- Larvae in soil penetrates bare feet - Travels (blood to lungs to trachea) then swallowed - Attaches to intestinal wall (upper small intestine) - Matures and sucks blood - Lives about 5 years and deposits 7000 eggs per day

Iron deficiency anemia - N. Americanus 0.03 ml blood/day - a. Duodenal 0.2 ml blood/day

Usually none High burden: - abd pain - intestinal obstruction Migrating wroms - symptomatic occlusion of the biliary tract - oral expulsion Lung phase - cough - hemoptysis - dypsnea - loeffler’s syndrome

15 - Nematodes Flashcards by michael english

Definition of nematodes?

Unsegmented worms with
elongated rounded body
pointed at both ends;
mostly free-living but
some are parasitic  of
varying length.  Anatomic
structures include mouth,
gut and anus.

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MC nematodes?

world: (ascariasis)

US: (pinworm)

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Intestinal nematodes?

Strongyloidiasis
Ascariasis
Hookworm
Enterobiasis

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Cutaneous larvae migrans?

Toxocariasis

Trichinosis (trichinellosis)

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Strongyloidiasis is found?

Worldwide
- tropical and subtropical

S. USA
- rural/poor/institutional areas

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Strongyloidiasis lifecycle?

Infection
• Larvae in soil penetrates bare feet
• Travels via blood to lungs - trachea then swallowed
• Attaches to intestinal wall, matures and lays eggs

Autoinfection
• Eggs travel with feces
• Some turn into larvae and infect colon
• Larvae penetrates colon wall
• Travels via blood to lungs - trachea and swallowed
• Attaches to intestinal wall - may disseminate •

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Asymptomatic strongyloidiasis pts?

1/3 of patients are asymptomatic

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strongyloidiasis s/s?

Gastrointestinal symptoms
• Abdominal pain
• Diarrhea

Pulmonary symptoms – Loeffler’s syndrome
• During pulmonary migration

Dermatologic manifestations
• Urticarial rashes

Disseminated strongyloidiasis

Eosinophilia
• Acute and chronic stages
• Absent with dissemination

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strongyloidiasis tests and diagnostics?

Microscopic infection of larvae

stool/duodenal fluid
enterotest string
duodenal aspiration

EIA

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With strongyloidiasis (and really all parasite) testing___?

Serial samples are probably necissary

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Tx for strongyloidiasis?

Ivermectin (Stromectol)

Albendazole (Albenza)

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2nd MC world wide worm?

Ancylostoma duodenal

Nectar americanus

(1 billion ppl infected)

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Hookworm infection?

Larvae in soil penetrates bare feet
Travels (blood to lungs to trachea) then swallowed
Attaches to intestinal wall (upper small intestine)
Matures and sucks blood
Lives about 5 years and deposits 7000 eggs per day

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S/s of hookworms?

“Ground itch” at site
Pneumonitis
Intestinal upset
IDA
Pica
Chronic protein malnutrition

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MC s/s of hookworm?

Iron deficiency anemia
- N. Americanus 0.03 ml blood/day

a. Duodenal 0.2 ml blood/day

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Tests and diagnostics for hookworm?

Microscope (eggs)

americanus and duodenale are morphologically identical
larvae can differentiate

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Tx for hookworm?

3rd world
- doesn’t treat asymptomatic cases

Albendazole (albenza)
Mebendazole (vermox)

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Mc helminth ww?

Ascaria lumbricoides

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Largest intestinal nematode?

Ascariasis (15-35cm)

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Ascariasis lifecycle?

Infection- fecal-oral
• Ingested eggs hatch into larvae 
• Larvae penetrates intestinal wall 
• Travels via blood to lungs 
• Then to trachea and swallowed 
• Back to intestinal lumen where it matures 
• Does not attach (jejunum and middle ileum) 
• Releases 200,000 eggs/day

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Ascariasis s/s?

Usually none

High burden:

abd pain
intestinal obstruction

Migrating wroms

symptomatic occlusion of the biliary tract
oral expulsion

Lung phase

cough
hemoptysis
dypsnea
loeffler’s syndrome

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Ascariasis testing and diagnostics?

