Pulmonary nodules in liver transplant recipients

Pulmonary Infections in Intestinal Transplant Recipients With Preexisting Pulmonary Nodules

BACKGROUND

Pulmonary nodules in asymptomatic patients could represent latent pulmonary infections. Intestinal transplant (ITx) recipients with preexisting lung nodules might be at higher risk for pulmonary infections. However, data is scarce.

METHODS

This retrospective study included adult patients who underwent ITx from May 2016 to May 2020. Chest computed tomography scans performed within 12 months before ITx were obtained to evaluate for preexisting pulmonary nodules. Screening for endemic mycoses, Aspergillus, Cryptococcus, and latent tuberculosis infection performed within 12 months before ITx was obtained. We assessed for worsening pulmonary nodules, and fungal and mycobacterial infections during the first year post-transplant. Survival and graft loss at 1-year post-transplant was also assessed.

RESULTS

Forty-four patients underwent ITx. Thirty-one had preexisting lung nodules. No invasive fungi were recorded in the pretransplant period and one individual had latent tuberculosis infection. In the post-transplant period, one individual developed probable invasive aspergillosis and had worsening nodular opacities, whereas one had disseminated histoplasmosis with stable lung nodules in chest computed tomography. No mycobacterial infections were documented. The cohort survival was 84% at 12 months after transplant.

CONCLUSION

Preexisting pulmonary nodules were common in the cohort (71%), yet latent and active pulmonary infections were rare. Appearance of new or worsening pulmonary nodules does not appear to directly correlate with pulmonary infections in the post-transplant period. Routine chest computed tomography is not recommended in the pretransplant period, but follow-up is favored in patients with confirmed nodular opacities. Clinical monitoring is essential.

The granuloma in cryptococcal disease

Although we have recognized cryptococcosis as a disease entity for well over 100 years, there are many details about its pathogenesis which remain unknown. A major barrier to better understanding is the very broad range of clinical and pathological forms cryptococcal infections can take. One such form has been historically called the cryptococcal granuloma, or the cryptococcoma. These words have been used to describe essentially any mass lesion associated with infection, due to their presumed similarity to the quintessential granuloma, the tubercle in tuberculosis. Although clear distinctions between tuberculosis and cryptococcal disease have been discovered, cellular and molecular studies still confirm some important parallels between these 2 diseases and what we now call granulomatous inflammation. In this review, we shall sketch out some of the history behind the term "granuloma" as it pertains to cryptococcal disease, explore our current understanding of the biology of granuloma formation, and try to place that understanding in the context of the myriad pathological presentations of this infection. Finally, we shall summarize the role of the granuloma in cryptococcal latency and present opportunities for future investigations.

Diagnosis and outcome of resected solitary pulmonary nodules after liver transplantation

OBJECTIVE

Solitary pulmonary nodules after liver transplantation are challenging clinical problems. Herein, we report the causes and clinical courses of resected solitary pulmonary nodules in patients who underwent liver transplantation.

METHODS

We retrospectively obtained medical records of 68 patients who underwent liver transplantation between March 2009 and June 2016. This study mainly focused on patients with solitary pulmonary nodules observed on computed tomography scans during follow-ups that were conducted until their deaths or February 2019.

RESULTS

Computed tomography scans revealed solitary pulmonary nodules in 7 of the 68 patients. Definitive diagnoses were obtained using video-assisted lung resection in all seven patients. None experienced major postoperative complications. The final pathologic diagnoses were primary lung cancer in three patients, pulmonary metastases from hepatocellular carcinoma in one patient, invasive pulmonary aspergillosis in one patient, post-transplant lymphoproliferative disorder in one patient, and hemorrhagic infarction in one patient. The three patients with lung cancer were subsequently treated with standard curative resection.

CONCLUSIONS

Solitary pulmonary nodules present in several serious but potentially curable diseases, such as early-stage lung cancer. Patients who present with solitary pulmonary nodules after liver transplantation should be evaluated by standard diagnostic procedures, including surgical biopsy if necessary.

