Trematodes and cestodes Flashcards

1
Q

Trematodes are (segmented/non segmented) parasites flukes with a GI tract, ___ intermediate host and ___ adult host

A

Trematodes are non segmented parasites flukes with a GI tract, mollusk intermediate host and vertebrate adult host

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2
Q

Briefly describe the lifecycle of Schistosomiasis

A

Lifecycle:

Eggs released in water >> hatch as miracidia and live in snails >> asexual replication within the mollusk host >> released as miracidia into the water >> develop into cercariae are free swimming and get into human host >> bug migrates to a preferred venous plexus

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3
Q

Which spp of Schistosoma likes the venous plexus close to the bladder?

S japonicum and S mansoni like the ___ plexus

A

S haematobium likes the venous plexus close to the bladder

S japonicum and S mansoni like the inferior venous plexus in the gut

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4
Q

The __ is the intermdeiate host for the circaria

A

snail

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5
Q

What type of immune response is mounted against schistosome infection (especially against the circaria)?

A

Th1 response, eosinophils and IgE to schistosomula

**might also get mild maculopapular rash at site of cercarial penetration**

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6
Q

What happens to the circaria once they make it into the human host?

A

Once they enter the circulatory system, the cercaria shed their glycocalyx, develop a primitive gut and migrate first thru the lungs, thru the heart and to the liver to a preferred plexus (here it’s the inferior mesenteric plexus)

Will then look for a mating pair and home to their plexus

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7
Q

___ is the result of a strong antigen – antibody response (aka serum sickness) that develops when the worms produce eggs

A

Katayama fever

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8
Q

Chronic schistosomiasis is also the result of an immunologic response to eggs. Explain how this happens

A

Chronic schistosomiasis results from aberrant egg migration (to organs such as the liver or the bladder)

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9
Q

Chronic schistomiasis is characterized by the formation of a __ after an intense eosinophilic rxn to eggs in the tissues

This disease can manifest as ___

A

Over time, the eggs become trapped in tissue and cause a very intense eosinophilic rxn >> granuloma followed by fibrosis

Can manifest as bloody diarrhea, intestinal polyps and strictures

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10
Q

Which stage of schistosomiasis is characterized by the pathology below?

A

Chronic schistosomiasis

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11
Q

___ is primarily characterized by hematuria

Eggs can also go to the nervous system and cause ___

A

Urinary schistosomiasis is primarily characterized by hematuria

Eggs can also go to the nervous system and cause transverse myelitis

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12
Q

Some urinary system abnormalities caused by Schistosomiasis include ureteritis, ___ (happens in the kidneys), ___ (can become adenocarcinoma) and squamous cell bladder cancer

A

Some urinary system abnormalities caused by Schistosomiasis include ureteritis, pyelonephritis (happens in the kidneys), cystitis cystica (can become adenocarcinoma) and squamous cell bladder cancer

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13
Q

How do you Dx schistosomiasis?

A

Dx: look for eggs within the stool or urine; serologic testing (doesn’t tell active infection. Only tells exposure)

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14
Q

What is the Rx for schistosomiasis?

A

Rx: praziquantel (but the cercaria are immune so treat initially then follow up a few months later)

Drug works by paralyzing the worm then its excreted out

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15
Q

What is the mechanism of drug resistance in schistosomiasis?

A

MOR: ATP binding cassettes that pump out the drug from the parasite cells

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16
Q

2 most clinically significant liver flukes are __ and __

A

Clonorchis and opisthorcis

17
Q

Liver flukes are an important etiological cause of ___

A

These flukes burrow thru the liver and cause inflammation and pain

Important etiological cause of cholangiocarcinoma

18
Q

Infection by Diphyllobothrium latum (aka the fish tapeworm) can be acquired by ___

A

Ingestion of poorly cooked or raw fish.

Infection with these is mostly asymptomatic

**note that they live in the small bowel**

19
Q

Describe the lifecycle of the fish tapeworm

A

Unembryonated eggs are released in the feces >> embryonate in the water (eggs have a cap that pops open) >> mature into coracidia >> invade fish >> fish eaten by human host (the mature bug/scoles everts once it his the small intestine

20
Q

Presentation of infection by fishworms

A

non specific abdominal discomfort, some patients develop Vitamin B12 deficiency >> Megaloblastic anemia

21
Q

Dx of fish tapeworm infection

Rx of fish tapeworm infection

A

Dx: proglottdids/eggs in stool

Rx: praziquantel (#Prazi the Prezident who treats all trematode and cestode infections) or niclosamide

22
Q

How does one get sparganosis?

A

Sparganosis: occurs upon ingestion of molluscan intermediate host; eosinophilic and itchy infection

23
Q

What symptoms of fish infection will you see with chlonorchiasis? (liver flukes)?

A

Affected systems: eyes/skin; liver; GI

**see diagram below**

24
Q

Symptoms of diphyllobothrium infection

A

Affected systems: CNS; skin; cardiac; muscular; GI

25
Q

Life cycle of taenia solium and saginata (pork and beef tapeworm)

A

Eggs/proglottids on moist grass taken up by grazing animals >> oncospheres hatch inside intestine and migrate to muscles/other organs >> growth into cystercerci >> human host eats undercooked pork or beef OR human ingestion of oncospheres >> development of cysticercosis

26
Q

Presentation and Rx of beef and pork tapeworm infection

A

Non specific symptoms

Rx: Praziquantel or Niclosamide

27
Q

Presentation of cysticercosis

A

Generally asymptomatic but can present with seizures, hydrocephalus and brain damage >> death

**causes adult-onset Epilepsy**

28
Q

Rx for cysticercosis

A

Mainly reduction in inflammation; surgery if abscesses are big

Drugs: albendazole/praziquantel

29
Q

The main presenting feature of echinococcus (also a type of cestode) is ___

A

Liver_cysts

**know that this is ass’d with pastoral transmission so expect someone who’s been rearing cattle and sheep**

30
Q

Dx of echinococcus infection

A

CT scan, ultrasound, serologic testing (CDC), aspirate

31
Q

How dou treat echinococcus liver cysts?

A

Inactivate cyst with hypertonic saline or toxic solution and surgically remove

PAIR technique: Percutaneous aspiration, injection, respiration

Albendazole/mebendazole: High dose, long-term therapy post surgery

32
Q

51 year old Guatemalan male who presents with one episode of tonic-clonic seizure activity. Arrived in the United States 2 years prior. Currently employed at McDonalds. He has a heavy history of tobacco use. Reports that he was a pig farmer while in Guatemala.

PMHx: Tobacco use

Symptoms: Normal physical exam without focal neurologic deficit

Laboratories: Normal laboratories. WBC = 10,000 Eosinophils= 8%

MRI- T1 and T2 weighted image

  1. 2 cm lesion: Left inferior frontal gyrus
  2. 0 cm lesion: Left superior and middle frontal lobes with ring enhancement

Tx: Surgical removal of large lesion, dexamethasone, dilantin x 6 months, albendazole bid x 10 days.

Imaging is shown below. What is the Dx?

A

Neurocysticercosis