EXPLANATION


American trypanosomiasis, commonly referred to as Chagas disease, is a protozoal infection caused by Trypanosoma cruzi, which is endemic to Central and South America. Increased international migration is responsible for a growing number of cases worldwide. It is responsible for the highest parasitic disease burden in the Western Hemisphere, with an estimated 6 million people infected worldwide and 300,000 infected in the United States. Nearly 1.2 million people are suspected to have Chagas cardiomyopathy, which is one of the most serious complications of chronic Chagas disease. Despite the widespread burden of disease, it is poorly recognized outside of endemic regions.


The vector for transmission of Trypanosoma cruzi (T. cruzi) is the triatomine insect commonly referred to as the “kissing bug”. The triatomine insect becomes infected with T. cruzi after feeding on an infected animal host. The infected insect draws blood during feeding and simultaneously deposits feces. The resulting bite causes itching, and when scratched, T cruzi-laden feces may be introduced into the bite wound, resulting in protozoal transmission. Transmission also occurs via the fecal-oral route or consumption of food or drink infected with insects and/or their waste. It can also occur during blood transfusion, organ transplantation, or placental transfer, resulting in congenital Chagas disease.


Acute Chagas disease is a multi-organ inflammatory disease presenting with lymphadenopathy, hepatomegaly, and splenomegaly. Cardiovascular involvement can lead to myocarditis, vasculitis, pericarditis complicated by pericardial effusion, and/or dilated cardiomyopathy. Chagas disease may also cause myocardial and endocardial necrosis, in addition to inflammation of and damage to the cardiac conduction system. The acute phase of infection persists for eight to twelve weeks. The majority of patients exhibit mild or nonspecific symptoms, such as fever or fatigue. The electrocardiogram most often shows sinus tachycardia and PR/QT prolongation. Rarely, patients may present with fulminant disease exhibiting myocarditis, pericardial effusion, meningitis, or death.


Chronic Chagas disease primarily affects the cardiovascular and gastrointestinal systems. The gastrointestinal manifestations are related to impaired esophageal or colonic motility. Megacolon and/or megaesophagus and bowel ischemia are the most severe manifestations. Chronic Chagas heart disease typically presents decades after the initial infection. Chagas cardiomyopathy results in the majority of Chagas morbidity and mortality. It is generally classified as a dilated cardiomyopathy. However, Chagas cardiomyopathy has a distribution of fibrosis to the posterior and apical regions of the LV and involvement of the sinus node and electrical conduction system that distinguishes it from other types of cardiomyopathies. Chagas heart disease is considered an arrhythmogenic cardiomyopathy, characterized by atrial and ventricular arrhythmias, along with abnormalities of the conduction system. Sudden cardiac death is the most common overall cause of mortality. Chagas cardiomyopathy carries a poor prognosis when compared to other causes of cardiomyopathy, likely due to irreversible ventricular remodeling and damage before presentation.


The most sensitive test for acute infection is PCR testing, while chronic disease is best diagnosed via serology. Both of these tests are only available in the United States via the Center for Disease Control Division of Parasitic Disease (CDCDPD). Further diagnostic tests may include an electrocardiogram, echocardiogram, Holter monitoring, cardiac stress testing, magnetic resonance imaging, and/or cardiac catheterization. Anti-parasitic treatment is with Benznidazole and/or nifurtimox, both of which must be obtained via consultation with the CDCDPD. Treatment of acute Chagas disease and congenital Chagas disease is typically more successful than chronic Chagas disease. Treatment of cardiac manifestations typically includes medical management of heart failure, treatment of arrhythmias, pacemaker implantation, and prevention of sudden cardiac death with insertion of an implantable cardiac defibrillator. Chagas disease is NOT a contraindication to heart transplantation. Primary prevention against stroke is also commonly indicated.


The patient described in the stem emigrated from a region endemic to Trypanosoma cruzi and has signs and symptoms of Chagas heart disease (Answer C). Plasmodium falciparum (Answer A) is endemic to the African continent and causes malaria. Malaria typically presents with neurological, hematological, and respiratory manifestations. Zika virus (answer B) typically presents with fever, arthralgias, and rash. Infection during pregnancy can result in birth defects.


REFERNCES


Nunes MCP, Beaton A, Acquatella H et al.American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee of the Council on Cardiovascular Disease in the Young; Council on Cardiovascular and Stroke Nursing; and Stroke Council. Chagas Cardiomyopathy: An Update of Current Clinical Knowledge and Management: A Scientific Statement From the American Heart Association. Circulation. 2018;138(12):e169-e209. doi: 10.1161/CIR.0000000000000599. PMID: 30354432.


Edwards MS, Stimpert KK, Bialek SR, Montgomery SP. Evaluation and Management of Congenital Chagas Disease in the United States. J Pediatric Infect Dis Soc. 2019;8(5):461-469. doi: 10.1093/jpids/piz018. PMID: 31016324; PMCID: PMC10186111.


Chancey RJ, Edwards MS, Montgomery SP. Congenital Chagas Disease. Pediatr Rev. 2023;44(4):213-221. doi: 10.1542/pir.2022-005857. PMID: 37002357; PMCID: PMC10313159.