A titanic drug resistance threat in Cryptococcus neoformans

Increasing resistance to frontline antifungals is a growing threat to global health. In the face of high rates of relapse for patients with cryptococcal meningitis and frequent drug resistance in clinical isolates, recent insights into Cryptococcus neoformans morphogenesis and genome plasticity take on new and urgent meaning. Here we review the state of the understanding of mechanisms of drug resistance in the context of host-relevant changes in Cryptococcus morphology and cell ploidy.

Cryptococcosis in solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of cryptococcosis in the pre- and post-transplant period. The current update now includes a discussion of cryptococcosis, which is the third most common invasive fungal infection in SOT recipients. Infection often occurs a year after transplantation; however, early infections occur and donor-derived infections have been described within 3 months after transplant. There are two main species that cause infection, Cryptococcus neoformans and C gattii. Clinical onset may be insidious, but headaches, fevers, and mental status changes should warrant diagnostic testing. The lateral flow cryptococcal antigen assay is now the preferred test from serum and cerebrospinal fluid due to its rapidity, accuracy, and cost. A lumbar puncture with measurement of opening pressure is recommended for patients with suspected or proven cryptococcosis. Lipid amphotericin B plus 5-flucytosine is used as initial treatment of meningitis, disseminated infection, and moderate-to-severe pulmonary infection, followed by fluconazole as consolidation therapy. Fluconazole is effective for mild-to-moderate pulmonary infection. Immunosuppression reduction as part of management may lead to immune reconstitution syndrome that may resemble active disease.

Noninfectious Pulmonary Complications of Liver, Heart, and Kidney Transplantation: An Update

Despite significant advances in surgical techniques, perioperative care, and immunosuppressive therapy, solid organ transplantation still carries considerable risk of complications. Pulmonary complications, in particular, are a major cause of morbidity and mortality. Although infectious complications prevail, the lungs are also vulnerable to a variety of noninfectious complications related to the transplant surgery and adverse effects of the immunosuppressive regimen. This article focuses on noninfectious pulmonary complications associated with the 3 most commonly performed solid organ transplant procedures: liver, kidney, and heart.

Pulmonary nodules in liver transplant candidates with hepatocellular carcinoma: Imaging characteristics and clinical outcomes

No guidelines exist for the management of pulmonary nodules in patients with hepatocellular carcinoma (HCC) who are being evaluated for liver transplantation. The 172 patients with HCC who were listed for liver transplant at our institution received both pretransplant chest computed tomography (CT) and follow-up CT. Pulmonary nodules on CT were characterized and followed on subsequent scans by a blinded radiologist, with a consensus review with a second radiologist being performed for equivocal cases. Nodule characteristics and outcomes were examined with chi-square tests, and the posttransplant survival of patients with different nodule outcomes was compared. Cumulative probabilities of waiting-list removal for nontransplant patients and cumulative probabilities of undergoing transplantation for all patients were also compared between patients with and without pulmonary nodules. Of all the patients, 76.2% had at least 1 pulmonary nodule on pretransplant CT, with 301 total nodules characterized; 2.7% of nodules represented HCC metastases, 1.0% represented other bronchopulmonary malignancies, and 2.7% represented infections. None of the malignant nodules exhibited a triangular/lentiform shape or calcifications. There were no statistically significant differences in pulmonary nodule outcomes between patients who underwent transplantation and those who did not undergo transplantation. No significant differences in posttransplant survival were found between patients with different nodule outcomes. There was also no significant difference between patients with and without nodules in the cumulative probabilities of waiting-list removal. However, the cumulative probability of undergoing liver transplantation was borderline significantly higher in patients without pulmonary nodules. In conclusion, despite the low prevalence of malignant nodules, all pulmonary nodules besides triangular/lentiform-shaped or calcified nodules should be followed with serial CT while the patient is on the transplant list, with biopsy performed for new and/or enlarged nodules. Both malignancy and active infection must be excluded when one is confronted with enlarged pulmonary nodules. Clinicians should also be aware of the possibility of reactivation of a granulomatous infection after transplantation.

Staphylococcus aureus infections in pediatric oncology patients: high rates of antimicrobial resistance, antiseptic tolerance and complications

BACKGROUND

: Patients with malignancies represent a population at high risk for drug-resistant infections. We sought to determine the clinical spectrum and molecular epidemiology of Staphylococcus aureus infections in pediatric oncology patients followed at Texas Children's Hospital (Houston, TX). Furthermore, we determined the prevalence of the chlorhexidine resistance gene qacA/B from isolates in this unique population.

