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Pulmonary aspergillosis: a clinical update

O.S. Zmeili, A.O. Soubani
DOI: http://dx.doi.org/10.1093/qjmed/hcm035 317-334 First published online: 24 May 2007


Aspergillus spp may cause a variety of pulmonary diseases, depending on immune status and the presence of underlying lung disease. These manifestations range from invasive pulmonary aspergillosis in severely immunocompromised patients, to chronic necrotizing aspergillosis in patients with chronic lung disease and/or mildly compromised immune systems. Aspergilloma is mainly seen in patients with cavitary lung disease, while allergic bronchopulmonary aspergillosis is described in patients with hypersensitivity to Aspergillus antigens. Recent major advances in the diagnosis and management of pulmonary aspergillosis include the introduction of non-invasive tests, and the development of new antifungal agents, such as azoles and echincandins, that significantly affect the management and outcome of patients with pulmonary aspergillosis. This review provides a clinical update on the epidemiology, risk factors, clinical presentation, diagnosis and management of the major syndromes associated with pulmonary aspergillosis.


Aspergillus spp are ubiquitous fungi acquired by inhalation of airborne spores and may cause life-threatening infections especially in immunocompromised hosts. Aspergillus spp are commonly isolated from the soil, plant debris, and the indoor environment, including hospitals. Pulmonary disease caused by Aspergillus, mainly A. fumigatus, presents with a spectrum of clinical syndromes in the lung (Figure 1).1

Figure 1.

The clinical spectrum of conditions resulting from inhalation of aspergillus spores. ICH, immunocompromised host; IPA, invasive pulmonary aspergillosis; ABPA, allergic bronchopulmonary aspergillosis. Reprinted by permission from Soubani and Chandrasekar (Chest 2002;121:1988-1999).

Invasive pulmonary aspergillosis (IPA) is a severe disease, and a major cause of mortality in severely immunocompromised patients. Critically ill patients without malignancy may also develop IPA without having the classic risk factors. Chronic necrotizing Aspergillosis (CNA), which is locally invasive, is another pulmonary disease caused by Aspergillus spp. CNA is seen mainly in patients who are mildly immunocompromised or have chronic lung disease. Aspergilloma and allergic bronchopulmonary aspergillosis (ABPA) are non-invasive pulmonary diseases caused by Aspergillus: aspergilloma is a fungus ball that develops in a pre-existing cavity in the lung parenchyma, while ABPA is a hypersensitivity disease of the lungs that almost always affects patients with asthma or cystic fibrosis.

We put forward an outline for this review that systematically described the main clinical syndromes associated with pulmonary aspergillosis according to incidence, risk factors, clinical presentation, radiological features, diagnostic criteria, management options and outcome. Then we performed a comprehensive literature search using the PubMed/Medline [http://www.pubmed.gov], and the phrase 'pulmonary aspergillosis'. Articles up to December 2006 were reviewed, and clinically relevant articles that satisfied the above outline were selected and studied. The reference lists of the selected articles were evaluated for additional papers. We also included articles from the authors’ personal files.

Invasive pulmonary aspergillosis (IPA)

IPA was first described in 1953.2 The incidence of IPA has increased during the past two decades due to widespread use of chemotherapy and immunosuppressive agents.3 Groll et al. documented that the rate of invasive mycoses increased from 0.4 to 3.1% of all autopsies performed between 1978 and 1992.4 In addition, invasive aspergillosis increased from 17% of all mycoses found on autopsy at the beginning of the study to 60% at the end of the 14-year study period. The mortality rate of IPA exceeds 50% in neutropenic patients, and 90% in hematopoietic stem-cell transplantation (HSCT) recipients.5,,6

Risk factors

IPA occurs predominantly in immunocompromised patients. Major risk factors for IPA (Table 1) include neutropenia, haematopoietic stem-cell and solid-organ transplantation, prolonged and high-dose corticosteroid therapy, haematological malignancy, cytotoxic therapy, advanced AIDS, and chronic granulomatous disease (CGD).1,,7,8

View this table:
Table 1

Major risk factors for IPA

Prolonged neutropenia (<500 cells/mm3 for >10 days) or neutrophil dysfunction
Transplantation (highest risk is with lung and HSCT)
Prolonged (>3 weeks) and high-dose corticosteroid therapy.
Haematological malignancy (risk is higher with leukaemia)
Cytotoxic therapy
Advanced AIDS

Neutropenia, especially absolute neutrophil count <500 cells/mm3, is the most important risk factor, and IPA is strongly related to the duration and degree of neutropenia. The risk of IPA in neutropenic patients is estimated to be 1% per day for the first 3 weeks, after which time it increases to 4% per day.7 Solid organ transplantation, especially lung transplantation, and HSCT are also significant risk factors for IPA.9,,10 There are several factors that predispose patients who underwent transplantation to have IPA: multiple immune defects including prolonged neutropenia in the pre-engraftment phase of HSCT, the use of multiple anti-rejection or anti-graft-vs.-host disease (GVHD) therapy, such as corticosteroids and cyclosporine, parenteral nutrition, use of multiple antibiotics, and prolonged hospitalization.

