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Parasitic Worms that cause Abdominal Pain 12-4

OM3 - Jackson - 1hr
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Describe Trematodes
Flatworms (bilaterally symmetric) with complex life cycles
Snails and fish for intermediate hosts
- Cause diseases of the lungs, liver, intestines, blood, with eosinophilia
describe the life cycle of Fasciolopsis buski (intestinal trematode)
contaminated pig feces gets into water where egg hatches and grows in snails then becomes free swimming & attaches to water plant which can infect a human if ingested
A __-year old patient from a place with poor sanitation presents with abdominal pain, + diarrhea. Stool cultures were negative for bacterial pathogens, but positive for helminth eggs. Hematological studies were remarkable for eosinophilia. Examination revealed hepatomegaly and abdominal tenderness. A few weeks ago the patient had a macular rash on his lower leg associated with wading in a local pond.
what is the cause?
schistosomiasis
Describe the characteristics of cestodes (tapeworms)
flat ribbon-like parasitic worms that lack complete digestive tracts, blood vessels & body cavities & are hermaphrodites.
3 body parts: head (scolex), neck & body segments (proglottids)
- can grow up to 10m long
A ___-year old patient from ___________ presents with abdominal pain, +/- diarrhea. Stool cultures were negative for bacterial pathogens. Hematological studies were remarkable for eosinophilia.
what is the most likely causative organism?
cestode; Taenia saginata or solium
Describe the life cycle of Taenia saginata & Solium (cestodes)
cows (saginata) & pigs (solium) eat vegetation contaminated with eggs which then penetrate the animal intestinal wall and develop in the muscle. Humans are infected by eating raw or undercooked infected meat
what is the diagnostic indication of T. saginata or solium?
eggs seen in feces
A __-year old patient who is a recent immigrant from ____________ presents complaining of headaches for several days and an epileptic-type seizure.

1. what is the most likely cause
2. what test can rule in your Diagnosis?
1. neurocysticercosis from ingestion of the eggs of T. solium
2. eggs seen in feces
describe the characteristics of Cysticercosis
- develop from ingested eggs (fecal-oral)
Cysticerci lodge in organs and tissues & can remain viable up to 5 years
-**Most prevalent parasitic infection of the CNS
Describe the clinical presentation of Cysticercosis
Hydrocephalus, seizures, meningitis, visual defects
A __-year old patient from ______________ presents with abdominal pain, + diarrhea. Stool cultures were negative for bacterial pathogens. Patient shows signs of anemia. The history includes eating raw fish.
what is the most likely causative organism?
diphyllobothrium latum! (the dreaded fish tapeworm)
what complication is associated with diphyllobothrium latum?
B12 deficiency anemia
where is diphyllobothrium latum (fish tapeworm) found?
cooler climates in fresh water lakes
A __-year old patient from ______________ presents with abdominal pain and distention, and jaundice. Stool cultures were negative for bacterial pathogens. History of contact with sheep dogs.

what is the most likely causative organism?
echinococcus spp.
describe the characteristics of echinococcus
small tapeworms (5mm long) with 3 proglottids, hooks & suckers for attachment.
Canines are definitive host
associated with hydatid cyst disease
what are hydatid cysts?
fluid filled cysts w/germinal material of echinococcus
- than most often form in the liver & lungs, although can grow anywhere
describe the common clinical presentations of echinococcus
- hepatomegaly with right upper quadrant pain, or
- cough, chest pain, dyspnea, or
- brain mass with neurologic symptoms
= depending on location of hydatid cyst formation
A ________-year old patient from rural S.E. U.S.A. presents with abdominal pain, +/- bloody diarrhea. Stool cultures were negative for bacterial pathogens. Hematological studies were remarkable for elevated IgE.

