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Trop Med > Trematodes > Flashcards

Trematodes Flashcards

1
Q

Life cycle of all trematodes?

A

Miracidium comes out of egg
Travels to snail - 1st intermediate host
Forms sporocyst inside snail
1st and 2nd gen redia form
Redia -> larvae known as cercariae
Cercariae (L3) -> metacercariae (encysted) on plant
Ingested by humans or penetrate skin

Cercariae only in schistosomiasis - need to penetrate skin

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2
Q

Multiple liver cysts

A

Fasciola
Chlonorchis sinensis Opistorchis viverrini /felineus
Toxacara
Echinococcus
Entamoeba

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3
Q

What is the difference in pathology between fasciola and chlonorchis/opistorchis?

A

Fasciola invades directly through bowel to liver

Chlonorchis/opistorchis travels through ampulla of water - less symptoms but does cause biliary obstruction

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4
Q

Why may you not see eggs in the faeces with fasciola?

A

In acute fasciola, immature flukes travel from bowel to liver, and do not produce eggs

Only chronic phase, adults live in biliary tract

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5
Q

Which other tests are helpful in ∆ of fasciola if the stool microscopy is negative?

A

Eosinophila
Serology - ELISA - Fas2 (vomit from parasite)

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6
Q

Rx of fasciola?

A

2 doses of Triclabendazole

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7
Q

How can you monitor Rx for fasciola?

A

Eosinophils
Stool samples - pass eggs in stool - live in biliary tract after acute infection where they are in liver

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8
Q

What are the symptoms of chronic fasciola infection?

A

Cholangitis, biliary obstruction - live in biliary tract

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9
Q

Acute symptoms and signs of fasciola?

A

weight loss, abdominal pain, fever, diarrhoea

hepatomegaly, jaundice, splenomegaly

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10
Q

Where does fasciola travel to?

A

Liver
Then lung, peritoneum, abdomen

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11
Q

What do you do if a patient fails initial Rx to fasciola?

A

Repeat triclabendazole Rx, same dose

There is some resistance to Rx being seen!

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12
Q

Intermediate/definitive host in fasciola hepatica?

A

Intermediate -
1st - snail
2nd - human

Definitive -
Sheep
Cattle

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13
Q

What alternative drug can you use for managing fasciola?

A

Nitazoxanide

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14
Q

How do fasciola affect the liver?

A

parenchimal destruction
Abscess formation

Later:
Obstruction and dilation of bile ducts, fibrosis, abscess and granuloma, cholangitis

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15
Q

What is this, why and what is distinct about it?

A

Fasciola hepatica

Partially opened operculum
LARGE!

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16
Q

What is the difference between a cercariae and metacercariae?

A

Metacercaricae encapsulated in a cyst
(Schisto does not have because doesn’t go through GI tract - I think)

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17
Q

What is the larval stage of trematodes known as?

A

Cercariae

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18
Q

What is specific about anatomy of trematodes?

A

Haemaphrodite - can produce eggs

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19
Q

What structure is this?

A

Cercariae

Look for any surface to form a cyst or can just form a cyst in water

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20
Q

How many months until you see eggs in stool following infection with fasciola?

A

3-4 months

(ELISA 2-3 weeks)

Adult only forms once larval stage have migrated to liver -> bile duct

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21
Q

When do you see eosinophilia in fasciola infection?

A

acute phase

Often normal in chronic phase

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22
Q

What will happen if you ingest the fasciola eggs?

A

Nothing!
Need to Ingest the metacircariae

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23
Q

6 yr old boy presenting with haemoptysis and new onset seizures, has a nodular appearance on CT head and nodular lesions on CT chest. ∆?

A

Paragonimus westermani (classical)

In Latin America - P.mexicana

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24
Q

How does paragonimus present?

A

Chronic cough, SOB, haemoptysis.
Can have CNS lesions
May get a skin nodule

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25
Q

How do you ∆ paragonimus?

A

Ova in sputum, stool, CSF, pleural fluid

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26
Q

How do you Rx paragonimus?

A

Praziquantel

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27
Q

Best test in the acute phase for F.Hepatica?

A

ELISA

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28
Q

Trematode most commonly found in Korea/China/Thailand/ Vietnam?

A

Chlonorchis sinensis and Opistorchis viverrini / felineus

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29
Q

Intermediate host for Chlonorchis sinensis and Opistorchis viverrini / felineus?

A

Fish

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30
Q

Which of the trematodes produce biliary obstruction and inflammation?