METHODS

: Patients with a history of malignancy and a culture-proven S. aureus infection were identified from 2001 to 2011. Antibiotic susceptibility, pulsed-field gel electrophoresis and detection of qacA/B by polymerase chain reaction were performed on all isolates. Medical records for all patients were reviewed.

RESULTS

: During the study period, 213 isolates were identified from 179 patients with malignancies. Thirty-one percent of the isolates were methicillin-resistant S. aureus. The most common infectious diagnosis was bacteremia (85/213 [39.9%], with 72/85 [84.7%] being catheter-associated). Thirteen patients with bacteremia were found to have pulmonary nodules at the time of presentation; only S. aureus was found in tissue in 5 of the 6 patients who underwent lung biopsy. After 2007, 18.2% of isolates were qacA/B positive with a steady increase in prevalence every year (χ for trend P = 0.04).

CONCLUSIONS

: S. aureus is a significant cause of morbidity and mortality in pediatric oncology patients at Texas Children's Hospital. In addition to the more well-known clinical manifestations, this pathogen can also be associated with pulmonary nodules. Furthermore, the prevalence of S. aureus isolates carrying antiseptic resistance genes increased in this population. Additional clinical and molecular studies and surveillance among pediatric oncology patients are warranted to further explore these findings.

Cryptococcosis in solid organ transplant recipients: current state of the science

Cryptococcosis remains a significant opportunistic infection in solid organ transplant recipients. Disease presentation and outcomes may be affected by, among other factors, the use of calcineurin inhibitor immunosuppressive agents. It is being increasingly recognized that rapid reversal of immunosuppression in transplant recipients treated for cryptococcosis incurs the risk of immune reconstitution inflammatory syndrome, which resembles worsening disease or relapse. This review summarizes the current state of knowledge regarding cryptococcosis in transplant recipients and highlights areas where future investigations are needed to further optimize outcomes for these patients.

Successful percutaneous ultrasound-guided drainage for treatment of a splenic abscess

We report a case of splenic abscess that was successfully treated with percutaneous ultrasound-guided drainage and without splenectomy. A 40-year-old woman was admitted to Nippon Medical School Hospital because of pyrexia and left upper quadrant pain, which had persisted despite antibiotic treatment. On admission, computed tomography demonstrated a low-density area in the spleen, which had been been seen on computed tomography 3 months earlier. Ultrasonography demonstrated a hypoechoic area in the spleen. Initial laboratory tests revealed a serum C-reactive protein concentration of 19.7 mg/dl and a white blood cell count of 15,800 /microl. The serum glucose concentration was 267 mg/dl, and the glycolated hemoglobin value was 7.7%. A splenic abscess was diagnosed and was treated with percutaneous drainage. Milky yellow fluid was obtained, and the patients left upper quadrant abdominal pain and pyrexia resolved. A culture of the drainage fluid yielded Escherichia coli. The drainage catheter was removed 12 days after insertion. The patient was discharged 6 days later. The splenic abscess has not recurred during 3 months of follow-up. Our results suggest that ultrasound-guided percutaneous drainage is a safe and effective alternative to surgery for the treatment of splenic abscess and allows preservation of the spleen.

Fungal infections in solid organ transplantation

Fungal infections in solid organ transplant recipients continue to be a significant cause of morbidity and mortality. Candida spp. and Aspergillus spp. account for most invasive fungal infections. The incidence of fungal infection varies with type of solid organ transplant. Liver transplant recipients have highest reported incidence of candida infections while lung transplant recipients have highest rate of Aspergillus infections. Recent epidemiological studies suggest the emergence of resistant strains of candida as well as mycelial fungi other than Aspergillus in these patients. The current review incorporates the recent changes in the epidemiology of fungal infections in solid organ transplant recipients and highlights the newer data on the diagnosis, prophylaxis and treatment of fungal infections in these patients.

