abx and anti-parasites

Question 1

describe the functions of the two C. Dif toxins

Answer 1

Toxin A= enterotoxin= diarrhea

Toxin B= cytotoxin= cytotoxic to the colonic cells

Question 2

what is the trx for C Dif

Answer 2

cessation of inciting abx
supportive care
fecal transplant

vancomycin OR
metronidazole OR
fidaxomicin

Question 3

which medication is the preferred trx (name and class) for C Dif

Answer 3

vancomycin = glycopeptide

Question 4

which med (name and class) do you give for C Dif when oral administration doesn’t work for patients

Answer 4

Metronidazole- 5-nitroimidazole

Question 5

what is the trx (name and class) for recurrent C Dif

Answer 5

fidaxomicin= macrolide

Question 6

what are the key meds (name and class) to trx H Pylori

Answer 6

PPI- omeprazole

5-nitroimidazole- metronidazole

Bismuth compounts- bismuth subsalicylate

tetracycline

Question 7

E. hystolitica complications

Answer 7

portal blood circulation
liver abscesses
pulmonary abscesses and often death

Question 8

what drugs will eliminate E. hystolitica

Answer 8

(5 nitroimidazoles) metronidazole if extraluminal amebiasis
OR tinidazole, which is better tolerated

metronidazole AND tinidazole if luminal amebicide

Question 9

what drugs(name and class) will eradicate intestinal carriage of E. hystolitica

what are adverse effects?

Answer 9

paromomycin (aminoglycoside) > iodoquinol (8-hydroxyquinolines)
NO EFFECT ON EXTRAINTESTINAL ORGANSIMS: 99% stay in intestine and excreted via feces

rash, pruritis

Question 10

how does giardia interact with the small intestine

Answer 10

it coats the small intestine and inerferes with fat absorption (creeping fat)

NO BLOOD IN STOOLS

Question 11

trx for giardia

Answer 11

correct fluids and electrolytes

first line= tinidazole (5 nitroimidazoles)
nitazoxanide

Question 12

when do you use nitazoxanide

MOA, kinetics, adverse effects

Answer 12

giardia
will inhibit pyruvate-ferredoxin oxidoreductase, needed for anaerobic E metabolism

rapid absorption

flatulence, enlarged salivary glands, yellow eyes, dysuria, bright yellow urine

Question 13

Cryptosporidium parvum with immunocompromised

Answer 13

immunocompetent- self limiting

compromised= severe life threatening diarrhea

Question 14

trx for cryptosporidium

Answer 14

anti-diarrheal –> loperamide

fluid management

antimicrobial –> nitazoxanide > paromomycin (aminoglycoside)

Question 15

what is the trx for Cryptosporidium in HIV patients

Answer 15

antiretroviral therapy + nitazoxanide

Question 16

what is the trx for Cryptosporidium in non-HIV, immunocompromised patients

Answer 16

reduced immunosuppressants and nitazoxanide

Question 17

describe the body’s response to works/nematodes

Answer 17

no immune response to the worms, just respond to dead worms and eggs
elevation of eosinophils

dx with visualization of microscopic eggs in feces

Question 18

the two hookworms are..?

sx of a hookworms infection

Answer 18

necator americanus + ancylostoma duodenale

diarrhea
abd pain
weight loss
anemia
intense itching at site of penetration

Question 19

sx of ascaris lumbricoides

Answer 19

abd cramping,
malnutrition
worm invasion

Question 20

differentiate the life cycle of a hookworm vs 
ascaris lumbricoides vs 
strongyloides stercoralis vs
trichuris trichiura vs
enterobius vermicularis

Answer 20

hookwork penetrate skin –> lungs –> coughed and swallowed–> intestine –> eggs in feces

ascaris lumbricoides is CONSUMED –>penetrate intestine–> lung–> coughed swallowed –> –> intestine –> EGGS in feces

strongyloides penetrate skin –> lungs –> coughed and swallowed–> intestine –> HATCHED LARVAE excreted in stools

tri tri eggs ingested via food –> hatch in small intestine –> migrate to cecum–> mature, hatch thousands of egg over a YEAR

enterobius –> eggs ingested –> mature in cecum, ascend large intestine –> females go to perianal area at night–>eggs infectious 4-6 hrs later

