GI Helminths Flashcards

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1
Q

nematode (morph, sex, intermediate host)

A

morph: cylindrical/spindle
sex: separate sexes
host: variable

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2
Q

cestode (morph, sex, intermediate host)

A

morph: flattened/segmented
sex: herm
host: one

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3
Q

trematode (morph, sex, intermediate host)

A

morph: leaf-shaped
sex: herm
host: two

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4
Q

intestinal nematodes

A
ascaris lumbricoides (roundworm)
enterobius vermicularis (pinworm)
trichuris trichiura (whipworm)
necator americanis, ancylostoma duodenale (hookworms)
strongyloides stercoralis (threadworm)
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5
Q

tissue-dwelling nematodes

A

toxicara canis
trichinella spiralis
anisakis

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6
Q

cestodes

A
taenia aginata
taenia solium
hymenolepis nana
diphylobothrium latum
echinococcus
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7
Q

trematodes

A

clonorchis sinensis

paragonimus westermani

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8
Q

worm burden

A
# adult worms
usually constant in host
exception: strongloides
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9
Q

nematode characteristics

A

cylindrical/unsegmented
can survive in host for months to years
immune response to infection

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10
Q

ascaris lumbricoides description

A

roundworm
15 - 30 cm
pinkish-white

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11
Q

most common nematode infection worldwide

A

ascaris lumbricoides

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12
Q

ascaris lumbricoides life cycle

A
ingest mature eggs (2-3 weeks)
hatch in SI 
penetrate --> liver --> lungs
cough/swallow 
mature to adults in SI
eggs in stool
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13
Q

ascaris lumbricoides clinicals

A

Migration: cough, pneumonitis, eosinophilia Gut: pain, obstruction DEPEND ON WORM BURDEN

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14
Q

enterobius vermicularis description

A

pin worm
m: 2-5 mm/f: 8 - 13 mm
whitish yellow

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15
Q

enterobius vermicularis life cycle

A

ingest mature eggs (1-2 hrs)
mature in cecum - mate
deposit eggs outside anus

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16
Q

enterobius vermicularis transmission

A

ingest mature eggs (1-2hrs)

  • person-to-person
  • re-infection
  • airborne
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17
Q

enterobius vermicularis clinicals

A

minimal pathology anal puritis
recover eggs with cellophane tape
common in school age kids

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18
Q

trichuris thrichiura description

A

whip worm
4 cm
feed on secretions (not blood)

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19
Q

trichuris thrichiura life cycle

A

ingest mature eggs (10 - 30 days
eggs hatch in cecum
mature in colon
eggs in feces

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20
Q

trichuris thrichiura clinicals

A

Light: may be asymptomatic; Heavy: eosinophilia, dysentery, weight loss, rectal prolapse
most common in kids

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21
Q

necator americanis description

A

hookworm
1 cm
plates to attach
feed on blood

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22
Q

necator americanis life cycle

A
mature larvae penetrate skin (9 days)
blood --> lungs
cough/swallow
adults attach to SI
eggs in feces
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23
Q

necator americanis clincals

A

iron deficient anemia, Penetration: dermatitis/puritus ; Migration: cough/eosinophilia

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24
Q

ancylostoma duodenale description

A

hookworm
1 cm
teeth to attach
feed on blood

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25
Q

ancylostoma duodenale life cycle

A
mature larvae penetrate skin (9 days)
blood --> lungs
cough/swallow
adults attach to SI
eggs in feces
26
Q

ancylostoma duodenale clinicals

A

iron deficient anemia, Penetration: dermatitis/puritus ; Migration: cough/eosinophilia

27
Q

strongyloides stercoralis description

A

Thread worm

smallest GI nematode - 2mm

28
Q

strongyloides stercoralis life cycle

A

larvae penetrate skin
blood –> lungs
cough/swallow
adults in SI
eggs (internal or external) mature to larvae
do cycle again (penetrate SI wall or perianal skin)

29
Q

strongyloides stercoralis clinicals

A

may be asymptomatic; Migration: pneumonitis; Gut: pain, diarrhea; life threatening for immunocomp

