High-resolution CT findings of pulmonary Mycobacterium tuberculosis infection in renal transplant recipients

Application of CTU-Assisted Doppler Ultrasound Puncture in Nontube Percutaneous Nephrolithotomy, Its Effect on Patients' Complications, and Its Clinical Value

Objective

To research the application of CTU-assisted Doppler ultrasound puncture in uncatheterized PCNL, its influence on patients' complications, and its clinical value in a case-control study.

Methods

One hundred and forty-four patients who went through percutaneous nephrolithotomy (PCNL) from March 2019 to June 2021 in our hospital were arbitrarily assigned into the CTU group (n = 72) and CT plain scan group (n = 72). CTA+CTU was adopted to determine the puncture passage in the CTU group, and CT scan was employed in the CT group. The intraoperative blood loss, postoperative blood loss, operation time, hospital stay, primary stone removal rate, and the incidence of intraoperative and postoperative complications were compared. The visual analogue score (VAS) was employed to assess the degree of postoperative wound pain.

Results

The first-stage stone removal rate in the CTU group was 95.83% (69/72), which was remarkably higher compared to the CT plain scan group, which was 81.94% (59/72), and the difference was statistically significant (P < 0.05). The overall rates of intraoperative complications were 6.94% (5/72) in the CTU group and 18.06% (13/72) in the CT plain scan group, respectively, which exhibited great differences (P < 0.05). In addition, the overall rates of intraoperative complications were 2.78% (2/72) in the CTU and 13.89% (10/72) in the CT plain scan group, respectively, and the difference was statistically significant (P < 0.05). The operation time and postoperative hospital stays in the CTU group were remarkably shorter compared to the CT group, and the difference was statistically significant (P < 0.05). The intraoperative and postoperative blood loss of CTU group displayed obvious less than that of the CT group, and the difference was statistically significant (P < 0.05). The VAS were compared 24 hours after surgery. After operation, the VAS of 24 hours after operation in the CTU group (0.92 ± 0.12) were remarkably lower compared to the CT group (1.22 ± 0.15), and the difference was statistically significant (P < 0.05). Discussion. PCNL is constantly being optimized by CTU-assisted Doppler ultrasound puncture to improve stone clearance rates, reduce postoperative bleeding, be less painful, provide rapid recovery, and provide safe and feasible results. It is therefore worthwhile to standardize and then widely promote it in clinical practice.

Melioidosis: Missed opportunities and opportunistic pathogens

A 31-year Indian homemaker, known to have Systemic Lupus Erythematosus (SLE) and lupus nephritis, was admitted previously in another medical care unit with fever, hemoptysis, arthralgia, and joint swelling. She had been treated with antibiotics and corticosteroids for probable diffuse alveolar hemorrhage (DAH) with clinical and radiological resolution. She was readmitted one month later for similar complaints. Her autoimmune workup revealed evidence of active lupus. Her chest imaging showed the presence of well-circumscribed macronodular lesions with halo sign, but Bronchoalveolar Lavage (BAL) cultures and serum galactomannan were negative. BAL tested positive for hemosiderin-laden macrophages. She was treated with corticosteroids, plasmapheresis, and empiric antibiotics with partial clinical response. One week later, her fever recurred, and she developed new-onset myositis. Bactec blood cultures grew Burkholderia pseudomallei. She received treatment for 3 months with good clinical and radiological resolution. In hindsight, a CT-guided biopsy of the lung lesion may have provided an earlier diagnosis of melioidosis.

Mycobacterium tuberculosis in solid organ transplant donors and recipients

PURPOSE OF REVIEW

Due to impaired immune response, solid organ transplant (SOT) recipients are susceptible to tuberculosis (TB) and its subsequent morbidity and mortality. Current prevention strategies, diagnostic and treatment approach to TB infection in donors and recipients were reviewed in this article.

