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108 Chapter 3: Respiratory system

on the degree of tissue invasiveness, the dose inhaled and Aspergilloma
the level of the host’s defence. This results from Aspergillus growing within an area of
previously damaged lung such as an old tuberculous
Allergic bronchopulmonary aspergillosis cavity (sometimes called a mycetoma). These are usu-
(ABPA) ally asymptomatic but occasionally may cause massive
haemoptysisandrequireresection.Antifungaltreatment
Pathophysiology
is rarely effective.
This results from Types I and III hypersensitivity reac-
tions to persistent airway infection with the organism in
Investigation
susceptible (atopic) individuals. Seen on X-ray as a round lesion with an air ‘halo’ above
i Initially it causes bronchospasm which commonly it. The fungal mycelium may be seen in sputum and the
presents as asthma. chronic antigenic stimulation gives rise to serum precip-
ii Recurrent episodes of eosinophilic pneumonia occur
itating antibody.
due to obstruction of the lumen, with the expecto-
ration of firm sputum plugs containing the fungal
Invasive aspergillosis
mycelium.
In immunosuppressed individuals with a low granulo-
iii Chronic infection and inflammation leads to irre-
cyte count, the organism may proliferate causing a severe
versible dilatation of the bronchi (classically proximal
pneumonia, causing necrosis and infarction of the lung.
bronchiectasis).
The organisms are present as masses of hyphae invad-
iv If left untreated progressive pulmonary fibrosis may ing lung tissue and often involving vessel walls. Invasive
develop, usually in the upper zones. aspergillosis presents as a pneumonia or septicaemia in
the immunocompromised. Systemic invasive aspergillo-
Clinical features sismaymanifestasmeningitis,cerebralabscessorlesions
ABPA presents as worsening of asthma symptoms with in bone or liver.
episodic wheeze and cough productive of mucus plugs.
Theremaybeintermittentfeverandmalaise.Alargemu- Investigation
cus plug may obstruct a bronchus causing lung collapse. Invasive aspergillosis can only by diagnosed by lung
biopsy.
Investigation
Theperipheralbloodeosinophilcountisraised,andspu- Management
tum may show eosinophilia and mycelia. Eosinophilic Invasive aspergillosis is treated with intravenous am-
pneumonia causes transient lung shadows on chest X- photericin B (often requiring liposomal preparations
ray. Precipitating antibodies are present in serum. Hy- due to renal toxicity), often combined with flucytosine.
persensitivity is usually confirmed by skin-prick testing. Itraconazole and voriconazole have been used more re-
Lung function testing confirms reversible obstruction in cently but current studies comparing efficacy with am-
all cases, and may show reduced lung volumes in cases photericin B have yet to prove definitive.
where there is chronic fibrosis.

Management Obstructive lung disorders
Generally it is not possible to eradicate the fungus. Itra-
conazole has been shown to modify the immunologic Asthma
activation and improves clinical outcome, at least over
the period of 16 weeks. Oral corticosteroids are used to Definition
suppress inflammation until clinically and radiograph- A disease with airways obstruction (which is reversible
ically returned to normal. Maintenance steroid therapy spontaneously or with treatment), airway inflammation
may be required subsequently. The asthmatic compo- and increased airway responsiveness to a number of
nent is treated as per asthma guidelines. stimuli.