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''
== Species ==
 
   
  +
===Microbiology===
* ''[[Schistosoma mansoni]]'': liver and gut
 
* ''[[Schistosoma haematobium]]'': GU/pelvis
 
* ''[[Schistosoma japonicum]]'': liver and gut
 
* ''[[Schistosoma mekongi]]'': Mekong basin
 
   
 
*''[[Schistosoma mansoni]]'': liver and gut
== Risk Factors ==
 
 
*''[[Schistosoma haematobium]]'': GU/pelvis
 
*''[[Schistosoma japonicum]]'': liver and gut
 
*''[[Schistosoma mekongi]]'': Mekong basin
   
 
===Risk Factors===
* Fresh water exposure in endemic countries
 
   
 
*Fresh water exposure in endemic countries
== Clinical Manifestations ==
 
   
 
==Clinical Manifestations==
== Investigations ==
 
   
  +
=== Swimmer's Itch ===
* 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
 
   
  +
* Cercariae penetrate exposed skin and cause prickling sensation and occasionally urticaria, followed hours later by a macular rash
== Management ==
 
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* Caused by schistosomes that do not cause systemic illness
* Acute
 
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* Common in Great Lakes region of North America, New England in the US, and other parts of North America and Europe
** [[Is treated by::Praziquantel]] 40mg/kg given over one day split into 3 doses
 
* Chronic
 
** [[Is treated by::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 ==
+
=== 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
* Increased risk of squamous cell carcinoma, which increase with young age at infection, duration of infection, high burden of infection, and bladder wall fibrosis
 
  +
* 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
  +
 
==Management==
  +
 
*Acute
 
**[[Is treated by::Praziquantel]] 40mg/kg given over one day split into 3 doses
 
*Chronic
 
**[[Is treated by::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
   
 
{{DISPLAYTITLE:''Schistosoma'' species}}
 
{{DISPLAYTITLE:''Schistosoma'' species}}

Revision as of 12:32, 21 September 2020

Background

  • Infection with a species of the genus Schistosoma

Microbiology

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

Management

  • Acute
  • 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

  1. ^  Archana Asundi, Alina Beliavsky, Xing Jian Liu, Arash Akaberi, Guido Schwarzer, Zeno Bisoffi, Ana Requena-Méndez, 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.