Infectious Disease (Block 6): Helminths (Nematodes)

Front 1

name the four nematodes that belong to the geohelminths group (the group that is soil dwelling)

Back 1

- Ascaris lumbricoides
- Trichuris trichiuria
- Ancylostoma duodenale
- Necator americanus

Front 2

how does ascaris lumbricoides infect humans?

Back 2

humans ingest egg from contaminated soid --> larvae hatch in duodenum and invade blood to go to lungs --> swallowed back down --> adults mature in small intestines and begin laying eggs

Front 3

clinical manifestations of ascaris lumbricoides (4). who's most commonly affected?

Back 3

- children most commonly affected, usually asymptomatic/passing worms
- can get worm ball --> intestinal obstruction
- Loeffler's syndrome: cough/wheezing + eosinophilia
- worms can migrate to bile duct (cholangitis) or to pancreatic duct (pancreatitis)

Front 4

dx and tx of ascaris lumbricoides

Back 4

dx: eggs/adult worms in stool

tx: albendazole

Front 5

name the "whipworm"

Back 5

trichuris trichiuris (ok...)

Front 6

T. trichiuris infects humans through _________. then what?

Back 6

ingestion of contaminated soil with eggs --> larvae hatch and go to COLON, penetrate intestinal epithelium adn mature in the crypts

Front 7

clinical manifestations of T. trichiurus

Back 7

- mostly infect children, usually asymptomatic
- heavy infection of adult worms (>200) can lead to diarrhea, bleeding, RECTAL PROLAPSE (rarely)

Front 8

dx and tx of T. trichiurus

Back 8

dx: eggs in stool
- proctoscopy: visualize worm

tx: albendazole

Front 9

name the 2 hookworms. which two groups of people do they tend to affect?

Back 9

Ancylostoma duodenale & Necator americanus

- children and child-bearing age women

Front 10

whats the main difference bw Necator americanus and Ancylostoma duodenale?

Back 10

A. duodenale has sharper teeth and cause more bleeding and blood loss compared to N. americanus

Front 11

what do heavy infections of hookworms cause?

Back 11

iron deficiency anemia (bc of all the blood sucking) -- hookworm dz is one of the leading causes of anemia in the world

Front 12

name the pruritic (itchy) serpentine rash that animal hook worms can cause as they penetrate/migrate through skin

Back 12

"Creeping eruption" or CUTANEOUS LARVAL MIGRANS (cuz they're "migrating" through the skin)

Front 13

dx and tx of hookworms

Back 13

dx: detection of hookworm eggs in stool

tx: albendazole

Front 14

name the two groupings under Filaria; give the 2 nematodes that are under each...oh yeah, tell me where each are more commonly found too!

Back 14

adult worms live in lymphatic system:
-Wucheria bancrofti (Africa/L. America)
- Brugia malayi (Asia)

adult worms live in subcutaneous tissue
- onchocerca volvulus (W. Africa/L. America)
- loa loa (Sudan, Congo, W. Africa)

Front 15

for Wucheria bancrofti and Brugia malayi, how are larvae transmitted?

Back 15

through the bite of mosquitoes

Front 16

the 2 filaria that have adults that live in lymph nodes (what are they called again?), what do they do next?

Back 16

they live in lymph nodes and cause lymphatic obstruction. they also send out microfiliarie (modified eggs) into the blood and these mature after mosquitoes draw out blood and begin the process of transmission again...

Front 17

clincal manifestations of W. bancrofti and B. malayi

Back 17

- lymphatic filariasis: chronic lymphatic obstruction (elephantiasis)
- tropical pulmonary eosinophilia (due to larvae in lungs with pulmonary infiltrates -- nocturnal wheezing/SOB; will show elevated IgE)

Front 18

dx and tx of W. bancrofti and B. malayi

Back 18

dx: peripheral blood for microfilariae (between 10 PM - 4AM)
- serology for circulating filarial antigens, EOSINOPHILIA

tx: diethylcarbamazine (DEC) and ivermectin

Front 19

name the filaria that's responsible for river blindness

Back 19

onchocerca volvulus (one of the most common causes of blindness in the world. 99% of blindness cases due to o. volvulus happen in sub-saharan Africa)

