Chagas’ Disease

Posted by Graham McMahon • June 29th, 2011

The latest article in our Clinical Therapeutics review series is, “Antitrypanosomal Therapy for Chronic Chagas’ Disease.”

A 42-year-old woman presents after donating blood and receiving a report that she is positive for Chagas’ disease. Chagas’ disease is caused by a parasite and is endemic in many parts of Latin America.

Chagas’ disease is caused by the protozoan parasite Trypanosoma cruzi. An estimated 8 to 10 million people are infected with this parasite, primarily in the Americas. T. cruzi is carried in the gut of hematophagous triatomine reduviid bugs. Transmission most often occurs when the feces of an infected bug are inoculated through a bite wound or intact mucous membranes.

Clinical Pearls

What are the cardiac manifestations of Chagas’ disease?

The earliest cardiac manifestations are usually conduction system abnormalities and segmental left ventricular wall motion abnormalities. Later manifestations include tachy- and bradyarrhythmias; apical aneurysm, usually in the left ventricle; embolic phenomena due to thrombus formation in the dilated left ventricle or aneurysm; and progressive dilated cardiomyopathy with congestive heart failure.

What are the gastrointestinal manifestations of Chagas’ disease?

Gastrointestinal Chagas’ disease usually affects the esophagus, colon, or both. Advanced disease results in megaesophagus, megacolon, or both. Gastrointestinal involvement is much less common than Chagas’ heart disease.

Morning Report Questions

Q: What is the first-line treatment for Chagas’ disease?

A: The only currently available drugs with proven efficacy against T. cruzi are benznidazole and nifurtimox. Because benznidazole is usually better tolerated, this drug is viewed by most experts as the first-line treatment.

Q: Which patients with Chagas’ disease should be treated?

A: Most experts now believe that the majority of patients up to age 50 years with chronic T. cruzi infection, including those without symptoms and those with early manifestations of cardiomyopathy, should be offered antitrypanosomal treatment. Because treatment is expected to reduce the probability of congenital transmission, stronger consideration may be warranted for reproductive-age women. For individuals older than 50 years, treatment decisions should take into account the current lack of certainty of benefit, prolonged course and frequent side effects. Patients with advanced Chagas’ cardiomyopathy, especially those with poorly compensated congestive heart failure, are not considered candidates for antitrypanosomal treatment. There is no evidence that antitrypanosomal treatment affects the progression of gastrointestinal Chagas’ disease. In patients with megaesophagus, absorption may be impaired, and treatment should be delayed until after corrective surgical intervention.

One Response to “Chagas’ Disease”

  1. Luciano Pereira says:

    Is there a paradigm change? Is it possible now the treatment in chronics stages of the disease?

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