Pulmonary Aspergillosis Diagnosis and Classification

Clinical Presentation and Diagnostic Criteria

The European Respiratory Society recommends that the diagnosis of pulmonary aspergillosis requires a combination of characteristic imaging findings, microbiological or immunological evidence of Aspergillus infection, and symptoms or radiological progression present for at least 3 months, with exclusion of alternative diagnoses 1, 2
Patients with chronic cavitary pulmonary aspergillosis (CCPA) typically present with pulmonary symptoms such as chronic cough, dyspnea, hemoptysis, and weight loss occurring over at least 3 months, and may have underlying lung disease such as prior tuberculosis, COPD, bronchiectasis, or sarcoidosis 1, 3, 4
The American Thoracic Society suggests that systemic symptoms such as fatigue, malaise, and fever may be present in patients with CCPA 1
Simple aspergilloma is characterized by minimal or no symptoms, a single fungal ball in a single pulmonary cavity, and no progression over at least 3 months 1, 3
Subacute invasive aspergillosis (SAIA) is characterized by rapid progression of symptoms over 1-3 months, and may occur in mildly immunocompromised patients with conditions such as diabetes mellitus, malnutrition, or chronic lung disease 1, 5, 6

The European Respiratory Society recommends that CT scan findings, including cavitary lesions, fungal balls, and nodules, are essential for the diagnosis of pulmonary aspergillosis 1, 3
Aspergillus IgG antibody testing is a primary diagnostic test, with a positive result in >90% of CPA cases, and is sufficient for diagnosis when a fungal ball is visible on imaging 2, 6, 9
Respiratory sample analysis, including sputum or bronchoscopic culture, may reveal Aspergillus fumigatus in 56-81% of cases, and microscopy may reveal fungal hyphae 7
PCR assay may be positive for Aspergillus DNA, but is insufficient alone for diagnosis 2, 7

The European Respiratory Society suggests that mycobacterial infection, including pulmonary tuberculosis or non-tuberculous mycobacterial infection, may precede, follow, or occur simultaneously with CPA, and requires exclusion through sputum smear, mycobacterial nucleic acid amplification, and culture 2, 7
Other fungal infections, such as chronic cavitary histoplasmosis, paracoccidioidomycosis, and coccidioidomycosis, may present similarly and require specific antibody/antigen detection and respiratory cultures for diagnosis 2, 7
Non-infectious causes, such as necrotizing lung cancer, pulmonary infarction, vasculitides, and rheumatoid nodules, may also present with similar symptoms and require exclusion through imaging and biopsy 2, 7, 8
The diagnostic algorithm involves identifying characteristic imaging findings, confirming Aspergillus involvement through microbiological testing, excluding alternative diagnoses, and classifying the disease type as simple aspergilloma, CCPA, or SAIA 1, 3, 5, 6