Diagnosis of pulmonary infections in immunocompromised patients by fiber-optic bronchoscopy with bronchoalveolar lavage and serology

Hemoptysis in Renal Transplant Recipients

Background:

Hemoptysis is the expectoration of blood from respiratory system. Clinical entities associated with hemoptysis in renal transplant recipients differ from those causing hemoptysis in common population. This review summarizes all reported clinical conditions related to hemoptysis in renal transplant patients, their causes, diagnostic approach and management.

Methods and Materials:

Primary literature was researched through MEDLINE/PubMed database and Google Scholar without restrictions. Relevant and current literatures related to hemoptysis in renal transplant recipients were used.

Results:

Overall 23 articles were included, since they report clinical conditions associated with hemoptysis in renal transplant recipients. Opportunistic lung infections, pulmonary hemorrhage associated with drugs and malignancies are usual causes of hemoptysis in these patients, sometimes with a fatal outcome.

Conclusions:

Hemoptysis is an important manifestation in renal transplant patients, caused frequently by rare clinical entities, different from those in common population.

BAL fluid analysis in the identification of infectious agents in patients with hematological malignancies and pulmonary infiltrates

The present study aims to evaluate the diagnostic yield of bronchoalveolar lavage (BAL) fluid in patients with hematological malignancies and describe the most common pathogens detected in BAL fluid (BALF.) An analysis of 480 BALF samples was performed in patients with hematological malignancies over a period of 7 years. The results of culture methods, PCR, and immunoenzymatic sandwich microplate assays for Aspergillus galactomannan (GM) in BALF were analyzed. Further, the diagnostic thresholds for Aspergillus GM and Pneumocystis jiroveci were also calculated. Microbiological findings were present in 87% of BALF samples. Possible infectious pathogens were detected in 55% of cases; 32% were classified as colonizing. No significant difference in diagnostic yield or pathogen spectrum was found between non-neutropenic and neutropenic patients. There was one significant difference in BALF findings among intensive care units (ICU) versus non-ICU patients for Aspergillus spp. (22% versus 9%, p = 0.03). The most common pathogens were Aspergillus spp. (n = 86, 33% of BAL with causative pathogens) and Streptococcus pneumoniae (n = 46, 18%); polymicrobial etiology was documented in 20% of cases. A quantitative PCR value of > 1860 cp/mL for Pneumocystis jirovecii was set as a diagnostic threshold for pneumocystis pneumonia. The absorbance index of GM in BALF of 0.5 was set as a diagnostic threshold for aspergillosis. The examination of BAL fluid revealed the presence of pathogen in more than 50% of cases and is, therefore, highly useful in this regard when concerning pulmonary infiltrates.

The Diagnostic Yield, Safety, and Impact of Flexible Bronchoscopy in Non-HIV Immunocompromised Critically Ill Patients in the Intensive Care Unit

Background

Flexible bronchoscopy (FB) and bronchoalveolar lavage (BAL) have major roles in the evaluation of parenchymal lung diseases in immunocompromised patients. Given the limited evidence, lack of standardized practice, and variable perception of procedural safety, uncertainty still exists on what constitutes the best approach in critically ill patients with immunocompromised state who present with pulmonary infiltrates in the era of prophylactic antimicrobials and the presence of new diagnostic tests.

Objective

To evaluate the diagnostic yield, safety and impact of FB and BAL on management decisions in immunocompromised critically ill patients admitted to the intensive care unit (ICU).

Methods

A prospective, observational study of 106 non-HIV immunocompromised patients admitted to the intensive care unit with pulmonary infiltrates who underwent FB with BAL.

Results

FB and BAL established the diagnosis in 38 (33%) of cases, and had a positive impact on management in 44 (38.3%) of cases. Escalation of ventilator support was not required in 94 (81.7%) of cases, while 18 (15.7%) required invasive and 3 (2.6%) required non-invasive positive pressure ventilation after the procedure. Three patients (2.6%) died within 24 h of bronchoscopy, and 46 patients (40%) died in ICU. Significant hypoxemia developed in 5% of cases.

Conclusion

FB can be safely performed in immunocompromised critically ill patients in the ICU. The yield can be improved when FB is done prior to initiation of empiric antimicrobials, within 24 h of admission to the ICU, and in patients with focal disease.

