Chest
ReviewFungal Pneumonia (Part 4): Invasive Pulmonary Aspergillosis
Section snippets
MYCOLOGY-EPIDEMIOLOGY
Aspergillus is a ubiquitous soil saprophyte, frequently isolated on settle plates on hospital wards where unfiltered outside air circulates through open windows.3 There is a significant decline in both settle plate Aspergillus counts and cases of nosocomial aspergillosis when mechanical ventilation air filtration systems are introduced in-hospital.4 This suggests that aspergillosis is acquired via airborne spore inhalation. In man aspergillosis most often is due to A fumigatus, A flavus, and A
PATHOGENESIS OF IPA
There have only been 15 documented cases of IPA in normal hosts.5, 6, 7 The vast majority of IPA cases occur in patients with hematologic malignancies,8, 9 especially during induction or maintenance chemotherapy for acute, nonlymphocytic leukemia. In addition, recipients of renal and cardiac transplants10, 11 are at increased risk for IPA, particularly during episodes of organ rejection, when immunosuppressive therapies are generally intensified. Occasionally, IPA has complicated such diseases
HISTOPATHOLOGY
The histopathology of human IPA has been elegantly delineated by Orr et al.13 On gross macroscopy, the typical early lesions are 1 to 3-cm nodules or target lesions composed of a central yellow-gray zone of tissue necrosis and a surrounding rim of hemorrhage, with a thrombosed artery at the edge of the lesion (Fig 2). These lesions arise via endobronchial hyphal proliferation followed by transbronchial invasion of subjacent pulmonary arterioles, with ischemic necrosis of small areas of the
EXTRAPULMONARY INVOLVEMENT IN IPA
In about 10 to 25 percent of patients with IPA, extrapulmonary dissemination is found at autopsy.8, 9 The organs most frequently involved are the gastrointestinal tract, brain, heart, liver, spleen, kidney, and thyroid.
CLINICAL FEATURES OF IPA
Physical findings in IPA are nonspecific, consisting generally of fever and pulmonary rales or rhonchi. Although extrapulmonary aspergillus dissemination occurs in only about 25 percent of patients with IPA, extrapulmonary Aspergillus dissemination may present dramatic clinical syndromes and should be carefully examined for clues to underlying IPA. Mucosal ulceration secondary to hyphal invasion may occur anywhere in the alimentary tract and present as major gastrointestinal hemorrhage.8 In the
DEFINITIVE DIAGNOSIS
Aspergillus has been recovered from sputum in <10 percent of patients with proved IPA, even when specifically sought in perspective studies of deep mycoses in leukemic patients.8, 9, 19 As noted previously, isolation of Aspergillus from surveillance nasal cultures of immunocompromised patients is significantly correlated with concurrent or subsequent IPA; negative nasal cultures, however, do not preclude the diagnosis of IPA.
To make the definitive diagnosis of IPA, parenchymal invasion of lung
SEROLOGIC STUDIES IN ASPERGILLOSIS
Since IPA (as well as disseminated aspergillosis) is a difficult diagnosis to establish without tissue biopsy, and empiric antifungal chemotherapy may be unwarranted because of potentially severe drug toxicities, much investigation into antibody sero-diagnosis of aspergillosis has been performed. The standard Aspergillus precipitin assay (by gel immunodiffusion), often positive in high titers in allergic bronchopulmonary aspergillosis and pulmonary aspergillomas, in IPA is generally
THERAPY FOR IPA
Parenteral antifungal therapy is the cornerstone of treatment of IPA. Unfortunately, there is a wide strain-to-strain variability in terms of in vitro sensitivity to amphotericin B; also, there is to date27 no standard accepted method for sensitivity testing of this fungus. In general, it appears that most A fumigatus strains have minimal fungistatic concentrations (MFCs) to amphotericin B within readily achievable serum levels of the drug (0.5 to 1.5 µg/ml); however, A flavus strains tend to
PROGNOSIS OF IPA
As in most deep mycoses in immunocompromised hosts, the outcome of IPA is directly correlated with early diagnosis and therapy, induction of remission of the underlying disease, and with reversal of chemotherapy-induced marrow suppression. Of note, the prognosis of IPA in patients with renal and cardiac transplantation appears more favorable than in patients with underlying leukemia. This may relate to the ability to adjust steroid-cytotoxic drug regimens more freely in organ transplantation
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Cited by (74)
Current Updates on Pediatric Pulmonary Infections
2017, Seminars in RoentgenologyCitation Excerpt :Children with IPA are critically ill with high fever, cough, dyspnea, and sometimes hemoptysis. Despite aggressive treatment, mortality from IPA remains high, exceeding 50% in most series.26-28 CT is the most sensitive imaging modality for the detection of IPA, and improved survival rates have been documented when CT leads to early detection and prompt antifungal therapy.29
Pneumopericardium due to invasive pulmonary aspergillosis
2007, Journal of Infection and ChemotherapyInvasive pulmonary aspergillosis in an insulin-dependent diabetic
1998, Respiratory MedicineSteroid treatment: A risk factor for invasive pulmonary aspergillosis
1998, Archivos de BronconeumologiaTracheoesophageal fistula and sinusitis from invasive aspergillosis
1997, Otolaryngology - Head and Neck SurgeryA case report of pulmonary thromboembolism following allergic bronchopulmonary aspergillosis
2020, Medicine (United States)
Parts 1-3 of this series have appeared in the May, June and July, 1981 issues of Chest.