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Chagas disease: Pathology and pathogenesis

J Antonio Marin-Neto, MD, PhD, FACC
Anis Rassi, Jr, MD, PhD, FACC, FAHA, FACP
Benedito C Maciel, MD, FACC
Section Editors
William J McKenna, MD
Peter F Weller, MD, MACP
Deputy Editors
Susan B Yeon, MD, JD, FACC
Elinor L Baron, MD, DTMH


Chagas disease is caused by infection with the protozoan parasite Trypanosoma cruzi; the major manifestations are Chagas cardiomyopathy and gastrointestinal disease. Issues related to the pathologic findings and the pathogenesis of infection will be reviewed here. The diagnosis, epidemiology, and management of Chagas disease are discussed in detail separately. (See "Chagas disease: Epidemiology and prevention" and "Chagas disease: Acute and congenital Trypanosoma cruzi infection" and "Chagas disease: Chronic Trypanosoma cruzi infection" and "Chagas heart disease: Clinical manifestations and diagnosis" and "Chagas heart disease: Treatment and prognosis" and "Chagas gastrointestinal disease".)


The natural history of infection consists of acute and chronic phases. (See "Chagas disease: Acute and congenital Trypanosoma cruzi infection" and "Chagas disease: Chronic Trypanosoma cruzi infection".)

In general, the acute phase consists of parasitemia, generally with nonspecific or no symptoms, and typically lasts 8 to 12 weeks; in a minority of patients, there is inflammation and swelling at the site of inoculation (chagoma). The chronic phase typically begins with a long period of latency (indeterminate form) characterized by lack of objective evidence of organ damage [1]. An estimated 30 percent of these individuals progress over a period of years to decades to clinically evident chronic disease; heart disease develops more commonly than gastrointestinal disease. The clinical aspects of these phases are outlined separately. (See "Chagas disease: Acute and congenital Trypanosoma cruzi infection" and "Chagas disease: Chronic Trypanosoma cruzi infection".)

Acute phase — Organ damage during the acute phase occurs as a result of high grade parasitemia and direct tissue parasitism. Affected sites typically include the heart, gastrointestinal tract (mainly esophagus and colon), and central nervous system. Lymphadenopathy, hepatomegaly, and splenomegaly are markers of widespread immunologic reaction, which leads to control of the acute infection but probably exacerbates tissue damage. Histopathology during the acute phase demonstrates intense parasitism in every involved organ system, with prominent inflammatory changes in the vicinity of ruptured infected cells [2-7].

All four cardiac chambers may become dilated, and pericardial effusion is common. Myocarditis is intense and diffuse with myocyte necrosis, interstitial edema, vascular dilation, and mononuclear and polymorphonuclear infiltration (picture 1). The inflammatory process may extend to the endocardium, resulting in thrombus formation. Involvement also includes the conduction system as well as the intramural and extracardiac neuronal ganglia.

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Literature review current through: Oct 2017. | This topic last updated: Mar 27, 2015.
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