In the case of HSCT, IPA is a major problem, with a steady rise in the documented cases of IPA following transplantation. The risk for IPA is much higher following allogeneic HSCT than following autologous transplantation (incidence 0.5–4% in autologous HSCT vs. 2.3–15% in allogeneic HSCT6, 11–14). In allogeneic HSCT, the highest risk is in patients with severe GVHD (grade III–IV). In these patients, the timeline for IPA infection follows a bimodal distribution, with a peak in the first month following HSCT, which is associated with neutropenia. The second peak is during the treatment for GVHD (median 78–112 days post transplantation).6,,12,15 The first peak is currently less significant, because the routine use of stem cells instead of bone marrow for transplantation, non-myeloablative regimens, the use of colony-stimulating factors during neutropenia, and the widespread use of antifungal agents have all significantly decreased the incidence of IPA during this period.12,,16

On the other hand, the incidence of IPA during the treatment of GVHD has become more significant, especially with the higher incidence of GVHD associated with unrelated allogeneic transplantation, and treatment with intensive immunosuppressive therapy, including corticosteroids, cyclosporine A, and anti-TNF agents.12,,13,17–19 In the study by Marr et al., the probability of IPA reached approximately 5% at 2 months, 9% at 6 months, and 10% at 1 year following allogeneic HSCT; by the third year after transplantation, the probability of IPA had increased slightly to 11.1%.13 There is also evidence that CMV infection in these patients increases the risk of IPA;13,,20 the hazard ratio for IPA in the setting of CMV disease increases by 13.3-fold (95%CI 4.7–37.7).6

Neutrophil dysfunction, which is primarily seen in CGD, is another risk factor for IPA, and IPA is an important cause of mortality in these patients.21

On the other hand, IPA is relatively uncommon in patients with HIV infection, especially with the routine use of highly active anti-retroviral therapy. In a recent report, the incidence of IPA in HIV-infected patients with Aspergillus isolated from their sputum was 2%.22 A low CD4 count, generally <100 cells/mm3, is present in almost all cases of AIDS-associated aspergillosis, and 50% of HIV-infected patients with IPA have coexistent neutropenia or are on corticosteroid therapy. The rest of the cases appear to have no particular risk factors other than advanced AIDS.23–25 There is increased incidence of trachebronchial involvement in these patients in addition to the usual clinical picture of IPA.25,,26 A histopathological diagnosis is usually required to establish the diagnosis of IPA in AIDS patients, since isolation of Aspergillus from respiratory secretions has poor predictive value for invasive disease.27 Response to therapy tends to be particularly poor in this patient population.22–25,27

Recent reports have documented invasive IPA in immunocompetent patients. Two at-risk groups stand out: patients with severe COPD and critically ill patients. Among 13 cases of IPA diagnosed in COPD patients admitted to an intensive care unit with acute respiratory distress, the only risk factor was corticosteroid treatment.28 Patients with COPD have increased susceptibility to IPA for several reasons, including structural changes in lung architecture, prolonged use of corticosteroid therapy, frequent hospitalization and antibiotics treatment, and co-morbid illnesses such as diabetes mellitus, alcoholism, or malnutrition. The vast majority of cases in the literature describe a fatal outcome.28–30

IPA is also becoming an important infectious disease in ICU patients without the classical risk factors for this condition. Aspergillus spp are isolated from lower respiratory tract samples in 0.7–7% of critically ill patients, and in around half of these patients, this finding represents IPA.31–35 In one retrospective study, 89 cases (70%) of invasive aspergillosis were found in patients admitted to the medical ICU without leukaemia or cancer.34 In another study of 172 critically ill patients who had positive sputum for Aspergillus, 83 had invasive disease, and 60% of these patients had no classic risk factors for IPA. The most common underlying problems in these patients were COPD and corticosteroid therapy.31 Although many of the critically ill patients with IPA do not have the classic risk factors for IPA (neutropenia, leukaemia, HSCT), they usually have conditions that affect their immune system such as COPD, systemic corticosteroid therapy, non-haematological malignancy, liver failure, diabetes mellitus, or extensive burns.31–34

The clinical signs and symptoms of IPA and radiographic features are often non-specific in the ICU patients, and the finding of Aspergillus spp in respiratory tract samples in these patients should not be routinely discarded as colonization, even if these patients are immunocompetent.31 Further diagnostic evaluation and early antifungal therapy should be considered once IPA is suspected in critically ill patients.36,,37 IPA in this patient population carries an attributable mortality of 18.9% after adjusting for confounding factors.34 A recent report suggests that the isolation of Aspergillus from lower respiratory tract samples was associated with a worse ICU outcome, regardless of whether finding represented IPA or colonization.38

Clinical presentation

Aspergillus is most often introduced to the lower respiratory tract by inhalation of the infectious spores. Less commonly, IPA may start in locations other than the lungs, like sinuses, the gastrointestinal tract, or the skin (intravenous catheters, prolonged skin contact with adhesive tapes, or burns).39–42

Patients present with symptoms that are usually non-specific, and consistent with bronchopneumonia: fever unresponsive to antibiotics, cough, sputum production, and dyspnoea. Patients may also present with pleuritic chest pain (due to vascular invasion leading to small pulmonary infarcts) and haemoptysis, which is usually mild, but can be massive. IPA is one of the most common causes of haemoptysis in neutropenic patients, and may be associated with cavitation that occurs with neutrophil recovery.43 Aspergillus may cause a tracheobronchitis with severe inflammation of the airways and associated with ulcerations and plaque formation, most often in AIDS patients and lung transplant recipients.44,,45 Aspergillus infection may also disseminate and spread haematogenously to other organs, most commonly the brain (leading to seizures, ring-enhancing lesions, cerebral infarctions, intracranial haemorrhage, meningitis, and epidural abscess), and less frequently other organs such as skin, kidneys, pleura, heart, oesophagus, and liver may be involved46 (Figure 2).

Figure 2.

Open-lung biopsy specimen showing Aspergillus acute branch hyphae invading a blood vessel causing thrombus formation (Methenamine silver/GMS stain).


The diagnosis of IPA remains challenging. Early diagnosis of IPA in severely immunocompromised patients is difficult, and a high index of suspicion is necessary in patients with risk factors for invasive disease.

Histopathological diagnosis, by examining lung tissue obtained by thoracoscopic or open-lung biopsy, remains the 'gold standard' in the diagnosis of IPA.47 The presence of septate, acute, branching hyphae invading the lung tissue samples, along with a culture that is positive for Aspergillus from the same site, is diagnostic of IPA (Figure 3). Histopathological examination also allows for the exclusion of other diagnoses, such as malignancy or non-fungal infectious diseases. The histopathological findings associated with IPA have been recently shown to differ according to the underlying host. In patients with allogeneic HSCT and GVHD, there is intense inflammation with neutrophilic infiltration, minimal coagulation necrosis, and low fungal burden. On the other hand, IPA in neutropenic patients is characterized by scant inflammation, extensive coagulation necrosis associated with hyphal angio-invasion, and high fungal burden. Dissemination to other organs is equally high in both groups.3

Figure 3.

