Use of adenosine deaminase (ADA) to diagnose suspected peritoneal tuberculosis in Rwanda: a cross-sectional study

Mistakes to avoid in the management of abdominal tuberculosis

INTRODUCTION

The diagnosis and management of abdominal tuberculosis, i.e Gastrointestinal Tuberculosis (GITB) and tuberculous peritonitis (TBP) is challenging. Abdominal tuberculosis, presenting usually with abdominal pain, intestinal obstruction, and constitutional symptoms, is typically a paucibacillary condition. The diagnosis hinges on a correct interpretation of clinical, radiological, histological, biochemical, and microbiological findings as also appropriately assessing response to therapy.

AREAS COVERED

The authors review potential missteps that could occur in managing GITB and TBP sourced from published literature and clinical experience. These include avoiding excess use of tests with limited accuracy, understanding limitations of ascitic adenosine deaminase (ADA) and granulomas, avoiding empirical antitubercular therapy (ATT) where possible but also understanding that microbiological tests may not always be positive, and finally not to bank solely on subjective clinical responses but to use objective markers in assessing response to therapy. In addition, diagnosis of predisposing immunosuppressed states, attention to nutrition, appropriate management of sequelae with endoscopic dilatation/surgery, and early surgery when indicated are some of the additional issues discussed.

EXPERT OPINION

In future, a more secure diagnosis banking on the use of better microbiological tools, multiparameter-based models, artificial intelligence-based approaches, and use of advances in -omics-based approaches can improve diagnosis and avoid some missteps.

Gastrointestinal tuberculosis: Diagnostic approaches for this uncommon pathology

A case report entitled "Primary gastroduodenal tuberculosis presenting as gastric outlet obstruction" recently published in the World Journal of Clinical Cases presented a rare cause of gastric outlet obstruction and highlighted the atypical manner in which gastrointestinal tuberculosis (TB) can present. The literature with regards to this rare pathology is limited to case reports and case series with the largest being published using data from between 2003 and 2013. However, since then the diagnostic tools available have significantly changed with more modern and increasingly accurate tests now available. This editorial reviews the current state of the art with regards to diagnosis in gastrointestinal TB.

Utility of human epididymis protein 4 in the differential diagnosis of ascites

BACKGROUND AND AIMS

Human epididymal protein 4 (HE4) may be a useful tool in the differential diagnosis of malignant ascites. The aim of this study was to evaluate the diagnostic utility of HE4 for detecting malignant ascites, taking into account the possible false positives identified with adenosine deaminase (ADA), C-reactive protein (CRP), % polynuclear cells (%PMN) and glomerular filtration rate (eGFR).

METHODS

Concentrations of HE4, ADA, %PMN and CRP were determined in 114 samples of peritoneal fluid and creatinine in serum in order to calculate eGFR.

RESULTS

Concentrations of HE4 presented significant differences (P = 0.028) in benign [median (interquartile range)] [582(372)] pmol/L) and malignant ascites ([8241(367)] pmol/L. Sensitivity was 21.2% and specificity 100%. Significant differences were also observed for HE4 between tumors of gynecological origin ([3165(8769)] pmol/L) and others ([665(663)] pmol/L), with a sensitivity of 67% and a specificity of 100%. Classifying according to possible false positives (ADA > 45U/L, CRP > 50 mg/L, %PMN > 90 and eGFR < 30 mL/min/1.73 m2) at maximum specificity, a sensitivity of 33.3% was obtained for HE4, with a cut-off point of 2660 pmol/L. Without possible false positives (ADA < 45U/L, CRP < 50 mg/L, %PMN < 90 and eGFR ≥ 30 mL/min/1.73 m2), a sensitivity of 37.7% was obtained at 100% specificity for a cut-off point of 1041 pmol/L. Applying these criteria to the entire group, a sensitivity of 36.4% was obtained at maximum specificity.

