Sketchy Micro Flashcards
Associate bird or bat droppings with what fungus?
Histoplasma
also spelunking
Where is histoplasma endemic to?
Midwestern US
How is histoplasma transmitted?
Spores, airborne
How big is histoplasma as compared with RBCs?
Smaller
Many histo spores (ovoid bodies) can be found within macrophages
What kind of fungus is histoplasma?
Dimorphic
Mold in the cold, yeast in the heat
What is the treatment for histoplasma?
Itraconazole
The calcified granulomas of histoplasma resemble what infection
TB
Where is blastomycosis endemic to?
Great lakes, Ohio River Valley, Southern US
Is blastomycosis dimorphic?
Yes
Mold in the cold, yeast in the heat
How is blastomycosis transmitted?
Inhalation of spores
How big is blastomycosis w/r/t RBCs?
Almost the same size as RBCs
How would a CXR look of a person with a blastomycosis infection?
Hazy, with patchy alveolar infiltrate
Disseminated infection with blastomycosis, as with an immunocompromised patient, presents with
Skin and bone issues such as osteomyelitis
T/F: Infection with blastomycosis can be either acute or chronic.
True
How is blastomycosis diagnosed?
KOH wet mount;
Culture;
Urine antigen test
How is blastomycosis treated?
azoles for local infection, ie itraconazole
amphotericin B for disseminated infection
How does blastomycosis appear under the microscope?
Broad based budding (looks like balls)
Where is coccidiodes endemic to?
Southwestern US
How is coccidiodes transmitted?
Inhalation
Earthquakes are a risk factor bc of dust.
What kind of organism is coccidiodes?
Dimorph
Mold in the cold
Spherules of endospores in the heat
How big is coccidiodes w/r/t RBCs?
Bigger than RBCs
What is the presentation of coccidiodes infection in a healthy person?
Asymptomatic subclinical - pneumonia-like with coughing and arthralgia
What does the CXR of a patient with coccidiodes infection look like?
CXR can show cavities or nodules
Seeing erythema nodosum on a patient with coccidiodes indicates what clinical scenario?
It indicates that the patient is having a robust immune response
Infection of coccidiodes in an immunocomprimised patient would show what?
Skin and bone involvement, as well as meningitis
How is coccidiodes diagnosed?
KOH
Culture
Serology for IgM
What is the treatment for coccidiodes?
Local lung infection, can use azole drugs;
Systemic infection, use amphotericin B
What is the regional distribution of paracoccidiodes?
South America
How does paracoccidiodes appear?
Captain’s wheel - multiple buds from one single center
What fungal form does paracoccidiodes assume in the lung?
Yeast in the lung;
Mold in the environment
What size is paracoccidiodes w/r/t RBCs?
Paracoccidiodes is larger than RBCs
What is the mode of transmission for paracoccidiodes?
Respiratory droplets
What are the symptoms of infection with paracoccidiodes?
Coughing
Cervical lymphadenopathy
Granulomas in lungs
Mucocutaneous lesions
How is infection with paracoccidiodes treated?
Itraconazole for mild infection;
Amphotericin B for severe infection
What is a unique feature of cryptococcus neoformans?
cryptococcus neoformans is heavily encapsulated
**Has a repeating polysaccharide capsular antigen which lends itself to being tested with the latex agglutination test
Where is cryptococcus neoformans found?
Soil
Pidgeon droppings
Can stay infectious for a LONG time
What is the mode of transmission of cryptococcus neoformans?
Inhalation
Primary focus of infection is the lungs
Is cryptococcus neoformans urease (+) or (-)?
Urease (+)
What population is most at risk for infection from cryptococcus neoformans?
The immunocomprimised, particularly HIV patients
How does infection with cryptococcus neoformans present?
Cryptococcal pneumonia, fever, cough, dyspnea
What is a severe presentation of cryptococcus neoformans infection?
Meningitis, often results in neurological deficits
How is cryptococcus neoformans grown in culture?
Sabauraud’s agar
silver stain = methanamine
red stain = mucicarmine
Under the microscope, what feature does cryptococcus neoformans have?
Wide capsular halo
On gross pathology, what distinctive features does cryptococcus neoformans have?
Soap bubble lesions on gray matter of brain
What is the treatment for infection with cryptococcus neoformans?
Amphotericin B and flucytozine (and fluconazole) - joint
What populations are particularly susceptible to infection with mucormycosis?
Leukemics
Diabetics
Neutropenics
(immunocompromised)
How is mucormycosis (or rhizopus) transmitted?
Spore inhalation
**DKA (excess ketones, as with unmanaged diabetes, is a major risk factor)
How does mucormycosis appear?
Wide angle branching rods, nonseptate
Where does mucormycosis like to profilerate?
Blood vessels
Where does mucormycosis like to go when it infects?
It like to cross the cribiform plate and go to the brain, it creates gigantic lesions ie rhinocerebral mucormycosis, results in eschars (abscesses) on the face
How is infection with mucormycosis treated?
Surgical debridement of necrotic tissue
Amphotericin B
this baby is a killer**