Basics
Description
- Multiple clinical syndromes including acute Chagas disease and chronic Chagas disease, both resulting from infection with the protozoan parasite Trypanosoma cruzi
- Multiple presentations including acute and chronic myocarditis with potentially devastating effects on conduction, myocyte function, and myocardial architecture
- Acute Chagas myocarditis demonstrates focal myocytolytic necrosis and degeneration with an intense mononuclear infiltrate and parasitism of myofibers.
- An intermediate clinically silent phase of up to 10-30 yr
- Chronic Chagas heart disease, however, presents with focal and diffuse chronic fibrosing myocarditis with accompanied lymphomononuclear infiltrate and no evidence of active parasitism.
- Destruction of the parasympathetic nervous system and loss of cardiac innervation is always seen.
- Patients remain infected for life.
- Case definition criteria for diagnosis:
- History of residence where Chagas disease is endemic, unequivocally positive serologic test for T. cruzi, clinical syndrome compatible with Chagas heart disease, no evidence of another cardiac disorder to account for findings
Epidemiology
- Transmission of T cruzi occurs only in the Americas, from southern U.S to southern Argentina.
- Estimated 8-11 million infected worldwide, and 300,000 infected Hispanic immigrants in the U.S.
- 45,000 people die yearly worldwide from T cruzi infection.
- Chagas disease is responsible for a greater disease burden than any other parasitic disease in the New World.
- Countries with highest prevalence: Bolivia, Argentina, El Salvador, Paraguay, Guatemala.
- In the U.S., an estimated 30,000-45,000 individuals likely have undiagnosed Chagas cardiomyopathy, and 63-315 congenital T cruzi infections occur per year.
- In the U.S, since blood screening for T cruzi in 2007, 797 positive donations have been confirmed with the highest numbers found in California, Florida, and Texas.
- Only 7 U.S vector-borne cases have been reported since 1955 (4 in Texas, and 1 each in California, Tennessee and Louisiana).
- The relatively high frequency of sudden death in young adults observed in some regions in the past was attributed to the disturbances of cardiac rhythm associated with Chagas disease, and in one highly endemic area in Brazil, Chagas cardiac disease was found to be the leading cause of death in young adults.
- Incidence of reactivation of Chagas disease after organ transplantation: 50-100% in heart transplantations, 9-16% in kidney transplants, 17-40% in bone marrow transplants.
Risk Factors
Geographic prevalence, rural substandard housing secondary to facilitation of Triatominae insects (kissing bugs), blood transfusion, organ transplantation, congenital acquisition (mother-to-child)
Etiology
- The parasite is transmitted to humans by various species of blood-sucking Triatominae insects (kissing bugs) through contaminated feces at the site of the blood meal.
- May be transmitted from an infected mother to the fetus
- May be transmitted through blood transfusion
- May be transmitted through organ transplantation.
- Acute-phase pathophysiology involves parasite persistence in tissue and inflammation.
- The chronic phase has less parasites and more diffuse interstitial fibrosis and atrophy of myocardial cells.
Associated Conditions
Chronic manifestations include megaesophagus and megacolon.
Diagnosis
- Acute Chagas disease and myocarditis:
- 5-10% develop severe myocarditis, most of which results in heart failure
- Incubation period lasts at least 1 wk
- Localized erythema and induration at the site of bite (chagoma), local periorbital swelling (Roma ±a sign), fever, generalized lymphadenopathy, hepatosplenomegaly, chest pain/discomfort (ischemic or atypical in quality), tachycardia, arrhythmia/palpitations
- Chronic Chagas disease and cardiomyopathy:
- The heart is the organ most commonly affected in chronic Chagas disease
- 20-30% will progress to chronic disease over 10-30 yr
- Symptoms secondary to bradyarrhythmias or tachyarrhythmias include palpitations, syncope, sudden death; symptoms of heart failure include dyspnea, right upper abdominal pain from hepatic congestion, orthopnea and paroxysmal nocturnal dyspnea; patient may also experience precordial or retrosternal pain, pulmonary emboli and stroke:
- Symptoms due to megaesophagus include dysphagia, odynophagia, esophageal reflux, weight loss, aspiration, cough, regurgitation, and symptoms of megacolon are constipation, abdominal pain, obstruction, volvulus.
Tests
EKG:
- Most commonly seen abnormalities are conduction abnormalities.
- Complete right bundle branch block with or without left anterior hemiblock signifies myocarditis.
- Atrioventricular block, complete heart block, left bundle branch block, sinus node dysfunction, supraventricular tachyarrhythmia (particularly atrial fibrillation) and ectopy can be seen.
- Abnormalities resembling MI or ischemia may be prominent in advanced disease.
Lab
- Xenodiagnosis (diagnosis of a disease by infecting a test animal) is considered by some the gold standard, but not very sensitive and not commonly used:
- Buffy coat exam of blood for motile parasites, as in the acute phase there is high level of parasites.
- Serologic testing is the mainstay of chronic clinical diagnosis:
- No single assay has sufficient sensitivity and specificity; 2 tests based on different antigens are used in parallel to increase accuracy.
- Antibodies appear within 3-6 wk of infection and remain for life.
