Role of fiberoptic bronchoscopy in the diagnosis of invasive pulmonary aspergillosis in patients with acute leukemia

Secondary fungal infections in SARS-CoV-2 patients: pathological whereabouts, cautionary measures, and steadfast treatments

The earliest documented COVID-19 case caused by the SARS-CoV-2 coronavirus occurred in Wuhan, China, in December 2019. Since then, several SARS-CoV-2 mutants have rapidly disseminated as exemplified by the community spread of the recent omicron variant. The disease already attained a pandemic status with ever-dwindling mortality even after two and half years of identification and considerable vaccination. Aspergillosis, candidiasis, cryptococcosis and mucormycosis are the prominent fungal infections experienced by the majority of SARS-CoV-2 high-risk patients. In its entirety, COVID-19's nexus with these fungal infections may worsen the intricacies in the already beleaguered high-risk patients, making this a topic of substantial clinical concern. Thus, thorough knowledge of the subject is necessary. This article focuses on the concomitant fungal infection(s) in COVID-19 patients, taking into account their underlying causes, the screening methods, manifested drug resistance, and long-term effects. The information and knowledge shared herein could be crucial for the management of critically ill, aged, and immunocompromised SARS-CoV-2 patients who have had secondary fungal infections (SFIs).

Is bronchoscopic view a reliable method in diagnosis of tracheobronchial aspergillosis in critically ill non-neutropenic patients?

INTRODUCTION

Pulmonary aspergillosis is the main respiratory fungal infection however; its diagnosis is missed or delayed in critically ill non-neutropenic patients. Despite the utility of fiberoptic bronchoscopy for the evaluation of tracheobronchial aspergillosis (TBA) in immunocompromised patients has been extensively studied, however its utility in critically ill non-neutropenic patients is underestimated.

OBJECTIVES

To assess the bronchoscopic changes suspected TBA relative to the microbiological and histopathological aspects in critically ill non-neutropenic patients admitted to respiratory intensive care unit (RICU).

METHODS

We prospectively studied 139 critically ill non-neutropenic patients admitted to RICU and had a clinical suspicion of broncho-pulmonary Aspergillus infection. Those patients were subjected to clinical and bronchoscopic assessment for the evaluation of suspected TBA. Microbiological culture of bronchoalveolar lavage (BAL) and histopathological examination of tracheobronchial biopsies were done.

RESULTS

Bronchoscopic changes suspected TBA were found in 48.2% of patients (67/139), where Aspergillus infection was confirmed microbiologically in 59.7% (40/67) and histopathologically in 56.7% (38/67). Of these changes, whitish plaques ± ulcers, pseudomembrane and/or sticky secretion with hyperemic mucosa were detected in 68.7%, 26.9% and 16.4% respectively. These changes were mostly seen in the main bronchi (54/67; 80.6%). The sensitivity, specificity, positive, negative predictive values and overall accuracy of these bronchoscopic changes as compared with BAL fluid results were 83.3%, 70.3%, 53.2%, 91.2% and 74.1% respectively.

CONCLUSIONS

Bronchoscopy could be a reliable procedure for TBA diagnosis in critically ill non-neutropenic patients. Whitish plaques ± ulcers were the prominent bronchoscopic changes with reasonable diagnostic accuracy for prediction of TBA.

Bronchoalveolar Lavage Fluid Cytology in Culture-Documented Invasive Pulmonary Aspergillosis in Patients with Hematologic Diseases: Analysis of 67 Episodes

There is a paucity of studies on the yield of Gomori-methenamine-silver (GMS) staining in bronchoalveolar lavage (BAL) fluid cytology and its comparison with fluorescent dye staining for the diagnosis of invasive pulmonary aspergillosis (IPA) in patients with hematologic malignancies. To that end, we analyzed the yield of direct fungal visualization in BAL fluid cytology with GMS staining, in a series of culture-positive IPA cases in 67 patients with hematologic malignancies, and we compared the results with those of direct examination with calcofluor white staining and BAL fluid galactomannan assays, when available. GMS staining in BAL fluid cytology was positive in 42% of the 67 cases and revealed coinfections in 7 cases. In contrast, only 2/67 (3.6%) BAL fluid samples were positive in direct smears stained with the fluorescent dye calcofluor white. Positive GMS staining results were significantly more frequent in IPA cases with cavitary lesions and IPA cases caused by >1 Aspergillus species, but the proportions of positive cytology results among Aspergillus species were not different.

Does Reverse Triiodothyronine Testing Have Clinical Utility? An Analysis of Practice Variation Based on Order Data from a National Reference Laboratory

BACKGROUND

Clinical laboratories are under pressure to increase value by improving test utilization. The clinical utility of reverse triiodothyronine (rT3) is controversial. A study was conducted to identify order patterns that might suggest inappropriate utilization of rT3.

METHODS

All orders for thyroid tests placed over a period of one year at a national reference laboratory were reviewed. Order patterns by client (hospital) and by provider were analyzed. A Pareto analysis was conducted to determine the percentage of orders placed as a function of the percentage of providers. A systematic review of the indexed literature and an informal review of the web were conducted to identify indications for rT3 testing.

RESULTS

There were 402,386 orders for 447,664 thyroid tests, including 91,767 orders for rT3. These orders were placed by 60,733 providers located at 1139 different organizations. Only 20% of providers who ordered thyroid tests placed an order for rT3. Of those who placed an order for rT3, 95% placed two orders or fewer for rT3. One hundred providers (0.1% of the 60,733 providers who placed orders for thyroid tests) accounted for 29.5% of the orders for rT3. Of the 100 providers, 60 with the highest order volumes for rT3 were classified as practitioners of functional medicine. A systematic review of Medline found little evidence to support the high volumes of orders for rT3. A survey of Web sites for functional medicine suggests that rT3 is useful for the diagnosis of rT3 dominance and can be used to direct triiodothyronine replacement therapy.

CONCLUSIONS

There is wide practice variation in rT3 testing. A high proportion of tests are ordered by a relatively small proportion of providers. There is little evidence to support high volumes of rT3 testing placed by some practitioners.

