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-
Radiology: intra-cavitary mass that changes position
with change in posture
-
Can expand over time – can expand into blood vessels and
cause major hemorrhage
There are antifungal treatments for Aspergillosis but
they can cause renal disease/renal compromise.
Therefore, they can not be administered by people who
already have renal compromise.
Blastomyces Dermatiditis
-
Granulomatous disease due to dimorphic soil fungus.
-
Central and Southeast USA
-
Primary infection usually subclinical
-
Inhalation primary route of infection
à
lungs and skin affected
-
Pulmonary: mild fever, cough, malaise
-
Cutaneous: macules on hands and face
-
Will cause a granulomatous reaction in the lung
à
will cause a necrotizing granuloma just like M. Tb so
remember this in your differential.
-
Generally localized but can disseminate to the genitals,
CNS, bone, and adrenal glands
-
Radiographic presentation: solitary pulmonary mass
- Dx:
Culture
Three granulomas due to Blastomyces.
Similar to what is seen in TB
à
culture is very important.
Blastomyces is a budding yeast.
The only way to identify it as a yeast is to notice the
presence of mother and daughter cells. Also notice that
what we see here are broad based buds.
Coccidiodes Immitis
-
Soil Fungus endemic in southwest USA (Las Vegas,
Phoenix, etc)
-
Route of infection: Inhalation
-
Epidemics follow excavation/earth moving (earthquakes)
-
Soil contains arthrospores which mature inside the lung
to spherules containing endospores
-
Highly infectious: illness usually asymptomatic (don’t
even want to send it to the lab because you then risk
getting the people who work there getting sick)
-
Two clinical Syndromes:
-
Benign Coccidiomycosis
-
Disseminated coccidiomycosis
Coccidiodes is most prevalent in the San Joaquin Valley
areas of the US and Mexico. This is why it is also
called Valley fever out West.
Coccidiodes immitis is a gaint spherule with little
fungal organisms inside
à
aka endospores. The spherules break open and the
endospores destroy the lung parenchyma. Once spherules
empty out, you just get the empty shells…fascinating…
When you put them into culture, the organisms will no
longer appear round – they will be arthrospores. These
are highly contagious.
Cryptococcus Neoformans
-
Soil fungus endemic in pigeon excreta (this is why park
service people often get this)
-
Encapsulated budding yeast
-
Demonstrated with India ink preparation
-
Radiographic presentation
-
Localized pulmonary nodule
-
Clinical Presentation
-
Often asymptomatic
*
Immunocompromized and non-immunocompromized hosts can be
affected
-
Headache and fever following pulmonary infection (3
months – if infection is not walled off)
-
Cutaneous, osseous, cardiac, GU, ophthalmologic, CNS
involvement
-
Diagnosis
-
Culture, serodiagnostics, direct smear
-
Prognosis
-
Localized vs. disseminated disease
-
Normal host vs. immunocompromised host
-
Therapy
-
Cryptococcus is another one of those diseases that must
be reported to the state.
Cryptococcus neoformans CSF – Indian ink prep.
Because the capsule is so thick, you get a negative
image of the yeast (in other words, the lack of staining
indicates yeast).
Cryptococcus in the lung.
Because of the mucopolysaccharide capsule, the
granulomas appear very glisteny, mucoidy, and slimy.
Once again, remember that Cryptococcus forms a
necrotizing granuloma (like M. Tb, Blastomyces, and H.
capsulatum – which is coming up next).
Histoplasma Capsulatum
-
Common granulomatous infection of world wide
distribution caused by budding yeast organism: H.
capsulatum
-
Primary Histoplasmosis
-
Benign type-95% asymptomatic
-
Radiographic: multiple calcified nodules/nodes
-
Chronic/reinfection histoplasmosis
-
Early chronic disease
-
Upper lobe consolidation
-
Fever, chest pain, weight loss
-
Chronic cavitary disease
-
Mimics TB
-
Disseminated histoplasmosis
-
Normal (uncommon) and immunocompromised hosts (common)
*
Just like with TB, usually patients are able to wall off
the infection early on and they are only left with a
calcified nodule/an area of fibrosis in the lung.
Granuloma caused by H. capsulatum in the subpleural area
of the lung. Could also be TB histologically.
The
organisms are extremely tiny budding yeasts inside
macrophages. Extremely hard to find.
Pneumocystis carinii
-
It
is an opportunistic pathogen, which now is
considered a fungus.
-
Natural habitat is the lung
-
On
chest x-ray it presents as an Interstitial lung
disease
o
We
now have 2 possible causes of interstitial disease :
viral and PCP
o
so
need to have a definitive diagnosis
-
Diagnosis is made by
o
Bronchoavlevolar lavage
o
Lung
biopsy
o
CAN’T be cultured and HIV patients tend to have dry
coughs and dyspnea so obtaining a sputum culture would
be difficult
-
If
it is not treated there is a rapid
pulmonary compromise
-
Treatment is normally Trimethoprim-sulfamethoxazole
or aerosolized pentamidine
-
on
silver stain see can approximately 7 micron organisms
that are about the size of RBC
-
they
are C shaped organisms
-
they
are hard to see after 1 day of treatment
-
P.
carinii can also be present with other viral infections
at the same time like CMV underlying the pneumonia
Lung
infiltrates can be divided into 2 categories, diffuse
and focal.
Diffuse infiltrate
Focal infiltrates
PCP
Staph aureus
CMV/
Viral pneumonitis
Aspergillus
Drug
reactions
Candida
Tumor
Cryptococcus
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