Brain CT image from a patient with acute myelogenous leukemia, neutropenia, and disseminated aspergillosis, showing multiple bilateral dense nodules consistent with Aspergillus brain involvement.

The significance of isolating Aspergillus spp in sputum samples depends on the immune status of the host. In immunocompetent patients, isolation of Aspergillus spp. from the sputum almost always represents colonization with no clinical consequences. In a study of 66 elderly hospitalized patients with Aspergillus isolated from the sputum, 92% were consistent with colonization, and only 4.5% had IPA.48 Similar observations were reported by others.49–51 In the immunocompetent patient with Aspergillus isolated from the sputum, antifungal therapy is generally not indicated, but appropriate diagnostic studies should be considered to exclude IPA. On the other hand, isolation of an Aspergillus species from sputum is highly predictive of invasive disease in immunocompromised patients. Studies have shown that sputum samples that are positive for Aspergillus in patients with leukaemia, or in those who have undergone HSCT, have a positive predictive value of 80–90%.50,,52,53 However, sputum samples that are negative do not rule out IPA; negative sputum studies have been noted in 70% of patients with confirmed IPA.53,,54 Blood cultures are rarely positive in patients with confirmed IPA.55

The chest radiograph is of little use in the early stages of disease, because the incidence of non-specific changes is high. Usual findings include rounded densities, pleural-based infiltrates that are suggestive of pulmonary infarctions, and cavitations. Pleural effusions are uncommon.56,,57 Chest CT scan, especially when combined with high resolution images (HRCT), is much more useful. The routine use of HRCT of the chest early in the course of IPA leads to earlier diagnosis and improved outcomes in these patients.58,,59 It also aids further diagnostic studies such as bronchoscopy and open-lung biopsy.60 The typical chest CT scan findings in patients suspected to have IPA include multiple nodules and the halo sign, which is mainly seen in neutropenic patients early in the course of infection (usually in the first week), and appears as a zone of low attenuation due to haemorrhage surrounding the pulmonary nodule (Figure 4). Another late radiological sign is the air crescent sign, which represents crescent-shaped lucency in the region of the original nodule secondary to necrosis.57,,61 Neither sign, however, is sensitive or pathognomic of IPA. The halo sign may be found as a result of metastasis, bronchoalveolar carcinoma, bronchiolitis obliterans organizing pneumonia, eosinophilic pneumonia, or other fungal infection.62 Greene et al. found that 94% of 235 patients with a confirmed diagnosis of IPA had at least one nodular region.63 In another report on HRCT chest findings in febrile neutropenic patients with pneumonia, the findings associated with IPA were ill-defined nodules (67%), ground glass appearance (56%), and consolidation (44%).64 In a retrospective study done on 45 patients, none of the early HRCT signs (nodule, consolidation, peribronchial infiltrates) predicted patient outcome or the development of pulmonary haemorrhage.65 However, pulmonary haemorrhage is expected to occur in the presence of large cavitating nodules or consolidations located close to larger pulmonary vessels.

Figure 4.

Chest CT image from an allogeneic HSCT recipient with severe GVHD, showing multiple nodular lesions. Thoracoscopic lung biopsy confirmed the diagnosis of IPA.

Bronchoscopy with bronchoalveolar lavage (BAL) is generally helpful in the diagnosis of IPA, especially in patients with diffuse lung involvement. The sensitivity and specificity of a positive result of BAL fluid are about 50% and 97%, respectively. This diagnostic yield of BAL in the diagnosis of IPA is not consistent, and much lower yields have been reported.50,,52,66–70 BAL is however a safe and useful tool in high-risk patients suspected to have IPA. In addition to obtaining samples for fungal stain and culture, it may also be useful in detecting Aspergillus antigens in the BAL fluid, and excluding other infections. Transbronchial biopsies usually do not add much to the diagnosis of IPA, and are associated with increased risk of bleeding, so are seldom performed.52

In the setting of diagnostic work-up for IPA, it is important to send samples such as sputum, BAL fluid, or lung tissue for culture as well as for histological examination. This is because other fungal species, such as zygomyces, scedosporium, pseudallescheria, and fusarium, may have similar histological appearance to Aspergillus.71 Furthermore, different species of Aspergillus may lead to IPA. While A. fumigatus is the most common cause of IPA, there are increasing reports of IPA in cancer patients due to other species such as A. niger, A. terreus and A. flavus.72–76 Some of these species (such as A. terreus and A. nidulans) are resistant to amphotericin B.73,,76

In a review of 300 cases with proven IPA, A. terreus was the second most common species, isolated with a frequency of 23%. The risk factors and outcome for A. terreus infection were similar to those for A. fumigatus infection, but the former was significantly more likely to be nosocomial in origin, and more likely to be resistant to amphotericin B.75 The new triazole antifungal agents such as voriconazole and posaconazole have significantly better efficacy against A. terreus.73,,74,77

The most recent advances in the diagnosis of IPA are related to detecting Aspergillus antigens in body fluids. Galactomannan is a polysaccharide cell-wall component that is released by Aspergillus during growth. A double-sandwich ELISA for the detection of galactomannan in serum was recently approved by the Food and Drug Administration for the diagnosis of IPA, with a threshold of 0.5 ng/ml. Serum galactomannan can be detected several days before the presence of clinical signs, an abnormal chest radiograph, or positive culture. This may allow earlier confirmation of the diagnosis, and serial determination of serum galactomannan values may be useful in assessing the evolution of infection during treatment.78,,79

A meta-analysis study was undertaken by Pfeiffer et al. to assess the accuracy of a galactomannan assay for diagnosing IPA. Twenty-seven studies from 1996 to 2005 were included, and cases were diagnosed with IPA according to the European Organization for Research on Treatment of Cancer/Mycoses Study Group (EORTC/MSG) criteria. Overall, the assay had a sensitivity of 71% and specificity of 89% for proven cases of invasive aspergillosis. The negative predictive value was 92–98% and the positive predictive value was 25–62%.80 Pfeiffer and colleagues concluded that galactomannan assay is more useful in patients who have haematological malignancy or who have undergone allogeneic HSCT, than in solid-organ transplant recipients or non-neutropenic patients.