Pleuro-Pulmonary Aspergillosis

We reviewed the US findings and the diagnostic yield of fine-needle aspiration biopsy (FNAB) for cytologic and microbiologic samples in 4 patients with pulmonary or pleural aspergillosis. All 3 apical Aspergillus abscesses were round, hypoechoic with irregular margins and one contained echo-densities with shadowing consistent with air. One pleural empyema was oval and hypoechoic. Cytology suggested inflammation in all cases and Aspergillus hyphae were detected in 2 of 4 aspirates. Culture of the aspirate was positive for Aspergillus in 3 of 4 cases, while one diagnosis was made after surgery. No complications occurred. Apico-pleural Aspergillus lesions are suitable targets for US-guided FNAB, thus avoiding more invasive methods. Our results suggest wider use of this procedure.

[Invasive pulmonary aspergillosis in patients with chronic obstructive pulmonary disease]

Invasive pulmonary aspergillosis (IPA) is a common infection in immunocompromised patients with hematological malignancies or allogenic stem cell transplantation, and is less frequent in the context of chronic obstructive pulmonary disease (COPD). Mucociliary activity impairment, immunosuppression due to the inhibition of alveolar macrophages and neutrophils by steroids, and receiving broad-spectrum antibiotics, play a role in the development of IPA in COPD patients. Colonized patients or those with IPA are older, with severe CODP stage (GOLD≥III), and have a higher number of comorbidities. The mortality rate is high due to the fact that having a definitive diagnosis of IPA in COPD patients is often difficult. The main clinical and radiological signs of IPA in these types of patients are non-specific, and tissue samples for definitive diagnosis are often difficult to obtain. The poor prognosis of IPA in COPD patients could perhaps be improved by faster diagnosis and prompt initiation of antifungal treatment. Some tools, such as scales and algorithms based on risk factors of IPA, may be useful for its early diagnosis in these patients.

CT-guided biopsies in lung infections in patients with haematological malignancies

CT-guided transparietal lung biopsy in imaging makes it possible to find the pathogenic agent in half of all fungal infections and most bacterial infections (sensitivity=55%, specificity=100%). Performance is decreased in consolidations (50% of infections) compared to masses. Complications, pneumothorax, alveolar bleeding and hemoptysis are generally benign and rarely (<5%) require specific treatment. On the other hand, the diagnostic performance increases significantly with the calibre of 18G co-axial systems compared to 20G. The risk is not related to the number of samples or platelet levels.

Aspergillosis: diagnosis and treatment

The incidence of invasive aspergillosis is increasing rapidly in the developed world with two Aspergillus spp., A. fumigatus and A. flavus, causing the majority of infections (85-90% and 5-10%, respectively). The major risk factors are profound neutropenia (< or =1000 x 10(6) cells/L), prolonged neutropenia, neutrophil function deficits, and corticosteroid therapy. Useful diagnostic techniques include sputum culture, CT scan, bronchoscopy with microscopy and culture, percutaneous lung biopsy, open lung biopsy and serology. Invasive aspergillosis has an almost 100% mortality rate if untreated. Amphotericin B is the usual first-line therapy although it is associated with a high failure rate. Itraconazole (> or =400 mg daily) is a useful alternative and surgical resection may be life saving in some cases. The efficacy of the initial therapy is critical for improving mortality rates.

Bronchogenic carcinoma and secondary aspergillosis--common yet unexplored: evaluation of the role of bronchoalveolar lavage-polymerase chain reaction and some nonvalidated serologic methods to establish early diagnosis

BACKGROUND

More cases of bronchogenic carcinoma have been reported in recent years, and these patients are more prone to secondary aspergillosis. However, the frequency of secondary aspergillosis in bronchogenic carcinoma still has not been defined clearly in the literature.

METHODS

The current study population was comprised of 69 patients with bronchogenic carcinoma and 16 healthy controls. Histopathologic examination was done to identify carcinoma cell types and to categorize aspergillosis types. Bronchoalveolar lavage (BAL) fluids were collected for direct fungal examination, culture, Aspergillus polymerase chain reaction (PCR), and galactomannan (GM) detection using a 1-stage immunoenzymatic sandwich microplate assay; and blood samples were collected for fungal serology by double immunodiffusion (DID), enzyme-linked immunosorbent assay (ELISA), and dot blot assay (DBA). The sensitivity, specificity, positive predictive value, and negative predictive value were analyzed for various nonvalidated tests. Twenty-five patients had follow-up data available for an analysis of clinical and diagnostic outcomes.

RESULTS

The cohort included patients with squamous cell carcinoma (n = 47), adenocarcinoma (n = 16), small cell carcinoma (n = 3), large cell carcinoma (n = 2), and undiagnosed type (n = 1), and patients were categorized with definite invasive pulmonary aspergillosis (IPA) (n = 6), probable IPA (n = 17), possible IPA (n = 13), and non-IPA (n = 33). Most patients were in the group ages 45 years to <60 years, and there was a preponderance of men (10.5:1). Cultures from 20 of 69 patients (29%) revealed the growth of Aspergillus species. Anti-Aspergillus antibodies were detected in 26 of 69 patients (37.7%) each by DID and DBA, whereas antibodies were detected in 28 of 69 patients (40.6%) by ELISA. GM was detected in BAL fluids from 25 of 69 patients (36.2%), whereas Aspergillus DNA was detected in 32 of 69 patients (46.4%) by PCR. The sensitivity of PCR and serologic tests (ELISA, DID, and DBA) was 100% for definite IPA, whereas the sensitivity of PCR was comparatively higher than that of serologic tests for probable IPA, possible IPA, and non-IPA.

CONCLUSIONS

The current study indicated that there frequently is an association between bronchogenic carcinoma and secondary aspergillosis, and definite IPA and probable IPA are common clinical problems in patients with nonsmall cell lung cancer.

Comparison of CT features of Aspergillus and bacterial pneumonia in severely neutropenic patients

PURPOSE

To establish whether a relationship exists between computed tomography features of lung opacities in severely neutropenic patients and their Aspergillus or bacterial etiology.

METHODS

Computed tomography scans of 124 patients with lung opacities larger than 5 mm occurring during severe (neutrophils <500/mm) and prolonged (>7 d) neutropenia-induced by bone marrow transplantation and/or high-dose chemotherapy for hematologic malignancies-were reviewed. Invasive pulmonary aspergillosis or bacterial pneumonia were assessed by means of bronchoalveolar lavage, bronchial washing, trans-bronchial biopsy or (for bacteria only) blood cultures. Pulmonary opacities were classified as nodules or as consolidations. The presence of a perinodular ground-glass halo, the similarity of consolidations to a pulmonary infarction and the presence of cavitation (crescent-shaped or not) were recorded.

