GI/GU Protozoans Flashcards
describe the transmission and life cycle of entamoeba histolytica
- mature cyst is ingested
- de-cyst in intestin, yeilding trophozoites
-
trophozoites can colonize colon, feeding via phagocytosis; multiply via binary fission
- can invade intestinal/liver tissues
- make more cysts passed in feces
unique histology of entamoeba histolytica
flask shaped infection
invades into submucosa; can go further in some cases
manifestation of entamoeba histolytica infection
intestinal disease ranging from asymptomatic colonization to colitis, megacolon, hemorrhage, fistulas
amebic liver abscess can cause fever, RUQ tenderness, hepatomegaly; can rupture and spread
pathology of entamoeba histolytica
(how do these bugs cause disease)
amoebas adhere to epithelial cells(gal/galnec lectin)
cysteine proteases degrade ECM
amebapores form pores in target cell
killed cells are EATEN; nomnomnomnom
diagnosis of entamoeba histolytica
- intestinal: stool antigen, PCR assay
- liver abscess: ultrasound, CT, CXR(elevated diaphragm from large liver), needle aspirate
treatment for entamoeba histolytica
asymptomatic
invasive
- asymptomatic: diloxanide furoate, paromomycin, iodoquinol
- invasive: metronidazole + luminal amebicide
invasive and noninvasive entamoeba species
invasive = e. histolytica
noninvasive = e. dispar
describe transmission and life cycle of giardia intestinalis
fecal-oral transmission of cysts(very resilient even in cold water)
cyst develops into infective trophozoite which attach to upper small intestine
pathology of giardia
trophozoites localize in upper small bowel
dont invade; attch via ventral sucker to brush border
induce mucosal inflammation, induce apoptosis, prevent absorption, disrupt tight jxns
clinical manifestation of giardia
malodorous watery diarrhea/flatulence
ab cramps, bloating, fatigue
low-grade fever
usually lasts > 2 wks
treatment for giardia
metronidazole, tinidazole
chronic, debilitating, life-threatening diarrhea in AIDS persons
frequent cause of recreational water outbreaks
intracellular
cryptosporidium (hominis and parvum)
transmission and life cycle of cryptosporidium spp.
fecal-oral transmisison or food/water
- oocyst enters mouth
- sporozoites released in small bowel
- mature into trophozoite IN brush border
- sexual cycle results in oocysts which pass in feces again
cryptosporidium disease
differentiate immunocompetent vs immunocompromised host
general: watery diarrhea, ab cramps, nausea, fever, malaise, wt. loss
compromised: voluminous watery diarrhea; marked weight loss; cant resolve spontaneously
competent: symptoms resolve after 5-12 days;
treatment for cryptosporidium
supportive therapy
immunocompetent: nitazoxanide
immunocompromised: reverse immune suppression, not many effective drugs for AIDS pts….
most common non-viral STD
trichomonas vaginalis
10-50% of sexually active women
manifestation of trichomonas vaginalis
women
men
Women
- dmg via direct contact = microulcerations
- vaginal discharge
- dysuria
- pregos can have low wt babies or preterm deliver
Men
usually asymptomatic; can have discharge;
complications: prostatitis, epididymitis, urethral sricture, infertility
diagnosis of trichomonas vaginalis
ID organism via wet mount or culture
treament for trichomonis vaginalis
metro/tinidazole
treatment for cyclospora
TMP-SMX
immunocompetent can prolly recover w/out treatment
diagnosis of cyclospora
multiple stool samples(at least 3)
find oocysts in stool; can use acid fast as well
clinical symptoms of cyclospora
sudden onset
fever, abdominal cramping
frequent watery diarrhea
can last several weeks if untreated
transmission/life cycle of cyclospora
fecal-oral; contaminated food/water
oocysts(each containing 2 sporozoites) are ingested
sporozoites infect epithelial cells of upper small intestine