A

F.Heptica/Gigantica
Chlonorchis sinensis and Opistorchis viverrini / felineus

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31
Q

∆ of Chlonorchis sinensis and Opistorchis viverrini / felineus

A

Eggs in Stool OR ELISA

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32
Q

Rx of Chlonorchis sinensis and Opistorchis viverrini / felineus

A

Praziquantel

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33
Q

What is the species also known as the Great Intestinal Fluke in China?

A

Fasciolopsis buski

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34
Q

∆ and Rx of Fasciolopsis buski?

A

Eggs in stool
Praziquantel

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35
Q

Which species has a crab as its intermediate host?

A

Paragonimus westermani/mexicanus

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36
Q

What is the classic clinical presentation of Paragonimus westermani/mexicanus?

A

Lung symptoms - haemoptysis, cough, SOB

(penetrate diaphragm)

Also
* Rash and urticaria
* Marked eosinophilia
* Abdominal symptoms

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37
Q

How do you ∆ paragonimiasis?

A

Eggs in sputum
Eggs in stool
CXR - soap bubble appearance of granulation

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38
Q

Rx of paragonimiasis?

A

Praziquantel

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39
Q

What are the 3 species of schistosoma?

A

Schistosoma mansoni
Schistosoma japonicum
Schistosoma haematobium

40
Q

Different patterns of disease of the schistosoma species?

A

Schistosoma mansoni - periportal fibrosis
Schistosoma japonicum - periportal fibrosis and CNS
Schistosoma haematobium

41
Q

Intermediate host for schistosoma?

A

Freshwater snail

42
Q

Difference of schistosoma to other trematodes in transmission?

A

Cercariae perforate skin directly as opposed to GI tract

43
Q

What is the name of the stage of the life cycle when schistosomiasis species penetrate the skin?

A

Schistosomulae (from cercariae)

Do not have metacercariae (encysted)

44
Q

Where do the schistoma adults migrate to?

A

Schistosoma mansoni and Schistosoma japonicum - venuous plexus of bowels - portal veins
Schistosoma haematobium - venous plexus of bladder

45
Q

Diagnostic test for schistosomiasis?

A

Eggs in stool or eggs in urine depending on species

46
Q

What is classic symptom for schistosomiasis?

A

Swimmers itch as the L3 larvae pass through skin, maculopapular rash as site

Go to lungs - eosinophilic pneumonitis - katayama fever

47
Q

Which of the schistosoma species is in South America?

A

Mansoni

48
Q

What is katayama fever and when does it occur?

A

Acute schistosomiasis (Katayama fever):
fever (not always), prostration,
hepatosplenomegaly, lymphadenopathy,
eosinophilia.

4-8 weeks after exposure
Reaction to egg-laying

49
Q

Symptoms of chronic schistosomiasis?

A

Chronic schistosomiasis (S.mansoni, S. japonicum)
- Early: abdominal pain, colonic polyps
- Late: portal fibrosis, portal hypertension, hepatosplenomegaly, variceal bleeding.

Chronic schistosomiasis (S. hematobium)
- Early: hematuria, dysuria, bladder polyposis
- Late (rare in Europe,N.Am.): hydroureter, hydronephrosis, UTI, female reproductive tract, ca of bladder

50
Q

Which species causes neuroschistosomiasis?

A

Japonicum (4%)

Very rarely haematobium, spinal cord

51
Q

How else can you test for schistosomiasis apart from direct exam of stool or urine? Who is this useful for?

A

ELISA

Expats with light infection (not see eggs)

52
Q

Name the species?

A

Mansoni

53
Q

What is a differential for swimmers itch?

A

Avian schistosomiasis - duck schistome, itchy cannot complete life cycle. Found in USA/Canada and SA.

54
Q

Rx of schistosomiais?

A

Praziquantel 4-6 weeks post infection (adulticidal)

55
Q

How else can you manage schistosomiasis acutely?

A

artemisinin - most effective against the schistosomula - can take it earlier than praziquantel.

56
Q

How do you Rx acute katayama fever?

A

Praziquantel and prednisolone

Plus praziquantel 4-6 weeks after predicted infection

57
Q

What is the species?

A

S.Haematobium

58
Q

Name the species?

A

S.Japonicum or S.Mekongi

59
Q

How do you differentiate a live vs dead schistosoma egg on microscopy?

A

Flame cell inside the embryo

60
Q

What type of organism is schistosomiasis?

A

Trematode

61
Q

What is the infective stage of schistosomiasis? How?