RESULTS

Invasive pulmonary aspergillosis was diagnosed in 68 patients; bacterial pneumonia in 56. Nodules (85) were more common than consolidations (39); their distribution among the patients with aspergillosis (52 nodules and 16 consolidations) and those with bacterial pneumonia (33 nodules and 23 consolidations) was even. Out of the 19 nodules surrounded by a halo 17 were due to aspergillosis. Nine consolidations (3 due to aspergillosis) were infarctionlike shaped. Cavitation appeared during 22/68 aspergillosis and 31/56 bacterial pneumonias; an air-crescent in 6 patients with aspergillosis and in 24 with bacterial pneumonia.

CONCLUSIONS

Although rare enough, the perinodular halo is highly specific for invasive aspergillosis. The nodular pattern of lung opacities, their similarity to a pulmonary infarction, the occurrence of cavitation and the air-crescent are not related to aspergillosis.

Percutaneous needle washing for the diagnosis of pulmonary thin-walled cavitary lesions filled with air

OBJECTIVE

It is difficult to obtain sufficient material from pulmonary thin-walled cavitary lesions filled with air by conventional percutaneous aspiration biopsy in order to make a diagnosis. In these cases, we performed percutaneous needle washing (PNW) and ascertained the diagnostic significance of this method.

MATERIALS AND METHODS

PNW was performed on 27 patients with a pulmonary thin-walled cavitary lesion whose diagnosis could not be made by sputum and bronchoscopic examinations. Before centesis, the depth of the lesion was measured on CT scan. After the 22-gauge needle was inserted under X-ray fluoroscopic guidance, normal saline was injected into the cavity and aspirated. The aspirated material was examined cytologically and microbiologically. The procedure was carried out during one 30-second breath-holding.

RESULTS

Upon performing PNW on 27 patients, malignant cells were detected in 10 patients and a bacterial or fungal pathogen was detected in 9 other patients [Aspergillus (4), Mycobacterium (3), Staphylococcus (1), Streptococcus (1)]. The diagnoses of 16 of the 17 patients who were negative for malignant cells on PNW, were ascertained as benign disease during their clinical course including 3 patients who were diagnosed as (or suspected of) having infectious disease clinically, while the diagnosis of one case was unknown. Therefore, the diagnostic sensitivity of PNW for malignant diseases was 91% (10/11), while that for infectious diseases was 69% (9/13). Mild pneumothorax was the only complication of PNW (2 cases).

CONCLUSION

PNW may be an appropriate diagnostic procedure for pulmonary thin-walled cavitary lesions whose diagnosis can not be established by other techniques.

Usefulness of the MSG/IFICG/EORTC diagnostic criteria of invasive pulmonary aspergillosis in the clinical management of patients with acute leukaemia developing pulmonary infiltrates

Invasive pulmonary aspergillosis (IPA) is a frequently fatal complication in patients with acute leukaemia. Because diagnosis is still difficult, non-invasive diagnostic criteria were recently proposed by MSG/IFICG/EORTC for study purposes. We have analysed their usefulness in the clinical management of acute leukaemic patients with pulmonary infiltrates. Twenty-seven infiltrates developed during 174 chemotherapy cycles given to 50 consecutive patients. According to diagnostic criteria, IPA was diagnosed in 42% of patients and 77.8% of pulmonary infiltrates. AML diagnosis and the first induction cycle were significant risk factors. "Proven" IPA was rare, occurring in one patient (2%). The diagnosis of "probable" IPA was made in seven patients (14%) and was strongly supported by the significant association of characteristic radiological lesions ("major" clinical criterion) with the positivity of one microbiological criterion (P = 0.026). Conversely, "possible" IPA was frequent (26%) because its pertinent diagnostic criteria were fulfilled in 48.1% of pulmonary infiltrates. However, in 84.6% of cases, the diagnosis of "possible IPA" aspecifically derived from the association of two conditions, a new pulmonary infiltrate with symptoms of lower respiratory tract infection ("minor clinical criterion"), together with the definition of "susceptible" host, which applied to 100% of our leukaemic patients. We conclude that, according to MSG/IFICG/EORTC criteria, a high number of pulmonary infiltrates would be diagnosed as IPA, but only a diagnosis of "proven/probable" IPA should be considered reliable in the clinical management of suspected IPA.

Clinical relevance of Aspergillus isolation from respiratory tract samples in critically ill patients

Introduction

The diagnosis of invasive pulmonary aspergillosis, according to the criteria as defined by the European Organisation for the Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG), is difficult to establish in critically ill patients. The aim of this study is to address the clinical significance of isolation of Aspergillus spp. from lower respiratory tract samples in critically ill patients on the basis of medical and radiological files using an adapted diagnostic algorithm to discriminate proven and probable invasive pulmonary aspergillosis from Aspergillus colonisation.

Methods

Using a historical cohort (January 1997 to December 2003), all critically ill patients with respiratory tract samples positive for Aspergillus were studied. In comparison to the EORTC/MSG criteria, a different appreciation was given to radiological features and microbiological data, including semiquantitative cultures and direct microscopic examination of broncho-alveolar lavage samples.

Results

Over a 7 year period, 172 patients were identified with a positive culture. Of these, 83 patients were classified as invasive aspergillosis. In 50 of these patients (60%), no high risk predisposing conditions (neutropenia, hematologic cancer and stem cell or bone marrow transplantation) were found. Typical radiological imaging (halo and air-crescent sign) occurred in only 5% of patients. In 26 patients, histological examination either by ante-mortem lung biopsy (n = 10) or necropsy (n = 16) was performed, allowing a rough estimation of the predictive value of the diagnostic algorithm. In all patients with histology, all cases of clinical probable pulmonary aspergillosis were confirmed (n = 17). Conversely, all cases classified as colonisation had negative histology (n = 9).

Conclusion

A respiratory tract sample positive for Aspergillus spp. in the critically ill should always prompt further diagnostic assessment, even in the absence of the typical hematological and immunological host risk factors. In a minority of patients, the value of the clinical diagnostic algorithm was confirmed by histological findings, supporting its predictive value. The proposed diagnostic algorithm needs prospective validation.

