Helminths/worms Flashcards

1
Q

what is a symbiont, commensal, parasite? define each.

A

Symbiont: mutual advantage
Commensal: no harm/no good
Parasite: thrives by doing harm

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2
Q

eosinophilia suggests what kind of infection?

A

allergic OR parasite (usually a helminth)

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3
Q

many helminths are ____, with lifespans that last _______

A

Many helminths are long-lived, with life spans that last decades

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4
Q

Absence of eosinophilia does not exclude _______

A

infection with parasite

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5
Q

what are two other names for pinworms? (one common and one scientific)

A

threadworms, enterobius vermicularis

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6
Q

what patient population gets pinworms?

A

Common helminthic infection in children

All social strata, all countries

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7
Q

what is the most prevalent worm infection in the US?

A

pinworms

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8
Q

hosts for pinworms?

A

only humans

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9
Q

pinworm: where do they live in the body and what is the process for this?

A

Normal habitat: lumen of the cecum

Gravid female migrates to perineal area during the evening, deposits eggs (thousands) in folds of perineal skin
-Contamination of bedding, etc., scratching, hand-to-mouth –> eggs ingested and migrate to cecum

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10
Q

cycle for pinworm: ___ to ____ days.

A

15-28 days

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11
Q

Pruritus ani, especially in children, at night… what do you think they have?

A

pinworms

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12
Q

Dx of pinworms

A

Scotch tape test, repeated

Visual inspection

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13
Q

severity of pinworm infection depends on what? is there eosinophilia with this infection?

A

Severity of infection depends on number of days out of six scotch tape test positive
-usually no eosinophilia

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14
Q

Txt for pinworms: hygiene and meds

A

Hygiene: wash hands, trim nails, wash bedding

Vermox® (mebendazole) 100 mg po stat repeat at 2 (and 4) weeks

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15
Q

why do you need to repeat vermox for pinworms at 2 and 4 weeks?

A

it doesn’t kill eggs, so you kill with drug when new eggs hatch

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16
Q

When a (reliable) parent comes in and says that she saw worms in her kid’s stool, or crawling out of anus,is that evidence enough to treat for pinworms?

A

yes!

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17
Q

what is the most common parasitic disease in the world? how many people are infected with this?

A

Ascariasis (round worm)

1 billion people

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18
Q

life cycle of ascariasis/round worm/nematodes

A

eggs passed in feces, where they can remain in the soil for 2-3 years.

Eggs are ingested and hatch; larvae penetrate the intestinal wall, the heart wall to the lungs, lymphatics, bloodstream.
They travel to lungs where they mature.
worms go to small bowel and grow to adult/reproductive age

19
Q

physical length and lifetime length of ascariasis

A

Adult worms are 20-30 cm long, live for a year

20
Q

4 symptoms for ascariasis. What may the people see

A

worms from mouth or anus

can cause obstruction, cough, stomach pain, malnutrition

21
Q

Dx for Ascariasis

A

Fecal smear/ O &P

22
Q

What drug txt do you us for ascariasis, when do you recheck? why?

A

Mebendazole (Vermox)

recheck stools in 2 weeks (b/c no resevoir for eggs for these)

23
Q

rare complications from ascariasis

A

bowel obstruction
perforation and peritonitis
abscess

24
Q

how does one get tapeworm/cestodes ?

A

Person eats contaminated food- undercooked beef or pork meat- and gets infected

25
Q

what is unique about the tapeworm lifecycle?

A

lies dormant in the beef or pork muscle (in cysterici), then when ingested by person were they mature, then eggs or proglottids passed in feces.
* if a person ingested just the eggs, they will not get the infections because the worm needs the pork/beef for part of its lifecycle.

26
Q

tapeworms. there are usually how many? any symptoms?

A

Usually only one tapeworm

Usually asymptomatic

27
Q

txt for tapeworms

A

Appropriate drug followed by laxative (laxative b/c the hooks hold on very tight and you need to flush out proglottids (segments) and eggs)

28
Q

what is cystircercosis ?

A

Infx caused by eating eggs of larval stage of pork tapeworm from infected feces.

29
Q

what do the larval tapeworms of cystircercosis do in the human? where in the body do they localize?

A

Host is “supposed to be” the pig, so larvae are at a dead end, just hang out, take up space.
can localize anywhere in the body, but usually to the CNS

30
Q

what is the causitive agent for cysticerosis?

A

Larval stage of Taenia solium (pork tapeworm)

31
Q

a recent immigrant with new onset seizures, what do you think it might be?

A

Cysticercosis

32
Q

what does “symptoms secondary to mass effect” mean?

A

for cystercercosis- larva take up space in the brain (expanding mass) and symptoms are from this- HA, seizure,etc.

33
Q

why is the txt for cysticercosis controversial?

A

treatment can cause inflammation and swelling in brain (leading herniation and death). if you treat- you need to give steroids as well to deal with the subsequent inflammation

leave them alone if you can (b/c larva wont grow )

only treat if seizures are bad, weight cost and benefit

34
Q

what is the most common protozoa associated with intestinal human illness? what kind of protozoa is it?

A

Giardia (a flagellate)

35
Q

what is the most virulent kind of protazoa ameba?

A

Entamoeba histolytica (“breaks tissues”)

36
Q

epidemiology of entamoeba histolytica: how many are infected worldwide?

A

50 million worldwide infected

37
Q

usual symptoms of entamoeba histolytica

A

Typically get colitis symptoms

“amebic dysentery”

38
Q

what is the non-pathogenic form of entamoeba histolytica? what is the difference between the two? (weeds maybe)

A

E. Dispar:

nonpathogenic form- looks the same (microscopically), but has no symptoms (usually)

39
Q

Dx to E. histolytica

A

Microscopy: ID parasite in stool: O & P X 3
Serology: antibodies positive only for histolytica
Colonoscopy

40
Q

Txt for E histolytica? what is the cure rate? what must you do after treatment?

A

Metronidazole (Flagyl): 750 mg po tid x 7-10 days
90% cure rate
Test of cure after Tx

41
Q

epidemiology for giardia: wary of locations with _____ ______. how is it transmitted?

A

poor sanitation. transmission if person-to-person and through food/water

42
Q

Dx and Treatment for giardia?

A

Dx: Stool O & P x 3
txt: metronidazole

43
Q

3 major points for summary of this unit

A

Wash your hands! Boil water or use a filter.
Remember to get a travel history
Have a high index of suspicion with immigrants and travelers