Clinical and radiologic factors associated with pulmonary nodule etiology in organ transplant recipients

Identifying clinical and radiographic factors that are associated with a specific etiology of pulmonary nodules (PNs) in solid-organ transplant (SOT) recipients might be helpful in guiding empiric therapy. Multivariable logistic regression was used to assess the relationship of clinical and radiographic variables to the etiology of PN in a retrospectively identified cohort of SOT recipients at a single transplant center. PNs in 55 SOT recipients (lung 15%, heart 22%, liver 42%, kidney 18% or kidney/pancreas 5%) were diagnosed at a mean of 1061 days post-transplant and were infectious in 31 of 55 (56%) (bacterial 22%, fungal 33%, viral 2%) and noninfectious in 24 of 55 (44%) [post-transplant lymphoproliferative disorder (PTLD) 25%, carcinoma 18%]. Radiographic 'consolidation' was independently associated with an infectious etiology (OR, 20.2, p < 0.01). Epstein-Barr virus seronegativity and lung transplant were each associated with PTLD (OR, 21.7, p < 0.01) and (OR, 36.6, p < 0.001), respectively. Diagnosis less than 90 days post-transplant was associated with Aspergillus infection (OR, 12.9, p = 0.007). Specific clinical and radiographic features are associated with specific etiologies of PNs in SOT recipients and might be useful for guiding empiric therapy while awaiting results of definitive diagnostic studies.

Noninfectious Pulmonary Complications of Liver, Heart, and Kidney Transplantation

Because of their chronically immunosuppressed status, solid organ transplant recipients are continually at risk for infectious pulmonary complications. In addition, however, a number of noninfectious pulmonary complications plague the transplant recipient. These complications arise because of numerous factors, including the underlying conditions that preceded transplantation, the transplant surgery itself, and toxicity of post-transplantation medications. This article focuses on noninfectious pulmonary complications in the three largest recipient populations: liver, kidney, and heart.

Pulmonary complications of solid organ and hematopoietic stem cell transplantation

The ability to successfully transplant solid organs and hematopoietic stem cells represents one of the landmark medical achievements of the twentieth century. Solid organ transplantation has emerged as the standard of care for select patients with severe vital organ dysfunction and hematopoietic stem cell transplantation has become an important treatment option for patients with a wide spectrum of nonmalignant and malignant hematologic disorders, genetic disorders, and solid tumors. Although advances in surgical techniques, immunosuppressive management, and prophylaxis and treatment of infectious diseases have made long-term survival an achievable goal, transplant recipients remain at high risk for developing a myriad of serious and often life-threatening complications. Paramount among these are pulmonary complications, which arise as a consequence of the immunosuppressed status of the recipient as well as from such factors as the initial surgical insult of organ transplantation, the chemotherapy and radiation conditioning regimens that precede hematopoietic stem cell transplantation, and alloimmune mechanisms mediating host-versus-graft and graft-versus-host responses. As the population of transplant recipients continues to grow and as their care progressively shifts from the university hospital to the community setting, knowledge of the pulmonary complications of transplantation is increasingly germane to the contemporary practice of pulmonary medicine.

Nodular pulmonary amyloidosis following liver transplantation: report of a case and review of the literature

Nodular pulmonary lesions seen in liver transplant recipients have a broad differential diagnosis including both infectious and noninfectious etiologies. Here, we report the first case of nodular pulmonary amyloidosis, an uncommon and benign localized form of amyloidosis occurring after orthotopic liver transplantation for end-stage primary biliary cirrhosis.

Pulmonary cytolytic thrombi: unusual complication of hematopoietic stem cell transplantation

Pulmonary complications of hematopoietic stem cell transplantation (HSCT), including peripheral blood stem cell transplantation (PBSCT) and bone marrow transplantation, are frequent and often life-threatening. Differentiating acute infectious from noninfectious pulmonary complications is difficult but critical for proper treatment. The authors describe an 11-year-old boy who developed a sudden fever and cough associated with a normal chest radiograph 2 months after successful haploidentical PBSCT for severe aplastic anemia. High-resolution chest computed tomography revealed numerous tiny peripheral pulmonary nodules. Lung biopsy demonstrated an unusual occlusive thrombotic vascular lesion associated with hemorrhagic infarction without evidence of infection. The thrombi were composed of intensely basophilic granular material recently described as "cytolytic" thrombi. Symptoms and chest computed tomography improved rapidly following intravenous corticosteroids and cyclosporin. However, the patient subsequently died of rapidly progressive pulmonary hypertension. Our patient illustrates the importance of considering this noninfectious complication in the acute pulmonary disorders associated with HSCT as this condition may represent a pulmonary manifestation of acute graft-versus-host disease.