Update on management of infections in cancer and stem cell transplant patients

Infections are the most important causes of morbidity and mortality in patients with aggressive malignancies and those undergoing allogeneic stem cell transplantation. The introduction of new therapeutic approaches including the use of nucleoside analogs and of monoclonal antibodies to CD20 and CD52 and the increased use of matched unrelated stem cell donors has resulted in new challenges with regard to systemic viral and fungal infections. In patients with bacterial infections, emergence of resistance to formerly widely used antibiotics as well as a shift of causative pathogens towards a predominance of multi-resistant gram-positive cocci has to be taken into consideration. In high-risk neutropenic patients with fever of unknown origin, prompt empiric monotherapy with piperacillin-tazobactam, cefepime, ceftazidime, or a carbapenem is mandatory. In patients with lung infiltrates, early preemptive intervention with an antifungal active against aspergilli is recommended, whereas in patients with catheter-related, skin or soft tissue infections, preemptive addition of a glycopeptide shows a high response rate. The prompt preemptive use of ganciclovir or foscarnet in allogeneic stem cell transplant recipients can reliably be guided by serial monitoring of cytomegalovirus antigen and polymerase chain reaction monitoring.

Cavitating Invasive Pulmonary Aspergillosis Visualized and Diagnosed by Ultrathin Bronchoscopy

A definitive diagnosis of invasive pulmonary aspergillosis (IPA), which usually occurs in immunocompromised patients, is often difficult. We report two cases of cavitating IPA in a peripheral pulmonary region in patients who were receiving corticosteroids, in whom the cavity was successfully visualized and sampled during ultrathin bronchoscopy. Ultrathin bronchoscopy provides a new option for definitive diagnosis of cavitating IPA.

Laboratory diagnosis of invasive aspergillosis

Invasive aspergillosis occurs in a wide range of clinical scenarios, is protean in its manifestations, and is still associated with an unacceptably high mortality rate. Early diagnosis is critical to a favourable outcome, but is difficult to achieve with current methods. Deep tissue diagnostic specimens are often difficult to obtain from critically ill patients. Newer antifungal agents exhibit differential mould activity, thus increasing the importance of establishing a specific diagnosis of invasive aspergillosis. For these reasons, a range of alternate diagnostic strategies have been investigated. Most investigative efforts have focused on molecular and serological diagnostic techniques. The detection of metabolites produced by Aspergillus spp and a range of aspergillus-specific antibodies represent additional, but relatively underused, diagnostic avenues. The detection of galactomannan has been incorporated into diagnostic criteria for invasive aspergillosis, reflecting an increased understanding of the performance, utility, and limitations of this technique. Measurement of (1,3)-beta-D glucan in blood may be useful as a preliminary screening tool for invasive aspergillosis, despite the fact that this antigen can be detected in a number of other fungi. There have been extensive efforts directed toward the detection of Aspergillus spp DNA, but a lack of technical standardisation and relatively poor understanding of DNA release and kinetics continues to hamper the broad applicability of this technique. This review considers the application, utility, and limitations of the currently available and investigational diagnostic modalities for invasive aspergillosis.

Surgical lung biopsy in patients with hematological malignancy or hematopoietic stem cell transplantation and unexplained pulmonary infiltrates: improved outcome with specific diagnosis

Using a retrospective review of medical records, we sought the findings of surgical lung biopsy (SLB) in patients with hematological malignancy or hematopoietic stem cell transplantation (HSCT) and unexplained pulmonary infiltrates and to determine the impact of this procedure on management and outcome of these patients. Sixty-two patients who underwent SLB were evaluated; 31 patients had underlying hematological malignancy and 31 patients were HSCT recipients; 58% of whom underwent allogeneic HSCT. Thirty-three patients (53%) had focal infiltrates on chest CT scan while 29 (47%) had diffuse infiltrates. Thirteen patients were mechanically ventilated prior to SLB, and 27 (43%) were neutropenic. There were 66 diagnoses in the 62 patients, 44 (67%) were specific and 22 (33%) were nonspecific. The most common specific diagnoses were infection (29%), malignancy (27%), and inflammatory conditions (11%). Aspergillosis was the most common diagnosis of all biopsies (21%). SLB led to a change in therapy in 40% of patients and was associated with complications in 7 patients (11%). Specific diagnosis was more likely to lead to a change in therapy (48% vs. 27%, P = 0.06) and was associated with a lower mortality when compared to a nonspecific finding (30% vs. 59%, P = 0.02). Nonspecific diagnosis, on the other hand, was seen more in patients on mechanical ventilation prior to SLB compared to those off mechanical ventilation (69% vs. 27%, P = 0.02). SLB provides a specific diagnosis in the majority of patients with hematologic malignancy or HSCT recipients and unexplained pulmonary infiltrates. Specific diagnosis is more likely to lead to a change in therapy and is associated with a better outcome.

Role of flexible bronchoscopy in immunocompromised patients with lung infiltrates

STUDY OBJECTIVE

To study the diagnostic role of flexible bronchoscopy (FB) in immunocompromised patients with pulmonary infiltrates.

DESIGN

Prospective, observational study.

SETTING

Tertiary care hospital.

PATIENTS

A total of 104 consecutive non-HIV-infected immunocompromised patients with lung infiltrates in whom FB was performed.

METHODS

The primary outcome measure was the diagnostic yield of FB, which was derived as the number of the diagnoses made using FB results divided by all final diagnoses. Final diagnoses were established using data from FB, surgical lung biopsy (SLB), and microbiology and serology testing, and by the clinical response to empiric therapy. We also studied the diagnostic yields of individual sampling procedures such as BAL, transbronchial biopsy (TBB), and protected-specimen brush (PSB) sampling.

RESULTS

Overall, 128 diagnoses were made in 104 patients. The overall diagnostic yield of FB was 56.2% (95% confidence interval [CI], 47 to 64%). FB provided at least one diagnosis in 53 of 104 patients (51%; 95% CI, 40 to 62%). FB was more likely to establish the diagnosis when the lung infiltrate was due to an infectious agent (81%; 95% CI, 67 to 90%) than to a noninfectious process (56%; 95% CI, 43 to 67%; p = 0.011). The diagnostic yields of BAL (38%; 95% CI, 30 to 47%) and TBB (38%; 95% CI, 27 to 51%) were similar (p = 0.94). The diagnostic yield of PSB sampling was lower (13%; 95% CI 6 to 24%; p = 0.001) than that of BAL. The combined diagnostic yield of BAL and TBB (70%; 95% CI, 57 to 80%) was higher than that of BAL alone (p < 0.001). Finally, the diagnostic yield of FB with PSB sampling, BAL, and TBB was similar to that of FB with BAL and TBB. The complication rate from FB was 21% (95% CI, 15 to 31%). Minor bleeding (13%) and pneumothorax (4%) were the most common complications.

