Examples include collapsed lungs which have formed bullae, chronic obstructive lung disease, lung cancer, and fibrocavitary sarcoidosis. Another risk factor is immunosuppression; most commonly, this includes allogeneic stem cell transplantation, prolonged neutropaenia, immunosuppressive drug therapy, chronic granulomatous disease and haematological malignancies. Certain demographics are also at higher risk, including the elderly, male gender and those with a low body mass index.There appears to be increasing evidence for complex genetic factors increasing the risk of developing chronic pulmonary aspergillosis, such as defects to toll-like receptor (TLR) 4, IL1 and IL15, TLR3, TLR10, TREM1, VEGFA, DENND1B, and PLAT. Mechanism
The full underlying pathogenesis is not completely understood. Most people with chronic pulmonary aspergillosis have functional immune status, but usually have underlying structural damage to the lungs from an underlying process or disease. Most commonly, pre-existing pulmonary cavities from other diseases such as tuberculosis become colonised with Aspergillus conidia which have been inhaled—humans inhale between 1,000 and 10 billion spores per day, of which A. fumigatus is the most common.Aspergillomas themselves usually form in existing cavities but the cavities may form directly from chronic pulmonary aspergillosis. People with pulmonary tuberculosis with a cavity larger than 2 cm appear to have a 20% increased risk of developing chronic pulmonary aspergillosis.It is postulated that conidia, once inhaled, are attacked by the host immune defences—specifically phagocytes and alveolar macrophage resident in the small airways. It is unknown whether these defences are sufficient to clear conidia or whether they are directly responsible for the inflammation leading to chronic pulmonary aspergillosis.
Furthermore, as with aspergilloma, there must be positive IgG testing but this can be with or without culture. To confirm Aspergillus nodules as opposed to aspergilloma, these must be seen directly on imaging or confirmed by percutaneous or surgical biopsy.The fibrosing form—chronic fibrosing pulmonary aspergillosis—has similar criteria to chronic cavitary pulmonary aspergillosis but will be accompanied by significant fibrosis seen on either biopsy, tomosynthesis, or high resolution computed tomography.If chronic pulmonary aspergillosis has progressed to subacute invasive pulmonary aspergillosis, there must be a degree of immunosuppression. The microbiological criteria are similar to those of invasive aspergillosis but normally slower in progression, i.e. months rather than weeks. Furthermore, there must be evidence of IgG or galactomannan in the blood and a confirmatory biopsy of affected tissue. Treatment
People with single aspergillomas generally do well with surgery to remove the aspergilloma, and are best given pre-and post-operative antifungal medications. Often, no treatment is necessary; however, if a person coughs up blood (haemoptysis), treatment may be required using surgery or injection of dye to locate the bleeding combined with embolisation using chemicals or tiny material meant to block the bleeding blood vessel. Studies of tranexamic acid for treating haemoptysis do not provide strong evidence for long-term benefit.For chronic cavitary pulmonary aspergillosis and chronic fibrosing pulmonary aspergillosis, lifelong use of antifungal medications is commonplace. Itraconazole and voriconazole are first- and second-line antifungal agents respectively.