Invasive diagnostic strategies in immunosuppressed patients with acute respiratory distress syndrome

Immunosuppression predisposes the host to development of pulmonary infections, which can lead to respiratory failure and the development of acute respiratory distress syndrome (ARDS). There are multiple mechanisms by which a host can be immunosuppressed and each is associated with specific infectious pathogens. Early invasive diagnostic modalities such as fiber-optic bronchoscopy with bronchoalveolar lavage, transbronchial biopsy, and open lung biopsy are complementary to serologic and noninvasive studies and assist in rapidly establishing an accurate diagnosis, which allows initiation of appropriate therapy and may improve outcomes with relative safety.

Outcome of Pneumocystis jirovecii pneumonia diagnosed by polymerase chain reaction in patients without human immunodeficiency virus infection

BACKGROUND AND OBJECTIVE

Pneumonia caused by Pneumocystis jirovecii (PCP) in patients without human immunodeficiency virus (HIV) infection is associated with high mortality. The diagnosis of PCP at our institution is based on detection of DNA using a polymerase chain reaction (PCR) assay. The aim of this study was to describe the clinical manifestations, outcomes and factors associated with mortality due to PCP, as diagnosed by PCR, in patients without HIV infection.

METHODS

Over a 6-year period, all HIV-negative immunocompromised patients suspected of having an opportunistic pulmonary infection underwent diagnostic bronchoscopy. A multigene PCR assay that detects Pneumocystis jirovecii DNA was used for the diagnosis of PCP. Patients were considered to have PCP if they had underlying immunodeficiency, compatible signs and symptoms, abnormal radiological findings, and Pneumocystis jirovecii DNA was detected in a bronchoalveolar lavage fluid sample. Data was collected retrospectively.

RESULTS

PCP was diagnosed in 58 patients. The underlying conditions included haematological malignancies (60.3%), solid tumours (17.2%) and immunosuppressive treatment (22.4%). The most common clinical features in patients with PCP were fever (94.6%), dyspnoea (67.2%) and cough (36.2%). The overall in-hospital mortality was 17.2% (10/58). Mortality was associated with co-infections, high lactate dehydrogenase levels, female gender, and higher pneumonia severity index and acute physiology and chronic health evaluation III scores.

CONCLUSIONS

In this study, the mortality of HIV-negative patients with PCP was low compared with previous reports. We hypothesize that this finding resulted from the increased sensitivity of a PCR-based assay, as compared with traditional methods, for the diagnosis of PCP in HIV-negative patients.

A real-time PCR assay for the differentiation of Candida species

AIMS

We established a real-time PCR assay for the detection and strain identification of Candida species and demonstrated the ability to differentiate between Candida albicans the most common species, and also Candida parapsilosis, Candida glabrata, Candida tropicalis and Candida dubliniensis by LightCycler PCR and melting curve analysis.

METHODS AND RESULTS

The DNA isolation from cultures and serum was established using the QIAmp Tissue Kit. The sensitivity of the assay was ≥ 2 genome equivalents/assay. It was possible to differentiate all investigated Candida species by melting curve analysis, and no cross-reaction to human DNA or Aspergillus species could be observed.

CONCLUSIONS

The established real-time PCR assay is a useful tool for the rapid identification of Candida species and a base technology for more complex PCR assays.

SIGNIFICANCE AND IMPACT OF THE STUDY

We carried out initial steps in validation of a PCR assay for the detection and differentiation of medically relevant Candida species. The PCR was improved by generating PCR standards, additional generation of melting curves for species identification and the possibility to investigate different specimens simultaneously.

BAL neutrophils, serum procalcitonin, and C-reactive protein to predict bacterial infection in the immunocompromised host

BACKGROUND

Bacterial pulmonary infection is a common life-threatening complication in immunocompromised patients. The results of BAL cultures are not immediately available, and their microbiological yield might be limited by empiric antibiotic prescriptions. We evaluated clinical signs and symptoms, leukocyte counts, C-reactive protein (CRP) levels, procalcitonin levels, and BAL fluid neutrophil percentages as potential markers for bacterial infection in a cohort of immunocompromised patients with pulmonary complications.

METHODS

One hundred seven consecutive patients who had been referred for bronchoscopy due to suspected pulmonary infection were included in this study. Based on clinical, laboratory, radiologic, microbiological, and histologic results, patients were classified as having proven bacterial infection (n = 27), possible bacterial infection (n = 11), and no bacterial infection (n = 69).

