The term "aspergillosis" refers to illness due to allergy, airway or lung invasion, cutaneous infection, or extrapulmonary dissemination caused by species of Aspergillus, which is ubiquitous in nature, and commonly transmitted via inhalation of fungal conidia.
These conidia then face the innate defenses of alveolar phagocytes and the activation of cellular immunity, which are important in the healthy host for preventing fungal invasion in the surrounding tissue, and determining the extent and nature of the immune response.
There are four common syndromes by which aspergillosis manifests:
1) Aspergilloma (fungal ball)
2) Allergic Bronchopulmonary Aspergillosis (hypersensitivity reaction of the airways that occurs when bronchi become colonized by Aspergillus species commonly seen in patients with a history of asthma)
3) Chronic Pulmonary Aspergillosis
4) Invasive Aspergillosis
To elaborate on the fourth, and most worrisome manifestation of asperillosis:
- Characterized by progression of the infection across tissue planes, eventually leading to vascular invasion with subsequent infarction and tissue necrosis.
- Classic risk factors include neutropenia, exogenous glucocorticoids, and impaired cellular immune function (e.g. AIDS, immunosuppresive medications).
- Signs and symptoms include fever, chest pain, shortness of breath, cough, and/or hemoptysis.
- Remember, neutropenic patients frequently present with fever in the absence of localizing pulmonary symptoms.
- Pulmonary aspergillosis typically manifests as single or multiple nodules with or without cavitation, patchy or segmental consolidation, or peribronchial infiltrates, with or without tree-in-bud patterns.
- In the presence of angioinvasive disease, Aspergillus species can hematogenously spread to the skin, brain, eyes, liver, and kidneys. This obviously portends a poor prognosis.
- To diagnosis invasive aspergillosis, consider initially sending serum biomarkers, such as galactomannan, and obtaining sputum for fungal staining and culture.
- If the diagnosis is not made, more invasive options include bronchoscopy, image-guided needle biopsy, or video-assisted thorascopic surgery.
- The recommended intial therapy is voriconazole, or lipophilic amphotericin B if there is a contraindication to voriconazole.
