GI Parasites Flashcards
Big 3 GI protazoan
Giardia (fatty stools from wilderness adventures)
Cryptosporidium (severe in AIDS)
Entoamoeba (blood diarrhea from slums)
Giardia Dx
detection of cysts in fecal matter
trophocytes in lumen
Sx of giardia
foul smelling, fatty diarrhea (KADE loss)
flatulence
Giardia Tx
metronidazole
Mechanism of giardia infection
loss of absorbativce surface area 2˚ to parasite presence
Cryptosporidium hosts
immunocompromised
Cryptosporidium Dx
oocytes in watery diarrhea
Cryptosporidium Sx
watery, frequent, nonbloody diarrhea
sometimes fever and nausea
Cryptosporidium outbreaks
pools
failed water cleaning systems
Entamoeba histolytica
story
tropical and subtropical regions
male homosexuals in US
Presenting Sx in entamoeba histolytica
bloody, mucous-y
right lobe liver abscess, anchovy-paste exudate
Amebic hepatitis
entamoeba histolytica
via blood invasion
single abscess in right liver lobe
Metronidazole, Tinidazole
MOA
TU
Tox
MOA: metabolites cause free radical damage and strand breaks in DNA
TU: Giardia
Tox: disulfuram
Nitazoxanide
MOA
PK
TU
MOA: inhibits pyruvate:ferredoxin oxidoreductase e- transfer, essential for anaerobic metabolism
PK: rapid metabolism to tizoxanide, remains lumenal
TU: cryptosporidium
Iodoquinol MOA PK TU Tox
MOA: unknown
PK: lumenal
TU: enamoeba
Tox: messes up thyroid tests, loss of visual acuity
Paromycin
MOA
PK
Tox
MOA: aminoglycocide, binds 30S and prevents mRNA misreading and stops translocation
PK: remains lumenal, low absorption
Tox: nephrotox, ototox (esp w/ loop diuretics), neuromuscular blockagde, teratogen
Enterobius vermicularis
disease
presentation
Dx
pinworm
perianal pruritis in daycare kids
scotch tape test for eggs in morning
Necator americanus/Ancylostoma duodenale
disease
presentation
Dx
hookworm
iron deficiency anemia
stool sample
Stronglyoides stercoralis
disease
presentation
Dx
threadworm
emesis, diarrhea, epigastric pain
stool sample
Trichinella spiralis
disease
presentation
Dx
trichinosis
bloody diarrhea, myalgias (barrels into striated muscle)
barrel-shaped eggs in feces
Ascaris lumbricoides
giant roundworm
obstruction @ ileocecal valve
Bendazoles (albendazole, mebendazole) MOA PK Tox
MOA: bind β-tubulin, inhibits microtubule formation
PK: lumenal
Tox: teratogen
Pyrantel pamoate, levamisole
MOA
PK
MOA: ACh –> increase Ca2+ –> contraction paralysis
PK: lumenal
Ivermectin
Class
MOA
TU
Class: macrolytic lactone
MOA: binds Glu-gated ion channels –> deactivation –> starvation
TU: Strongyloides