Role of galactomannan determinations in bronchoalveolar lavage fluid samples from critically ill patients with chronic obstructive pulmonary disease for the diagnosis of invasive pulmonary aspergillosis: a prospective study

Aspergillus tracheobronchitis in critically ill patients with chronic obstructive pulmonary diseases

Aspergillus tracheobronchitis (ATB) is considered as an unusual form of invasive aspergillosis and has a fatal outcome. There is little current information on several aspects of chronic obstructive pulmonary diseases (COPD) complicated by ATB, the frequency of which is expected to increase in the coming years. In a prospective study of invasive bronchial-pulmonary aspergillosis (IBPA) in a critically ill COPD population, three proven cases of ATB were identified. The three new cases, combined with eight previously reported cases of COPD with ATB over a 30-year period (1983-2013), were analysed. Among 153 critically ill COPD patients admitted to the ICU, eight cases were complicated by ATB [23.5% of IBPA (8 of 34); and 5.2% of COPD (8 of 153)], and three cases were finally diagnosed as proven ATB by histopathological findings. Among the three new cases reported and the eight published cases, the overall mortality rate was 72.7% (8 of 11 cases), with a median of 11.5 days (range, 7-27 days) between admission to death. The mortality rate was significantly higher in patients with invasive pulmonary aspergillosis (IPA) [100% (8 of 8 patients)] than in patients without parenchyma invasion [0% (0 of 3 patient), P = 0.006]. Seven patients (77.8%) received systemic corticosteroid therapy and three patients (33.3%) inhaled corticosteroids before diagnosis with ATB. Dyspnoea resistant to corticosteroids (77.8%) was the most frequent symptom. The radiological manifestations progressed rapidly in three patients (75%) who had normal chest X-rays (CXRs) at admission. Pseudomembranous lesions were the most frequent form (54.5%) observed by bronchoscopy. Aspergillus fumigatus was the most frequently isolated pathogen (40%). ATB is an uncommon cause of exacerbation in approximately 5% of critically ill COPD patients admitted to the ICU, and may progress rapidly to IPA with a high mortality rate. Dyspnoea resistant to corticosteroids and appropriate antibiotics with a negative CXR should raise the suspicion of ATB. Early diagnosis of ATB is based on bronchoscopic examination and proven diagnosis maybe safely established with a bronchial mucous biopsy.

Frequency, diagnosis and management of fungal respiratory infections

PURPOSE OF REVIEW

This review highlights key recent advances in fungal respiratory infections, encompassing developments in epidemiology, diagnostics and management, focussing on Aspergillus, Pneumocystis and Cryptococcus as key pathogens.

RECENT FINDINGS

Chronic pulmonary aspergillosis complicates existing lung diseases, particularly those associated with cavities or bullae, with a high global disease burden (prevalence estimate >1.1 million following tuberculosis) and significant under diagnosis (using Aspergillus IgG antibody). Several new treatment studies have been published (using caspofungin and voriconazole). Pneumocystis jirovecii demonstrates airborne transmission between infected and noninfected individuals necessitating isolation, and possibly identifying colonized patients. Early detection of serum cryptococcal antigenaemia in HIV may prevent development of meningitis, reducing morbidity and mortality, and routine testing of serum in community-acquired pneumonia cases in high endemicity areas may be helpful. Respiratory Aspergillus antigen and PCR testing is more sensitive than culture or serum testing. A new lateral flow antigen testing device may provide rapid bedside diagnosis of aspergillosis. Azole resistance to Aspergillus fumigatus is increasing across Europe.

SUMMARY

The field of fungal respiratory infection continues to evolve and develop, with many recent key advances. Patients, and possibly colonized patients, with Pneumocystis require isolation in hospitals and preferably segregation in outpatients. Challenges remain in almost all areas, with further work needed to identify the true burden of Aspergillus disease and address the increasing problem of azole resistance.

Stem cell transplantation and lung dysfunction

PURPOSE OF REVIEW

To identify factors that impact the incidence and severity of lung dysfunction after haematopoietic stem cell transplantation (HSCT) for preventive and therapeutic purposes.

RECENT FINDINGS

Respiratory failure from lung dysfunction after HSCT is a serious and often fatal transplant-related complication, but recent data reveal decreasing incidence and improving outcome over time. Idiopathic pneumonia syndrome (IPS) and bronchiolitis obliterans are now recognized as part of a spectrum of post-HSCT lung diseases involving both aspects of innate and adaptive immune responses, but may differ in the main lung structure affected: alveolar versus airway epithelium. There exists a strong association between acute graft-versus-host disease (GVHD) and IPS, and bronchiolitis obliterans is pathognomonic of chronic GVHD. Experimental models of IPS and bronchiolitis obliterans have proven useful to test strategies designed to limit lung injury including the effects of allogeneity, chemoradiotherapy and stem cell therapy. Recent advances in critical care practices, early diagnosis and utilizing ARDS Network ventilatory and conservative fluid management recommendations have also contributed to better outcome from lung dysfunction after HSCT.

SUMMARY

Understanding the factors that contribute to post-HSCT lung injury should lead to safer transplant practices that will allow the broader use of HSCT for sicker children with comorbidities.

Laboratory diagnosis of invasive aspergillosis: from diagnosis to prediction of outcome

Invasive aspergillosis (IA), an infection caused by fungi in the genus Aspergillus, is seen in patients with immunological deficits, particularly acute leukaemia and stem cell transplantation, and has been associated with high rates of mortality in previous years. Diagnosing IA has long been problematic owing to the inability to culture the main causal agent A. fumigatus from blood. Microscopic examination and culture of respiratory tract specimens have lacked sensitivity, and biopsy tissue for histopathological examination is rarely obtainable. Thus, for many years there has been a great interest in nonculture-based techniques such as the detection of galactomannan, β -D-glucan, and DNA by PCR-based methods. Recent meta-analyses suggest that these approaches have broadly similar performance parameters in terms of sensitivity and specificity to diagnose IA. Improvements have been made in our understanding of the limitations of antigen assays and the standardisation of PCR-based DNA detection. Thus, in more recent years, the debate has focussed on how these assays can be incorporated into diagnostic strategies to maximise improvements in outcome whilst limiting unnecessary use of antifungal therapy. Furthermore, there is a current interest in applying these tests to monitor the effectiveness of therapy after diagnosis and predict clinical outcomes. The search for improved markers for the early and sensitive diagnosis of IA continues to be a challenge.