RESULTS

Most common underlying conditions were hematologic malignancy (n = 62) and solid organ transplantation (n = 20). Clinical parameters were similar in patients with and without bacterial infection (difference was not significant). The percentage of BAL fluid neutrophils had the highest area under the curve (0.818; 95% confidence interval [CI], 0.700 to 0.935; p < 0.001), followed by absolute neutrophil counts (0.797; 95% CI, 0.678 to 0.916; p < 0.001), procalcitonin level (0.746; 95% CI, 0.602 to 0.889; p = 0.001), and CRP level (0.688; 95% CI, 0.555 to 0.821; p = 0.015) to predict proven bacterial infection (in opposition to no or possible bacterial infection) in the receiver operating characteristic analysis. Conversely, neither infiltrates (p = 0.123) nor leukocyte counts (p = 0.429) were useful in diagnosing bacterial infection. The percentage of BAL fluid neutrophils and procalcitonin level were independent predictors of bacterial infection in the multivariate regression.

CONCLUSIONS

Neutrophil percentage in BAL fluid, procalcitonin level, and CRP level might be potentially useful to differentiate bacterial infection from nonbacterial conditions in immunocompromised hosts with pulmonary complications.

Infectious pulmonary complications after stem cell transplantation or chemotherapy: diagnostic yield of bronchoalveolar lavage

Hematologic patients are at high risk for infectious pulmonary complications after stem cell transplantation (SCT) or chemotherapy. The aim of this study was to detect the range of pulmonary pathogens in these patients, analyzing 95 bronchoalveolar lavage (BAL) samples with classic and molecular (polymerase chain reaction [PCR]) detection methods. Human cytomegalovirus (HCMV) was detected in 33, herpes simplex virus in 21, human herpesvirus 6 in 24, and other viruses in 16 samples. Aspergillus species were detected in 19, Candida species in 25, and Gram-positive bacteria in 29 samples. The additional use of PCR detection methods increased the diagnostic yield from 56% to 73%, especially concerning viral and fungal infections in BAL samples. No infectious agent was detected in 26 samples. Interestingly, a high incidence of polymicrobial infections (50/95) was detected, dominated by HCMV co-infections, especially after allogeneic SCT. Within 3 years of follow-up, a poor outcome of co-infections of Aspergillus species with HCMV in 9 of 10 cases could be documented, whereas only 7 of 20 patients died with noninfectious BAL results. Herpesviruses, fungi, and Gram-positive bacteria were detected most frequently, and in 53%, polymicrobial infections were diagnosed.

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.

Diagnosis of invasive pulmonary aspergillosis using polymerase chain reaction-based detection of aspergillus in BAL

STUDY OBJECTIVE

To assess the value of Aspergillus polymerase chain reaction (PCR) test performed on the BAL in diagnosing invasive pulmonary aspergillosis (IPA).

DESIGN

Between January 1996 and 1997, we prospectively followed up 249 cancer patients with pulmonary infiltrates suggestive of pneumonia. Bronchoscopy with fungal stains, cultures, and PCR was performed on all patients. PCR was used for the detection of Aspergillus mitochondrial and alkaline protease gene DNA. The PCR products were visualized either directly on polyacrylamide gel or after Southern transfer and probing with specific probes for mitochondrial and alkaline protease DNA.

RESULTS

The 249 patients consisted of 10 patients with proven IPA (tissue invasion), 22 patients with probable IPA (microbiologic culture), 18 patients with possible IPA (consistent clinical and radiologic findings), and 199 control patients with no evidence of IPA. PCR positivity was strongly associated with all forms of IPA (p < 0.002). The sensitivity, specificity, positive predictive value, and negative predictive value of PCR were 80%, 93%, 38%, and 99%, respectively, for proven IPA, and 64%, 93%, 52%, and 96%, respectively, for probable IPA. Southern blotting analysis did not improve the diagnostic yield of the PCR test.

CONCLUSION

PCR performed on BAL is associated with high specificity and negative predictive value for IPA. The low positive predictive value could be related to the transient colonizing presence of aspergilli in the respiratory tract. The sensitivity correlates with the certainty of the diagnosis based on tissue invasion.

