Difference between revisions of "Giardia lamblia"

(Diagnosis)
(Management)
 
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*A single diarrheal stool may contain hundreds of millions of cysts or parasites
 
*A single diarrheal stool may contain hundreds of millions of cysts or parasites
  
==Clinical Presentation==
+
==Clinical Features==
 
*Often asymptomatic
 
*Often asymptomatic
 
*Most common symptoms include:
 
*Most common symptoms include:
 
**Abdominal distension
 
**Abdominal distension
**Colicky pain
+
**Colicky [[abdominal pain]]
 
**Flatulence
 
**Flatulence
 
**[[Diarrhea]] (pale, loose, floating, foul odor)
 
**[[Diarrhea]] (pale, loose, floating, foul odor)
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==Differential Diagnosis==
 
==Differential Diagnosis==
 +
{{Diarrhea DDX}}
  
*Viral infection (e.g. rotavirus)
+
==Evaluation==
*Bacterial diarrhea
+
*Normal WBC, no eosinophilia
**[[Campylobacter]]
+
*Stool O&P
**[[Shigella]]
+
**Motile trophozoites or cysts
**[[Salmonella]]
+
**Able to diagnose infection readily in acute illness
**[[E. Coli]]
+
**More difficult to diagnose in chronic or asymptomatic infection
**[[E. Coli O157:H7]]
+
*Antigen testing with ELISA, DFA, etc starting to replace microscopic examination with similar cost <ref>http://www.ncbi.nlm.nih.gov/pubmed/22632642</ref>
**[[Yersinia]]
+
*Suspect protozoan illness in patients with diarrhea > 2 weeks
**[[Vibrio cholera]]
 
**[[Clostridium difficile]]
 
*Parasitic infection
 
**[[Cryptosporidium]]
 
**[[Enteromonas hominis]]
 
**[[Entamoeba histolytica]]
 
*Toxin-mediated
 
**[[Staphylococcus aureus]]
 
**[[Bacillus cereus]]
 
  
 
==Management==
 
==Management==
 
''Treatment is not always successful <ref>http://www.ncbi.nlm.nih.gov/pubmed/20086650 </ref>''
 
''Treatment is not always successful <ref>http://www.ncbi.nlm.nih.gov/pubmed/20086650 </ref>''
 
*[[Metronidazole]]
 
*[[Metronidazole]]
**Adult: 250 mg TID x 7-10 days
+
**Adult: 250mg TID x 7-10 days
**Children: 5 mg/kg TID x 7 days (max dose 500 mg TID)
+
**Children: 5mg/kg TID x 7 days (max dose 500mg TID)
 
*[[Albendazole]]<ref>http://www.ncbi.nlm.nih.gov/pubmed/23235648</ref>
 
*[[Albendazole]]<ref>http://www.ncbi.nlm.nih.gov/pubmed/23235648</ref>
**400 mg PO daily x 5-10 days
+
**400mg PO daily x 5-10 days
*Tinidazole
+
*[[Tinidazole]]
 
**Adult: 2 grams PO x 1 dose
 
**Adult: 2 grams PO x 1 dose
**Children: 50 mg/kg PO x 1 dose
+
**Children: 50mg/kg PO x 1 dose
 
*Quinacrine
 
*Quinacrine
**> 8 years old: 100 mg TID x 7 days
+
**> 8 years old: 100mg TID x 7 days
**< 8 years old: 2 mg/kg TID x 7 days
+
**< 8 years old: 2mg/kg TID x 7 days
*Nitazoxanide
+
*[[Nitazoxanide]]
**> 12 years old: 500 mg BID x 3 days
+
**> 12 years old: 500mg BID x 3 days
**4-11 years old: 200 mg BID x 3 days
+
**4-11 years old: 200mg BID x 3 days
**12-47 months old: 100 mg BID x 3 days
+
**12-47 months old: 100mg BID x 3 days
  
