Schistosoma: Difference between revisions
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Schistosoma
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+ | ==Background== |
*Infection with a species of the genus ''Schistosoma'' |
*Infection with a species of the genus ''Schistosoma'' |
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==Clinical Manifestations== |
==Clinical Manifestations== |
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+ | ===Swimmer's Itch=== |
| β | * |
+ | *Cercariae penetrate exposed skin and cause prickling sensation and occasionally urticaria, followed hours later by a macular rash |
| β | * |
+ | *Caused by schistosomes that do not cause systemic illness |
| β | * |
+ | *Common in Great Lakes region of North America, New England in the US, and other parts of North America and Europe |
| β | === |
+ | ===Katayama Fever=== |
| β | * |
+ | *Syndrome of acute schistosomiasis that follows 4 to 8 weeks (range 2 to 12 weeks), after the flukes have migrated, developed into adults, and have started producing eggs |
| β | * |
+ | *The syndrome represents a hypersensitivity reaction to the eggs produced by adult worms |
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+ | *More common with [[Schistosoma japonicum]] and [[Schistosoma mansoni]], and less common with [[Schistosoma haematobium]] |
| β | * |
+ | *Symptoms include abrypt onset of fever, chills, fatigue, headache, myalgias, abdominal pain, diarrhea, and occasionally bloody stool |
| β | * |
+ | *Most also develop cough, dyspnea, chest pain, and diffuse infiltrates on chest x-ray |
| β | ** |
+ | **Lung nodules contain granulomas around eggs |
| β | * |
+ | *Hepatomegaly, splenomegaly, and lymphadenopathy are common |
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+ | *Eggs may not be seen in stool until later in the course of the disease |
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+ | *Symptoms usually resolve within 2 to 10 weeks |
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+ | *Can involve symptoms anywhere the worms migrate and deposit eggs: CNS, genital tract, and skin |
| β | ** |
+ | **However, an induced small-vessel vasculitis can also cause neurological symptoms |
| β | === |
+ | ===Chronic Schistosomiasis=== |
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+ | *Can be asymptomatic or paucisymptomatic |
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+ | *Chronic granulomatous inflammation causes weight loss, anemia, stunted growth |
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+ | *[[Eosinophilia]] is common |
==Investigations== |
==Investigations== |
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**Eggs can cause granulomatous disease in various organs |
**Eggs can cause granulomatous disease in various organs |
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**Bladder polyps and obstruction may be seen on ultrasound |
**Bladder polyps and obstruction may be seen on ultrasound |
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| + | == Diagnosis == |
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| + | * Usually based on serology |
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| + | ** Can cross-react with other helminth co-infections, including [[trichinosis]] and [[filariasis]] |
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==Management== |
==Management== |
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Revision as of 10:28, 30 April 2021
Background
- Infection with a species of the genus Schistosoma
Microbiology
- Schistosoma mansoni: liver and gut
- Schistosoma haematobium: GU/pelvis
- Schistosoma japonicum: liver and gut
- Schistosoma mekongi: Mekong basin
Risk Factors
- Fresh water exposure in endemic countries
Clinical Manifestations
Swimmer's Itch
- Cercariae penetrate exposed skin and cause prickling sensation and occasionally urticaria, followed hours later by a macular rash
- Caused by schistosomes that do not cause systemic illness
- Common in Great Lakes region of North America, New England in the US, and other parts of North America and Europe
Katayama Fever
- Syndrome of acute schistosomiasis that follows 4 to 8 weeks (range 2 to 12 weeks), after the flukes have migrated, developed into adults, and have started producing eggs
- The syndrome represents a hypersensitivity reaction to the eggs produced by adult worms
- More common with Schistosoma japonicum and Schistosoma mansoni, and less common with Schistosoma haematobium
- Symptoms include abrypt onset of fever, chills, fatigue, headache, myalgias, abdominal pain, diarrhea, and occasionally bloody stool
- Most also develop cough, dyspnea, chest pain, and diffuse infiltrates on chest x-ray
- Lung nodules contain granulomas around eggs
- Hepatomegaly, splenomegaly, and lymphadenopathy are common
- Eggs may not be seen in stool until later in the course of the disease
- Symptoms usually resolve within 2 to 10 weeks
- Can involve symptoms anywhere the worms migrate and deposit eggs: CNS, genital tract, and skin
- However, an induced small-vessel vasculitis can also cause neurological symptoms
Chronic Schistosomiasis
- Can be asymptomatic or paucisymptomatic
- Chronic granulomatous inflammation causes weight loss, anemia, stunted growth
- Eosinophilia is common
Investigations
- Labs
- CBC, showing eosinophilia
- Schisto serology (only positive 6 weeks after infection)
- Egg detection in stool, urine, semen, or tissue biopsy
- Imaging
- Eggs can cause granulomatous disease in various organs
- Bladder polyps and obstruction may be seen on ultrasound
Diagnosis
- Usually based on serology
- Can cross-react with other helminth co-infections, including trichinosis and filariasis
Management
- Acute
- Praziquantel 40mg/kg given over one day split into 3 doses
- Chronic
- Praziquantel 20-40 mg/kg or 40-60 mg/kg (if at risk for S. japonica)
- Given over one day split into 3 doses, then repeated 6 weeks later
Prognosis
- Increased risk of squamous cell carcinoma, which increase with young age at infection, duration of infection, high burden of infection, and bladder wall fibrosis
References
- ^ Archana Asundi, Alina Beliavsky, Xing Jian Liu, Arash Akaberi, Guido Schwarzer, Zeno Bisoffi, Ana Requena-MΓ©ndez, Ian Shrier, Christina Greenaway. Prevalence of strongyloidiasis and schistosomiasis among migrants: a systematic review and meta-analysis. The Lancet Global Health. 2019;7(2):e236-e248. doi:10.1016/s2214-109x(18)30490-x.
