Infecções Flashcards
Infecção fúngica - Quais os padrões morfológicos dos patógenos?
Levedura
Hifa
Dimórfico
Infecção leveduras - Principais patógenos?
Cryptococcus neoformans
Candida albicans
Cryptococcus neoformans - Where the organism can be found?
Bird feces (pigeo droppings)
Cryptococcus neoformans - Where does the infection start?
In the lungs through inhaled spores
Cryptococcus neoformans - How is the diagnosis made?
India ink stain
Cryptococcus neoformans - How does the yeast enter the CNS?
Through hematogenous dissemination
Cryptococcus neoformans - Patterns of lesion
Leptomeningeal enhancement (may be nodular) Cryptococcomas Pseudocysts in the basal ganglia
Cryptococcus neoformans - Cryptococcoma size
Miliary (< 3 mm) or Larger
Cryptococcus neoformans - Pseudocyst occupy which space?
Perivascular spaces with gelatinous material
Candida albicans - Common in which population?
Patient receiving immunosuppressive therapy or with indwelling catheters
Candida albicans - Which characteristics make the fungus more invasive?
The ability to shift from yeast to pseudohyphal form
Candida albicans - Pattern
Microabscesses (< 3 mm)
Angioinvasion with thrombosis and hemorrhage
Candida albicans - Uncommon patterns
Meningitis
Macroabscesses
Molds - Pathogens
Aspergillus
Mucorales
Molds - Patterns of invasion
More likely to invade the parenchyma
Molds - Dissemination patterns
Hematogenic
Angiotropic or perineural spread from paranasal sinus or orbital infection
Aspergillosis - Image pattern
Ring-enhancing abscesses
Hypointense on T2
Hemorrhage, stroke, mycotic aneurysm (angioinvasion)
Aspergillosis - ADC pattern
Hypointense without corresponding enhancement (characteristic of fungal abscesses this finding helps the distinction with pyogenic and tubercular abscesses)
Aspergillosis - Mecanism of angioinvasion
Production of elastase
Dimorphic fungi - Pathogens
Blastomyces dermatitidis
Coccidioides immitis
Histoplasma capsulatum
Coccidioidomycosis - Image pattern
Thick exudate and enhancement in the basal cisterns and subarachnoid space
Coccidioidomycosis - Vasculitis is observed in 40% of cases. What’s the pattern?
Small perforators vasculitis resulting in deep brain infarcts
Subarachnoid hemorrhage secondary to large vessel inflammation may occur
Neurocysticercosis - Pathogen
Taenia solium
Neurocysticercosis - Transmission
Fecal-oral from a tapeworm carrier
Neurocysticercosis - When does the symptons appear?
When the scolices begin to die or from cysts in the ventricular system
Neurocysticercosis - Vesicular stage
Small non-enhancing cyst with a “dot” inside (representing the scolex) without surrounding edema
Neurocysticercosis - Vesicular colloidal stage
Ringlike enhancement on post-contrast images with surrouding edema
Neurocysticercosis - Granular nodular stage
Cyst retraction with surrounding gliosis
Neurocysticercosis - Calcified nodular stage
Calcification of the nodule (last stage)
Neurocysticercosis - Multiple lesions corresponding to varying stages are typical (T/F)
True
Neurocysticercosis - Cistern and Sylvian fissure pattern
A cluster of cysts (racemose form) without enhancement and scolices
Toxoplasmosis - Image patterns
Multifocal abscesses with a predilection for the basal ganglia
Toxoplasmosis - Enhacement pattern
Ringlike enhancement
Toxoplasmosis - What’s the name of the highly suggestive sign?
Eccentric target sign
Echinococcosis - Image Pattern
Cystic lesions with signal intensity similar to CSF without enhacement
Surrounding halo of hyperintensity on T2