Microscopic exam of eggs in stool (MC)

Barium exam of intestines

Tx for ascariasis

Albendazole

Mebendazole

Human pinworm is aka?

Enterobius vermicularis

Hosts for enterobiasis?

Only humans

Size of enterobiasis?

Females - 8-13mm | Males - 2-5mm

MC helminth infection in US?

Enterobiasis Especially school kids

Enterobiasis lifecycle?

Orally ingested eggs hatch into larvae Then mature and reside in the colon (cecum) After mating, female pinworms travel to the anus • Usually at night -- lay eggs (11,000/night) • Pruritus ani ``` Eggs associated with: • Hands (fingernails) • Night clothes/pajamas • Bedding • Air and dust ```

Enterobiasis s/s?

Asymptomatic (go figure) ``` Perianal puritis (night) Excoriations and bacterial super infection Invasion of female genital tract - pelvic or peritoneal granulomas Appendicitis or chronic salpingitis ```

Tests for enterobiasis?

Microscopic exam - perianal area (AM) - before defecating and washing Scotch tape test - up to 5 may be required

Tx for enterobiasis?

Mebendazole (vermox)

Pt and fam education for enterobiasis?

Prevention of reinfection Personal hygiene Laundering of bedding

Cutaneous larva migrans (CLM) is aka?

Ancylostoma caninum

How does CLM transfer?

Penetrates the skin (like hookworm)

with CLM, humans are?

Accidental host

CLM is the MC ___?

Tropically acquired dermatosis

S/c of CLM?

Intense prurititus Erythematous - linear lesions that advance

CLM diagnosis?

The classic appearance of the lesion Slide 33

Tx for CLM?

Albendazole Ivermectin (stromectol) Avoid going barefoot in endemic regions (so anywhere outside your bubble)

Toxocariasis is?

Larvae of toxocara canis (dog roundworm)

Toxocariasis causes?

Visceral larva migrans (VLM) Ocular larva migrans (OLM)

Lifecycle of toxocariasis?

Fecal-oral Penetrate gut lumen - travel through body

Toxicariasis s/s?

Usually asymptomatic or mild febrile illness - fever - wt loss - cough - wheezing - rashes - hepatosplenomegaly - hypereosinopilia - ocular larva migrans (OLM) - opthalmologic lesions - leukokoria

Toxocariasis is sometimes misdiagnosed as?

Retinoblastoma (leukokoria) | - leads to accidental surgical enucleation (removal of tumor)

Toxocaris diagnosis?

NO O and P findings Presumptivs/clinical dx

Tx for toxocariasis?

Albendazole (albenza) | Mebendazloe (vermox)

Trichinellosis is aka?

Trichionosis

Trichinellosis comes from?

Eating carnivores (humans are accidental host)

What doesnt prevent Trichinellosis?

Smoking Salting Drying Does not kill the cysts

Different types of trichinella spiralis?

T. Pseudospiralis - mammals/birds w/w T. Nativa - arctic bears T. Nelsoni - African predators T. Britovi - carnivores of EU, W Asia

S/s of trichinellosis?

Light infections are asymptomatic Intestinal invasion • Diarrhea • Abdominal pain • Vomiting ``` Larval migration –invasive phase • Periorbital and facial edema- 77% • Conjunctivitis- 55% • Fever- up to 104 F • Myalgias/weakness- 88% • Rash macular or petechial- 15-65% • Splinter hemorrhages- 8% ``` Life-threatening manifestations • Cardiac involvement- Myocarditis • Central nervous system involvement- encephalitis, meningitis • Pneumonia

Trichinellosis diagnosis?

``` Usually clinical Eosinophilia during migratory phase Antibody detection/EIA Muscle biopsy CT/MRI - 3-8mm nodules ```

Tx for trichinellosis?

Steroids (severe) Albendazole Mebendazole

Back in my day we played outside barefoot

And sneered at the idea of getting pinworms