Lung Infection, Aspergillosis

• • Infection via inhalation of conidia into areas of lung with impaired mucociliary function (ie, tuberculous cavities)

  • 3 types of aspergillosis infections:

  • 1. Allergic bronchopulmonary aspergillosis

    2. Invasive aspergillosis

    3. Aspergilloma (fungus balls)

Allergic Bronchopulmonary Aspergillosis

• • Occurs in patients with asthma or cystic fibrosis

  • Fungal growth leads to dilated airways filled with mucus and fungus

  • 5 stages of infection:

  • 1. Acute infection

    2. Corticosteroid-induced remission

    3. Asymptomatic worsening of laboratory and x-rays

    4. Onset of corticosteroid-dependent asthma

    5. End-stage fibrosis

Invasive Aspergillosis

• • Found only in immunocompromised patients

  • Patients with leukemia: 50-70% of cases

  • Dissemination frequent

  • 3 types of pulmonary disease described

  • 1. Tracheobronchitis: Larger airways with mucosal ulceration, fungal plugs

    2. Necrotizing bronchopneumonia

    3. Hemorrhagic infarction: Occlusion of arteries with necrosis

Aspergilloma (Fungus Balls)

• • Divided into 2 types:

  • 1. Simple, thin-walled cysts with ciliated epithelium surround by normal lung

    2. Complex cavities with abnormal surrounding lung tissue

  • Most often in upper lobes, multiple (22%), calcification and air-fluid levels rare

  • Associated with cavitary lung disease (TB, histoplasmosis, sarcoidosis, bronchiectasis, etc)

Epidemiology

• • Pulmonary fungal infections are rising due to widespread use of broad-spectrum antibiotics, immunosuppressive drugs, and HIV infection

  • Occur anywhere in world, some with characteristic endemic areas

Aspergillosis

• • Aspergillus fumigatus (most common), Aspergillus niger, Aspergillus flavus, Aspergillus glaucus

  • Second most common opportunistic fungal infection after candidiasis

  • Third most common fungal infection requiring hospital care

Symptoms and Signs

Allergic Bronchopulmonary Aspergillosis

• • Cough, fever, wheezing, dyspnea, pleuritic pain, hemoptysis

Invasive Aspergillosis

• • Cough, dyspnea, wheezing, aspergilloma

  • Hemoptysis (50-80%), can be multiple recurrent episodes

Imaging Findings

Allergic Bronchopulmonary Aspergillosis

• • Chest film: Homogenous densities in "gloved finger," inverted "Y," or "cluster of grapes" pattern

Invasive Aspergillosis

• • Chest film: Patchy areas of atelectasis secondary to bronchial obstruction, cavitation common, "air crescents" of mycotic lung

Aspergilloma

• • Chest film: 3-6 cm round, mobile density with crescent of air

• • Definitive diagnosis: Demonstration of hyphal tissue invasion or documentation of hyphae on silver stain in suspected aspergilloma

  • Diagnosis suggested: Culturing uniform septate hyphae with dichotomous branching at 45 degrees, detection of specific IgG or IgE antibodies

• • Chest x-ray

  • Chest CT scan

  • Sputum culture

Allergic Bronchopulmonary Aspergillosis

• • Medical therapy (corticosteroids)

Invasive Aspergillosis

• • Amphotericin B (mortality still 90%)

Aspergillomas

• • Surgery indicated for complications of aspergillous infections

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