USMLE

Trypanosoma cruzi

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Parasites
  1. Giardia lamblia
  2. Toxoplasma gondii
  3. Entamoeba histolytica
  4. Cryptosporidium
  5. Naegleria fowleri
  6. Trypanosoma brucei
  7. Plasmodium Overview
  8. Plasmodium Disease (Malaria)
  9. Babesia
  10. Trypanosoma cruzi
  11. Leishmania
  12. Trichomonas vaginalis
  13. Enterobius vermicularis (pinworm)
  14. Ascaris lumbricoides (giant roundworm)
  15. Strongyloides stercoralis (threadworm)
  16. Ancyclostoma and Necator
  17. Trichinella spiralis
  18. Trichuris trichiura (whipworm)
  19. Toxocara canis
  20. Onchocerca volvulus
  21. Loa loa
  22. Wuchereria bancrofti
  23. Taenia solium
  24. Diphyllobothrium latum
  25. Echinococcus granulosus
  26. Schistosoma
  27. Clonorchis sinensis
  28. Sarcoptes scabiei (Scabies)
  29. Pediculus humanis and Phthirus pubis (Lice)

Summary

Trypanosoma cruzi is an intracellular parasite that is transmitted by the bite and defecation of the Reduviid bug. This bug is common to poorly constructed houses in Central and South America. An infection with T. cruzi subsequently causes Chagas Disease. In the acute term, chagas disease presents with a sore at the reduviid bug bite site, called a chagoma. If left untreated, chronic Chagas Disease can cause important complications like heart disease and dilated cardiomyopathy, as well as damage to the GI tract in the form of megaesophagus and megacolon. To diagnose Chagas Disease, blood smears are examined under the microscope for the visual appearance of trypomastigotes. First-line treatment for Chagas Disease consists of Benznidazole, though Nifurtimox is another, less commonly prescribed treatment. 

Key Points

  • Trypanosoma cruzi 
    • Transmission
      • Transmitted by reduviid bug
        • Also known as “kissing bugs” or triatomine bugs
        • Endemic in Central or South America
    • Pathogenesis and Presentation
      • Chagas Disease
        • Also known as American trypanosomiasis
        • Acute: Chagoma (swollen bug bite)
        • Chronic
          • Myopericarditis
            • May lead to arrhythmias, thromboembolism, or heart failure (dilated cardiomyopathy)
          • Destroys myenteric plexus
            • Esophagus → achalasia (megaesophagus)
            • Colon → megacolon
            • Ureters → megaureter
    • Diagnosis
      • Trypomastigotes seen on blood smear
    • Treatment
      • Benznidazole
      • Nifurtimox as second-line