RECENT FINDINGS

Screening of latent tuberculosis infection (LTBI) in donors and recipients is the cornerstone of TB-preventive strategy in recipients and requires an assessment of TB risk factors, TB-specific immunity testing, and radiographic evaluation. Interferon-gamma release assay has superseded the tuberculin skin test in LTBI evaluation despite its recognized limitations. LTBI treatment should be offered to transplant candidates and living donors before transplantation and donation, respectively. Diagnosis of TB disease can be challenging because of nonspecific clinical presentation in the recipient and is limited by the sensitivity of current diagnostics. The approach to LTBI and TB disease treatment is similar to the general population, but can be challenging because of potential drug interactions and toxicities.

SUMMARY

The appropriate evaluation of donors and recipients for TB can mitigate posttransplant TB disease. Current approaches to diagnosis and treatment parallels that of immunocompetent hosts. Future research evaluating existing and novel diagnostics and treatment in transplant recipients is needed.

Nodular distribution pattern on chest computed tomography (CT) in patients diagnosed with nontuberculous mycobacteria (NTM) infections

BACKGROUND

This study evaluated the prevalence of spreading pathways in nontuberculous mycobacteria (NTM) pulmonary infections according to nodular distribution patterns seen on chest computed tomography (CT).

METHODS

This study included 63 patients diagnosed with NTM lung infections who underwent CT at our institution. A retrospective analysis of CT images focused on the presence and distribution of nodules, presence of intrathoracic lymphadenopathy and the predominant side of infection in the lungs. The findings were classified into five groups; centrilobular (bronchogenic spread), perilymphatic (lymphangitic spread), random (hematogenous spread), combined pattern and no nodules present. The groups were then compared according to other CT findings.

RESULTS

Among 51 (81%) patients identified with a nodular pattern on chest CT, 25 (39.8%) presented with centrilobular, 7 (11.1%) with perilymphatic, 6 (9.5%) with random and 13 (20.6%) with combined nodular patterns but located in different areas of the lungs. The right side of the lungs was predominant in 38 cases (60.3%). Intrathoracic lymphadenopathy was evident in 20 patients (31.7%). Significant differences in distributions of nodular patterns were seen in patients infected with Mycoplasma avium complex (MAC) associated with centrilobular pattern (p = 0.0019) and M. fortuitum associated with random pattern (p = 0.0004). Some of the findings were related to perilymphatic nodules between other isolated species of NTM (p = 0.0379).

CONCLUSION

The results of this study showed a high proportion of perilymphatic nodules and right-sided predominance in the upper lobe, which, combined with intrathoracic lymphadenopathy is highly suggestive of the lymphangitic spread of lung NTM infections.

Cavitary tuberculosis: the gateway of disease transmission

Tuberculosis continues to be a major threat to global health. Cavitation is a dangerous consequence of pulmonary tuberculosis associated with poor outcomes, treatment relapse, higher transmission rates, and development of drug resistance. However, in the antibiotic era, cavities are often identified as the most extreme outcome of treatment failure and are one of the least-studied aspects of tuberculosis. We review the epidemiology, clinical features, and concurrent standards of care for individuals with cavitary tuberculosis. We also discuss developments in the understanding of tuberculosis cavities as dynamic physical and biochemical structures that interface the host response with a unique mycobacterial niche to drive tuberculosis-associated morbidity and transmission. Advances in preclinical models and non-invasive imaging can provide valuable insights into the drivers of cavitation. These insights will guide the development of specific pharmacological interventions to prevent cavitation and improve lung function for individuals with tuberculosis.

Diagnosis of severe respiratory infections in immunocompromised patients

An increasing number of critically ill patients are immunocompromised. Acute hypoxemic respiratory failure (ARF), chiefly due to pulmonary infection, is the leading reason for ICU admission. Identifying the cause of ARF increases the chances of survival, but may be extremely challenging, as the underlying disease, treatments, and infection combine to create complex clinical pictures. In addition, there may be more than one infectious agent, and the pulmonary manifestations may be related to both infectious and non-infectious insults. Clinically or microbiologically documented bacterial pneumonia accounts for one-third of cases of ARF in immunocompromised patients. Early antibiotic therapy is recommended but decreases the chances of identifying the causative organism(s) to about 50%. Viruses are the second most common cause of severe respiratory infections. Positive tests for a virus in respiratory samples do not necessarily indicate a role for the virus in the current acute illness. Invasive fungal infections (Aspergillus, Mucorales, and Pneumocystis jirovecii) account for about 15% of severe respiratory infections, whereas parasites rarely cause severe acute infections in immunocompromised patients. This review focuses on the diagnosis of severe respiratory infections in immunocompromised patients. Special attention is given to newly validated diagnostic tests designed to be used on non-invasive samples or bronchoalveolar lavage fluid and capable of increasing the likelihood of an early etiological diagnosis.