CONCLUSIONS

FB has a high diagnostic yield in immunocompromised patients with pulmonary infiltrates. Based on our results, we recommend performing TBB in these patients, whenever possible.

The clinical spectrum of pulmonary aspergillosis

Aspergillus is a ubiquitous fungus that causes a variety of clinical syndromes in the lung, ranging from aspergilloma in patients with lung cavities, to chronic necrotizing aspergillosis in those who are mildly immunocompromised or have chronic lung disease. Invasive pulmonary aspergillosis (IPA) is a severe and commonly fatal disease that is seen in immunocompromised patients, while allergic bronchopulmonary aspergillosis is a hypersensitivity reaction to Aspergillus antigens that mainly affects patients with asthma. In light of the increasing risk factors leading to IPA, such as organ transplantation and immunosuppressive therapy, and recent advances in the diagnosis and treatment of Aspergillus-related lung diseases, it is essential for clinicians to be familiar with the clinical presentation, diagnostic methods, and approach to management of the spectrum of pulmonary aspergillosis.

Cardiac infections in the immunosuppressed patient

This article presents the various manifestations of cardiac infections found in the immunosuppressed host. Emphasis is placed on the correlation between specific impairments of host defenses and the occurrence of certain types of pathogens. The effect of immunosuppression on the clinical manifestations of these infections is discussed. Finally, appropriate diagnostic modalities are presented for the major types of infections.

Increasing volume and changing characteristics of invasive pulmonary aspergillosis on sequential thoracic computed tomography scans in patients with neutropenia

PURPOSE

In patients with neutropenia, thoracic computed tomography (CT) halo and air-crescent signs are recognized as major indicators of invasive pulmonary aspergillosis (IPA). Nevertheless, the exact timing of CT images is not well known.

PATIENTS AND METHODS

Seventy-one thoracic CT scans were analyzed in 25 patients with neutropenia with surgically proven IPA.

RESULTS

On the first day of IPA diagnosis with early CT scan (d0), a typical CT halo sign was observed in 24 of 25 patients. At that time, the median number of thoracic lesions was two (range, one to six), and pulmonary involvement was bilateral in 12 cases. The halo sign was present in 68%, 22%, and 19% of cases on d3, d7, and d14, respectively. Similarly, the air-crescent sign was seen in 8%, 28%, and 63% of cases on the same days. Otherwise, a nonspecific air-space consolidation aspect was seen in 31%, 50%, and 18% of cases on the same days. The analysis of calculated aspergillary volumes on CT showed that, despite antifungal treatment, the median volume of lesions increased four-fold from d0 to d7, whereas it remained stable from d7 to d14. Overall, 21 patients (84%) were cured by the medical-surgical approach.

CONCLUSION

In patients with neutropenia, CT halo sign is a highly effective modality for IPA diagnosis. The duration of the halo sign is short, and it demonstrates the value of early CT. The increase of the aspergillosis size on CT in the first days after IPA diagnosis is not correlated with a pejorative immediate outcome when using a combined medical-surgical approach.

Five-year-survey of invasive aspergillosis in a paediatric cancer centre. Epidemiology, management and long-term survival

The epidemiology, management, and long-term survival of invasive aspergillosis was assessed in a prospective, 5-year observational study in 346 unselected paediatric cancer patients receiving dose-intensive chemotherapy for newly diagnosed or recurrent malignancies. Invasive aspergillosis occurred exclusively in the context of haematological malignancies, where it accounted for an incidence of 6.8% (n = 13 of 189). The lung was the primary site in 12 cases, and dissemination was present in three of those. Prior to diagnosis, the overwhelming majority of patients had been profoundly neutropenic for at least 14 days (n = 11 of 13) and were receiving systemic antifungal agents (n = 10 of 13). Clinical signs and symptoms were nonspecific but always included fever. All 11 patients who were diagnosed and treated during lifetime for a minimum of 10 days responded to either medical or combined medical and surgical treatment, and seven were cured (64%). Nevertheless, the overall long-term survival was merely 31% after a median follow-up of 5.68 years after diagnosis. Apart from refractory or recurrent cancer, the main obstacles to successful outcome were failure to diagnose IA during lifetime and bleeding complications in patients with established diagnosis. The frequency of invasive aspergillosis of greater than 15% in paediatric patients with acute myeloblastic leukaemia and recurrent leukaemias warrants the systematic investigation of preventive strategies in these highly vulnerable subgroups.

[Usefulness of routine investigation of fungal infections through bronchoscopy in HIV-infected and non-HIV-infected patients in a general hospital, reference to AIDS]

The diagnostic yields and the spectrum of pulmonary fungal-infection obtained in samples collected by fiberoptic bronchoscopy from HIV-positive and HIV-negative patients were evaluated from 1990 to 1995. A total of 1943 bronchoscopies were performed during this period, 47% in the HIV-positive group and 53% in the HIV-negative group. Of 908 HIV-positive patients, 38 (4%) had a fungus isolated from the pulmonary sample whereas of 1035 HIV-negative patients, only 4 (0.2%) had a fungus isolated. Histoplasmosis and Cryptococcosis were more frequently found in HIV-positive than in HIV-negative patients (p < 0.001). Paracoccidioides brasiliensis was found in only 3 patients, all of them immunocompetent. The study demonstrated that, despite the low yields, the HIV-positive group may benefit from routine screening for fungal elements in specimens obtained by fiberoptic bronchoscopy.

Aspergillus fumigatus and aspergillosis

Aspergillus fumigatus is one of the most ubiquitous of the airborne saprophytic fungi. Humans and animals constantly inhale numerous conidia of this fungus. The conidia are normally eliminated in the immunocompetent host by innate immune mechanisms, and aspergilloma and allergic bronchopulmonary aspergillosis, uncommon clinical syndromes, are the only infections observed in such hosts. Thus, A. fumigatus was considered for years to be a weak pathogen. With increases in the number of immunosuppressed patients, however, there has been a dramatic increase in severe and usually fatal invasive aspergillosis, now the most common mold infection worldwide. In this review, the focus is on the biology of A. fumigatus and the diseases it causes. Included are discussions of (i) genomic and molecular characterization of the organism, (ii) clinical and laboratory methods available for the diagnosis of aspergillosis in immunocompetent and immunocompromised hosts, (iii) identification of host and fungal factors that play a role in the establishment of the fungus in vivo, and (iv) problems associated with antifungal therapy.

