli (AFB) staining, and histopathology have low sensitivity, so other investigations are needed. Latest molecular-based diagnostic modalities such as GeneXpert, interferon-gamma (IFN-γ) release assays (IGRA), polymerase chain reaction (PCR), multiplex-PCR, and immunological markers are expected to help diagnose intestinal tuberculosis. This article review will examine the latest diagnostic modalities that can be used as a tool in establishing the diagnosis of intestinal tuberculosis.

RESULTS

Through a literature search, we were able to review the diagnostic values of various available diagnostic modalities as the appropriate additional test in intestinal tuberculosis. Culture as a gold standard has a sensitivity and specificity value of 9.3% and 100% with the MGIT BACTEC system as the most recommended medium. The sensitivity values of AFB staining, histopathology examination, GeneXpert, IGRA, PCR, multiplex-PCR and, immunological markers were ranged between 17.3 and 31%; 68%; 81-95.7%; 74-88%; 21.6-65%; 75.7-93.1%; and 52-87%, respectively. Meanwhile the specificity values were 100%; 77.1%; 91-100%; 74-87%; 93-100%; 96.4-100%; and 70-95%, respectively.

CONCLUSION

The combination of clinical examination, conventional examination, and the latest molecular-based examination is the best choice for establishing the diagnosis of intestinal tuberculosis. Most recent modalities such as multiplex PCR and immunological marker examinations are diagnostic tools that deserve to be used in diagnosing intestinal tuberculosis as their sensitivity and specificity values are quite high and more evidences are expected to support the application of these examinations shortly soon.

Recent updates in diagnosis of abdominal tuberculosis with emphasis on nucleic acid amplification tests

INTRODUCTION

Abdominal tuberculosis (TB) is a common epitome of extrapulmonary TB (EPTB), wherein peritoneal and intestinal TB are the most prevalent forms. Diagnosis of abdominal TB is a daunting challenge owing to variable anatomical locations, paucibacillary nature of specimens and atypical clinical presentations that mimic other abdominal diseases, such as Crohn's disease and malignancies. In this review, we made a comprehensive study on the diagnosis of abdominal TB.

AREA COVERED

Various modalities employed for abdominal TB diagnosis include clinical features, imaging, bacteriological tests (smear/culture), histopathological/cytological observations, interferon-gamma release assays and nucleic acid amplification tests (NAATs). Among NAATs, loop-mediated isothermal amplification assay, PCR, multiplex-PCR, nested PCR, real-time PCR and GeneXpert® MTB/RIF were discussed. Identification of circulating Mycobacterium tuberculosis cell-free DNA by real-time PCR within ascitic fluids is another useful approach.

EXPERT OPINION

Several novel molecular/immunological methods, such as GeneXpert Ultra, aptamer-linked immobilized sorbent assay, immuno-PCR (I-PCR) and nanoparticle-based I-PCR have recently been developed for detecting pulmonary TB and several EPTB types, which may also be explored for abdominal TB diagnosis. Precise and prompt diagnosis of abdominal TB may initiate an early therapy so as to reduce the complications, i.e. abdominal pain, ascites, abdominal distension, intestinal obstruction/perforation, etc., and avoid surgical involvement.Plain Language SummaryAbdominal tuberculosis (TB) is a manifestation of extrapulmonary TB (EPTB), where peritoneal and intestinal TB are two major forms. Diagnosis of abdominal TB is difficult owing to low bacterial load present in clinical samples and non-specific clinical presentations as it mimics other diseases such as inflammatory bowel diseases, abdominal malignancies, etc. Bacteriological tests (smear/culture) almost fail owing to poor sensitivities and it is not always possible to get representative tissue samples for histopathological and cytological observations. In recent years, molecular tests i.e. nucleic acid amplification tests (NAATs), such as PCR/multiplex-PCR (M-PCR), nested PCR and GeneXpert are widely employed. Markedly, PCR/M-PCR and nested PCR exhibited reasonable good sensitivities/specificities, while GeneXpert revealed low sensitivity in most of the studies but high specificity, thus it could assist in differential diagnosis of intestinal TB and Crohn's disease. Further, novel molecular/immunological tests employed for pulmonary TB and other EPTB types were described and those tests can also be utilized to diagnose abdominal TB. Reliable and rapid diagnosis of abdominal TB would initiate an early start of anti-tubercular therapy and reduce the severe complications.

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.

Difficulties in the differential diagnosis of intestinal tuberculosis and Crohn‘s disease

The differential diagnosis of intestinal tuberculosis and Crohn’s disease is a difficult task for most specialists due to their high similarity in clinical manifestations, instrumental diagnosis and histological pattern.

