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Flashcards in SCHISTOSOMIASIS Deck (13)
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1
Q

What is the organism that causes schistosomiasis? What are the three main species?

A

Trematode called Schistoma
S. mansoni
S. japonicum
S. haematobium

2
Q

In what parts of the world is schistosomiasis endemic?

A

Sub-Saharan Africa
Southern China
Brazil
Phillipines

3
Q

What is the intermediate host of schistoma species?

A

Mollusc

4
Q

What is the cause of the pathology seen in schistosomiasis?

A

A type IV hypersensitivity to the schistoma eggs. The healing post inflammation leads to fibrosis, which is what causes the clinical problems.

5
Q

What is the initial clinical feature of schistosomiasis infection?

A

Local dermatitis at the cercarial invasion site - known as swimmer’s itch

6
Q

What are the initial clinical features of schistosomiasis after the incubation period?

A

Fever
Malaise
Myalgia
Known as Katayama fever

7
Q

How long is the incubation period of schistosomiasis?

A

1-3 weeks

8
Q

As well as Katayama fever, what are the clinical features of infection by Schistoma mansoni and S. japonicum?

A

Abdominal pain
Diarrhoea (sometimes bloody) - can mimic IBD
Wheeze and cough - more likely with S. japonicum
Hepatosplenomegaly
Transverse myelitis - more likely with S. mansoni

9
Q

What is the underlying mechanism of pathology caused by Schistoma mansoni and S. japonicum?

A

Worm passes from skin into blood stream
Settle in veins supplying bowel
Trapped egg results in inflammation and fibrosis in portal vein which leads to portal hypertension.

10
Q

As well as Katayama fever, what are the clinical features of infection by Schistoma haematobium?

A
Increased frequency of passing 
Dysuria
Haematuria
Haematospermia
Incontinence
Hydronephrosis
Renal failure
Transverse myelitis
11
Q

What is the underlying mechanism of pathology caused by Schistoma haematobium?

A

Worm passes from skin into blood stream
Settle in veins supplying bladder
Trapped eggs result in inflammation and fibrosis resulting in obstruction of ureters, hydronephrosis and renal failure.

12
Q

How is the diagnosis of schistosomiasis made?

A

Travel history
Isolating characteristic eggs from faeces or urine depending on species
Liver biopsy will show inflammation and fibrosis
Eosinophilia on FBC during Katayama fever

13
Q

How are patients diagnosed with Schistosomiasis managed?

A

Praziquantel - 1 dose for S. haematobium, 2 for other two species