Changing role of invasive aspergillosis in AIDS--a case control study

OBJECTIVE

From December 1993 until January 1996 we observed 10 cases of invasive aspergillosis in a cohort of 140 patients with AIDS (7%). By contrast, no invasive aspergillosis was diagnosed in a cohort of 278 patients with AIDS between 1986 until 1993.

METHODS

Case controls were assigned randomly to each patient with invasive aspergillosis from the total pool of HIV-infected patients. Patients with invasive aspergillosis were studied retrospectively by matched-pairs analysis with respect to risk factors, radiological, microbiological and autopsy findings.

RESULTS

Patients with aspergillosis had more AIDS-defining events (3.5 [2-5] vs. 2 [2-3], median [range], P < 0.05) and a longer median survival time with full-blown AIDS (31.5 [14-45] months vs. 20.5 [5-32] months, P < 0.005) than their case controls. Patients with invasive aspergillosis tended to have lower white blood cell counts and exhibited significantly decreased median CD4 counts (7 [0-44]/mm3 vs. 27 [8-57]/mm3, P < 0.05).

CONCLUSIONS

Due to better management of opportunistic diseases and improved antiretroviral therapy, the lifespan of patients with full blown AIDS is prolonged. Patients who have survived four or more AIDS-defining events are at risk for invasive aspergillosis. This risk is associated with low white blood cell counts and CD4 cell counts.

Molecular typing of environmental and patient isolates of Aspergillus fumigatus from various hospital settings

Fingerprinting of more than 700 clinical and environmental isolates of Aspergillus fumigatus from four differential hospital settings was undertaken with a dispersed repeated DNA sequence. The analysis of the environmental isolates showed that the airborne A. fumigatus population is extremely diverse, with 85% of the strains being represented as a single genotype isolated once. The remaining 15% of the strains were isolated several times and were able to persist for several months in the same hospital environment. No strains were found to be associated with a specific location inside the hospital, and identical strains were isolated from different buildings of the hospital and outdoors. Isolation of the same strain both from patients and from the environment of the same hospital is highly suggestive of a nosocomial infection. The characteristics of the environmental fungal population explains the two main results obtained from the typing of the clinical isolates: (i) the absence of a common strain responsible for an invasive aspergillosis outbreak results from the extreme diversity of the environmental population of A. fumigatus in contact with the patients, and (ii) patients hospitalized in different wards of the same hospital can be infected with the same strain since every patient might inhale the same spore population.

Invasive aspergillosis. Clinical features of 35 proven cases at a single institution

Thirty-five patients with clinical features and histologically or microbiologically proven infection met predetermined stringent criteria for invasive aspergillosis over a 5-year period at our institution. Underlying conditions included hematologic malignancy, solid tumor, bone marrow and solid organ transplantation, and immunosuppressive therapy. The majority of patients (94%) presented with respiratory symptoms and abnormal pulmonary chest radiography; only 40% had neutropenia at time of infection. Invasive aspergillosis was suspected in only 21 cases (60%). Concomitant infections were present in 83% of patients. Half of patients had pathogenic or potentially pathogenic microorganisms other than Aspergillus spp. isolated from pulmonary specimens at time of aspergillosis. Aspergillus spp. were recovered from sputum in 75% of patients and from bronchoalveolar lavage in only 52%. Invasive aspergillosis is an unexpectedly unrecognized disease with poor outcome; overall mortality was 94% in our series. The lack of sensitivity of diagnostic procedures, together with the high frequency of concomitant infections, delays the time of diagnosis. Early diagnostic tests are needed, and presumptive antifungal therapy among high-risk patients is mandatory.

Serum Aspergillus galactomannan antigen testing by sandwich ELISA: practical use in neutropenic patients

The double sandwich ELISA detecting Aspergillus galactomannan (GM) was prospectively evaluated for the diagnosis of invasive aspergillosis (IA) in 50 haematological patients at risk for IA. Serum samples were collected once weekly as long as the risk factors persisted. Six patients had proven or probable IA (3 A. fumigatus, 1 A. flavus, 1 A. niger, 1 A. ustus) and the GM titres were parallel to the clinical evolution of IA. Six of nine patients with suspected IA had at least two consecutive serum GM titres above 1 ng/ml and died with increasing titres, whereas the GM-negative patients survived. Positive GM titres did not anticipate the isolation of fungi. Unfortunately, positive GM titres did not anticipate the initiation of antifungal therapy, based on clinical suspicion. Moreover, if a true-positive result was defined as two consecutive positive serum samples, four patients out of 35 without proven, probable or suspected IA were positive. Then, the rate of false-positive results was high (12%) in the range previously reported. Nevertheless, the GM ELISA appears useful to assess IA and to follow the efficacy of antifungal treatment.

Outcome of ICU treatment in invasive aspergillosis

OBJECTIVE

To assess the outcome of intensive care treatment in invasive aspergillosis.

DESIGN

Retrospective study.

SETTING

University Hospital, Medical Intensive Care Unit (ICU).

PATIENTS

Twenty-five patients with invasive aspergillosis who were admitted to the medical ICU in a 5 1/2 year period. Twenty-two had received high-dose chemotherapy for (mainly hematologic) malignancies, one had been treated with cyclosporine and prednisolone for systemic lupus erythematosus, one with high-dose methylprednisolone for polyarteritis nodosa and one had an ARDS after near-drowning.

MEASUREMENTS AND RESULTS

The medical records were reviewed for patient and disease characteristics, outcome, reasons for admission to the ICU, supportive care and antifungal therapy as well as for the results of cultures and autopsy. Out of 25 patients, a definite ante mortem diagnosis could be established in seven. When autopsied patients were included, a total of 15 suffered from proven invasive aspergillosis. Although standard antifungal treatment and maximal available supportive care were given, 23 of 25 patients (92%) died after a mean of 15 (1-51) days in the ICU. Both patients who recovered had received high-dose chemotherapy for hematologic malignancy and showed bone marrow recovery and/or had a localized pulmonary infection.

CONCLUSIONS

In patients with highly suspected or proven invasive aspergillosis, admission to an ICU and mechanical ventilation should be considered in cases of localized infection and obvious signs of hematologic recovery. In most other circumstances ICU admission for mechanical ventilation does not seem to improve survival.