what is the most likely causative organism?
trichuris trichiura (whipworm)
Describe the pathogenesis of trichuris trichiura infection
due to poor sanitation.
- infection due to human ingesting egg in contaminated soil (eggs must mature in soil)
- found worldwide & S.E. US
describe the clinical presentation of trichuris trichiura (whipworm) infection
abdominal pain/discomfort, diarrhea, nausea, anemia, and rectal prolapse may occur
A ________-year old patient from rural S.E. U.S.A. presents with abdominal pain, + diarrhea, and a history of asthma-like symptoms. Stool cultures were negative for bacterial pathogens. Hematological studies were remarkable for eosinophilia and elevated IgE.

what is the most likely causative organism?
ascaris lumbricoides
what are the characteristics of ascaris lumbricoides & pathogenesis of infection
large intestinal nematode
- infection due to ingestion of eggs in contaminated soil (eggs must mature in soil for 2-3 weeks).
larvae migrate thru lungs
-found in warm climates & poor sanitation
describe life cycle of ascaris lumbricoides
fertilized egg in soil is ingested. larva hatch from eggs in gut & penetrate intestinal wall & enter blood & migrate to lungs causing pulmonary symptoms. It can then be coughed up & reinfect person.
- free swimming & can cause obstruction in intestine
Describe the clinical presentation of ascaris lumbricoides
ranges from asymptomatic -> fever -> pneumonitis -> abdominal pain and/or obstruction -> liver damage -> appendicitis -> pancreatitis
A 11-year old girl was brought to your clinic by her mother for evaluation. She complained of crampy abdominal pain and some diarrhea for the last 7 -10 days. On the afternoon she was brought in the patient thought she had an "accident" in her pants. Her mother found something moving in her underpants which she thought looked like an earthworm.
There was no fever, cough, or significant travel history. Physical exam was unremarkable.

what is the most likely organism?
ascaris lumbricoides
A ________-year old patient from rural S.E. U.S.A. presents with abdominal pain, +/- bloody diarrhea. Stool cultures were negative for bacterial pathogens. Hematological studies were remarkable for eosinophilia, elevated IgE and anemia. There may be a history of ground itch.

what is the most likely causative organism?
ancylostoma & Necator (hookworms)
Describe the characteristics of ancylostoma & necator
Infective filariform larvae penetrate skin ('Ground itch')
Larvae migrate through lungs -> -> intestines
Adult worms attach in the gut and suck blood

-repeated infection can cause anemia
Describe the characteristics of Strongyloides stercoralis
Found in S.E. U.S.A and tropics
Infective filariform larva penetrates skin
Eggs hatch in the intestines -> larvae passed

*Autoinfection can lead to hyperinfection*
Describe the clinical presentation of strongyloides stercoralis infection
Cause pneumonitis, epigastric pain, vomiting, diarrhea, eosinophila
Describe the process of autoinfection with strongyloides stercoralis
larvae in the large intestine become filariform larvae form & penetrate intestinal mucosa or perianal skin & enter circulatory system & travel to lungs where they enter alveoli & are coughed up & swallowed & can reinfect as adult worms in the intestine by depositing eggs in the mucosa, which will repeat the lifecycle.
A 20-year-old college student presents to your office for a routine sports physical. Two years ago he spent six months in Europe visiting relatives on their sheep farm. Vital signs are normal, but you note an enlarged liver on physical exam, and 6% eosinophilia in the blood. CT scan of the abdomen revealed a cyst lesion within the right lobe of the liver. What infectious agent most likely responsible?
echinococcus - small tapeworm
Describe the clinical presentation of enterobius vermicularis (pinworm) infection
peri-anal itch, abdominal pain
-scotch tape will reveal eggs on peri-anal skin
most often seen in young children & most common worm infection in US
describe the characteristics of enterobius vermicularis
Infection usually acquired from ingesting eggs
pinworm
Describe cutaneous larva migrans
Caused by dog and cat hookworms
Infective larvae penetrate skin & travel under skin
Describe the characteristics of larva migrans
d/t toxocara spp. (intestinal nematode of cats & dogs)
- humans accidentally ingest eggs
-symptoms dependent on migration & # of larvae
Your patient is a 6-year-old boy who lives in a small town in the southeast U.S.A. He has been generally well, although a little below average in size. He appears slightly malnourished. His mother explains that he has had some abdominal pain, nausea, and lack of appetite for the past 2 weeks. A routine cbc revealed elevated eosinophils. Which of the organisms would be on your list of suspects?
ascaris lumbricoides
strongyloides stercoralis
A five-year-old child from a southern U.S. state develops abdominal pain, projectile vomiting and a swollen abdomen. An x-ray shows dilated loops of bowel consistent with small bowel obstruction. What parasite is the most likely cause?
ascaris lumbricoides
Describe the following for flukes (trematodes):
1. transmission
2. clinical disease & unique characteristics
1. Ingesting raw fish, crabs, or water plants