The aim: to consider the clinical and diagnostic features of intestinal tuberculosis and Crohn’s disease, to show the role of various methods of their diagnosis (CT of the abdominal cavity, CT-enterography, colonoscopy with biopsy).

A clinical example shows a case illustrating the difficulties of diagnosing intestinal tuberculosis, initially diagnosed as Crohn’s disease. The features of the course, complex diagnosis and treatment of intestinal tuberculosis and its complications during immunosuppression are demonstrated. At the first stage of treatment, the patient’s data related to CT of the chest organs, colonoscopy and histological examination of biopsy samples were incorrectly interpreted. As a result, a wrong diagnosis of Crohn’s disease was made, and immunosuppressive therapy was prescribed that provoked a generalization of the existing tuberculosis process. Subsequently, repeated surgical interventions were performed for complications of intestinal tuberculosis – perforation of tuberculous ulcers, peritonitis. Based on the analysis of the literature data and our own observation, it is shown that granulomatous inflammation in the study of intestinal biopsies doesn’t always allow us to make a clear diagnosis, first of all, there are intestinal tuberculosis and Crohn’s disease in the differential diagnostic series. The use of histobacterioscopy according to Ziehl – Neelsen, the study of fecal matter by luminescent microscopy, as well as molecular genetic methods for detecting DNA MTB allow us to verify the diagnosis. If Crohn’s disease is misdiagnosed as intestinal tuberculosis, then the prescribed anti-tuberculosis therapy can cause harm and lead to a delay in the underlying disease treatment. The reverse misdiagnosis is potentially more dangerous: if tuberculosis is misdiagnosed as Crohn’s disease, then the appointment of immunosuppressive therapy can lead to the generalization of tuberculosis and the development of fatal complications. 

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.

Application value of tissue tuberculosis antigen combined with Xpert MTB/RIF detection in differential diagnoses of intestinal tuberculosis and Crohn's disease

Background

The purpose of this study was to examine the value of Xpert MTB/RIF assay and detection of additional Mycobacterium tuberculosis complex (MTBC) species antigens from intestinal tissue samples in differentiating intestinal tuberculosis (ITB) from Crohn’s disease (CD).

Methods

Several clinical specimens of intestinal tissue obtained by either endoscopic biopsy or surgical excision were used for mycobacteriologic solid cultures,Xpert MTB/RIF assays, immunohistochemistry, and histological examinations. Four antigens (38KDa, ESAT-6, MPT64, and Ag85 complex) of MTBC in the intestinal tissue were detected by immunohistochemical analysis.

Results

The study included 42 patients with ITB and 46 with CD. Perianal lesions and longitudinal ulcers were more common in patients with CD, while caseating granuloma and annular ulcers were more common in patients with ITB. The positive rate of MTBC detected by Xpert MTB/RIF in intestinal tissues of patients with ITB was 33.33%, which was significantly higher than that in patients with CD and that detected using acid-fast staining smears. It was also higher than that detected by tissue MTBC culture, but the difference was not statistically significant. The positive MPT64 expression rate in patients with ITB was 40.48%, which was significantly higher than that observed in patients with CD. The sensitivity of parallelly combined detection of tuberculosis protein MPT64 and Xpert MTB/RIF in diagnosing ITB was 50.0%.

Conclusions

The detection of Xpert MTB/RIF in intestinal tissue is a rapid and useful method for establishing an early diagnosis of ITB. The detection of MTBC using Xpert MTB/RIF and MPT64 antigen in intestinal tissues has a definitive value in the differential diagnosis ofITB and CD. The combination of these two methods can improve the detection sensitivity.

Intestinal Tuberculosis Presenting as an Ileocecal Mass in a Renal Transplant Patient

Abdominal tuberculosis accounts for approximately 5% of tuberculosis cases. However, recognition of this entity can be challenging in the absence of concomitant pulmonary involvement. Immunocompromised and immunosuppressed patients are at elevated risk for this infection and are confronted with increased side effects, drug interactions, and disease complications. We report the case of a 53-year-old female renal transplant recipient with a remote history of tuberculosis exposure who presented with sepsis and abdominal pain and was found to have an obstructive ileocecal mass. Serologic and pathologic testing ultimately led to the diagnosis of abdominal tuberculosis, and she was treated successfully with a course of antimycobacterial therapy with only minor complications.

Surgical management of abdominal tuberculosis: A prospective single-center study

Objective

Tuberculosis (TB) can affect any part of the gastrointestinal tract. It is estimated that in 2018, 10 million people were affected with TB worldwide and there were 1.2 million TB deaths among human immunodeficiency virus-negative people. India has the highest TB burden in the world (27%), a significant proportion of which are of intestinal TB. The aims of this study were to assess clinical features and investigations for the diagnosis of abdominal TB and to analyze its various surgical manifestations and its management.