Galactomannan is found in food, and may be absorbed by the digestive tract, especially in patients with postchemotherapy mucositis, resulting in a false-positive reaction. Also, medications such as β-lactam antibiotics (e.g. piperacillin/tazobactam) may be associated with a false-positive assay, while antifungal agents with activity against Aspergillus may lead to a false-negative result.81–84

One of the major limitations of the galactomannan test is the species-specificity of the assay. Consequently, it is not possible to exclude the involvement of other moulds such as Fusarium, Zygomycetes, and dematiaceous fungi.85 Galactomannan detection does not remove the need for careful microbiological and clinical evaluations.

There is evidence that galactomannan is detected in other body fluids such as BAL, urine, and cerebrospinal fluid, and that these tests may become positive prior to clinical and radiological findings suggestive of IPA.85–88 Prospective studies are needed to study and compare the performance of Aspergillus antigen detection in samples other than serum. In a retrospective study, incorporating galactomannan assay and quantitative PCR assay into standard BAL fluid analysis appeared to enhance bronchoscopic identification of Aspergillus species as the cause of pulmonary disease in HSCT recipients.86

Polymerase chain reaction (PCR) is another way to diagnose IPA, by the detection of Aspergillus DNA in BAL fluid and serum. A positive Aspergillus PCR in BAL fluid has an estimated sensitivity of 67–100% and specificity of 55–95% for IPA.89 PCR sensitivity and specificity have also been reported as 100% and 65–92%, respectively, in serum samples.89–92 However this test is often associated with false-positive results, because it does not discriminate between colonization and infection. PCR for Aspergillus nucleic acid detection remains restricted to highly specialized laboratories, and cannot be considered a routine exam.

Detection of serum (1 → 3)-β-D-glucan, a fungal cell wall constituent, has recently received Food and Drug Administration approval, and is a highly sensitive and specific test for invasive deep mycosis, including candidiasis, fusariosis, and aspergillosis, that could be useful in immunocompromised patients.93 However, the utility of this assay in non-neutropenic and in allogeneic HSCT recipients at high risk for IPA is not yet known.

The role of galactomannan and other serological studies in the diagnosis of IPA is evolving. Furthermore, their role in different hosts, as surveillance tools, and their impact on the outcome of patients, are all unclear. Ongoing prospective studies are attempting to address these issues, but until solid data are available, these tests should be considered as adjunct diagnostic studies, and should not replace appropriate clinical and radiological evaluation (and in selected cases, invasive procedures) to confirm the diagnosis of IPA.

The EORTC/MSG has proposed several criteria for the diagnosis of invasive fungal infections.94 These criteria consist of host factors, microbiological factors, and minor and major clinical criteria (Table 2). Two consecutive positive serum galactomannan measurements, with the appropriate host and clinical factors, can be considered 'probable' IPA.94 However, the EORTC/MSG criteria are neither evidenced-based, nor prospectively validated. They are meant to serve as a guide for clinical and epidemiological research, and need not be present in every patient to treat for IPA.

View this table:
Table 2

Diagnostic criteria for IPA

Proven IPAHistopathological or cytopathological examination of lung tissue showing hyphae from needle aspiration, or biopsy specimen with evidence of associated tissue damage; OR
Positive culture result for Aspergillus from a sample obtained by sterile procedure from the lung and clinically or radiologically abnormal site consistent with infection
Probable IPAHost risk factor (Table 1); AND
Microbiological criteria (positive Aspergillus microscopy or culture from the sputum or BAL, or positive galactomannan assay); AND
Clinical criteria consistent with the infection (1 major or 2 minor)*
Possible IPAHost risk factor (see Table 1); AND
Microbiological criteria (positive Aspergillus microscopy or culture from the sputum or BAL, or positive galactomannan assay); OR
Clinical criteria consistent with the infection (1 major or 2 minor)*
  • *Major clinical criteria: new characteristic infiltrates on CT imaging (halo sign, air-crescent sign, or cavity within area of consolidation). Minor clinical criteria: symptoms of LRTI (cough, chest pain, haemoptysis, or dyspnoea); physical finding of pleural rub; any new infiltrate not fulfilling major criteria; pleural effusion.


Treatment of IPA is difficult, and mortality remains high despite the introduction of several new antifungal agents. Therapy should be considered as soon as there is a clinical suspicion of IPA, and while a workup is underway. For many years, amphotericin B has been the first line of therapy for IPA, recommended dose 1–1.5 mg/kg/day. However, amphotericin B can cause serious side-effects, including nephrotoxicity, electrolyte disturbances, and hypersensitivity. For these reasons, newer lipid-based preparations of amphotericin B (e.g. liposomal amphotericin B and lipid complex amphotericin B) have been introduced to reduce these side-effects. Higher doses of the lipid formulations are needed for equivalent antifungal efficacy to the older version.

