Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Micro2 Unit 6 > GI Parasites > Flashcards

GI Parasites Flashcards

1
Q

what are the most common protozoa in the united states?

A

Giardia lamblia and Cryptosporidium parvum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what causes intestinal amebiasis? where is it endemic?

A

entamoeba histolytica

more common in south America, Egypt, the middle east and other places where sanitation is poor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are helminthes? what are cestodes? what are nematodes?

A

multicellular organisms that cannot multiply in the human body in their adult forms
flat worms
round worms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe a cestode. what are the medically important examples?

A

a round head (scolex) and a segmented flat body (each segment is a proglottid)
taenia solium and saginata, diphyllobothrium latum and echinococcus granulosus (pork, beef, fish and dog tapeworms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe a nematode. which are medically important?

A

roundworm with a cylindrical body and a complete digestive tract
enterobius vermicularis, trichuris trichiura, ascaris lumbricoides, necator americanus, ancylostoma duodenale and strongyloides stercoralis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is one common result of GI parasitc infection?

A

asymptomatic infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what predisposes to giardiasis?

A

young age, international adoptees, travelers, immunocompromise, hypochlorhydria and cystic fibrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe the lifecycle of giardia lamblia.

A

cysts are infectious form- can survive in moist environments for prolonged periods. they are ingested and excystation occurs in the small bowel with release of trophozoites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the infectious dose of giardia? what is the usual transmission method?

A

10-25 cysts

fecal oral transmission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the possible outcomes of giardiasis?

A

1/2 clear the infection without symptoms, 5-15% are asymptomatic and shed cysts and the rest have symptomatic infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the symptoms of acute giardiasis? how long does it last?

A

diarrhea, malaise, steatorrhea, abdominal cramps, flatulence, nausea, weight loss
less frequent vomiting and fever
lasts 2-4 wks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what percentage of infected people develop chronic giardiasis? describe the illness.

A

16% (half of symptomatic individuals)
waxing and waning symptoms of loose stools, steatorrhea, weight loss, malabsorption, malaise, abdominal cramping, borborygmi, flatulence, burping, fatigue and depression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how is giardia diagnosed?

A

stool microscopy- sensitive and specific

immunoassays have greater sensitivity than stool microscopy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe cryptosporidium parvum. where does it reproduce?

A

intracellular protozoan parasite

reproduces in the epithelial cells of the digestive or respiratory tracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

cryptosporidiosis is most commonly associated with which illnesses?

A

diarrhea and biliary tract disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the clinical presentations of cryptosporidium infection?

A

asymptomatic infection, mild diarrheal illness or severe enteritis with or without biliary tract involvement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

describe the time frame of most cryptosporidium infections

A

incubate 7-10 days. diarrhea and fever for 10-14 days with resolution without therapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

which conditions could cause a prolonged cryptosporidium infection?

A

immunocompromise and infants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how is cryptosporidium diagnosed?

A

microscopy of stool, duodenal aspirates, bile secretions, biopsy specimens or respiratory secretions
enzyme immunoassays can also be performed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the common results of intestinal amebiasis?

A

most infection is asymptomatic
otherwise can cause amebic dysentery and extraintestinal disease (liver abscess, pulmonary, cardiac or brain involvement)- last 3 more rare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what two forms of E histolytica exist and what is the lifecycle?

A

cyst stage is infective- ingested by human

passes through the SI where they excysts to form trophozoites (invasive form)

22
Q

how does E histolytica cause disease?

A

trophozoites invade and penetrate the mucous barrier of the colon cauing tissue destruction and increased intestinal secretion- bloody diarrhea

23
Q

who is at increased risk of intestinal amebiasis?

A

travelers, immigrants and institutionalized people

24
Q

what causes asymptomatic infection by E histolytica? what is different when symptoms develop?

A

trophozoites aggregate in mucin layer and form new cyss

instead the trophozites adhere to and lyse the colonic epithelium

25
Q

how long does it take for an amebic liver abscess to form and what is its relation to intestinal amebiasis? how does infection establish?

A

8-20 weeks- concurrent diarrhea is not always the case, many report history of dysentary
ascending the portal venous system

26
Q

humans are the definitive hosts for which tapeworms? for which are they intermediate hosts? what is the exception to this rule and why?

A

definitive- d latum and t saginata
intermediate- echinococcus spp
exception- t solium: develops into a cysticercus if ingested as an egg or as a tapeworm if ingested as a cystiecercus in infected pork

27
Q

if humans are the definitive host for a tapeworm, which stage is most associated with disease? if intermediate host?

