Tuberculosis of the Liver, Biliary Tract, and Pancreas

Role of PE family of proteins in mycobacterial virulence: Potential on anti-TB vaccine and drug design

Macrophages are the primary targets of mycobacterial infection, which plays crucial roles both in nonspecific defence (innate immunity) as well as specific defence mechanisms (adaptive immunity) by secreting various cytokines, antimicrobial mediators and presenting antigens to T-cells. Sequencing of the mycobacterial genome revealed that 10% of its coding ability is devoted to the Pro-Glu motif-containing (PE) and Pro-Pro-Glu motif-containing (PPE) family proteins. While the function of most of the genes belonging to the PE-PPE family initially remained unannotated, recent studies have shown that many proteins of this family play critical roles in bacterial growth and cell functions, and manipulation of host immune responses, indicating their potential roles in mycobacterial virulence. In this review, we have focussed on describing the immunological importance of particularly the PE group of proteins in the context of 'virulence' determinants and outcome of tuberculosis disease. Additionally, we have discussed about the roles of these proteins on host-pathogen-interaction and how some of these genes can be targeted which may help us in designing effective anti-TB therapeutics.

Beyond cholangiocarcinoma: imaging features of mimicking pathologies in the biliary tract

Cholangiocarcinoma (CCA) is the second most common primary malignancy of the hepatobiliary system and presents as a heterogeneous disease with three distinct morphological subtypes: mass-forming, periductal-infiltrating, and intraductal-growing, each characterized by distinguishing imaging features. Accurate diagnosis of CCA is challenging due to the overlap of imaging findings with a broad range of benign and malignant conditions. Therefore, it is essential for radiologists to recognize these mimickers and offer a reasonable differential diagnosis, as this has a significant impact on patient management. Although histopathological confirmation is often required for a definitive diagnosis, understanding specific imaging characteristics that differentiate CCA from its mimickers is crucial. This article highlights a variety of benign and malignant conditions that resemble CCA on imaging, emphasizing features that enhance diagnostic accuracy in clinical practice.

Diagnosis, prevention and risk-management of drug-induced liver injury due to medications used to treat mycobacterium tuberculosis

INTRODUCTION

Many of the first line medications for the treatment of active and latent M. tuberculosis are hepatoxic and cause a spectrum of anti-tuberculosis drug induced liver injury (ATLI), including acute liver failure (ALF). Despite advances in recognition of and prevention of ATLI, isoniazid remains one of the leading causes of DILI as well as drug-induced ALF.

AREAS COVERED

A literature search of the incidence, risk factors, current societal guidelines, monitoring, and prophylactic medication usage in ATLI was performed using PubMed and institutional websites. Relevant articles from 1972 to 2024 were included in this review.

EXPERT OPINION

Current societal guidelines regarding ATLI monitoring are mixed, but many recommend liver enzyme testing of high-risk populations. We recommend liver test monitoring for all patients on multi-drug therapy as well as those on isoniazid therapy. Precision medicine practices, such as N-acetyltransferase-2 polymorphism genotyping, are thought to be beneficial in reducing the incidence of ATLI in high-risk populations. However, broader implementation is currently cost prohibitive. Hepatoprotective drugs are not currently recommended, although we do recognize their potential. In patients who develop ATLI but require ongoing anti-TB treatment, strategies to restart the same or less hepatotoxic regimens are currently being followed.

Peripancreatic tuberculosis

Peripancreatic tuberculosis (PTB) is a very rare variant of tuberculosis and its clinical and radiological findings are similar to those of pancreatic malignancy. Diagnosis of PTB is usually incidental and is made after surgical resection. We are presenting a male patient who had complaints of prolonged fever, significant weight loss and yellowish discolouration of eyes and dark-coloured urine. Investigations revealed that there was a pancreatic mass causing obstructive jaundice. However, the aetiology of the mass, whether tubercular or malignant, was not clear. Hence, the patient was planned for endoscopic ultrasound-guided fine needle aspiration cytology. Cytology and aspirate were sent for a cartridge-based nucleic acid amplification test which revealed the presence of Mycobacterium tuberculosis, sensitive to rifampicin. The patient improved completely after treatment with antitubercular therapy.

The great masquerader of pancreatic tuberculosis

Background

Pancreatic tuberculosis is a rare clinical entity. It represents a diagnostic challenge as the clinical presentation may mimic pancreatic malignancy.