Opportunistic infections in oncologic patients

Oncologic patients constitute a population whose susceptibility to infections is conditioned by a broad variety of factors. Advances in antineoplastic treatments have resulted in significant prevalence of severe immunosuppression among such patients. Although impairment of more than one distinct effector limb of host defenses occurs in each patient, infections can usually be attributed to a particular deficiency. Major risk factors for infections include granulocytopenia and defects of cell-mediated immunity or of humoral immunity. In the extreme situation of allogeneic bone marrow transplantation, the multitude and the timing of infections can be explained by significant dysfunction of all types of specific immune deficiencies. Treatment of bacterial infections has become more effective with the advent of broad-spectrum antibiotics; however, the dreadful emergence of polyresistant strains may be a serious problem in the near future. Prevention strategies have reduced the risk posed by important pathogens such as CMV or PCP, whereas we still lack reliable treatment against invasive mycoses. The advent of growth factors is a useful adjunct in our armamentarium; in addition to shortening the neutropenic periods after chemotherapy, they may restore qualitative defects of phagocytes. Their exact usefulness and role in managing infections remains to be defined.

Pulmonary infiltrates in the cancer patient. New approaches to an old problem

A variety of etiologies may produce pulmonary infiltrates in a patient with cancer. Infectious etiologies, of an ever-increasing number, are always of paramount concern due to their high mortality in this patient population. Patients may be rendered immunosuppressed for prolonged periods of time and therefore are highly susceptible to infection. We present an overview of the many causes of pulmonary infiltrates in the cancer patient and an approach to diagnosis and treatment.

The use of respiratory-tract cultures in the diagnosis of invasive pulmonary aspergillosis

PURPOSE

To define the role of lower-respiratory-tract cultures in the diagnosis of invasive pulmonary aspergillosis (IPA) in immunocompromised hosts.

METHODS

Immunocompromised patients with a positive, nonbiopsy, lower-respiratory-tract culture for Aspergillus species were classified as having definite, probable, indeterminate, or no IPA. Culture data, positive predictive values (PPVs), correlation with clinical and radiographic findings, and the relationship between the number of specimens submitted and the likelihood of recovering Aspergillus were assessed.

RESULTS

Definite or probable IPA was diagnosed in 72% of episodes from patients with hematologic malignancy, granulocytopenia, or bone-marrow transplant; in 58% of those with solid-organ transplant or using corticosteroids; and in 14% of those with human immunodeficiency virus infection. The PPV of cultures ranged from 14% in the latter group to 72% in the first group (bone-marrow-transplantation subgroup, 82%). Fungal cultures were more often positive than were routine cultures (P < 0.001). Clinical and radiographic findings suggestive of IPA were present more frequently in infected than uninfected patients (59% versus 24%, P < 0.025); and 73% versus 6%, (P < 0.0001, respectively). Infected patients with > or = 1 positive node had more cultures submitted than a control group of patients with no positive cultures (5.8 +/- 4.7 versus 2.1 +/- 2.2 cultures, P < 0.001).

CONCLUSION

Recovery of Aspergillus species from high-risk patients is associated with invasive infection. Clinical and radiographic correlations help to separate true- from false-positive cultures. At least 3 sputum specimens should be submitted for fungal culture whenever fungal infection is suspected.

Hospital-acquired candida and aspergillus pneumonia--diagnostic approaches and clinical findings

Bronchoscopy with bronchoalveolar lavage (BAL), collection of bronchial secretions (BS) and/or high resolution computed tomography (CT) of the lungs was performed in 70 patients with candida and/or aspergillus pneumonia. The sensitivity of bronchoscopy in detecting histologically proven fungal disease was 59%. Characteristic CT signs were found in 11 of 14 patients with candida pneumonia and 16 of 19 patients with aspergillosis. The more frequent use of bronchoscopy and CT scans between 1990 and 1992 compared with 1986-1989 for the differential diagnosis of new pulmonary infiltrates in immunocompromised patients resulted in earlier antifungal treatment (14 vs. nine days; P < 0 center dot 025). In the second treatment period survival was improved from 36 to 50% (not significant). Bronchoscopy and high resolution CT scans are mutually complementary diagnostic tools and should be performed as early as possible in the course of pneumonia in patients at high risk of fungal diseases.

Detection of Aspergillus species DNA in bronchoalveolar lavage samples by competitive PCR

A competitive PCR assay involving the use of bronchoalveolar lavage (BAL) samples for the diagnosis of invasive pulmonary aspergillosis (IPA) was developed. For this purpose, a 1-kb mitochondrial DNA fragment of Aspergillus fumigatus was sequenced. The primers used allowed amplification of A. fumigatus, A. flavus, A. terreus, and A. niger DNAs but not DNAs of other fungi and yeasts. BAL samples from 55 consecutively enrolled patients were tested. Three samples were excluded because of failure of correct amplification of the internal competitive control. Of 28 immunocompromised patients, 6 were PCR positive; 3 died of IPA and their BAL cultures yielded A. fumigatus; and 3 were culture negative and did not develop IPA. Of 15 human immunodeficiency virus-positive patients and 9 immunocompetent patients, 5 and 4, respectively, were both PCR positive and culture negative, and none developed aspergillosis. Thus, PCR confirmed IPA in three patients but gave positive results for 25% (12 of 49) of the patients who did not develop aspergillosis. The predictive value of PCR-positive results seems low for patients at risk for aspergillosis. Moreover, the risk of contamination of reaction buffers or biological samples with Aspergillus conidia seems high and has to be weighed in regard to the potential diagnostic benefit of PCR testing as a routine procedure.

Pulmonary infiltrates in patients with haematologic malignancies: clinical usefulness of non-invasive bronchoscopic procedures

In a prospective study 90 patients with haematologic malignancies (57 acute leukaemias, 6 Hodgkin's Diseases, 15 Non-Hodgkin Lymphomas, 12 other diseases), with fever exceeding 38.4 degrees C and newly developed pulmonary infiltrates underwent bronchoscopy obtaining bronchoalveolar lavage, bronchial washings and protected brush specimen (n = 71). Pneumonias due to gram-negative bacteria (n = 38) and fungi (n = 34) were most frequent. Bronchoscopic specimens yielded 226 isolates (2 different organisms/bronchoscopy on average). 112 organisms were finally regarded as causing pneumonia. Sensitivity of bronchoscopy in diagnosing infectious episodes was 66%, but only 4 out of 13 non-infectious pulmonary infiltrates could be identified. Bronchoscopy was most effective in the diagnosis of pneumocystis carinii and herpes virus pneumonia, whereas sensitivity and specificity of detecting fungal and bacterial pneumonia were low. Empirical antimicrobial therapy was verified by evaluation of bronchoscopic samples in 25 out of 90 cases. Empirical therapy was successfully changed according to the results of invasive samplings in 34 out of 90 cases. Early identification of causative pathogens had a significant impact on survival.

