The Diagnostic Deceiver: Radiological Pictorial Review of Tuberculosis

Tuberculosis (TB) is a bacterial infection with Mycobacterium tuberculosis; it is a public health problem worldwide and one of the leading causes of mortality. Since December 2019, the COVID-19 pandemic has created unprecedented health challenges and disrupted the TB health services, especially in high-burden countries with ever-increasing prevalence. Extrapulmonary and even pulmonary TB are an important cause of nonspecific clinical and radiological manifestations and can masquerade as any benign or malignant medical case, thus causing disastrous conditions and diagnostic dilemmas. Clinical manifestations and routine laboratory tests have limitations in directing physicians to diagnose TB. Medical-imaging examinations play an essential role in detecting tissue abnormalities and early suspecting diagnosis of TB in different organs. Radiologists and physicians should be familiar with and aware of the radiological manifestations of TB to contribute to the early suspicion and diagnosis of TB. The purpose of this article is to illustrate the common radiologic patterns of pulmonary and extrapulmonary TB. This article will be beneficial for radiologists, medical students, chest physicians, and infectious-disease doctors who are interested in the diagnosis of TB.

Antibiotic scintigraphy in tuberculosis: A new horizon?

Tuberculosis (TB) continues to be a major cause of death worldwide that can be effectively treated with timely diagnosis and treatment. With the advent of nuclear imaging techniques like ¹⁸Fluorine Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography (¹⁸F-FDG) PET/CT, the diagnosis of tuberculosis, particularly its extrapulmonary forms, has received great impetus in cases where microbiological confirmation cannot be achieved. Although detection of mycobacteria either by staining, culture or nucleic acid amplification techniques still form the gold standard of diagnosis, newer diagnostic techniques are always welcome in the field which can expedite clinical management. Use of radiolabeled antibiotics is one such evolving sphere which needs further research. Moving ahead from radiolabeled leukocytes, antibiotics are being increasingly focused upon to act as a vehicle to locate infectious lesions. Antibiotics like ciprofloxacin have been labeled with diagnostic radionuclides such as Technetium-99m (Tc-99m) and used to image many infectious diseases with encouraging results in TB. However, the nonspecific attributes of ciprofloxacin have hindered its growth to assist the diagnosis of TB. A novel approach would be to utilize ethambutol, a specific antitubercular agent, which has been found to be safe and effective in the diagnosis of TB in the available published studies. Ethambutol is known to be taken up specifically by tubercular lesions. This forms the basis of using Tc-99m labelled ethambutol for imaging TB lesions. An added advantage would be its ability to differentiate tubercular from malignant and fungal lung lesions that are the usual differentials in patients suspected of having TB. Most of the studies involving ethambutol have been done in skeletal TB and its validation in other forms of TB is still awaited. Recently the role of PET-CT has also been explored in human studies using ¹¹C Rifampicin to study the antibiotic uptake in tubercular lesions. This review summarizes the available evidence regarding diagnosis of TB by radiolabeled antibiotic imaging to emphasize the need for accelerated research in the fight against TB.

Interaction of Host Pattern Recognition Receptors (PRRs) with Mycobacterium Tuberculosis and Ayurvedic Management of Tuberculosis: A Systemic Approach

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb), infects the lungs' alveolar surfaces through aerosol droplets. At this stage, the disease progression may have many consequences, determined primarily by the reactions of the human immune system. However, one approach will be to more actively integrate the immune system, especially the pattern recognition receptor (PRR) systems of the host, which notices pathogen-associated molecular patterns (PAMPs) of Mtb. Several types of PRRs are involved in the detection of Mtb, including Toll-like receptors (TLRs), C-type lectin receptors (CLRs), Dendritic cell (DC) -specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN), Mannose receptor (MR), and NOD-like receptors (NLRs) related to inflammasome activation. In this study, we focus on reviewing the Mtb pathophysiology and interaction of host PPRs with Mtb as well as adverse drug effects of anti-tuberculosis drugs (ATDs) and systematic TB treatment via Ayurvedic medicine.

Isolated anterior mediastinal tuberculosis in an immunocompetent patient

Background

The differential diagnosis of a mediastinal mass is a common challenge in clinical practice, with a wide range of differential diagnosis to be considered. One of the rarer causes is tuberculosis. Atypical presentations of tuberculosis are well documented in immunocompromised patients, but should also be considered in the immunocompetent.

Case presentation

This case outlines a previously healthy 22 year-old immunocompetent male presenting with worsening chest pain, positional dyspnea, dry cough and dysphagia. Chest x-ray showed evidence of an isolated anterior mediastinal mass, which was confirmed on computed tomography. A mediastinoscopy was diagnostic as histology revealed necrotizing granulomatous inflammation and the presence of acid-fast bacilli, indicating mediastinal tuberculosis.

Conclusion

Typically the underlying presentation of mediastinal tuberculosis is mediastinal lymphadenitis. This case was unusual in that we detected an isolated large anterior mediastinal mass accompanied by a relatively small burden of mediastinal lymphadenitis. Cases similar to this have been documented in immunosuppressed patients however in our case no evidence of immunosuppression was found. This case report emphasizes the importance that a detailed and logical pathway of investigation is pursued when encountering a mediastinal mass.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0175-7) contains supplementary material, which is available to authorized users.