A

definitive- adult tapeworm in intestine

intermediate- hyatid cycts or cysticercus

28
Q

what are the possible infections of T solium in humans?

A

adult tapeworm if ingested undercooked pork, cysts if ingested eggs (fecal oral rout) or both (can be caused by autoinfection from adult)

29
Q

under what condition is t solium infection symptomatic?

A

if cysticercosis supervenes- can create cysts in the brain, muscle or other tissues
suspect infection if tapeworm is diagnosed

30
Q

how are taenia infections diagnosed?

A

detecting eggs during stool examination

31
Q

describe the disease neurocysticercosis. where does it affect? what is a common presentation?

A

taenia cysts in the brain- most often intracerebral if there is symptomatic disease
seizures in 70% of patients. may also have mass effects (intracranial hypertension)

32
Q

when is cysticercosis asymptomatic?

A

when cysteicerci develop without much inflammation-remain in this stage for many years

33
Q

how is taenia saginata infection established? what are the common presentations?

A

eating undercooked beef containing larval cysts

asymptomatic infection- mall number report mild abdominal cramps and malaise

34
Q

how is infection with d latum acquired?

A

eating undercooked freshwater fish containing cysts (especially salmon)

35
Q

what are the symptoms of d latum infection?

A

normally asymptomatic- proportion have weakness, dizziness, salt craving, diarrhea and intermittent abdominal discomfort

36
Q

what is one major potential complication of d latum infection? what could happen as a result of this occurrence?

A

prolonged or heavy (multiple worm) infection may cause megaloblastic anemia by causing a vitamin B12 deficiency
may lead to peripheral neuropathy and severe combined degeneration of the CNS

37
Q

how does d latum cause decreased absorption of vit B12?

A

parasite mediated dissociation of vit B12-IF complex in the lumen and heavy vitamin uptake and use by the parasite

38
Q

what is the most common helminthic infection of humans? where does this parasite live in the human?

A

ascaris lumbricoides

in the lumen of the SI- esp the jejunum

39
Q

what are the possible outcomes of ascaris lumbricoides infection?

A

most are asymptomatic
small proportion develop pulmonary symptoms during the second week (hypersensitivity response)
severe caes- dyspnea and eosinophilic pneumonia

40
Q

describe the ascaris lifecycle

A

adult worms live in SI and eggs are passed in feces
fertlle eggs embryonate and become infective- if swallowed the larvae hatch in intestinal mucosa. larvae hatch and are carried to the lungs via circulation where they mature. they ascend the bronchial tree and are swallowed where they live as adults

41
Q

what are complications of chronic ascariasis?

A

intestinal obstruction, obstruction of bile and pancreatic ducts, appendicitis and intestinal perforation
obstruction especially concerning in children near the iliocecal valve

42
Q

what is the enterobius vermicularis? where do adults reside?

A

a pinworm that is highly prevalent (small)

inhabits cecum, appendix and gut

43
Q

where do enterobius worms deposit their eggs? what is the most common mode of transmission?

A

deposited in the perianal regions. transmitted via the hands of the patient where they have scratched themselves or handled their clothes

44
Q

what are the most common symptoms of enterobiasis? how is it diagnosed

A

most are asymptomatic
symptom is often perianal itching
diagnosed by detecting eggs in the perianal region early in the morning. more collections yields more diagnosis

45
Q

what is common name of trichuris trichiura? what are the common presentations?

A

whipworm

most are asymptomatic (<20 worms). heavy worm burden may cause recurrent rectal prolapse

46
Q

how is tricuriasis diagnosed?

A

finding adult worms in the mucosa of prolapsed rectum or at colonoscopy or demonstrating eggs in the stool

47
Q

which two species of parasites are hook worms? what is the major health problem that they cause?

A

ancylostoma duodenale and necator americanus

cause iron deficiency anemia

48
Q

what conditions are needed for hookworm transmission?

A

several months of warm weather, enough rainfall and people not wearing shoes (infects bare feet)

49
Q

what are the symptoms of hookworm infection?

A

mostly asymptomatic.
iron deficiency anemia, protein energy malnutrition (blood loss) and maculopapular rash at site of penetration. migration through the lungs may cause transient pneumonitis (less frequent than ascaris)

50
Q

what symptoms occur with strongyloides infection?

A

most are asymptomatic- 75% have fluctuating eosinophilia

some people develop macuopapular or urticarial rashes

51
Q

what is the hyperinfection of strongyloidiasis?

A

severe complicated infection including disseminated infection- especially when immunocompromise
larvae also found in CNS, kidneys, liver and most other organs

Micro2 Unit 6 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions