What is the pathophysiology of Chagas disease (American trypanosomiasis)?

Updated: Apr 26, 2019
  • Author: Louis V Kirchhoff, MD, MPH; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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An inflammatory lesion called a chagoma caused by T cruzi that may appear at the site of entry in patients with acute Chagas disease. Histologic changes may include interstitial edema, lymphocytic infiltration, and reactive hyperplasia of adjacent lymph nodes due to intracellular parasitism of muscle and other subcutaneous tissues. When parasitized host cells rupture, trypomastigotes are released and can often be detected by microscopic examination of anticoagulated blood. As the infection spreads systemically, muscles, including the myocardium, and various other tissues become parasitized. [51]

Acute myocarditis, consisting of patchy areas of necrosis and infected cells, may develop (see image below). [52, 53] The pseudocysts occasionally seen in sections of infected tissues are intracellular aggregates of amastigotes. The patent parasitemias of the acute illness may be accompanied by lymphocytosis, and transaminase levels may be elevated. The cerebrospinal fluid may contain parasites. [54]  

Trypanosoma cruzi in heart muscle of a child who d Trypanosoma cruzi in heart muscle of a child who died of acute Chagas disease in Texas. (H&E, x900).

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