ACR Appropriateness Criteria® Acute Respiratory Illness in Immunocompromised Patients

The immunocompromised patient with an acute respiratory illness (ARI) may present with fever, chills, weight loss, cough, shortness of breath, or chest pain. The number of immunocompromised patients continues to rise with medical advances including solid organ and stem cell transplantation, chemotherapy, and immunomodulatory therapy, along with the continued presence of human immunodeficiency virus and acquired immunodeficiency syndrome. Given the myriad of pathogens that can infect immunocompromised individuals, identifying the specific organism or organisms causing the lung disease can be elusive. Moreover, immunocompromised patients often receive prophylactic or empiric antimicrobial therapy, further complicating diagnostic evaluation. Noninfectious causes for ARI should also be considered, including pulmonary edema, drug-induced lung disease, atelectasis, malignancy, radiation-induced lung disease, pulmonary hemorrhage, diffuse alveolar damage, organizing pneumonia, lung transplant rejection, and pulmonary thromboembolic disease. As many immunocompromised patients with ARI progress along a rapid and potentially fatal course, timely selection of appropriate imaging is of great importance in this setting. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking, or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Chest X-ray and chest CT findings in patients diagnosed with pulmonary tuberculosis following solid organ transplantation: a systematic review

The objective of this systematic review was to select articles including chest X-ray or chest CT findings in patients who developed pulmonary tuberculosis following solid organ transplantation (lung, kidney, or liver). The following search terms were used: "tuberculosis"; "transplants"; "transplantation"; "mycobacterium"; and "lung". The databases used in this review were PubMed and the Brazilian Biblioteca Virtual em Saúde (Virtual Health Library). We selected articles in English, Portuguese, or Spanish, regardless of the year of publication, that met the selection criteria in their title, abstract, or body of text. Articles with no data on chest CT or chest X-ray findings were excluded, as were those not related to solid organ transplantation or pulmonary tuberculosis. We selected 29 articles involving a collective total of 219 patients. The largest samples were in studies conducted in Brazil and South Korea (78 and 35 patients, respectively). The imaging findings were subdivided into five common patterns. The imaging findings varied depending on the transplanted organ in these patients. In liver and lung transplant recipients, the most common pattern was the classic one for pulmonary tuberculosis (cavitation and "tree-in-bud" nodules), which is similar to the findings for pulmonary tuberculosis in the general population. The proportion of cases showing a miliary pattern and lymph node enlargement, which is most similar to the pattern seen in patients coinfected with tuberculosis and HIV, was highest among the kidney transplant recipients. Further studies evaluating clinical data, such as immunosuppression regimens, are needed in order to improve understanding of the distribution of these imaging patterns in this population.

Mycobacterial Infections in Patients With Chronic Kidney Disease and Kidney Transplantation

Patients with chronic kidney disease have impaired immunity that increases their risk of infection. Increased incidence of mycobacterial infections, in particular Mycobacterium tuberculosis, is described in patients undergoing hemodialysis and peritoneal dialysis as well as after kidney transplantation in low-prevalence and high-prevalence settings. Diagnosis of this infection can be challenging because of atypical presentations that may lead to treatment delay and, consequently, increased mortality; however, recent advances in molecular testing have improved diagnostic accuracy. It is imperative to try to identify those patients at increased risk and offer adequate prophylaxis. There are controversies and insufficient data regarding treatment agents, duration, and dosages. Most studies in nontuberculous mycobacteria are based on case series and retrospective studies.

