Invasive Pulmonary Aspergillosis in Critically Ill Patients

Invasive pulmonary aspergillosis (IPA) is identified in critically ill patients without the typical host factors of immunocompromised patients, such as in COVID-19 patients (incidence 4–33%) and in cases with influenza (incidence 6.9–28.1%). Aspergillus spp. is isolated in lower respiratory samples of 0.7–7% of critically ill patients, with half of these cases representing invasive disease. Chronic obstructive pulmonary disease, influenza, COVID-19 pneumonia, corticosteroids and other immunosuppressant, liver cirrhosis, non-hematological malignancy, diabetes, chronic alcohol abuse, HIV, malnutrition, and severe burn injury increase the risk of IPA in critically ill patients. The reported mortality in ICU patients with IPA approaches 80%, whereas attributable mortality is estimated at approximately 18.9%. Aspergillus conidia are inhaled and normally removed by alveolar macrophages at the respiratory epithelium but if they escape the host’s innate immune defense and transform into hyphae, they may develop invasive disease. Clinical presentation of IPA in the ICU patient is nonspecific and radiological findings are nonspecific (commonly include unilateral or bilateral consolidations and atypical infiltrates). The diagnosis of IPA involves noninvasive (serum biomarkers: galactomannan, beta-d-glucan assays, polymerase chain reaction testing, and sputum for fungal staining and culture) and invasive modalities (bronchoscopy with bronchoalveolar lavage, transbronchial biopsy, computed tomography-guided transthoracic needle biopsy, and video-assisted thoracoscopic surgery). Optimal management entails the timely identification and prompt initiation of antifungal therapy (mainly with isavuconazole or voriconazole), surgery, and reduction in immunosuppression. Posaconazole or liposomal formulations of amphotericin B are preferred alternatives. Antifungal resistance should be taken into account. The duration of antifungal therapy varies.