Chagas disease

Chagas disease (or trypanosomiasis) is a tropical parasitic infection caused by a protozoan, Tripanosoma cruzi. It is commonly transmitted to humans by an insect vector. Although it has a wide spectrum of clinical manifestations, since it can virtually affect any organ, there are characteristic radiological features.

Radiographic features

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

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

Symptoms begin with an acute myocarditis, after which patients enter a latent phase. ~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

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

Gastrointestinal manifestationmanifestations, affecting 10-15% of patients with chronic infection, include :

• esophageal dismotility and megaesophagus (aperistaltism and dilatation)
• megaduodenum and small bowel dilatation
• megacolon : left colon and rectosigmoid colon are more commonly affected 

Chagas disease is also known to cause dilatation of the ureter, myocarditis and meningoencephalitis.

Etymology

Named after Carlos Justiniano Ribeiro Chagas (1879-1934) , a Brazilian physician. 

See also

• achalasia