Case presentation

A 66-year-old gentleman presented with an incidental finding of a pancreatic tail mass on routine ultrasonography of the abdomen whilst working up on chronic kidney disease. He denied abdominal pain, fever, night sweats, constitutional symptoms or tuberculosis contact. On examination, there was no palpable mass per abdomen. The tumour marker of Ca 19-9 was normal. Ultrasonography revealed a lobulated heterogeneous hypovascular and hypoechoic mass at the tail of the pancreas. Contrast-enhanced computed tomography (CT) of the thorax and abdomen revealed a thickened right pleura, right pleural effusion with right lung collapsed consolidation and multiple mediastinal lymph nodes. There is an ill-defined hypodense mass seen in the tail and body of the pancreas measuring 3 × 7 × 3 cm with the presences of calcification within. The constellation of CT findings suggests a pancreatic malignancy with metastasis to the lungs. Endoscopic ultrasonography (EUS) assessment showed an irregular hypoechoic mass measuring 3.0 × 2.7 cm at the tail of the pancreas. Multiple rounded hypoechoic lesions were also seen scattered within the body of the pancreas with multiple enlarged para-aortic lymph nodes. A fine-needle aspiration biopsy of the lesion was consistent with granulomatous inflammation. The diagnosis of disseminated tuberculosis was made. The patient was subsequently started on antitubercular medication and recovered well.

Conclusion

A high index of suspicion is needed to diagnose pancreatic tuberculosis, especially in patients whose radiological imaging shows a pancreatic mass with necrotic peripancreatic lymphadenopathy in endemic countries. EUS-guided fine-needle aspiration is the diagnostic modality of choice, and vigorous attempts should be made at obtaining a preoperative histological or bacteriological diagnosis to avoid unnecessary surgery.

Disseminated tuberculosis following invasive procedures for peripancreatic lymph node tuberculosis with portal vein obstruction: a case report

Peripancreatic tuberculous lymphadenopathy can mimic pancreatic cancer on imaging. There have only a few reports on varices from portal vein obstruction due to abdominal tuberculous lymphadenopathy. Iatrogenic disseminated tuberculosis is also rare. Herein, we present a rare case of peripancreatic tuberculous lymphadenopathy with ruptured duodenal varices due to portal vein obstruction. The patient presented to our hospital with hematemesis. Computed tomography revealed a peripancreatic mass. Duodenal varices rupture from portal vein obstruction due to pancreatic cancer were initially suspected. The patient underwent portal vein stenting for portal vein obstruction and endoscopic ultrasound-guided fine-needle aspiration for diagnosis, which revealed granulomas indicative of tuberculosis. The patient was discharged once because fine-needle aspiration did not lead to a definitive diagnosis of tuberculosis. Subsequently, he developed disseminated tuberculosis. Peripancreatic tuberculous lymphadenopathy can cause ectopic varices with portal vein obstruction. Tuberculosis should also be included in the differential diagnosis in the case of portal vein obstruction, to facilitate early treatment and avoid unnecessary surgery. Furthermore, fine-needle aspiration or portal vein stenting for tuberculous lesions can cause disseminated tuberculosis. Since a diagnosis might not be made until after several fine-needle aspirations have been conducted, careful follow-up is necessary after the procedure for such lesions.

Tuberculous perihepatic abscess and neurosarcoidosis: report of 2 uncommon manifestations of 2 common granulomatous diseases in 1 patient

Infections caused by pathogens of the Mycobacterium tuberculosis complex, i. e., tuberculosis (TB), and the non-infectious, autoimmune disease sarcoidosis are among the most common granulomatous diseases worldwide. Typically, the lung is the primary site of infection and manifestation, respectively which makes the two diseases important differential diagnoses. Both diseases can affect virtually all organ systems, albeit with significantly lower incidence. CASE PRESENTATION:  We report the case of a 50-year-old Indian man presenting with a tuberculous perihepatic abscess and a systemic inflammatory response after being diagnosed with neurosarcoidosis presenting as a single granuloma in the frontal lobe with lymphadenopathy in 2014. On day of admission the patient presented with right upper abdominal pain and fever for two weeks. With increased inflammatory parameters in serum and after finding of external CT images, a perihepatic abscess was suspected. This encapsulated cave was drained percutaneously under CT control. A high concentration of acid-fast rods was detected using ZN, PCR was positive for M. tuberculosis. Several samples of sputum and urine were microscopically negative but yielded growth of Mycobacteria after four weeks. DISCUSSION:  This is a case presenting with two different granulomatous diseases, each of which manifested itself in an atypical form. The tuberculous liver abscess might either be explained as a flare-up of latent tuberculosis under azathioprine therapy or as a reinfection acquired during one of several visits in the high-prevalence country India. In addition, it must be discussed whether the cerebral granuloma in 2014 could have been an early stage of tuberculous granuloma. Sensitivity of ZN staining is significantly reduced in cerebral samples, and negative PCR-results might be due to low germ load or methodical issues, e. g., decreased sensitivity in formalin fixated samples.