Micro 2 Flashcards
What are some facts about all systemic mycoses
All the ones to know can cause pneumonia and can disseminate. All are dimorphic fungi that are mold in cold and yeast at body temperature, escept cocidio which is a spherule in tissue.
Treatment for systemic mycoses
Fluconazole or itraconazole for local infection; amphotericin B for systemic infection.
Difference between systemic mycoses and TB
Similar in that they form granulomas, but there is NO person-person transmission.
Histoplasmosis mnemonic
Histo hides (within macrophages).
Where can you find histo?
Bird or bat droppings in the Mississippi and Ohio River valleys.
Histo causes what disease
PNA
Histo yeast size?
Smaller than RBC
Blasto mnemonic
Blasto buds broadly.
Blasto on histo
Broad-base budding (same size as RBC)
Blasto diasease
inflammatory lung disease and can disseminate to skin and bone. Forms granulomatous nodules.
Blasto origin
States east of the Mississippi River and Central America.
Coccidio histo
Spherule is much larger than RBC and is filled with endospores.
Coccidio location
Southwest US, California.
Coccidio diseases
PNA and meningitis, can disseminate to bone and skin. Case rate inreases after eartquakes (spores thrown up in dust)
Paracoccidiomycosis location and histo
Latin America. Budding yeast with “captain’s wheel” formation (much larger than RBC)
Tinea versicolor organism
Malassezia furfur
Tinea versicolor path
Degradation of lipids produces acids that damage melanocytes and cause hypopigmented and/or hyperpigmented patches.
Tinea versicolor environment
Hot, humid weather
Tinea versicolor tx
Topical miconazole, selenium sulfide (Selsun).
Tinea versicolor histo
“Spaghetti and meatball” appearance
Tineae apperance on skin
Pruritic lesions with central clearing resembling a ring, caused by dermatophytes (Microsporum, Trichophyton, and Epidermophyton.)
Tineae histo
Mold hyphae in KOH prep, not dimorphic
Candida vaginal tx
Topical azole
Candida oral/esophageal tx
Fluconazole or caspofungin
Candida systemic tx
Fluconazole, amphotericin B, or caspofungin
Candida histo
Dimorphic yeast. Pseudohyphae and budding yeasts at 20 degrees celsius and germ tubes at 37 degrees.
Can Aspergillus cause hepatocellular carcinoma?
Some species produce aflatoxins, so YES
Aspergillus fumigatus mnemonic
Think “A” for Acute Angles in Aspergillus.
Aspergillus morphology.
Not dimorphic. Septate hyphae that branch at 45 degrees. Conidiophore with radiating chaisn of spores.
Cryptococcus brain imaging
Soap bubble lesions in brain
Is cryptococcus dimorphic?
Not dimorphic, but heavily encapsulated.
Where to find crypto?
Soil, pigeon droppings and inhaled with hematogenous spread to meninges.
Specific test for cryptococcus?
Latex agglutination test detects polysaccharide capsular antigen
Mucor and Rhizopus spp. disease
Mucormycosis in DKA and leukemic patients.
Mucor morphology
irregular, broad, nonseptate hyphae branching at wide angles.
PCP tx
Bactrim, pentamidine, dapsone (PPx only), atovaquone (PPx only). Start PPx when CD4 <200 in HIV patients.
PCP morphology
Disc-shaped yeast on methenamine silver stain.
Sporothrix scheckii dz and path
Sporotrichosis (rose gardener’s disease) causes an ascending lymphanigitis with little systemic illness. Local pustule or ulcer with nodules along draining lymphatics.
Sporotrichosis tx
Itraconazole or Potassium Iodide
Giardia transmission
cysts in ater
Giardia diagnosis
Trophozoites or Cysts in stool
What is dysentery?
Any inflammation of the colon causing bloody diarrhea.
Entamoeba histolytica presntation
Amebiasis: bloody diarrhea (dysentery), liver abscess (Anchovy past exudate), RUQ pain (histology shows flask-shaped ulcer if submucosal abscess of colon ruptures)
Entamoeba transmission
Cysts in water
Entamoeba dx
Serology and/or trophozoites (with RBCs in the cytoplasm) or cysts (with up to 4 nuclei) in stool.
Entamoeba tx
Flagyl; iodoquinol for asx cyst passer
Crytopsoridium presentation
Severe diarrhea in AIDS, mild watery diarrhea in immunocompetent
Cryptosporidium transmission
oocysts in water
Cryptosporidium dx
oocysts on acid-fast stain
Cryptosporidium prevention
Filtering city water supplies
Cryptosporidium tx
Nitazoxanide in immunocomptenent hosts…what about in AIDS?
Congenital toxo
Classic Triad: Chorioretinitis, hydrocephalus, and intracranial calcifications.
Toxo in HIV presentation
Brain abscess with ring-enhancing lesions on CT/MRI
Toxo transmission
Cysts in meat or oocysts in cat feces; crosses placenta (pregnant women should avoid cats)
Toxo dx
Serology, biopsy (tachyzoite)
Toxo tx
Sulfadiazine + pyrimethamine
Naegleria fowleri transmission
Enters cribriform plate in fresh water lakes
Naegleria dx
Amoebas in spinal fluid
Naegleria tx
Amphotericin B: slim chance of survival either way
African sleeping sickness caused by
Trypanosoma brucei.
Trypanosoma transmission
Tsetse fly, a painful bite
Trypanosoma dx
Blood smear