Materials and Methods

From October 1, 2014, to October 30, 2016, a total of 50 patients meeting the inclusion criteria for the study, age between 15 and 65 years and diagnosis of symptomatic intestinal TB requiring surgery, were enrolled in the study. We used descriptive statistics to analyze the data.

Results

Abdominal TB was most commonly seen in young adults. Intestinal obstruction was the most frequent presentation. The most common site of involvement in the present study was the ileum. Ultrasonography (USG) and X-ray were an integral part of the diagnosis, with computed tomography (CT) scan being rarely required. Although both anemia and erythrocyte sedimentation rate (ESR) are nonspecific, they may help in supporting the clinical and pathological findings. Most operations were elective, with intestinal obstruction being the most common indication and resection and end-to-end anastomosis performed most often. Histopathological examination was performed in all patients and showed caseating granuloma in 90% of cases, while 10% of cases had chronic noncaseating granulomas with ill-defined aggregates of epithelioid histiocytes.

Conclusion

Abdominal TB causes a significant problem in diagnosis due to nonspecific symptomatology and lack of specific laboratory tests. USG and X-ray were an integral part of the diagnosis. CT scan is rarely required. Although anemia and ESR are both nonspecific features, they may help in supporting the clinical and pathological findings. The most common site of involvement in the present study was the ileum. Intestinal obstruction was the most common indication for operation, with resection and end-to-end anastomosis being the most common operation. The mainstay of treatment is medical therapy and timely surgical intervention is required in a sizable number of patients.

GeneXpert in stool: Diagnostic yield in Intestinal Tuberculosis

Background

Diagnosing intestinal (Luminal) tuberculosis is challenging due to limited yield of diagnostic modalities like CT scan, colonoscopy with blind ileal biopsies. GeneXpert MTB/RIF (Xpert) assays for diagnosing tuberculosis have been performed in the body secretions with excellent results. Its yield in stool is tested in this study.

Objective

The study aims to evaluate the yield of GeneXpert assay in stool of suspected cases of intestinal tuberculosis.

Methods

Hundred patients with suspected intestinal tuberculosis underwent routine biochemical tests, radiological investigations, colonoscopy with caecal and blind ileal biopsies for histopathology. Fresh stool samples were collected, processed for DNA extraction, tested using 2:1 ratio of GeneXpert reagent to sample to give positive or negative results for Mycobacterium tuberculosis and Rifampicin resistance.

Results

Out of hundred participants, 52% were female. Mean age was 28.21 ± 12.13. CT scan and colonoscopy findings suggestive of TB were present in 47% and 43% participants respectively. GeneXpert in stool was positive in 20% cases. Considering mucosal biopsy with histopathology of intestinal specimens as diagnostic of abdominal Tuberculosis, sensitivity and specificity of GeneXpert was 39.1% and 85.7% respectively.

Conclusion

Stool GeneXpert assay offers an alternative approach to detect intestinal tuberculosis rapidly with good diagnostic accuracy. Although it cannot replace the AFB culture and histopathology but contribute for early diagnosis and management.

Analysis of Phenotypic Variables and Differentiation Between Untypical Crohn's Disease and Untypical Intestinal Tuberculosis

BACKGROUND

The differentiation between untypical intestinal tuberculosis (UITB) and untypical Crohn's disease (UCD) is a challenge.

AIMS

To analyze phenotypic variables and propose a novel prediction model for differential diagnosis of two conditions.

METHODS

A total of 192 patients were prospectively enrolled. The clinical, laboratory, endoscopic, and radiological features were investigated and subjected to univariable and multivariable analyses. The final prediction model for differentiation between UCD and UITB was developed by logistic regression analysis and Fisher discriminant analysis on the training set. The same discriminant function was tested on the validation set.

RESULTS

Twenty-five candidates were selected from 52 phenotypic variables of typical Crohn's disease (TCD), UCD, and UITB patients. UCD's variables overlapped with both TCD and UITB. The percentages of tuberculosis history, positive PPD, and positive T-SPOT result in UCD were all significantly higher than that in TCD (11.6% vs. 0.0%, 27.9% vs. 0.0%, 25.6% vs. 4.5%, respectively, P < 0.05). The regression equations and Fisher discriminant function for discrimination between UCD and UITB were developed. In the training data, the area under the receiver operating characteristic of equations was 0.834, 0.69, and 0.648 in the clinical-laboratory, endoscopic, and radiological model, respectively. The accuracy of Fisher discriminant function for discrimination was 86% in UCD and 73% in UITB in the validation data.

CONCLUSIONS

Phenotypes of UCD patients in TB-endemic countries may be associated with TB infection history. Fisher discriminant analysis is a good choice to differentiate UCD from UITB, which is worthy of verification in clinical practice.