Voriconazole is a new broad-spectrum triazole that has been approved as the initial treatment of invasive aspergillosis, and is currently considered the treatment of choice in many patients with IPA.95–97 In a large prospective, randomized, multicentre trial, voriconazole was compared to amphotericin B as the primary therapy for IPA.98 Patients receiving voriconazole had a higher favourable response rate at week 12 (53%, vs. 32% in patients receiving amphotericin B), and a higher 12-week survival (71% vs. 58%). Voriconazole is available in both intravenous and oral formulations. The recommended dose is 6 mg/kg twice daily intravenously on day one, followed by 4 mg/kg/day. After seven days, switching to 200 mg PO twice daily may be considered. Voriconazole has a milder side-effect profile, and is much better tolerated than amphotericin B. The most frequent adverse effect is visual disturbances, described as blurred vision, photophobia, and altered colour perception. Liver function test abnormalities and skin reactions are less common side-effects. Voriconazole is however associated with significant number of drug–drug interactions, such as with cyclosporine, warfarin, terfenadine, carbamazepine, quinidine, rifampin, statins, and sulfonylureas.95

Posaconazole is another broad-spectrum triazole that is effective and safe as salvage therapy in patients with invasive aspergillosis refractory to standard antifungal therapy.21,,77,99

Echinocandin derivatives such as caspofungin, micafungin, and anidulafungin are effective agents in the treatment of IPA refractory to standard treatment, or if the patient cannot tolerate first-line agents.100,,101 Since echinocandins inhibit the (1 → 3)-β-D-glucan constituent of the fungal cell wall, unlike polyenes and azoles which target the fungal cell membrane, combination antifungal therapy could be a strategy to treat refractory IPA.102,,103 There are no prospective randomized studies that show improved efficacy with combination therapy (rather than single agents) in the management of primary IPA. There are however in vitro and limited clinical studies (case reports and retrospective case series) that suggest a benefit from combining antifungal agents as salvage therapy in refractory IPA.103–106 The combination of caspofungin and liposomal amphotericin B as a salvage therapy showed a an overall response rate of 42%, although in patients with progressive documented IPA, the response rate was only 18%.103 A survival advantage of voriconazole plus caspofungin compared with voriconazole alone was reported in one retrospective analysis of salvage therapy for IPA.105 On the other hand, another report showed no difference in the response rate between patients who received micafungin alone or those who received it in combination with other antifungal agents as primary or salvage therapy for acute IPA.107 Combination therapy of an echinocandin with either a lipid formulation of amphotericin B or triazole agent appears promising, but cannot be recommended for the routine treatment of primary IPA. Controlled randomized prospective studies are needed to document the value of this approach. Because galactomannan is covalently bound to (1 → 3)-β-D-glucan in the fungal cell wall, an initial increase in circulating galactomannan might be expected in patients treated with echinocandins.108 Surgical resection has a limited role in the management of patients with IPA, but should be considered in cases of massive haemoptysis, or pulmonary lesions close to the great blood vessels or pericardium, or the resection of residual localized pulmonary lesions in patients with continuing immunosuppression or those who are expected to have immunosuppressive therapy in the future. Several reports have shown the relative efficacy and safety of surgical intervention (in addition to antifungal therapy) in these situations.59,,109–114

Immunomodulatory therapy, such as using colony-stimulating factors (i.e. granulocyte colony-stimulating factor, granulocyte macrophage colony-stimulating therapy) or interferon-γ could be used to decrease the degree of immunosuppression, and as an adjunct to antifungal therapy for the treatment of IPA. Colony-stimulating factors stimulate the bone marrow to produce more neutrophils, and have been shown to augment the phagocytic activity of neutrophils against fungi, including Aspergillus spp.115–117 There is a theoretical advantage from adding these agents to the treatment of neutropenic patients suspected to have IPA.

In one randomized study in patients receiving chemotherapy for acute myelogenous leukemia, prophylaxis with GM-CSF led to a lower frequency of fatal fungal infections compared with placebo (1.9 vs. 19%, respectively) and reduced overall mortality.118 It is recommended to consider colony-stimulating factors in neutropenic patients with serious infections, but there are no definitive studies that show benefit in patients with IPA.119

Interferon-γ is another cytokine that has been shown in vitro and in animal models to augment immunity by increasing neutrophil and monocyte activity against Aspergillus,116,,120,121 and it has been used to decrease the risk of Aspergillus infection in patients with CGD.122 Evidence on the value of adding interferon-γ as an adjunct treatment of IPA is limited to case reports and small reports, and there are no guidelines on its role in the treatment of IPA.123 There was a concern about the use of interferon-γ in allogeneic HSCT recipients, since it may worsen GVHD; however in a recent trial, GVHD actually improved during this therapy.124

Granulocyte transfusion is another potential supportive therapy for patients with prolonged neutropenia and life-threatening infections refractory to conventional therapy. It has been shown that it is safe for potential donors to donate neutrophils by granulocytophoresis, but there are no randomized studies that prove the benefit of adjuvant granulocyte transfusion in the treatment of IPA.125 It is also important in patients with IPA, whenever possible, to decrease the dose of systemic corticosteroids and immunosuppressive agents.

The management of IPA is difficult, and an important approach to this problem is prophylaxis in patients at increased risk for IPA. Avoiding the hospitalization of patients in areas where there is construction, and the use of high-efficiency particulate air (HEPA) filtration, with or without laminar air flow ventilation, have both proven useful.126 A meta-analysis suggested that itraconazole was effective in preventing fungal infections in neutropenic patients.127 Preliminary data also suggest the efficacy of posaconazole as IPA prophylaxis in patients with acute myelogenous leukemia or myelodysplastic syndrome.128 Currently, chemoprophylaxis trials using other antifungal agents (such as voriconazole, caspofungin, micafungin) are underway in high-risk patients.

Chronic necrotizing aspergillosis (CNA)

Chronic necrotizing aspergillosis, also called semi-invasive or subacute invasive aspergillosis, was first described by Gefter et al. and Binder et al. in 1981.129,,130 It is an indolent, cavitary, and infectious process of the lung parenchyma secondary to local invasion by Aspergillus species, usually A. fumigatus.131 In contrast to IPA, CNA runs a slowly progressive course over weeks to months, and vascular invasion or dissemination to other organs is unusual. This syndrome is rare, and the available literature is based on case reports and small case series.129–131

Risk factors

CNA usually affects middle-aged and elderly patients with altered local defences, associated with underlying chronic lung diseases such as COPD, previous pulmonary tuberculosis, thoracic surgery, radiation therapy, pneumoconiosis, cystic fibrosis, lung infarction, or (less commonly) sarcoidosis.132 It may also occur in patients who are mildly immunocompromised due to diabetes mellitus, alcoholism, chronic liver disease, low-dose corticosteroid therapy, malnutrition, and connective tissue diseases such as rheumatoid arthritis and ankylosing spondylitis.130