The Pathogenesis of Tuberculosis: The Early Infiltrate of Post-primary (Adult Pulmonary) Tuberculosis: A Distinct Disease Entity

It has long been recognized that tuberculosis (TB) induces both protective and tissue damaging immune responses. This paper reviews nearly two centuries of evidence that protection and tissue damage are mediated by separate disease entities in humans. Primary TB mediates protective immunity to disseminated infection while post-primary TB causes tissue damage that results in formation of cavities. Both are necessary for continued survival of Mycobacterium tuberculosis (MTB). Primary TB has been extensively studied in humans and animals. Post-primary TB, in contrast, is seldom recognized or studied. It begins as an asymptomatic early infiltrate that may resolve or progress by bronchogenic spread to caseous pneumonia that either fragments to produce cavities or is retained to produce post-primary granulomas and fibrocaseous disease. Primary and post-primary TB differ in typical age of onset, histopathology, organ distribution, x-ray appearance, genetic predisposition, immune status of the host, clinical course and susceptibility to protection by BCG. MTB is a highly successful human parasite because it produces both primary and post-primary TB as distinct disease entities in humans. No animal reproduces this sequence of lesions. Recognition of these facts immediately suggests plausible solutions, animal models and testable hypotheses to otherwise inaccessible questions of the immunity and pathogenesis of TB.

Tuberculosis Infectiousness and Host Susceptibility

The transmission of tuberculosis is complex. Necessary factors include a source case with respiratory disease that has developed sufficiently for Mycobacterium tuberculosis to be present in the airways. Viable bacilli must then be released as an aerosol via the respiratory tract of the source case. This is presumed to occur predominantly by coughing but may also happen by other means. Airborne bacilli must be capable of surviving in the external environment before inhalation into a new potential host-steps influenced by ambient conditions and crowding and by M. tuberculosis itself. Innate and adaptive host defenses will then influence whether new infection results; a process that is difficult to study owing to a paucity of animal models and an inability to measure infection directly. This review offers an overview of these steps and highlights the many gaps in knowledge that remain.

Tuberculosis After Renal Transplant

Tuberculosis is one of the leading infections after renal transplant, particularly in developing countries where the incidence and prevalence in the general population are high. Diagnosis requires bacteriologic and histologic confirmation. Interactions among the antitubercular drugs and the immunosuppressive agents have to be considered while prescribing, and surveillance for adverse effects is required. Although rare, case reports are available on extrapulmonary tuberculosis in allograft recipients. Here, we present a 25-year-old kidney transplant recipient who was diagnosed with lymph node tuberculosis under uncommon circumstances but who had a good outcome. This case report illustrates the difficulties in diagnosis of tuberculosis, changes in therapeutic protocols, and prognostic factors and highlights the effects of infectious complications with immunosuppressive therapy in this particular patient population.

Cord factor as an invisibility cloak? A hypothesis for asymptomatic TB persistence

Mycobacterium tuberculosis (MTB) has long been known to persist in grossly normal tissues even in people with active lesions and granulomas in other parts of the body. We recently reported that post-primary TB begins as an asymptomatic infection that slowly progresses, accumulating materials for a massive necrotizing reaction that results in cavitation. This paper explores the possible roles of trehalose 6,6' dimycolate (TDM) or cord factor in the ability of MTB to persist in such lesions without producing inflammation. TDM is unique in that it has three distinct sets of biologic activities depending on its physical conformation. As a single molecule, TDM stimulates macrophage C-type lectin receptors including Mincle. TDM can also form three crystal like structures, cylindrical micelles, intercalated bilayer and monolayer, that have distinct non receptor driven activities that depend on modulation of interactions with water. In the monolayer form, TDM is highly toxic and destroys cells in minutes upon contact. The cylindrical micelles and an intercalated bilayer have surfaces composed entirely of trehalose which protect MTB from killing in macrophages. Here we review evidence that these trehalose surfaces bind water. We speculate that this immobilized water constituites of an "invisibility cloak" that facilitates the persistence of MTB in multiple cell types without producing inflammation, even in highly immune individuals.