30
Q

toxocara canis vector

A

dogs

31
Q

toxocara canis life cycle

A

ingest eggs
eggs hatch in intestines
penetrate - circulation
various tissues - never mature

32
Q

toxocara canis clinicals

A

Hypereosinophilia
Visceral larval migrans: liver (hepatomegaly), lungs, brain, heart;
Ocular larval migrans: eye –> inflammation, blindness

33
Q

trichinella spiralis vector

A

rats and swine

34
Q

trichinella spiralis life cycle

A
ingest cyst (undercooked pork)
excyst in guut
adults in SI
larvae to blood to striated muscle 
encyst
35
Q

trichinella spiralis clinicals

A

Mild GI symptoms; Migration/Encystment: fever, myalgia, rashes

36
Q

anisakis description

A

round worm of fish

37
Q

anisakis life cycle

A

ingest encysted larvae (in undercooked fish)
excyst in stomach
larve in stomach, maybe SI

38
Q

anisakis clinicals

A

violent abdominal pain, nausea, vomiting

SI –> imitate Crohns

39
Q

pathology of cestodes due to

A

larval phase

adults confined to gut

40
Q

taenia saginata description

A

beef tapeworm
30 ft
use scolex to attach to SI
live up to 30 years

41
Q

taenia saginata life cycle

A

ingest cysticerus (encysted larve) from undercooked beef
adult in SI
eggs in feces

42
Q

taenia saginata clinicals

A

asymptomatic or mild GI symptoms

taeniasis

43
Q

taenia solium description

A

pork tapeworm

10 ft

44
Q

taenia solium life cycle

A
  1. ingest cysticercus in undercooked pork
    adult in SI
  2. ingest eggs
    become cysticercus in tissue (muscle, brain, eye)
45
Q

taenia solium clinicals

A
  1. taeniasis: asymptomatic or mild GI symptoms
  2. cysticerosis: small # is asymptomatic, large # –> inflammtory rxn, fever, muscle pain, eosinophilia, neurologic abnormalities, seizures, neurocysticerosis
46
Q

hymenolepis nana description

A

dwarf tapeworm
smallest TW - 15 - 40 mm
adults live 4 - 6 weeks
no intermediate host needed

47
Q

most common human TW in US

A

hymenolepis nana

48
Q

hymenolepis nana life cycle

A

ingest eggs in contaminated food/water
adults in SI
eggs in stool
some mature and penetrate SI

49
Q

hymenolepis nana clinicals

A

often asymptomatic; Heavy: pain, diarrhea, weight loss

50
Q

diphyllobothrium latum description

A

fish tapeworm
largest TW (> 10 m)
crustaceans and fish as host

51
Q

diphyllobothrium latum life cycle

A

ingest larvae in undercooked fish

adult in SI

52
Q

diphyllobothrium latum clinicals

A

may be asymptomatic; abdominal discomfort, diarrhea, vomiting, weight loss, vit B12 deficient anemia, intestinal obstructuion

53
Q

echinococcus life cycle

A

ingest eggs
larvae in SI
wall to liver to lungs to CNS or bone

54
Q

echinococcus clinicals

A

hydatid cysts: fluid filled around larvae (2L) –> pressure damage to organs; anaphylaxis due to ruptured cysts

55
Q

clonorchis sinensis description

A

chinese liver fluke
Asian
snail/fish hosts

56
Q

clonorchis sinensis life cycle

A

ingest encysted larvae (metacercariae)
excyst in duodenum
migrate directly to biliary ducts

57
Q

clonorchis sinensis clinicals

A

liver damage

gallstones (high worm burden)

58
Q

paragonimus westermani description

A

Asian
live 65 - 90 days
snails/crustacean hosts

59
Q

paragonimus westermani life cycle

A

ingest encysted larvae (metacercariae)
excyst in duodenum
directly invade lungs

60
Q

paragonimus westermani clinicals

A

acute (invasion/migration): diarrhea, abdominal pain, cough, fever; chronic (pulmonary): cough, expectoration of discolored mucous, abnormal chest radiographs