CONCLUSIONS

HE4 allows the identification of malignant ascites with moderate sensitivity at maximum specificity. HE4 levels can differentiate between tumors of gynecological origin and others. Classification according to possible false positives increases sensitivity without losing specificity.

Peritoneal and Pulmonary Tuberculosis in a Postpartum Female with Elevated Cancer Antigen 125 and Ascites

BACKGROUND

Peritoneal tuberculosis is a rare form of extrapulmonary tuberculosis and presents a challenging diagnosis because of its nonspecific clinical manifestations. Peritoneal TB mimics other pathologies, including abdominal carcinomatosis, especially when the patient presents with ascites and an elevated cancer antigen (CA)-125 levels. Case Presentation. A postpartum 20-year-old Hispanic female recently discharged after transverse cesarean surgery, presented to the ER with fever, chills, edema, abdominal distension, nausea, and vomiting. The patient was febrile, tachycardic, and hypotensive. Chest X-ray demonstrated alveolar and interstitial consolidations; chest CT revealed tree-in-bud opacities in the right lower lobe, suggestive of atypical (TB)/fungal infection. CT of the abdomen and pelvis demonstrated ascites, omental thickening, peritoneal thickening, and mesenteric adenopathy, suggestive of carcinomatosis. She was admitted with a presumed diagnosis of sepsis secondary to pneumonia and started empirically on broad-spectrum antibiotics without clinical improvement. A battery of oncology markers was ordered and revealed a mildly elevated cancer antigen (CA)-125. Diagnostic paracentesis showed lymphocytic predominance with positive mycobacteria PCR, elevated adenosine deaminase (ADA), and no malignant cells. Subsequently, the sputum acid-fast bacilli (AFB) stain returned positive for tuberculosis, confirming the diagnosis of pulmonary tuberculosis. A peritoneal biopsy was obtained and demonstrated caseating granulomas consistent with peritoneal tuberculosis. The patient was started on standard antituberculosis therapy with clinical improvement.

CONCLUSIONS

This case highlights the need for a high-level of suspicion for peritoneal tuberculosis in a patient with pulmonary tuberculosis who presents with intra-abdominal ascites, omental thickening, peritoneal thickening, and mesenteric lymphadenopathy, despite the presence of an elevated CA-125 level.

Diagnostic performance of adenosine deaminase for abdominal tuberculosis: A systematic review and meta-analysis

Background and aim

Abdominal tuberculosis (TB) is a common type of extrapulmonary TB with an insidious onset and non-specific symptoms. Adenosine deaminase (ADA) levels increase rapidly in the early stages of abdominal TB. However, it remains unclear whether ADA serves as a diagnostic marker for abdominal TB.

Methods

We performed a systematic literature search for relevant articles published in PubMed, Web of Science, Cochrane Library, and Embase up to April 2022. First, we used the Quality Assessment of Diagnostic Accuracy Studies tool-2 (QUADAS-2), to evaluate the quality of the included articles. Bivariate and hierarchical summary receiver operating characteristic (HSROC) models were then utilized to analyze pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and area under the receiver operating characteristic curve (AUROC). In addition, we explored a subgroup analysis for potential heterogeneity and publication bias among the included literature.

Results

Twenty-four articles (3,044 participants, 3,044 samples) which met the eligibility criteria were included in this study. The pooled sensitivity and specificity of ADA for abdominal TB detection were 93% [95% confidence interval (CI): 0.89-0.95] and 95% (95% CI: 0.93-0.96), respectively. PLR and NLR were 18.6 (95% CI: 14.0-24.6) and 0.08 (95% CI: 0.05-0.12), respectively. DOR and AUROC were 236 (95% CI: 134-415) and 0.98 (95% CI: 0.96-0.99), respectively. Furthermore, no heterogeneity or publication bias was found.

Conclusions

Our meta-analysis found ADA to be of excellent diagnostic value for abdominal TB and could be used as an auxiliary diagnostic tool.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42022297931.