Question 21

sx of strongyloides steroralis

Answer 21

anemia
weight loss
vomiting, diarrhea
abd pain

Question 22

what immunosuppressive medications can lead to severe autoinfection in the setting of strongyloides steroralis

Answer 22

prednisone

asthma

Question 23

how do you dx a strongyloides infection

Answer 23

larvae in feces

Question 24

sign difference in lifecycle of trichuris trichiura vs other works

Answer 24

no transit through the intestinal wall
no lung involvement
no eosinophilia
no auto-infection

Question 25

transmission methods of enterobius vermicularis how do you diagnose

Answer 25

hand to mouth via severe perianal itching scotch tape test

Question 26

what are the broad spectrum oral anti-helminthic agents MOA kinetics adverse effects

Answer 26

albendazole, mebendazole, thiabendazole MOA= inhibit micro-tubule synthesis--> paralysis are prodrugs THIABENDAZOLE ONLY= rapidly absorbed, largely excreted, can be ingested or absorbed from skin THIABENDAZOLE ONLY= most toxic of the three, dizzy, anorexia, irreversible liver failure, fatal Stevens-Johnson syndrome

Question 27

ivermectin anti-helminth MOA kinetic AEs

Answer 27

intensify GABA-mediated signal transmission in peripheral Ns of the nematode kinetics= rapidly absorbed, oral only, excreted in feces AEs= no combine w other GABA altering drugs= barbituates, benzodiazepines, valproic acid

Question 28

pyrantel pamoate antihelminth MOA kinetics AEs

Answer 28

MOA= NMSK blocker, cause Ach release and inhibit cholinesterase--> paralysis and explusion kinetics= poorly absorbed, half of the administered dose will be excreted unchanged in feces AEs= --

Question 29

which drugs are used to trx N. americanus + A. duodenale (hookworms)

Answer 29

primary= albendazole alternate= mebendazole, pyrantel pamoate poor= ivermectin

Question 30

trx of A lumbricoides

Answer 30

primary= albendazole or mebendazole alternate= ivermectin

Question 31

trx of S stercoralis

Answer 31

primary= ivermectin alternate= albendazole no longer primary= thiabendazole

Question 32

trx of T. trichiura

Answer 32

primary= mebendazole alternate= abendazole second alternate= ivermectin

Question 33

trx of E. vermicularis

Answer 33

primary= albendazole, mebendazole, pyrantel pamoate

Question 34

how does schistosoma infect

Answer 34

invade venous system through exposed skin, found in fresh water portal V

Question 35

Schistosoma japonicum geography resides where deposit eggs where

Answer 35

easter asia Vs in intestinal tract eggs in feces

Question 36

Schistosoma mansoni geography resides where deposit eggs where

Answer 36

south america and africa Vs in intestinal tract eggs in feces

Question 37

schistosoma haematobium geography resides where deposit eggs where

Answer 37

africa in Vs around bladder deposit in urine

Question 38

life cycle of schistosoma (blood flukes)

Answer 38

``` eggs hatch water mature in a snail leave snail infect humans mate in the intrahepatic portion of the portal venous system mates move to intestine orbladder enter lumen to be excreted ```

Question 39

clinical manifestations of schistosoma

Answer 39

dermatitis immediately ``` katayama fever (4-8 weeks) chronic fibrosis (years) ```

Question 40

trx for schistosoma MOA kinetics AE

Answer 40

praziquantel MOA= increase permeability of cell membrane to Ca --> paralysis, dislodgement, death kinetics: oral admin, rapid absorb, excreted in urine AE= immediate= drowsy, lassitude, fatigue after days, low grade fever, pruritis, rash

Question 41

life cycle of cestodes= tapeworms

Answer 41

ingested through undercooked meat containing larvae

Question 42

freshwater tapeworm ingested by raw freshwater fish cause --> anemia

Answer 42

diphyllobothrium latum

Question 43

extra-intestinal tapeworm infection, ingested from dog feces

Answer 43

echinococcus granylosus

Question 44

trx for cestodes

Answer 44

praziquantel niclosamide- an alternative for most tapeworms albendazole

Question 45

niclosamide MOA kinetics

Answer 45

uncouples ox phos, block glucose uptake--> parasite death kinetics= oral admin,