Trypanosoma cruzi

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Key Points

  • Trypanosoma cruzi
    • Note: Contrast vs. Trypanosoma brucei (African Sleeping Sickness)
    • Characteristics
      • Intracellular protozoan parasite
    • Transmission
      • Transmitted by reduviid bug
        • Also known as “kissing bugs” or triatomine bugs
        • Endemic in Central or South America
        • Live in floors and walls of poorly constructed homes
        • Bug bites painlessly (as if “kissing skin”) through skin and defecates on the skin of the host, allow organism to enter
        • May also affect eyelid and conjunctiva
    • Pathogenesis and Presentation
      • Chagas Disease
        • Also known as American trypanosomiasis
        • Acute: Chagoma (swollen bug bite)
          • Inflammation and swelling around bite site
          • Involvement around eyelid can lead to swelling known as Romaña’s sign
        • Chronic
          • Myopericarditis
            • May lead to arrhythmias, thromboembolism, or heart failure (dilated cardiomyopathy)
            • All patients with Chagas are screened for heart abnormalities, even if asymptomatic
          • Destroys myenteric plexus
            • Parasite antigen binds to enteric neurons, which stimulates an immune-mediated response vs. both
            • Neuronal death causes smooth muscle denervation in GI tract
            • Esophagus → achalasia (megaesophagus)
              • Presents with dysphagia (inability to swallow)
            • Colon → megacolon
              • Presents with constipation, bloating, abdominal pain
            • Ureters → megaureter
    • Diagnosis
      • Trypomastigotes seen on blood smear
      • Anti-Chagas serum antibodies detected on ELISA
      • PCR detection of parasite DNA
    • Treatment
      • Benznidazole
        • Better tolerated than nifurtimox; first line
      • Nifurtimox