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.

Diagnostic yield of bronchoalveolar lavage following renal transplantation

Organ transplant recipients are at high risk of infectious pulmonary complications. In this retrospective study, the diagnostic yield of bronchoalveolar lavage (BAL) was evaluated in renal transplant recipients. The results were analysed in special regard to the clinical presentation of pulmonary infections and the possible impact of new immunosuppressive agents. Over a 5-year period 91 BAL were performed in 71 renal transplant recipients. Microorganisms were isolated from 69% of BAL (63/91): bacteria 32%; cytomegalovirus (CMV) 27%; Pneumocystis carinii (PC) 22%; other viruses 9% (HSV; EBV, RSV, adenovirus, HHV8); Aspergillus fumigatus 1%. Total cell counts and neutrophil counts in BAL were significantly elevated in bacterial infection, whereas BAL positive for PC showed eosinophilia (P<0.05). There was no association between clinical symptoms and the radiological pattern of infiltrates and the type of infection. Immunosuppression containing tacrolimus or mycophenolate mofetil was associated with a significantly higher percentage of PC and CMV infections compared to cyclosporin-based immunosuppression (65% vs. 30%, P<0.005). A considerable number of PC and CMV infections occurred beyond 6 months after transplantation. In conclusion, BAL has a high diagnostic yield in renal transplant recipients. Infection with CMV and PC should also be considered beyond 6 months after transplantation, and prophylaxis for opportunistic infections should be given if the immunosuppression is intensified.

Bronchoalveolar lavage in the diagnosis of pulmonary complications of bone marrow transplant patients

Bronchoalveolar lavage (BAL) has proved valuable in the diagnosis of pulmonary complications in immunosuppressed patients. We evaluated the diagnostic yield of BAL in pulmonary complications in bone marrow transplantation (BMT) recipients. We reviewed sequentially the records of 89 patients during an 18-month period. BAL was diagnostic in 42 patients (47%). The most common pulmonary complication diagnosed by BAL was diffuse alveolar hemorrhage (n = 15); followed by bacterial pneumonia (n = 10), respiratory syncytial virus (n = 8), aspergillosis (n = 6), Pneumocystis carinii pneumonia (n = 5), cytomegalovirus (CMV) (n = 4), and others (n = 4). The final diagnoses in the BAL non-diagnostic group were: bacterial pneumonia (n = 6), CMV (n = 6), idiopathic pneumonia syndrome (n = 5), cancer recurrence (n = 4), cardiogenic pulmonary edema (n = 4), and others (n = 9). We conclude that BAL is a useful diagnostic tool in BMT-related pulmonary complications.

[Usefulness of bronchoalveolar lavage in the renal transplant patient with suspected respiratory infection]

In this retrospective study we aimed to assess the diagnostic yield of bronchoalveolar lavage (BAL) in kidney transplant patients who were suspected of having severe respiratory infection or in whom empirical antibiotic treatment had failed. All BAL procedures performed on kidney transplanted patients suspected of having respiratory infections between January 1, 1988 and July 31, 1996 were analyzed. BAL was carried out in the standard way and samples were sent for cytologic and bacteriologic study. Thirty-three patients with a mean age of 48.5 years were enrolled. All had been receiving immunosuppressive treatment and the mean time following transplantation was 320 days. Thirty-one had received antibiotic treatment before BAL. BAL was positive for 21 of the 33 patients (64%). Twenty-two pathogens were identified: 6 Pneumocystis carinii, 4 Cytomegalovirus, 3 Mycobacterium tuberculosis, 2 Aspergillus fumigatus, 2 Herpes simplex type I, 1 Streptococcus pneumoniae, 1 Staphylococcus aureus, 1 Streptococcus mitis, 1 Legionella pneumophila, 1 Legionella longbeachae. BAL was negative for 12 patients, of whom 8 were tentatively diagnosed of bacterial infection, 3 of acute pulmonary edema and one of pulmonary infarction. Based on the results, therapy was changed for 20 patients (61%), 19 (58%) because an unsuspected pathogen was identified and 1 because treatment could be simplified. The diagnostic yield of BAL is high (64%) in kidney transplant patients suspected of respiratory infection and is useful for managing such cases, as evidenced by the fact that a high proportion (19/33) of our patients were infected by pathogens not covered by empirical treatment.