It may be difficult to distinguish CNA from aspergilloma, especially if a previous chest radiograph is not available.133 However, in CNA there is local invasion of the lung tissue and a pre-existing cavity is not needed, although a cavity with a fungal ball may develop in the lung as a secondary phenomenon, due to destruction by the fungus. In a recent report of aspergillomas in AIDS, progression over time was seen, with considerable morbidity and some mortality.133 This probably reflects that an aspergilloma may invade the cavity wall, causing local parenchyma destruction, as seen in patients with CNA.131

Clinical presentation and diagnosis

Patients frequently complain of constitutional symptoms such as fever, weight loss of 1–6 months’ duration, malaise, and fatigue, in addition to chronic productive cough and haemoptysis, which varies from mild to severe.133 Occasionally, patients may be asymptomatic.

The chest radiograph and chest CT scan usually show consolidation, pleural thickening, and cavitary lesions in the upper lung lobes. Aspergilloma may be seen in nearly 50% of patients.130 Adjacent pleural thickening, which may progress to form a broncho-pleural fistula, is considered an early indication of a locally invasive process.129,,134 Characteristically, these radiological findings tend to be progressive over weeks to months.134

The vast majority of patients with CNA have positive serum IgG antibodies to A. fumigatus, which varies over time and may be negative at some points in the course of CNA.133 Immediate skin reactivity for Aspergillus antigens is another helpful, but not diagnostic test. Sputum and bronchoscopy samples may also be positive for Aspergillus by culture.133

Confirmation of the diagnosis requires a histological demonstration of tissue invasion by the fungus, and the growth of Aspergillus species on culture. Pathologically, CNA is characterized by necrosis of lung tissue, acute or chronic inflammation of the cavity wall, and presence of hyphae consistent with Aspergillus species.135 However, the yield of transbronchial biopsy specimens or percutaneous aspirates is relatively poor, and a thoracoscopic or open-lung biopsy is rarely performed in these patients. Confirmation of the diagnosis is thus difficult, and delayed diagnosis is common, which may contribute to the morbidity and mortality associated with CNA. Therefore, early diagnosis needs a high index of suspicion. The combination of characteristic clinical and radiological findings and either serological results positive for Aspergillus or the isolation of Aspergillus from respiratory samples is highly indicative of CNA.136 Denning et al. have proposed criteria for diagnosis of chronic pulmonary aspergillosis, including CNA, which could be helpful to in the earlier diagnosis and therapy of CNA, and may thus improve the prognosis for patients with this condition136 (Table 3).

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Table 3

Diagnostic criteria for CNA

Diagnostic criteriaCharacteristics
ClinicalChronic (>1 month) pulmonary or systemic symptoms, including at least one of: weight loss; productive cough; haemoptysis
No overt immunocompromising conditions (e.g. haematological malignancy, neutropenia, organ transplantation)
No dissemination
RadiologicalCavitary pulmonary lesion with evidence of paracavitary infiltrates
New cavity formation, or expansion of cavity size over time
LaboratoryElevated levels of inflammatory markers (C-reactive protein, plasma viscosity, or erythrocyte sedimentation rate)
Isolation of Aspergillus spp from pulmonary or pleural cavity, or Positive serum Aspergillus precipitin test
Exclusion of other pulmonary pathogens, by results of appropriate cultures and serological tests, that are associated with similar disease presentation, including mycobacteria and endemic fungi


Antifungal therapy is the mainstay of treatment for patients diagnosed with CNA. Amphotericin B was intially used, in doses of 0.5–1 mg/kg/day (4–5 mg/kg/day for the lipid formulation) with favourable results.130,,131 Itraconazole later became an effective alternative to the relatively toxic amphotericin B,131,,137 and more recently, voriconazole has emerged as a primary therapy for CNA. In a recent prospective study, where voriconazole 200 mg was given twice daily for a period of 4–24 weeks as primary or salvage therapy for 39 patients with CNA,96 a complete or partial response was seen in 43% of patients, and improvement or stability in 80%. The authors concluded that voriconazole was a safe and effective treatment to be used as a primary or salvage therapy for patients with CNA.

Treatment is best evaluated by following clinical, radiological, serological, and microbiological parameters.133 Useful parameters of response include weight gain and energy levels, improved pulmonary symptoms, falling inflammatory markers and total serum IgE level, improvement in paracavitary infiltrates, and eventually a reduction in cavity size.133

Surgical resection plays a minor role in the treatment of CNA, being reserved for healthy young patients with focal disease and good pulmonary reserves, patients not tolerating antifungal therapy, and patients with residual localized but active disease despite adequate antifungal therapy. Binder et al. reported that 90% of patients who underwent surgical resection had good responses, but surgery was associated with significant post-operative complications.130

The reported mortality of CNA varies widely and may be limited by incomplete follow-up.131 Mortality was 39% in the reported American experience, but less than 10% in European reports using itraconazole.131


Aspergilloma is the most common and best recognized form of pulmonary involvement due to Aspergillus. Pulmonary aspergilloma usually develops in a pre-existing cavity in the lung. The aspergilloma (fungus ball) is composed of fungal hyphae, inflammatory cells, fibrin, mucus, and tissue debris. The most common species of Aspergillus recovered from such lesions is A. fumigatus; however, other fungi may cause the formation of a fungal ball, such as Zygomycetes and Fusarium. Many cavitary lung diseases are complicated by aspergilloma, including tuberculosis, sarcoidosis, bronchiectasis, bronchial cysts and bulla, ankylosing spondylitis, neoplasm, and pulmonary infection;138,,139 of these, tuberculosis is the most common associated condition.140 In a study on 544 patients with pulmonary cavities secondary to tuberculosis, 11% had radiological evidence of aspergilloma.141 Less frequently, aspergilloma has been described in cavities caused by other fungal infections.142,,143

Inadequate drainage is thought to facilitate the growth of Aspergillus on the walls of these cavities. The fungus ball may move within the cavity, but does not usually invade the surrounding lung parenchyma or blood vessels, although exceptions have been noted.144,,145 In the majority of cases, the lesion remains stable, but in 10% of cases the aspergilloma may decrease in size or resolve spontaneously without treatment.146 The aspergilloma rarely increases in size.

