pulmonary aspergillus infections Flashcards
define
= lung disease associated w/ aspergillus fungal infection
in which 5 ways are the lungs affected
- asthma: T1HS reaction to fungal spores
- ABPA: allergic bronchopulmonary aspergillosis
- Aspergilloma [mycetoma]
- invasive aspergillosis
- EAA- extrinsic allergic alveolitis
ABPA: define
= results from an allergy to Aspergillus spores. I
the exam questions often give a history of bronchiectasis and eosinophilia.
ABPA: features
- bronchoconstriction: wheeze, cough, dyspnoea
- bronchiectasis (proximal)
ABPA: ix
- eosinophilia
- flitting CXR changes
- Chest x-rays are usually abnormal, but are inadequate in the diagnosis or quantification of bronchiectasis.
- increase in bronchovascular markings, and bronchi seen end on may appear as ring shadows
- positive radioallergosorbent (RAST) test to Aspergillus
- positive IgG precipitins (not as positive as in aspergilloma)
- raised IgE
- CT
- classic finger in glove appearance which represents of mucous filling dilated bronchi (i.e. bronchocoeles). Bronchocoeles are a common feature of allergic bronchopulmonary aspergillosis (ABPA)
ABPA: mx
steroids
itraconazole is sometimes introduced as a second line agent
aspergilloma: define
An aspergilloma is a mycetoma (mass-like fungus ball) which often colonises an existing lung cavity (e.g. secondary to tuberculosis, lung cancer or cystic fibrosis)
aspergilloma features
Usually asymptomatic but features may include
- cough
- haemoptysis (may be severe)
aspergilloma: ix
- chest x-ray containing a rounded opacity
- demonstrate a rounded soft tissue attenuating masses located in a surrounding cavity.
- high titres Aspergillus precipitins
aspergilloma: mx
consider excision for solitary lesions/severe hemoptysis
invasive aspergillosis: define
- occurs in presence of immunosuppression
- presents as a suppurative pneumonia which fails to respond to conventional antibiotic therapy.
- This condition has a poor prognosis.
invasive aspergillosis: ix
- chest radiograph, which may show:
- widespread parenchymal infiltration
- abscess formation
- sputum microscopy and culture
- CT or MRI scanning of the chest has a high sensitivity for detecting invasive aspergillosis:
- halo lesions:
- ground-glass appearance around a nodule or area of consolidation
- cavitating lesions
- Test for galactomannan antigenaemia [an aspergillus ag]
* a positive test on consecutive days in combination with CT/MRI evidence is considered diagnostic in the appropriate clinical circumstances (1)
invasive aspergillosis
Treatment is with antifungal drugs
Voriconazole is usually more effective than amphotericin B; serum levels of voriconazole and itraconazole must be monitored and individually adjusted.
Extrinsic allergic alveolitis definition
Extrinsic allergic alveolitis (EAA, also known as hypersensitivity pneumonitis) is a condition caused by hypersensitivity induced lung damage due to a variety of inhaled organic particles.
It is thought to be largely caused by immune-complex mediated tissue damage (type III hypersensitivity) although delayed hypersensitivity (type IV) is also thought to play a role in EAA, especially in the chronic phase.
EAA- examples
Examples
- bird fanciers’ lung: avian proteins
- farmers lung: spores of Saccharopolyspora rectivirgula (formerly Micropolyspora faeni)
- malt workers’ lung: Aspergillus clavatus
- mushroom workers’ lung: thermophilic actinomycetes*
