Chagas disease

Last revised by Travis Fahrenhorst-Jones on 22 Aug 2021

Chagas disease, also known as American trypanosomiasis (plural: trypanosomiases), is a tropical parasitic infection with a wide spectrum of clinical manifestations since it can virtually affect any organ, but there are characteristic radiological features.

Chagas disease is endemic to Central and South America. An estimated 24 million people are infected with 60,000 deaths each year attributed to this infection 8

Cardiac sequelae are common in endemic regions. The pathogenesis is unclear since the parasite is not often found in heart tissue on autopsy, and immunologic myocarditis has been suggested as the origin.

Symptoms begin with acute myocarditis, after which patients enter a latent phase. Approximately 20% of these patients experience gradual fibrous replacement of myofibrils and Purkinje fibers. Eventually, dilated cardiomyopathy ensues, with arrhythmias and heart block. Segmental wall motion abnormalities and apical aneurysm may occur. Heart transplantation has been performed for end-stage disease 6.

10-15% of patients are affected by chronic infection, and manifestations include:

Chagas disease is also known to cause dilatation of the ureter.

Chagas disease is caused by the protozoan Trypanosoma cruzi. It is commonly transmitted to humans by an insect vector.

Radiographic features of Chagas disease can be seen on plain films, contrast studies, echocardiography, CT and MRI.

On cardiac MR, delayed enhancement has been reported in the left ventricular wall in both CAD and non-CAD distributions. The delayed enhancement is progressive over time, and increasing delayed enhancement corresponds with decreasing cardiac performance 7.

  • acute Chagas cardiomyopathy 10
  • chronic Chagas cardiomyopathy
    • may present with an idiopathic dilated cardiomyopathy phenotype
    • regional wall motion abnormalities
      • basal inferior segment most commonly affected
    • left ventricular apical aneurysms
      • small subset have right ventricular apical aneurysms 
    • diastolic dysfunction
      • degree correlates with symptomatology
        • asymptomatic patients may have grade I (impaired relaxation) dysfunction
        • severely symptomatic patients often demonstrate an irreversible restrictive (grade III) pattern

Named after Carlos Justiniano Ribeiro Chagas (1879-1934), a Brazilian physician who completely described this infectious disease: the pathogen, the vector, the host, the clinical manifestations and its epidemiology 5.

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