parasitic diseases of GI tract (5)

Question 1

what are the most common protozoa infections in the US (2)

Answer 1

giardia lamblia

cryptosporidium parvum

Question 2

what are the 2 morphological forms of giardia?

Answer 2

cysts (infectious

trophozoites

Question 3

it can be difficult to recognize a water supply with infected giardiasis while it goes on affecting a whole community, why is this?

Answer 3

because the asymptomatic infection occurs in 50% of people, and in 5-15% of people there is shedding of the cysts

Question 4

how do you diagnose a giardia infection

Answer 4

initially stool microscopy and then immunoassays for greater sensitivity

Question 5

how is cryptosporidium transmitted

Answer 5

oocysts in the feces to person, food or water

Question 6

besides GI effects, what other system can be involved in cryptosporidium

Answer 6

biliary tract infection

Question 7

what causes intestinal amebiasis

Answer 7

protozoan Entamoeba histolytica

Question 8

what some extraintestinal manifestations of entamoeba histolytcia

Answer 8

amebic liver abscesses

more rare: pulmonary, cardiac and brain involvment

Question 9

in most infections with e. histolytica, the trophozoites in the intestines just aggregate in the intestinal mucin layer, form new cysts and cause a self limited/asymptomatic infection..what is the other possibility of what could happen? explain how this happens

Answer 9

adherence to and lysis of the colonic epithelium, mediated by the galactose and N acetyl D galactosamine specific lectin which initiates the invasion of the colon by the trophozoites

Question 10

what is the most common disease manifestation of infection with E. histolytica

Answer 10

amebic diarrhea without dysentery

Question 11

what is amebic dysentery (aka amebic colitis)?

Answer 11

diarrhea with mucus or visible or microscopic blood

Question 12

a patient just came back from traveling and has right upper quad pain and fever, what are you thinking about

Answer 12

amebic liver abscess from a E. histolytica infection

Question 13

common name for taenia solium

Answer 13

pork tape worm

think, solium looks like sodium and ham is known for being salty

Question 14

common name for taenia saginata

Answer 14

beef tapeworm

Question 15

common name for dihyllobothrium latum

Answer 15

fish tapeworm

Question 16

what is the rule about humans being a host a cestode parasite

Answer 16

humans are either definitive or intermediate host but not both

1 exception- T. solium

Question 17

what tapeworms are humans the definitive host

Answer 17

D latum and T. saginata

Question 18

if a human ingests an egg in food or water contaminated with T. solium what develops?

Answer 18

cysticercus (esp in the brain)

Question 19

how does T. saginata infect humans? what disease does it cause

Answer 19

larvae in undercooked beef

causes adult tapeworm

Question 20

how does D. latum infect humans? what disease does it cause

Answer 20

larvae in undercooked fish

adult tapeworm

Question 21

which tapeworm can cause B12 deficiency

Answer 21

D. latum

Question 22

how does echinococcus granulosus infect humans? what disease does it cause?

Answer 22

eggs in food or water contaminated with DOG feces

causes hydatid cysts, esp in liver and lungs

Question 23

which of the tapeworms is a major cause of adult onset seizures

Answer 23

T. solium cysticercosis

Question 24

so your patient just ingested an undercooked piece of pork that you suspect has T. solium infection, so now you should look out for seizures?

Answer 24

NO. undercooked pork cannot cause cysticercosis.. it results in intestinal tapeworm (which can be asymptomatic) if the pork indeed had larval cysts

Question 25

what are cestodes? and what helminths are in this group

Answer 25

flat worms Taenias D. latum echinococcus granulosus

Question 26

what are the 2 main parts that make up a cestode

Answer 26

rounded head- scolex | flat body with multiple segments (each segment is called a proglottid)

Question 27

so you said D. latum can cause vit B12 deficiency. what are the 2 ways it does this

Answer 27

1. parasite mediated dissociation of the vit B12-IF complex in the gut lumen 2. the parasite actually uptakes the vitamin and uses it for is SHELLFISH self (get it..selfish, but also shellfish because this is transmitted via undercooked fish)

Question 28

what are the 6 nematodes (roundworms)

Answer 28

1. enterobius- pinworm 2. trichuris- whipworm 3. ascaris-giant roundworm 4. necator- hookworm 5. ancylostoma- hookworm 6. strongyloides- small roundworm

Question 29

how do you get an infection with enterobius (pinworm) trichuris (whipworm) ascaris (giant worm) how is it diagnosed?

Answer 29

ingestion of eggs dx by eggs on the skin

Question 30

how do you get an infection with ancylostoma and necator (hookworm) strongyloides (small roundworm) how is it diagnosed?

Answer 30

larval penetration of skin dx by eggs in stools

Question 31

where are the adult worms in an ascaris infection

Answer 31

free in lumen of small bowel | mainly jejnum

Question 32

where are the adult worms in an trichuris infection

Answer 32

anchored in superficial mucosa of cecum and colon

Question 33

where are the adult worms in an necator and ancylostoma (the hookworms) infection

Answer 33

attached to mucosa of mid to upper portion of small bowel

Question 34

where are the adult worms in an strongyloides infection

Answer 34

embedded in mucosa of duodenum, jejnum

Question 35

where are the adult worms in an enterobius (pinworm) infection

Answer 35

free in lumen of cecum, appendix, adjacent colon

Question 36

whats the most common helminthic infection in humans? in the US?

Answer 36

ascariasis in the world enterobiasis (pin worm) in the US

Question 37

ascariasis infection is usually asymptomatic, but if it invades the lung tissue, what can it cause

Answer 37

provokes an immune mediated hypersensitivity response nonproductive cough, chest discomfort, fever and eosinophilia severe can develop loffler syndrome

Question 38

what are the most common symptoms of enterobiasis (pin worm)

Answer 38

perianal itching (at night time the worms migrate to the perianal area and lay their eggs)

Question 39

what helmith can you see anal prolapse

Answer 39

trichuriasis

Question 40

what deficiencies can hookworm be assoc with

Answer 40

iron deficiency anemia and protein energy malnutrition