Front 20

Onchocerca volvulus infects humans after larva are deposited on ____ after bite of the ___ fly. adult worms live in _______ and lay eggs (microfilariae) that migrate to ____ and____. tell me about the dx's that could happen at these 2 places

Back 20

skin; black (simulium)
subcutaneous nodules
skin and eyes

skin: hypersensitivity rxn with severe pruritis + eosinophilia and thickening (onchodermatitis)

eyes: keratitis with scarring ==> blindness

Front 21

dx and tx of onchocerca volvulus

Back 21

dx: - skin biopsy: identification of larvae

tx:ivermectin
- if eye is involved, give steroids

Front 22

cause of african eye worm

Back 22

loa loa (found sudan, congo, w. africa)

Front 23

Loa loa is transmitted by bite of ____ fly. adult worms migrate in ___ and ___. name the dz's they cause at each site.

Back 23

mango (Chrysops)
- soft tissues (Calabar swellingL localized cutaneous/subcutaneous allergic rxns around the migratory adult worms)
- eyes (Loiasis: migration of adult worm across conjunctiva)

Front 24

dx and tx of loa loa

Back 24

dx: - peripheral blood for microfilariae
- serologic anti-filarial antibody tests

tx: ivermectin and diethylcarbamzine (DEC)

Front 25

for all filaria, treat with_____ + _____, except for ____, which you should just use -_____.

Back 25

ivermectin + diethylcarbamazine (DEC)

onchocerca volvulus
ivermectin

Front 26

name the pinworm. what does it cause? how do you dx and tx it?

Back 26

enterobius vermicularis
- pruritis ani (itchy butt)

dx: "scotch tape" collection of eggs from perianal area

tx: albendazole

Front 27

infection of pinworms (do you rmemeber the name?) is acquired through _____. adult worms reside in the ____. eggs are deposited in the perianal area by migrating female worms. eggs cause itching. scratching brings eggs to fingers, for further transfer...

Back 27

ingestion of eggs
colon

Front 28

strongyloides is acquired through ______. how does it work in the body?what is unique about stronyloides?

Back 28

penetration of skin by contaminated soil (with larvae)

larvae migrate through the lungs, get swallowed, mature into adult worms in the intestine

what's unique is that the eggs can AUTOINFECT (unlike hookworms)
and what gets pooped out are larvae (NOT EGGS; this too is unlike hookworms)

Front 29

clinical manifestation of strongyloides

Back 29

- mostly asymptomatic
- heavy worm burden: iron deficiency, bleeding, diarrhea
- can go to llungs to give pneumonia (CAUSES EOSINOPHILIA)

Front 30

dx and tx of strongyloides. what's important about treating autoinfections?

Back 30

dx: - detection of LARVAE (NOT EGGS) in stool, sputum, biopsy

tx: ivermectin
DON'T GIVE GLUCOCORTICOIDS TO AUTOINFECTIONS OF STRONGYLOIDES

Front 31

name the nematode that you get from eating insufficiently cooked pork containing larvae

Back 31

trichinella spiralis!!

Front 32

clinical manifestation of trichinella

Back 32

myalgia, eosinophilia, periorbital edema + eye pain with fever

Front 33

dx and tx of trichinella

Back 33

dx: muscle biopsy
serology may be helpful

tx: corticosteroids!!
albendazole to kill larvae (but only with steroids)

Front 34

what 2 nematodes cause visceral larval migrans?

Back 34

toxocara canis (ingesting larvae of dogs)

toxocara catis (ingesting larvae of cats)

Front 35

where do toxocara canis/catis larvae migrate to and what do they cause?

Back 35

brain, eyes, lungs, liver, and other tissues to form cysts and granulomas

-cause abdominal pain, pulmonary infiltrates, hepatomegaly, headache, myositis, EOSINOPHILIA
- visual changes

Front 36

dx and tx of toxocara

Back 36

dx: serology
- parasites in eyes may be seen by fundoscope exam

tx: corticosteroids and albendazole

Front 37

which nematodes are ingested (3)?
which nematodes are through cutaneous invasions (3)?

Back 37

ingested: Enterobius, Ascaris, Trichinella

"You'll get sick if you EAT these!

cutaneous: Strongyloides, Ancylostoma, Necator

"These get into your feet from othe SANd"