The imaging spectrum of pulmonary tuberculosis

Tuberculosis has still an important impact on public health because it is an important cause of death, particularly in developing countries. On the other hand recent studies have shown that tuberculosis is again becoming concentrated in big cities of Western Europe, especially among immigrants, drug addicts, poor people, and the homeless, despite progress in reducing national rates of the disease. Diagnostic imaging is challenging for radiologists because signs of tuberculosis may easily mimic other diseases such as neoplasms or sarcoidosis. Clinical signs and symptoms in affected adults can be non-specific and a high level of pre-test clinical suspicion based on history is fundamental in the diagnostic work-up. Impact of tuberculosis in the world is extremely important considering the high incidence estimated during 2011 that was 8.7 million cases. This article gives a review of imaging patterns of chest tuberculosis as may be detected on conventional radiography and computerized tomography (CT). The main aim is to improve radiologist's familiarity with the spectrum of imaging features of this disease and facilitate timely diagnosis. Furthermore, we consider the emerging role of alternative methods of imaging, such as magnetic resonance imaging (MRI), that can be helpful and highly accurate for a better definition of some signs of tuberculosis.

Unusual spinal tuberculosis in an Avar Age skeleton (Csongrád-Felgyő, Ürmös-tanya, Hungary): A morphological and biomolecular study

The paleopathological analysis of a well-preserved young adult female skeleton from the AD 7-8th century (Avar Age) in Hungary revealed multiple lytic lesions in all of the thoracic and lumbar vertebral bodies. The lesions were characterized by smooth marginal zones and space-occupying mass appearance. The considerable loss of spongy bone in the thoracolumbar vertebrae resulted in angular deformity and fusion, characteristic of the healing stage of TB. Osteolytic lesions were also observed on the vertebral processes, ribs and sternum. On the endocranial surface, abnormal blood vessel impressions were revealed, indicating some kind of meningitis. The X-ray and CT analysis of the affected bones detected abnormal structures and cystic zones of destruction. The lesions were however not always bordered by areas of increased density, which is typical in cystic TB. Vertebral remains were also subjected to biomolecular analysis in two different laboratories, which attested the presence of Mycobacterium tuberculosis complex (MTBC) DNA and supported the paleopathological diagnosis of TB. Spoligotyping analysis confirmed the presence of MTBC DNA and more specifically an infection caused by bacteria belonging to the M. tuberculosis lineage. This case study provides new data for the paleoepidemiology of TB in this geographical area and historical period, and draws attention to the great variability of TB lesions in the human skeleton.

Imaging in tuberculosis

Despite many advances in both diagnosis and treatment, tuberculosis still remains one of commonest causes of morbidity and mortality from any infectious cause in the world. Although the overall incidence and mortality rate for tuberculosis has decreased over the years, timely and accurate diagnosis of tuberculosis is essential for the health of the patient as well as the public. For the diagnosis of tuberculosis, a high degree of clinical suspicion is required, and this becomes much more important in high-risk populations. Tuberculosis may masquerade as any disease; therefore, tissue and microbiological assessment is sometimes important for establishing the diagnosis. However, in daily practice, the clinician and radiologist should be familiar with the imaging features of pulmonary and extrapulmonary tuberculosis, as well as manifestations of tuberculosis in immunocompromised patients. Imaging provides a very important role in the diagnosis and management of tuberculosis. Although chest X rays remain the basic imaging modality for pulmonary tuberculosis, computed tomography, magnetic resonance imaging, and nuclear medicine techniques, including positron emission tomography/computed tomography, are extremely helpful in the assessment of both pulmonary and extrapulmonary tuberculosis.

HIV-Mycobacterium tuberculosis co-infection: a 'danger-couple model' of disease pathogenesis

Tuberculosis (TB) and human immunodeficiency virus (HIV) infection interfere and impact the pathogenesis phenomena of each other. Owing to atypical clinical presentations and diagnostic complications, HIV/TB co-infection continues to be a menace for healthcare providers. Although the increased access to highly active antiretroviral therapy (HAART) has led to a reduction in HIV-associated opportunistic infections and mortality, the concurrent management of HIV/TB co-infection remains a challenge owing to adverse effects, complex drug interactions, overlapping toxicities and tuberculosis -associated immune reconstitution inflammatory syndrome. Several hypotheses have been put forward for the exacerbation of tuberculosis by HIV and vice versa supported by immunological studies. Discussion on the mechanisms produced by infectious cofactors with impact on disease pathology could shed light on how to design potential interventions that could decelerate disease progression. With no vaccine for HIV and lack of an effective vaccine for tuberculosis, it is essential to design strategies against HIV-TB co-infection.

Multi-site abdominal tuberculosis mimics malignancy on 18F-FDG PET/CT: Report of three cases

¹⁸F-fluorodeoxyglucose positron emission/computed tomography (¹⁸F-FDG PET/CT) imaging, an established procedure for evaluation of malignancy, shows an increased ¹⁸F-FDG uptake in inflammatory conditions. We present three patients with abdominal pain and weight loss. Conventional imaging studies indicated that abdominal neoplasm and ¹⁸F-FDG PET/CT for assessment of malignancy showed multiple lesions with intense ¹⁸F-FDG uptake in abdomen of the three cases. However, the three patients were finally diagnosed with multi-site abdominal tuberculosis (TB). Of them, two were diagnosed with TB by pathology, one was diagnosed with TB clinically. They recovered after anti-TB therapy. Few reports on accumulation of ¹⁸F-FDG in abdominal TB are available in the literature. A high index of suspicion is necessary to achieve an early diagnosis and a better outcome of the disease.