Pulmonary fungal infections in patients with hematological malignancies--diagnostic approaches

In a retrospective study of 56 patients with hematological malignancies and fungal pneumonia we have analyzed the value of different diagnostic procedures. In all patients (Candida n = 29, Aspergillus n = 23, mixed fungal infection n = 4) bronchoscopy and/or high-resolution computed tomography of the lungs was performed. Cultural detection of fungi in bronchoalveolar lavage was successful in 23/32 Candida and 11/23 Aspergillus pneumonias. Other relevant pathogens were identified by bronchoscopy in 21 cases. Thorax CT scans showed diagnostic evidence of fungal pneumonia in 10/13 Candida and in 16/18 Aspergillus infections. Blood cultures were positive in 9/33 Candida pneumonias and in none of aspergillosis cases. Serological testing and surveillance cultures had only limited value for the early diagnosis of pulmonary mycosis. Our data suggest that bronchoscopy and high resolution CT scans are mutually complementary diagnostic tools with high sensitivity in patients with hematological malignancies and new pulmonary infiltrates. These procedures facilitate the early and reliable recognition of invasive fungal disease which may have a bearing on the initiation, length, and differential therapy of antimycotic drugs.

Association therapy as a prognostic factor in deep fungal infection complicating oncohaematological diseases

A group of 31 oncohaemopathic patients (17 male, mean age 44 +/- 6 years), diagnosed as having primary deep fungal infection involving the lungs, were retrospectively evaluated. When infection was suspected on a clinical basis the major associated risks for death were the duration of bone marrow aplasia (12 +/- 7 versus 21 +/- 6 days, P < 0.001), increase in white blood cells and, in particular, prolonged granulocytopenia (11 +/- 5 versus 24 +/- 8 days, P < 0.001) when survivors were compared with patients, who died. Our therapeutic empirical approach was based on the association of i.v. amphotericin B, 1 mg kg-1 day-1, with oral 5-fluorocytosine (5-FC) 150 mg kg-1 day-1. Only 9 subjects received combination therapy for more than 7 days. For majority of them, oral 5-FC was interrupted because of altered compliance or sustained liver damage. A chi 2 test for independent parameters showed (P = 0.0021) a concentration of deaths among patients who received amphotericin B alone (15/22); none of the patients treated with amphotericin B + 5-FC (9 cases) died. Results generally suggest that a more favourable outcome was statistically associated with empirical antifungal combination therapy in deep fungal infection, although both treatment regimens showed effectiveness in terms of survival. Nevertheless the low 5-FC compliance and the small sample do not indicate the safe use of this drug in a large population.

Pulmonary fungal infections in immunocompromised patients: incidence and risk factors

In a prospective study, 178 patients with fever > 38.4 degrees C and newly diagnosed pulmonary infiltrates underwent bronchoscopy with bronchoalveolar lavage (BAL), aspiration of bronchial secretions (BS) and, in 71 cases, protected specimen brushing (PSB). In 42/143 immunocompromised patients (haematological malignancies, n = 92; AIDS, n = 22; immunosuppressant therapy, n = 29) and in 4/35 patients with no defined underlying disease fungal pneumonia was present (candidosis, n = 35; aspergillosis, n = 8 mixed fungal infection, n = 3). Candidosis was combined, in 17 cases, with Aspergillus (n = 3), bacterial (n = 15) or cytomegalovirus (n = 2) infection. Aspergillosis was combined in eight cases with infection with Candida (n = 3), Pneumocystis carinii (n = 1) or bacteria (n = 5). The sensitivity of BAL and PSB in Candida pneumonia was 48% and 50%, respectively; specificity was 75% and 74% respectively. Bronchial secretions were more sensitive in detecting Candida pneumonia, but specificity was only 55%. In aspergillosis, the specificity of BAL, BS and PSB in each case was 100%; the sensitivity of BAL, BS and PSB was 38%, 64% and 100%. Twenty-four fungal infections were fatal. Unfavourable prognostic factors were respiratory failure needing mechanical ventilation, diffuse bilateral pulmonary infiltrates, mixed fungal infections and start of i.v. antifungal treatment > 14 days after fever onset, which were associated with a mortality rate of 74%, 67%, 67% and 63% respectively.

Pulmonary infiltrations in febrile patients with neutropenia. Risk factors and outcome under empirical antimicrobial therapy in a randomized multicenter study

BACKGROUND

Different empirical approaches to antimicrobial treatment of lung infiltrates in patients with neutropenia were studied within a prospective, randomized multicenter trial.

METHODS

Patients with neutropenia with hematologic malignancies and fever of 38.5 degrees C or higher associated with newly diagnosed lung infiltrates were randomized for an initial therapy with acylaminopenicillin plus aminoglycoside (Group A), third-generation cephalosporin plus aminoglycoside (Group B), or the double beta-lactam combination (Group C), each in combination with rifampin. Nonresponders were given empirical amphotericin B plus 5-fluorocytosine beginning on day 4, day 5, or day 6 under study.

RESULTS

Of 295 patients entered, 91.2% were evaluable. Complete response was obtained in 61.3% with no significant difference between treatment groups. The addition of rifampin did not improve treatment results. Only 27.1% of patients achieved a complete response by antibiotic therapy without additional antifungal therapy. Fungi dominated in cases of microbiologically documented infections and were associated with a poorer outcome compared with bacterial pneumonias. The trend of leukocyte counts under study had a highly significant effect on the outcome of infection.

CONCLUSIONS

Lung infiltrates in febrile patients with neutropenia represent a high risk of treatment failure. Persistent neutropenia has a significantly adverse effect on the outcome of infection. Incorporation of systemic antifungal agents into first-line therapy, particularly in selected high-risk subgroups, might improve future treatment results. The quality of diagnostic techniques to establish the etiology of pulmonary infiltrates needs to be improved.