Clinical presentation

Most patients with aspergilloma are asymptomatic. When symptoms are present, most patients will experience mild haemoptysis, but severe and life-threatening haemoptysis may occur, particularly in patients with underlying tuberculosis.147 Bleeding usually occurs from bronchial blood vessels, and may be due to local invasion of blood vessels lining the cavity, endotoxins released from the fungus, or mechanical irritation of the exposed vasculature inside the cavity by the rolling fungus ball.144,,148,149 The mortality rate from haemoptysis related to aspergilloma ranges between 2% and 14%.150–154 Less commonly, patients may develop cough, dyspnoea that is probably more related to the underlying lung disease, and fever, which may be secondary to the underlying disease or bacterial superinfection of the cavity.

Several risk factors have been associated with poor prognosis of aspergilloma. These include the severity of the underlying lung disease, increasing size or number of lesions as seen on chest radiographs, immunosuppression (including corticosteroids), increasing Aspergillus-specific IgG titers, recurrent large volume haemoptysis, underlying sarcoidosis, and HIV infection.155


The diagnosis of pulmonary aspergilloma is usually based on the clinical and radiographic features, combined with serological or microbiologic evidence of Aspergillus spp. Chest radiography is useful in demonstrating the presence of a mass in a pre-existing cavity. Aspergilloma appears as an upper-lobe, mobile, intra-cavitary mass with an air crescent in the periphery.156 A change in the position of the fungus ball after moving the patient on his side or from supine to prone position is an interesting but variable sign.157 Chest CT scan may be necessary to visualize aspergilloma that is not apparent on chest radiograph.157 These radiological appearances may be seen in other different conditions such as haematoma, neoplasm, abscess, hydatid cyst, and Wegener's granulomatosis. Aspergilloma may coexist with any of the above mentioned conditions.158,,159 Sputum cultures for Aspergillus spp are positive only in 50% of cases.160 Serum IgG antibodies to Aspergillus are positive in almost every case, but may be negative in patients on corticosteroid therapy.145 Aspergillus antigen has been recovered from the bronchoalveolar lavage fluid of patients with aspergilloma, but the diagnostic value of this test is variable.161,,162


There is no consensus on the treatment of aspergilloma. Treatment is considered only when patients become symptomatic, usually with haemoptysis. Inhaled, intracavitary, and endobronchial instillations of antifungal agents have been tried and reported in small numbers of patients, without consistent success.153,,163,164

Administration of amphotericin B percutaneously guided by CT scan can be effective for aspergilloma, especially in patients with massive haemoptysis, with resolution of haemoptysis within few days.165,,166 The role of intravenously administered amphotericin B is uncertain, and some small studies failed to show a benefit.167

Oral itraconazole has been used, with radiographic and symptomatic improvement in half to two-thirds of patients, and occasional patients having a complete response.168–170 Itraconazole is a useful agent for aspergilloma management, because it has a high tissue penetration. In a recent study, significant itraconazole levels within the aspergilloma cavities were demonstrated after using the standard dose of itraconazole (100–200 mg/day).171 The major limitation of itraconazole is that it works slowly and would not be useful in cases of life-threatening haemoptysis.161

Surgical resection of the cavity and removal of the fungus ball is usually indicated in patients with recurrent haemoptysis, if their pulmonary function is sufficient to allow surgery. Surgical treatment is associated with relatively high mortality rates, ranging from 7% to 23%.149–151,172–175 The most common causes of death post-operatively are severe underlying lung disease, pneumonia, acute myocardial infarction, and IPA.153,,175 Other postoperative complications include haemorrhage, residual pleural space, bronchoalveolar fistula, empyema, and respiratory failure.

Bronchial artery embolization should be considered as a temporary measure in patients with life-threatening haemoptysis, since haemoptysis usually recurs due to the presence of massive collateral blood vessels.176 The role of newer antifungal azoles such as voriconazole in the treatment of aspergilloma has yet to be determined.

Allergic bronchopulmonary aspergillosis (ABPA)

ABPA is a pulmonary disease that results from hypersensitivity to Aspergillus antigens, mostly due to A. fumigatus. The majority of cases of ABPA occur in people with asthma or cystic fibrosis. It is estimated that 7–14% of corticosteroid-dependent asthmatics and 6% of patients with cystic fibrosis develop ABPA.177,,178 The pathogenesis of ABPA is not completely understood: Aspergillus-specific IgE-mediated type I hypersensitivity reactions, specific IgG-mediated type III hypersensitivity reactions, and abnormal T-lymphocyte cellular immune responses all appear to play important roles in its pathogenesis.179–182 In one study, 18 pathological specimens were taken from patients diagnosed with ABPA and the most significant findings were involvement of the bronchi and bronchioles, with bronchocentric granulomas in 15 specimens and mucoid impaction in 11.183 Other findings included granulomatous inflammation consisting of palisading histiocytes surrounded by lymphocytes, plasma cells, and eosinophils. Fungal hyphae were seen, but without evidence of tissue invasion.183

