Page 199 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

Microbiology ` microbiology—mycology Microbiology ` microbiology—Parasitology SEcTioN ii 155

` microbiology—Parasitology

Protozoa—gastrointestinal infections
orgaNism Disease traNsmissioN DiagNosis treatmeNt
Giardia lamblia Giardiasis—bloating, flatulence, Cysts in water Multinucleated Metronidazole
foul-smelling, fatty diarrhea trophozoites A or
(often seen in campers/hikers)— cysts B in stool,
think fat-rich Ghirardelli antigen detection
chocolates for fatty stools of
Giardia
Entamoeba Amebiasis—bloody diarrhea Cysts in water Serology, antigen Metronidazole;
histolytica (dysentery), liver abscess testing, and/or paromomycin or
(“anchovy paste” exudate), RUQ trophozoites (with iodoquinol for
pain; histology of colon biopsy engulfed RBCs C asymptomatic cyst
shows flask-shaped ulcers in the cytoplasm) passers
or cysts with up to
4 nuclei in stool D;
Entamoeba Eats
Erythrocytes
Cryptosporidium Severe diarrhea in AIDS Oocysts in water Oocysts on acid-fast Prevention (by
Mild disease (watery diarrhea) in stain E , antigen filtering city
immunocompetent hosts detection water supplies);
nitazoxanide in
immunocompetent
hosts
A B C D E

FAS1_2019_03-Microbiology.indd 155 11/14/19 12:21 PM