2. Dependent on the species may be: hepatomegaly, abdominal pain, diarrhea, cough, dyspnea, eosinophilia
Describe the following for schistosoma (blood flukes) (trematodes):
1. transmission
2. clinical disease & unique characteristics
1. Cercariae in contaminated water penetrate skin
2. Abdominal pain, diarrhea, hepatosplenomegaly, fever, eosinophilia
Describe the following for Taenia saginata & solium (cestode):
1. characteristic
2. transmission
3. clinical disease & unique characteristics
1. tapeworm
2. ingesting contaminated beef or pork
3. Mild GI upset, cramps; Abdominal discomfort, diarrhea
Describe the following for Cysticercosis:
1. transmission
2. clinical disease & unique characteristics
1. Cysticerci develop from ingested eggs
2. Seizures, hydrocephalus, meningitis, visual defects
Describe the following for Diphyllobothrium latum (fish tapeworm):
1. characteristic
2. transmission
3. clinical disease & unique characteristics
1. tapeworm
2. Ingestion of raw fish
3. Abdominal pain, diarrhea, nausea, vomiting, vitamin B12 deficiency anemia
Describe the following for Echinococcus spp.:
1. characteristic
2. transmission
3. clinical disease & unique characteristics
1. hydatid cyst disease; cestode, tapeworm
2. Ingestion of eggs; associated with canines
3. Hydatid cysts can cause brain, liver, bone, kidney damage; anaphylaxis with ruptured cyst
Describe the following for Trichuris trichiura (whipworm):
1. characteristic
2. transmission
3. clinical disease & unique characteristics
1. nematode
2. Ingesting eggs; worldwide; warm climate
3. Diarrhea with blood, rectal prolapsed
Describe the following for Ascaris lumbricoides:
1. characteristic
2. transmission
3. clinical disease & unique characteristics
1. nematode (resembles earth worm)
2. Ingesting eggs; worldwide; warm climate
3. Abdominal pain, obstruction;
Migrating larval form produces asthma-like symptoms, eosinophilia
Describe the following for Ancylostoma & Necator (hookworms):
1. characteristic
2. transmission
3. clinical disease & unique characteristics
1. nematode
2. Larval form penetrates skin
3. Diarrhea, anemia, migrating larvae cause pneumonitis & eosinophilia
Describe the following for Strongyloides stercoralis:
1. characteristic
2. transmission
3. clinical disease & unique characteristics
1. nematode
2. Larval form penetrates skin
3. Epigastric pain, diarrhea, migrating larvae cause pneumonitis, eosinophilia; "Autoinfection", "Hyperinfection syndrome"
Describe the following for Enterobius vermicularis (pinworm):
1. characteristic
2. transmission
3. clinical disease & unique characteristics
1. nematode
2. Ingestion of eggs from contaminated soil
3. Peri-anal itch; children in day care; scotch tape prep
Describe the following for cutaneous larva migrans:
1. characteristic
2. transmission
3. clinical disease & unique characteristics
1. dog & cat hookworms
2. Larval form penetrates skin
(Beaches)
3. Raised serpiginous skin lesions, "Creeping eruption"
Describe the following for visceral larva migrans:
1. characteristic
2. transmission
3. clinical disease & unique characteristics
1. toxocara spp.; nematode (dog or cat)
2. Ingestion of eggs
3. Symptoms depend on organ(s) involved and the number of worm larvae; eosinophilic granulomas