Molecular targets in cellular response to ionizing radiation and implications in space radiation protection

DNA repair systems and cell cycle checkpoints closely co-operate in the attempt of maintaining the genomic integrity of cells damaged by ionizing radiation. DNA double-strand breaks (DSB) are considered as the most biologically important radiation-induced damage. Their spatial distribution and association with other types of damage depend on radiation quality. It is believed these features affect damage reparability, thus explaining the higher efficiency for cellular effects of densely ionizing radiation with respect to gamma-rays. DSB repair systems identified in mammalian cells are homologous recombination (HR), single-strand annealing (SSA) and non-homologous end-joining (NHEJ). Some enzymes may participate in more than one of these repair systems. DNA damage also triggers biochemical signals activating checkpoints responsible for delay in cell cycle progression that allows more time for repair. Those at G1/S and S phases prevent replication of damaged DNA and those at G2/M phase prevent segregation of changed chromosomes. Individuals with lack or alterations of genes involved in DNA DSB repair and cell cycle checkpoints exhibit syndromes characterized by genome instability and predisposition to cancer. Information reviewed in this paper on the basic mechanisms of cellular response to ionizing radiation indicates their importance for a number of issues relevant to protection of astronauts from space radiation.

Thoracic radiology in kidney and liver transplantation

Renal transplantation accounts for more than half of all solid organ transplants performed in the U.S., and the liver is the second most commonly transplanted solid organ. Although abdominal imaging procedures are commonplace in these patients, there has been relatively little attention paid to thoracic imaging applications. Preoperative imaging is crucial to aid in the exclusion of infectious or malignant disease. In the perioperative time period, thoracic imaging focuses both on standard intensive care unit care, including monitoring devices and their complications, and on the early infections that can occur. Postoperative management is divided into three time periods, and the principles governing the occurrence of infections and malignancies are reviewed. Anatomic and pathologic aspects unique to kidney and liver transplantation patients are also discussed.

Pneumonias in the compromised host

The choice of diagnostic modality depends on the patient's status, the expertise of the operator and pathologic resources of the hospital, and is a decision that should be guided by the infectious disease consultant and the clinicians involved in the care of the patient. Although the diagnosis must be tissue based, every attempt must be made to arrive at a tissue diagnosis as soon as possible in order to start specific therapy as soon as possible. It is as important to determine that the cause of the patient's pulmonary infiltrate is noninfectious versus infectious. Pulmonary embolic disease, CHF, ARDS, pulmonary hemorrhage, and pulmonary drug reactions may be reversible and require nonantimicrobially based therapies to treat the patient. Often clinicians are overwhelmed by differential diagnostic possibilities of exotic infectious disease pathogens and overlook easily treatable noninfectious disease mimics of pneumonia. Although differential diagnostic possibilities are great in the compromised host, clinicians should not be overwhelmed by diagnostic possibilities. Instead, clinicians should try to approach the patient syndromically, taking into account the degree and type of immunosuppression, the appearance and behavior of the infiltrates on the chest radiograph and the nature of the host defense defects and time relationships that will limit the differential diagnosis to relatively few diagnostic possibilities. The clinician can then treat empirically patients with presumed bacterial pneumonias and devise a diagnostic plan designed to arrive at a specific tissue diagnosis as soon as possible in patients who are likely to have nonbacterial infection of the lungs.