 
===Public Health Measures===
 
===Public Health Measures===

Latest revision as of 18:18, 28 March 2017

Background

  • Flagellated protozoan
  • Most common cause of parasitic diarrhea worldwide
  • Transmitted by water contaminated with feces (human, beaver, muskrat, dogs, raccoons, etc)
  • Common among campers and is also known as “backpacker’s diarrhea”
  • Common in travelers to former Soviet Union, Caribbean, Latin America, India, Africa
  • Infection rate is twice as high during summer months
  • Also may be transmitted by contaminated food or close physical contact (sexual activity, daycare centers, etc)
  • Patients with decreased gastric acidity, immunoglobulin deficiency, or immunocompromise are more susceptible
  • Other names: “beaver fever”, “the Trotskys” (common in travelers to Leningrad) [1] [2] [3]

Pathophysiology

  • Trophozoites infect duodenum, jejunum, and ileum where they form cysts
  • Cysts are passed in feces; viable for long periods of time
  • A single diarrheal stool may contain hundreds of millions of cysts or parasites

Clinical Features

  • Often asymptomatic
  • Most common symptoms include:
  • No blood or mucus in stool
  • Sudden onset after incubation period of 1-3 weeks
  • Symptoms usually resolve in 7-10 days
  • 85% of the time infection resolves spontaneously within 6 weeks
  • May cause chronic malabsorption-like illness, especially in those with immunoglobulin deficiency
  • Chronic infections cause weight loss, anemia, lactose intolerance

Differential Diagnosis

Acute diarrhea

Infectious

Noninfectious

Watery Diarrhea

Traveler's Diarrhea

Evaluation

  • Normal WBC, no eosinophilia
  • Stool O&P
    • Motile trophozoites or cysts
    • Able to diagnose infection readily in acute illness
    • More difficult to diagnose in chronic or asymptomatic infection
  • Antigen testing with ELISA, DFA, etc starting to replace microscopic examination with similar cost [5]
  • Suspect protozoan illness in patients with diarrhea > 2 weeks

Management

Treatment is not always successful [6]

  • Metronidazole
    • Adult: 250mg TID x 7-10 days
    • Children: 5mg/kg TID x 7 days (max dose 500mg TID)
  • Albendazole[7]
    • 400mg PO daily x 5-10 days
  • Tinidazole
    • Adult: 2 grams PO x 1 dose
    • Children: 50mg/kg PO x 1 dose
  • Quinacrine
    • > 8 years old: 100mg TID x 7 days
    • < 8 years old: 2mg/kg TID x 7 days
  • Nitazoxanide
    • > 12 years old: 500mg BID x 3 days
    • 4-11 years old: 200mg BID x 3 days
    • 12-47 months old: 100mg BID x 3 days

Public Health Measures

  • Strict adherence to handwashing (toileting, diaper changes, playing with pets, etc)
  • Treat household members and/or sexual contacts if infected
  • Treat asymptomatic infections in those at high-risk of transmitting to others (children in daycare, food handlers, etc) or those at risk of chronic symptoms
  • Reinfection universal within 3 months in heavily infected endemic areas; treatment is not cost-effective in this setting

Disposition

  • Disease is usually self-limited
  • Admit those with systemic symptoms, severe dehydration, inability to tolerate PO fluids, or those with significant co-morbidities
  • Supplementation with zinc and probiotics reduce severity/duration of diarrhea [8]

References

  1. Marx, John A., Robert S. Hockberger, Ron M. Walls, James Adams, and Peter Rosen. "Chapter 94 -- Gastroenteritis." Rosen's Emergency Medicine Concepts and Clinical Practice. Philadelphia: Mosby/Elsevier, 2010. Print.
  2. Tintinalli, Judith E., and J. Stephan. Stapczynski. "Chapter 156 -- World Traveler." Tintinalli's Emergency Medicine: A Comprehensive Study Guide. New York: McGraw-Hill, 2011. Print.
  3. Tintinalli, Judith E., and J. Stephan. Stapczynski. "Chapter 154 -- Foodborne and Waterborne Diseases." Tintinalli's Emergency Medicine: A Comprehensive Study Guide. New York: McGraw-Hill, 2011. Print.
  4. Marx et al. “Cholera and Gastroenteritis caused by Noncholera Vibrio Species”. Rosen’s Emergency Medicine 8th edition vol 1 pg 1245-1246.
  5. http://www.ncbi.nlm.nih.gov/pubmed/22632642
  6. http://www.ncbi.nlm.nih.gov/pubmed/20086650
  7. http://www.ncbi.nlm.nih.gov/pubmed/23235648
  8. http://www.ncbi.nlm.nih.gov/pubmed/23192407