Tuesday, 7 September 2010

MRCP revision battle 4.3: Aspergillus

Aspergillus is a group of molds/fungi.  Allegedly they got their name from looking like water does when it falls from an aspergillum, which is an instrument for sprinkling holy water (that fact is unlikely to be necessary in MRCP but its nice for the brain to read bits its not obligated to remember every now and then)

Aspergillus can affect the lungs in 6 main different ways:
  1. It can cause asthma
    • a type 1 hypersensitivity reaction
    • prick test +, precipitans/culture +
  2.   It can cause an aspergilloma
    • = a fungal ball inside a pre-existing cavity
    • usually asymptomatic but may cause haemoptysis, lethargy or weight loss
    • treated by ?surgery ?amphotericin paste under bronchoscopy
    • prick test -, precipitans/culture ++
  3.  It can cause allergic bronchopulmonary aspergillosis
    • type 1 and type 3 hypersensitivity
    • CXR may show bronchietasis, lobar collapse or upper lobe fibrosis, or patchy lesions
    • prick test +, precipitans/culture +
    • also IgE levels are raised
  4. It can cause invasive aspergillosis
    • only occurs in immunocompromised individuals
    • prick test +/-, precipitans/culture +/-
  5. It can cause EAA
    • + serum precipitans to aspergillus clavatus
  6. It can simply colonise.

After that slightly heavy-going section, lets go on to think about BAR TAPS...