Lung nodular lesions in heart transplant recipients

To describe the characteristics and etiology of lung nodules after heart transplantation (HT). During a 6-year period 147 patients received HT and 130 survived more than 1 week. Nodular lesions were demonstrated after HT in 13 patients (10%). Median age was 53 years, and all patients were male. Nodules were detected 23 to 158 days after HT (median, 66 days). An etiologic diagnosis was made in all but 1 case: Aspergillus (5), Nocardia-Rhodococcus (4), and cytomegalovirus (CMV) (3). Previous severe infection was present in 50% of the patients and rejection in 33% (75% with nocardiosis). Initially all patients with Nocardia but only 1 patient with aspergillosis were asymptomatic. The most common symptoms were fever (67%) and cough (50%). Central nervous system (CNS) involvement appeared in only one Aspergillus-infected patient. An average of 1.8 diagnostic procedures per patient were performed. Median time to establish a diagnosis was 8 days (0 to 24). Median hospital stay was 36 days and reached 60 in patients with Aspergillus. No patient died, although aspergillosis, which must be suspected in the presence of dyspnea, pleuritic pain, and CNS symptoms, caused the highest morbidity. Overall diagnostic yield was 60% for transtracheal aspiration, 70% for bronchoalveolar lavage, and 75% for transthoracic aspiration. Ten percent of HT patients developed lung nodules that were mainly caused by Aspergillus, Nocardia, and CMV. The time of appearance and some clinical manifestations may suggest the etiology and may help in the empirical treatment.

Methicillin-resistant Staphylococcus aureus: the other emerging resistant gram-positive coccus among liver transplant recipients

We undertook a study of the characteristics and clinical impact of infections due to methicillin-resistant Staphylococcus aureus (MRSA) after liver transplantation. Of 165 patients who received liver transplants at our institution from 1990 through 1998, 38 (23%) developed MRSA infections. The predominant sources of infection were vascular catheters (39%; n=15), wound (18%; n=7), abdomen (18%; n=7), and lung (13%; n=5). A significant increase in MRSA infections (as a percentage of transplant patients infected per year) occurred over time (P=.0001). This increase was greater among intensive care unit patients (P=.001) than among nonintensive care unit hospital patients (P=.17). Cytomegalovirus seronegativity (P=.01) and primary cytomegalovirus infection were significantly associated with MRSA infections (P=.005). Thirty-day mortality among patients with MRSA infections was 21% (8/38). Mortality was 86% in patients with bacteremic MRSA pneumonia or abdominal infection and 6% in those with catheter-related bacteremia (P=.004). Thus the incidence of MRSA infection has increased exponentially among our liver transplant recipients since 1990. These infections have unique risk factors, time of onset, and a significant difference in site-specific mortality; deep-seated bacteremic infections, in particular, portend a grave outcome.

Pulmonary cytolytic thrombi: a newly recognized complication of stem cell transplantation

Over the past 5 years we have recognized a new pulmonary complication of hematopoietic stem cell transplantation (HSCT) associated with fever and pulmonary nodules termed 'pulmonary cytolytic thrombi' (PCT). Retrospective analysis of medical and radiographic records and pathologic material from 13 HSCT recipients with PCT and a review of the Blood and Marrow Transplant Database for all patients with radiographic evidence of pulmonary nodules or who underwent open-lung biopsy from 1 January 1993 to 31 December 1998 (n = 1228) were performed. The median age of patients with PCT was 11.9 years (range, 1.3-29.7 years). All patients developed fever at a median of 72 days (range, 8-343 days) post transplant, followed by pulmonary nodules on chest CT. Eleven patients were receiving therapy for active GVHD (acute, grades I-IV (n = 10); extensive chronic (n = 1)). Biopsy of the pulmonary nodules revealed a unique pattern of necrotic, basophilic thromboemboli with amorphous material suggestive of cellular breakdown products. This was descriptively labeled 'pulmonary cytolytic thrombi'. Immunohistochemical staining revealed entrapped leukocytes and disrupted endothelium, but was negative for histiocytes. Cultures and immunohistochemical stains were negative for infectious agents. Empiric therapy included systemic corticosteroids (n = 9) and amphotericin (n = 7). Nine patients survive with resolution of PCT at a median follow-up of 1.5 years. Bone Marrow Transplantation (2000) 25, 293-300.

The utility of CT in imaging chest infections in HIV-negative patients

This article focuses on the recent developments in CT imaging of chest infections in patients who are immunocompetent or immunosuppressed, but not infected with HIV. Although simple viral and bacterial infections predominate, more "exotic" infections are now being encountered. First, a re-emergence of mycobacterial disease has occurred. Second, a growing population of transplant recipients (i.e., lung, solid organ, and bone marrow) is susceptible to a wide range of pathogens. These trends are reflected in the forthcoming discussion. In particular, several important articles on immunosuppressed (HIV-negative) patients and on imaging fungal disease have been written within the past year.