A

Cercariae - Penetrate skin. Larval stage L3

62
Q

How does schistosoma cause disease?

A

Migration through skin, through venous system to portal system, liver, bladder (depending on species)

63
Q

What is the intermediate host for schistosomiasis?

A

Fresh water snails

64
Q

How do you treat schistosomiasis?

A

Praziquantel 4-6 weeks after exposure

65
Q

Name the species

A

Schistosomiasis mansoni - lateral spine

66
Q

What is acute katayama fever? How do you treat it?

A

Acute toxaemic schistosomiasis. fever (not always), prostration,
hepatosplenomegaly, lymphadenopathy, eosinophilia.
Prednisolone + praziquantel plus repeat prazi 4-6 weeks later

67
Q

What are the intermediate and definitive hosts for Fasciola hepatica/fasiola gigantica?

A

Intermediate: Lymnea snail
Definitive: Sheep or cattle

68
Q

What are the symptoms of Fasciola hepatica/fasiola gigantica?

A

*Liver parenchimal destruction and dilatation of bile ducts
* Abscess formation in liver
* Adults flukes - release protests - can cause dilation of bile ducts, fibrosis, abscess and granuloma (particularly around egg) - abdo pain, fever, weight loss, diarrhoea

69
Q

How do you diagnose fasciola hepatica?

A

ELISA
Rapid sedimentation technique of stool

70
Q

Management of F.hepatica?

A

Triclabendazole

71
Q

Name the species

A

Chlonorchis sinensis

72
Q

How do you treat the haemaphroditic trematodes?

A

praziquantel (except F.hepatica)

73
Q

What is the giant intestinal fluke?

A

Fasciolopsis buski

74
Q

What are the first/second hosts for fasciolopsis buski?

A
  1. Snails -> microcircariae travel to plants (ingested by humans)
75
Q

How does paragonimus westermani present and why?

A

From gut - Penetrate diaphragm - lung symptoms

76
Q

How is paragonimus transmitted?

A

1st host snail. Cercariae travel to 2nd host - crustacean or crab

77
Q

What is the liver fluke, lung fluke, blood fluke and intestinal fluke?

A

Liver = fasciola hepatica/gigantica, Chlonorchis sinensis and Opistorchis viverrini / felineus
Lung = paragonimus westermani/mexicana
Blood = schistosoma spp

78
Q

Anatomical features of a trematode (not schistosomiasis)?

A

2 ventral suckers
no digestive tract
Haemaphrodites

79
Q

What first intermediate host is common to all trematodes?

A

Snail

80
Q

Infective stage of all trematodes?

A

Metacercariae (Cercariae in schistosomiasis)

81
Q

What is this and why?

A

Fasciola hepatica/gigantica
- Cephalic cone

82
Q

What is this?

A

Fasciola hepatica

83
Q

Name the species and the Rx

A

Fasciola hepatica (unembryonated egg - big egg, open operculum and symmetrical)
Triclabendazole

84
Q

Clonorchis/opistorchis why presents with jaundice?

A

Travels up biliary tree instead of through the intestine

85
Q

Which trematode has an association to Cholangiocarcinoma?

A

Opistrochis/Clonorchis

86
Q

Name the species, life cycle stage and the Rx?

A

Adult Clonorchis/Opistorchis spp.
SAUSAGE shaped, no cephalic cone
Praziquantel

87
Q

Where do you get Clonorchis/Opistorchis?

A

Asia

88
Q

Name the species

A

Clonorchis/Opistorchis
20-30microm
Shoulders (more obvious in clonorchis)
Tail like a hook
Looks like a mouse!

89
Q

What is this species?

A

Adult clonorchis sinensis/opistorchis viverrini

90
Q

What is this species?

A

Paragonimus
No cephalic cone
Ventral sucker is very low down - like
Tiny adults

91
Q

What is this species and why? Where will you isolate it from?

A

Egg of paragonimus.
Asymmetrical egg
Has shoulders
Thickened operculum
From sputum and stool

92
Q

What is this species?

A

Schistosoma spp
Male big
Female small

93
Q

What is the name of the schistosomiasis life cycle stage that travels to the venules of venous Plexi?

A

Schistosomulae

94
Q

How do you get eggs in faeces of schistosomiasis?

A

Block hepatic portal triads, they rupture and causes eggs in faeces

95
Q

What investigations would you do in the case of schistosomiasis positive either O&P or serology?

A

LFTs, fibroscan, renal tract imaging etc.

Trop Med (49 decks)

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