Clinical presentation and diagnosis

ABPA is usually suspected on clinical grounds, and the diagnosis is confirmed by radiological and serological testing. Almost all patients have clinical asthma, and patients usually present with episodic wheezing, expectoration of sputum containing brown plugs, pleuritic chest pain, and fever.184 Chest radiograph findings may be normal in the early stages of the disease. During acute exacerbations, fleeting pulmonary infiltrates are characteristic feature of the disease that tends to be in the upper lobe and central in location. There may be transient areas of opacification due to mucoid impaction of the airways, which may present as band-like opacities emanating from the hilum with rounded distal margin (gloved finger appearance).185 The 'ring sign' and 'tram lines' are radiological signs that represent the thickened and inflamed bronchi may be seen on chest radiographs. Central bronchiectasis and pulmonary fibrosis may develop at later stages. Chest CT scan, with high-resolution images, is helpful for better defining bronchiectasis and more sensitive in demonstrating the above changes (Figure 5). Typically, total serum IgE is elevated, and sputum cultures reveal Aspergillus spp. Serum IgE could be used as a marker for flare-ups and responses to therapy.186 A positive sputum culture is not necessary to diagnose ABPA. Immediate skin test reactivity to A. fumigatus antigens and elevated levels of serum IgG and IgE antibodies to Aspergillus are usually documented.179 Lung biopsies are rarely performed, since ABPA is usually suspected on clinical rounds. Greenberger and Patterson have standardized the criteria for the diagnosis of ABPA (Table 4),184,,186 not all of which need to be present for the diagnosis to be made.

View this table:
Table 4

Diagnostic criteria for ABPA

Immediate skin reactivity to Aspergillus
Serum precipitins to A. fumigatus
Increased serum IgE and IgG to A. fumigatus
Total serum IgE >1000 ng/ml
Current or previous pulmonary infiltrates
Central bronchiectasis
Peripheral eosinophilia (1000 cells/μl)
Figure 5.

High-resolution chest CT image from a patient with ABPA, showing moderate bronchiectasis, with areas of mucoid impaction and atelectasis of the right middle lobe.

Early detection and treatment of ABPA before the development of all clinical symptoms and bronchiectasis is paramount, since delayed treatment may result in irreversible pulmonary damage. Therefore, patients with ABPA can be subdivided in two groups: patients with or without central bronchiectasis (ABPA-CB and ABPA-seropositive, respectively).1 The minimal essential criteria to diagnose patients with ABPA-central bronchiectasis include asthma, immediate skin reactivity to Aspergillus antigens, serum IgE level >1000 ng/ml, and central bronchiectasis. On the other hand, the minimal criteria to diagnose ABPA-seropositive patients include asthma, immediate skin reactivity to Aspergillus antigens, serum IgE > 1000 ng/ml, history of pulmonary infiltrates, and elevated levels of serum IgE and IgG antibodies to A. fumigatus.187

Patterson et al. have also subdivided the clinical course of ABPA into five stages that help to guide the management of the disease.188 These stages need not occur in order. The first four are potentially reversible, with no long-term sequelae. Stage I (acute stage) is the initial acute presentation with asthma, elevated IgE level, peripheral eosinophilia, pulmonary infiltrates, and IgE and IgG antibodies to A. fumigatus. In practice, patients are seldom identified in this stage. In Stage II (remission stage), the IgE falls but usually remains elevated, eosinophilia is absent, and the chest radiograph is clear. Serum IgG antibodies to Aspergillus antigen may be slightly elevated. Stage III (exacerbation stage) is the recurrence of the same findings as in Stage I in patients known to have ABPA. IgE rises to at least double the baseline level. Stage IV (the corticosteroid-dependent stage) occurs in patients who have asthma in which control of symptoms is dependent on chronic use of high-dose corticosteroid therapy and exacerbations are marked by worsening asthma, radiographic changes, and an increase in IgE level may occur. Frequently, the chest CT scan will show central bronchiectasis. Unfortunately, most patients are diagnosed at this stage.189 In stage V (fibrotic stage), bronchiectasis and fibrosis develop, and usually lead to irreversible lung disease. Patients in this stage, may present with dyspnoea, cyanosis, rales, and cor pulmonale. Clubbing may be present. The serum IgE level and eosinophil count might be low or high. Fortunately, few patients progress to this stage.


Treatment of ABPA aims to treat acute exacerbations of the disease, and to limit progressive lung disease and bronchiectasis. Oral corticosteroids targeting the hypersensitivity have formed the main aspect of treatment in ABPA. Corticosteroids suppress the inflammatory response provoked by A. fumigatus rather than eradicating the organism. Treatment with corticosteroids leads to the relief of bronchospasm, the resolution of radiographic infiltrates, and the reduction in serum total IgE and peripheral eosinophilia.190,,191 Two weeks of daily therapy of oral prednisone (0.5 mg/kg/day), followed by gradual tapering, has been recommended for new ABPA infiltrates.192,,193 The duration of therapy should be individualized according to the patient's clinical condition. However, most patients require prolonged low-dose corticosteroid therapy to control their symptoms and decrease the rate of relapse.192,,193 Total serum IgE serves as a marker of ABPA disease activity, and should be checked 6–8 weeks after the initiation of therapy, then every 8 weeks for 1 year after that to determine a baseline range for each individual patient.194 Inhaled corticosteroids may help to control symptoms of asthma, but small studies have failed to demonstrate the efficacy of inhaled corticosteroids in preventing the progression of lung damage in patients with ABPA.195,,196

Several studies have been done on the utility of the antifungal agent itraconazole in the management of patients with ABPA. Itraconazole has been effective in improving symptoms, facilitating weaning from corticosteroids, decreasing Aspergillus titres, and improving radiographic abnormalities and pulmonary function.161 A randomized, double-blind, placebo-control trial of itraconazole 200 mg twice daily for 16 weeks for patients with ABPA already receiving corticosteroids was recently conducted by Steven et al.197 Forty-six percent of patients treated with itraconazole achieved significant response, which was defined as a reduction of at least 50% in the corticosteroid dose, decrease of at least 25% in the serum IgE concentration, and one of the following: a 25% improvement in exercise tolerance or pulmonary function test results, or partial or complete resolution of pulmonary infiltrates. Importantly, however, itraconazole may augment the activity of corticosteroids via inhibition of their metabolism, which may lead to abnormal ACTH stimulation and adrenal insufficiency.198 There are no randomized trials on the efficacy of voriconazole in the management of ABPA, but one study of small number of children with cystic fibrosis and ABPA treated with voriconazole demonstrated significant clinical and serological improvements.199


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