- Serologic testing with, IgG antibodies to T cruzi
- ELISA and immunofluorescent antibody (IFA) test
- PCR on blood or tissue
Imaging
- CXR:
- Low sensitivity for the detection of Chagas disease, but cardiomegaly could be predictive of sudden death
- Two-dimensional (2D) Doppler echo:
- Done as baseline in all patients suspected of having Chagas disease
- Hallmark finding of marked segmental ventricular wall motion abnormalities (hypokinesis or akinesis)
- Narrow neck aneurysm involving localized area of surroundings (50% of patients)
- May resemble segmental changes of ischemic cardiac disease; LV or apical thrombus
Differential Diagnosis
Toxoplasmosis, viral myocarditis ( enterovirus, adenovirus, HIV, hepatitis C, coxsackie virus), postpartum cardiomyopathy, alcoholic cardiomyopathy, endomyocardial fibrosis, ischemic cardiomyopathy, idiopathic cardiomyopathy, toxic cardiomyopathy (anthracycline, cobalt, etc), neuromuscular dystrophies, hemochromatosis, amyloidosis, sarcoidosis, Kawasaki disease, arrhythmogenic cardiomyopathy, Lyme carditis, eosinophilic myocarditis
Treatment
Medication
- In the U.S. medications for Chagas are available only from the CDC.
- Nifurtimox 10 mg/kg/d given in 4 divided doses each day and continued for 90-120 days and benznidazole 5 mg/kg/d for 60 days
- Either of this drug therapy is recommended for all acute cases, congenital infections, chronically infected children, those with immune suppression and reactivation.
- No consensus or official recommendation for drug therapy in chronic Chagas disease, but evidence suggests that it may slow or prevent progression of cardiomyopathy.
- Supportive regimens identical to those for CHF, arrhythmic events, and thromboembolism
- Side effects:
- GI toxicity for nifurtimox
- Side effects of benznidazole include peripheral neuropathy, rash and granulocytopenia
Additional Treatment
General Measures
- Antitrypanosomal therapy exists for acute Chagas disease (active parasitemia) with evidence for cure and prevention of development of sequelae of chronic manifestations.
- Antitrypanosomal therapy is also recommended for treatment of patients diagnosed with congenital infection, those with suppressed immune systems and children with chronic infection.
- Evidence exists that chronically infected patients benefit from antitrypanosomal treatment.
- Supportive treatment is also very important in treating and preventing complications of CHF, thromboembolism, arrhythmogenic events, and cardiac conduction abnormalities.
Surgery
Heart transplantation is indicated in select patients.
In-Patient Considerations
Admission Criteria
No specific indications
Ongoing Care
Follow-Up Recommendations
Patient Monitoring
Periodic clinical evaluation in addition to relevant testing (EKG, echo) to monitor for signs of cardiac disease
Prognosis
- Most important determinant of prognosis is the likelihood of progression to heart disease.
- New evidence suggests that using drug therapy in chronic Chagas disease slows disease progression, but there are no official recommendations regarding drug therapy in this population.
- Overall mortality best predicted by LV function, dilatation, aneurysm, and development of heart disease at an early age.
Additional Reading
1
Altclas JD, Barcan L, Bagel C. Organ Transplantation and Chagas Disease. JAMA. 2008;299(10):1134. [View Abstract] 2
Bern C, Montgomery SP, Herwaldt BL. Evaluation and treatment of Chagas disease in the United States: A systematic review. JAMA. 2007;298(18):2171-2181. [View Abstract] 3
Bern C, Montgomery SP.
An estimate of the burden of Chagas disease in the United States. Clin Infect Dis. 2009;49:52-54. 4
Bestetti RB, Theodoropoulos TAD.
A systematic review of studies on heart transplantation for patients with end-stage Chagas heart disease. J Card Fail. 2009;15:249-255. [View Abstract] 5
Devireddy C.
Chagas Disease and the Heart In: Nixon JV, Alpert J, The AHA Clinical Cardiac Consult, 2nd ed.Orlando: Lippincott, Williams & Wilkins, 2007;126-127. 6
Dorn PL, Perniciaro L, Yabsley MJ. Autochthonous transmission of Trypanosoma cruzi, Louisiana. Emerg Infect Dis. 2007;13(4):605-607. [View Abstract] 7
Gascon J, Albajar P, Canas E. Diagnosis, management, and treatment of chronic Chagas Heart disease in areas where Trypanosoma cruzi infection is not endemic. Rev Esp Cardiol. 2007;60(3):285-293. [View Abstract] 8
Mandell GL, Bennett JE, Dolin R.
Principles and Practice of Infectious Diseases (Ch. 274 Trypanosoma species), 6th ed.New York: Churchill Livingstone2005:3156-3163. 9
Viotti R, Vigliano C, Lococo B. Long-term cardiac outcomes of treating chronic Chagas Disease with benznidazole versus no treatment. Ann Intern Med. 2006;144(10):724-734. [View Abstract] 10
www.cdc.gov/chagas
Codes
ICD9
,086.0 Chagas' disease with heart involvement
SNOMED
- 998008 Chagas' disease with heart involvement (disorder)
- 186813004 acute Chagas' disease with heart involvement (disorder)
Clinical Pearls
- Chagas disease is a disease of the Americas.
- Chagas disease is the leading cause of systolic heart failure in endemic areas.
- Chagas disease can be transmitted through blood transfusions and organ transplantation.
- Obtain good travel and social history, and consider Chagas disease even many years after patient left endemic area.
- Chagas disease can reactivate in immunocompromised patients.
- In the U.S., medications are only available from the CDC.