Allergic bronchopulmonary aspergillosis (ABPA): a hypersensitivity reaction caused by exposure to Aspergillus that mostly occurs in patients with cystic fibrosis or asthma
Chronic pulmonary aspergillosis: a long-term Aspergillus infection of the lung which can manifest as:
Aspergilloma: an opportunistic infection of a pre-existing cavitary lesion (e.g. from previous tuberculosis)
Chronic necrotizing pulmonary aspergillosis: a subacute and semi-invasive form of chronic pulmonary aspergillosis characterized by localized, slowly progressive, inflammatory destruction of lung tissue and commonly associated with alcohol use disorder
Invasive aspergillosis: a severe form of Aspergillus infection which manifests with severe pneumonia and septicemia with potential involvement of other organs (e.g., skin, CNS) and mostly occurs in immunocompromised individuals
Allergic Bronchopulmonary Aspergillosis (ABPA)
Patho/Etiology
A Type I and Type III hypersensitivity reaction to Aspergillus antigens colonizing the bronchial mucus.
Almost exclusively seen in patients with pre-existing asthma or cystic fibrosis (CF).
Clinical Presentation
Worsening asthma symptoms (wheezing, dyspnea), cough with brownish mucus plugs, fever, and malaise.
Diagnosis
Skin Test: Positive immediate (Type I) skin test to Aspergillus antigens.
Labs: High total serum IgE (>1,000 IU/mL is classic), eosinophilia, and elevated Aspergillus-specific IgE and IgG antibodies.
Imaging (CXR/CT): Fleeting pulmonary infiltrates and central bronchiectasis (pathognomonic).
Management
Tx: Systemic corticosteroids (e.g., prednisone) to control the inflammatory response. Antifungal therapy (e.g., itraconazole) can be added as a steroid-sparing agent.
Aspergilloma (Fungus Ball)
Patho/Etiology
Aspergillus colonizes a pre-existing lung cavity without invading tissue.
Commonly occurs in cavities from tuberculosis (TB), sarcoidosis, or emphysema.
Clinical Presentation
Often asymptomatic.
The most common symptom is hemoptysis, which can be life-threatening.
Diagnosis
Imaging (CXR/CT):A solid mass within a cavity that is mobile with changes in patient position.
Labs:Aspergillus IgG precipitins are usually present in the blood.
Management
Tx: Asymptomatic lesions are often observed. For symptomatic patients (especially with hemoptysis), surgical resection is the treatment of choice. Antifungals have a limited role as they do not penetrate the fungus ball well.
Invasive Aspergillosis
Patho/Etiology
Occurs in severely immunocompromised patients, classically those with neutropenia (e.g., leukemia, chemotherapy), prolonged corticosteroid use, or post-transplant.
The fungus invades blood vessels, leading to thrombosis, tissue infarction, and hematogenous dissemination.
Clinical Presentation
Fever, pleuritic chest pain, cough, and hemoptysis.
May present with classic triad of fever, pleuritic chest pain, and hemoptysis.
Diagnosis
Imaging (CT): Shows nodules with a “halo sign” (ground-glass opacity surrounding a nodule, an early sign) or an “air-crescent sign” (a late sign representing cavitation).
Labs: Detection of galactomannan antigen or beta-D-glucan in serum or bronchoalveolar lavage (BAL) fluid is highly suggestive.
