Aspergillus Lung Disease

And another respiratory condition- Aspergillus Lung Disease- because it can’t always be about bacteria and viruses.

Just remembered a lecture we had on fungi when I was in first year. It was a really long lecture, which had me shuddering every few seconds because the lecturer kept saying fungi, pronounced fun-ji, rather than fun-guy. You can’t pronounce it fun-ji because then my favourite primary school joke makes no sense! Why was the mushroom invited to all the parties? (Answer at the bottom, if you really can’t figure it out). It was just super weird.


Aspergillus Lung Disease

Definition: Aspergillus is a genus of fungi that can affect the lung in 5 different ways: asthma, Allergic Bronchopulmonary Aspergillosis (ABPA), Aspergilloma (mycetoma), Invasive aspergillosis and Extrinsic Allergic Alveolitis.

Aetiology/ risk factors:

Inhalation of Apergillus spores can produce different clinical pictures:

Asthma: type I hypersensitivity (atopic) reaction to fungal spores leading to asthma. See post for condition details.

ABPA: results from type I and III hypersensitivity reactions to Aspergillus fumigatus.

Aspergillus colonisation of the airways (usually in asthmatics) leads to IgE and IgG-mediated immune responses. Involves Th2 cells, eosinophilic and neutrophilic inflammation. Results in airway damage and central bronchiectasis.

Aspergilloma: growth of a A.fumigatus myecetoma fungus ball within a pre-existing cavity (often caused by TB, sarcoidosis, old infarct or abscess)

Invasive aspergillosis: invasion of Aspergillus into lung tissue and fungal dissemination. Secondary to immunosuppression e.g. HIV, leukaemia, burns, Wegener’s, SLE, or after broad-spectrum antibiotic therapy.

Extrinsic allergic alveolitis: may be caused by sensitivity to Aspergillus clavitus (malt worker’s lung). See post for condition details.

Epidemiology: uncommon. Most common in elderly and immunocompromised.

-ABPA affects 1-5% of asthmatics and 2-25% of cystic fibrosis patients

Symptoms:

ABPA:

-wheeze (difficult to control asthma), cough, sputum (plugs of mucus containing fungal hyphae), dyspnoea

-recurrent episodes of pneumonia with wheeze, cough, fever and malaise

Early on, the allergic response causes bronchoconstriction but as the inflammation persists, permanent damage occurs, causing bronchiectasis.

Aspergilloma:

-usually asymptomatic

-may cause cough, haemoptysis (may be torrential), lethargy +/- weight loss

Invasive aspergillosis:

-dyspnoea

-rapid deterioration

-septic picture

Signs:

ABPA:

-dullness in affected lung

-reduced breath sounds

wheeze

Aspergilloma:

-dullness in affected lung

-reduced breath sounds

tracheal deviation in large aspergillomas

Invasive aspergillosis:

-dullness in affected lung

-reduced breath sounds

cyanosis may develop

Investigations:

ABPA:

Chest x-ray: transient segmental collapse or consolidation, bronchiectasis

Transient patchy shadows, distended mucus-filled bronchi producing tubular shadows (gloved fingers appearance).

Signs of complications: fibrosis in upper lobes, parallel-line shadows and rings  (bronchiectasis)

 

Image result for abpa chest x ray gloved finger

CXR shows mucoid impaction with the classic finger-in-glove pattern (arrow) (If you say so…)

 

CT: lung infiltrates, central bronchiectasis

/best-practice/images/bp/en-gb/836-4_default.jpg

CXR and CT in a patient with ABPA: glove-finger shadow due to mucoid impaction in central bronchiectasis in a patient with asthma

Sputum culture: contains aspergillus

Aspergillus skin test: positive (immediate skin test reactivity to Aspergillus antigens)

-Aspergillus-specific IgE RAST (radioallergosorbent test): positive

Positive serum precipitins

FBC: eosinophilia

-Raised serum IgE

Aspergilloma:

Chest x-ray: round opacity within a cavity (with a crescent or air around it), usually apical

Image result for aspergilloma cxr

Image result for aspergilloma cxr

-CT or MRI- if CXR does not clearly delineate a cavity

Sputum culture: contains aspergillus or may be negative if there is no communication between the cavity and the bronchial tree

Aspergillus skin test: positive in 30%

-Strongly positive serum precipitins

Invasive aspergillosis:

Sputum culture: detection of Aspergillus (septated hyphae with acute angle branching)

Bronchoalveolar lavage– detection of Aspergillus

Biopsy– detection of Aspergillus in by histological examination

-Positive serum precipitins

Chest x-ray: consolidation, abscess

Chest CT: may show nodules surrounded by a ground-glass appearance (halo sign =haemorrhage into the tissue surrounding the area of fungal invasion)

 

Image result for invasive aspergillosis x ray halo sign

-Early chest CT and serial measurements of galactomannan (an Aspergillus antigen) may be helpful

Management:

ABPA:

Prednisolone 30-40mg/24h PO for acute attacks, maintenance dose 5-10mg/d

-Sometimes itraconazole (anti-fungal) is used in combination with corticosteroids

Usual duration of therapy = 3-6M

-Inhaled steroids and bronchodilators may help control symptoms of asthma.

-Sometimes bronchoscopic aspiration of mucous plugs is needed

-Response measured with serial measurements of serum total IgE

Aspergilloma:

-only if symptomatic- consider surgical excision for solitary symptomatic lesions or severe haemoptysis

-Oral itraconazole and other antifungals have been tried with limited success (may be used if concern for residual disease following surgery)

-Local instillation of amphotericin (anti-fungal) paste under CT guidance yields partial success in carefully selected patients e.g. in massive haemoptysis

Invasive aspergillosis:

-decrease immunosuppression if possible

-voriconazole (initially IV, oral when stabilised) is superior to IV amphotericin.

-Alternatives: IV miconazole or ketoconazole (less effective)

Complications:

-ABPA: worsening of asthma, lobar collapse, bronchiectasis, lung fibrosis, respiratory failure

-Aspergilloma: massive haemoptysis or haemorrhage, secondary bacterial infection

-Invasive aspergillosis: septic shock, respiratory failure

Prognosis:

-Grave prognosis for invasive aspergillosis- 30% mortality

-Good prognosis for ABPA and aspergillomas but bronchospasm and haemoptysis can still lead to death .

References: Cheese & Onion, Rapid Medicine

(Because he was a fun guy!)

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2 thoughts on “Aspergillus Lung Disease

  1. jedidahmoses says:

    Fun-ji *smiles*
    I have a first degree in Biochemistry, I hope to get into medical school soon. You are doing a great job. Success in your medical journey.

    Like

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