Aspergillus lung disease
D E FI N I T ION
Lung disease associated with Aspergillus fungal infection.
AE T IOLOGY
Inhalation of the ubiquitous Aspergillus (usually Aspergillus fumigates) spores
can produce three different clinical pictures:
1. Aspergilloma: Growth of an A. fumigatus mycetoma ball in a preexisting lung cavity (e.g.
post-TB, old infarct or abscess).
2. Allergic bronchopulmonary aspergillosis (ABPA): Aspergillus colonization of the
airways (usually in asthmatics) leads to IgE- and IgG-mediated immune responses.
Proteolytic enzymes and mycotoxins released by fungi, CD4/Th2 cells producing IL-4 and
IL-5 and mediating eosinophilic inflammation, and IL-8 mediated neutrophilic inflammation
result in airway damage and central bronchiectasis.
Invasive aspergillosis: Invasion of Aspergillus into lung tissue and fungal dissemination.
Secondary to immunosuppression (e.g. neutropaenia, steroids, haematopoietic stem cell/
solid organ transplantation, AIDS).
E P IDEMIOLOGY
Uncommon. Most common in elderly and immunocompromised.
H ISTORY
Aspergilloma: Asymptomatic, haemoptysis, which may be massive.
ABPA: Difficult to control asthma, recurrent episodes of pneumonia with wheeze, cough,
fever and malaise.
Invasive aspergillosis: Dyspnoea, rapid deterioration, septic picture.
EXAMINA T I ON
Tracheal deviation in large aspergillomas.
Dullness in affected lung, # breath sounds, wheeze (in ABPA).
Cyanosis may develop in invasive aspergillosis.
INVE S T I G A T IONS
Aspergilloma: CXR: Round opacity may be seen with a crescent of air around it (usually in the
upper lobes).
CT or MR imaging if CXR does not clearly delineate a cavity.
Cultures of the sputum may be negative if there is no communication between the cavity and
the bronchial tree. Also Aspergillus is a common colonizer of an abnormal respiratory
tract.
ABPA:
Immediate skin test reactivity to Aspergillus antigens.
Eosinophilia.
" Serum total IgE.
" Serum specific IgE and IgG to A. fumigatus or precipitating serum antibodies to A.
fumigates.
CXR: Transient patchy shadows, collapse, distended mucus-filled bronchi producing tubular
shadows (‘gloved fingers’ appearance). Signs of complications: Fibrosis in upper lobes
(similar to tuberculosis), parallel-line shadows and rings (bronchiectasis).
CT: Lung infiltrates, central bronchiectasis.
Lung function tests: Reversible airflow limitation, # lung volumes/gas transfer in progressive
cases.
Invasive aspergillosis: Detection of Aspergillus in cultures or by histologic examination
(septated hyphae with acute angle branching). Diagnosis may be made in patients with
risk factors, suggestive clinical findings and microscopic evidence of septate hyphae on
examination of either bronchoalveolar lavage fluid or sputum or a positive serum
galactomannan or beta-D-glucan assay (constituents of Aspergillus cell walls).
Chest CT scan may show nodules surrounded by a ground-glass appearance (halo sign) in
invasive pulmonary aspergillosis (haemorrhage into the tissue surrounding the area of
.fungal invasion)
Aspergillus lung disease (continued)
MANAGEMENT
Aspergilloma: Surgical resection for large aspergillomas if uncontrolled or symptomatic
(recurrent haemoptysis). Adjunctive itraconazole or voriconazole, if there is concern for
residual disease following surgery, or tissue invasion beyond the confines of the cavity.
ABPA: Combination of steroids and itraconazole. Monitor LFTs. The usual duration of therapy
is 3–6 months. Inhaled steroids and broncholdilators may help control symptoms of
asthma. The response is monitored with serial measurement of the serum total IgE level.
Invasive aspergillosis: # Immunosuppression if possible. Voriconazole (initially IV, when
stabilized orally). Monitor serum voriconazole trough concentrations. If intolerant of
voriconazole, use liposomal amphotericin B. Add caspofungin in patients who do not
respond. Continue antifungal therapy until all signs, symptoms and radiographic evidence
of the infection have resolved for at least 2 weeks. Debridement is essential in the
treatment of Aspergillus sinusitis.
COMPL I C A T IONS
Aspergilloma: Secondary bacterial infection, massive haemoptysis or haemorrhage.
ABPA: Worsening of asthma, bronchiectasis, lobar collapse, lung fibrosis or respiratory
failure.
Invasive aspergillosis: Septic shock, respiratory failure.
P ROGNOS I S
Grave prognosis for invasive aspergillosis. Good prognosis for ABPA and
aspergillomas but bronchospasm and haemoptysis can still lead to death.
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