What are the symptoms and signs of Chagas disease?

Symptoms and Signs of Chagas Disease

Chagas disease presents with distinct symptoms and signs across three clinical phases: acute, indeterminate, and chronic, with cardiac involvement being the most serious long-term complication affecting 10-30% of infected individuals. 1

Acute Phase

• Typically a mild illness with low case-fatality rate, lasting 1-2 months 1
• Fever, malaise, and edema of the face and lower extremities 1
• Generalized lymphadenopathy and hepatosplenomegaly 1
• Severe myocarditis may develop in a small proportion of symptomatic patients 1
• Most acute infections are asymptomatic or have mild, nonspecific manifestations 2
• Life-threatening myocarditis or meningoencephalitis can occur in approximately 5% of infected individuals 3

Indeterminate Phase

• Follows the acute phase and may last 10-20 years 3
• No overt symptoms but lifelong, low-grade parasitemia with detectable antibodies 1
• Many people have subtle signs of cardiac or gastrointestinal involvement before becoming symptomatic 1
• Most infected people (70% or more) remain in this phase for life without developing clinical manifestations 3
• This carrier state can be a major cause of transfusion-associated transmission 1

Chronic Phase

• Develops in approximately 10-30% of infected people, years or decades after initial infection 1
• Cardiac involvement is most common and serious manifestation 1

Cardiac Manifestations

• Biventricular enlargement, thinning of ventricular walls, apical aneurysms, and mural thrombi 1
• Conduction system abnormalities: right bundle-branch block, left anterior fascicular block, or complete atrioventricular block 1
• Cardiac arrhythmias, including atrial fibrillation and complex ventricular ectopy 1, 4
• Heart failure symptoms with poor prognosis (50% mortality within 4 years) 1, 4
• Sudden cardiac death can occur in all phases of the disease 4

Gastrointestinal Manifestations

• Megaesophagus and megacolon (primarily in Brazil) 3
• Gastrointestinal abnormalities occur in approximately 5% of chronically infected individuals 1

Clinical Findings by Prevalence

• Cardiovascular disease: 19% of infected individuals 1
• Gastrointestinal abnormalities: 5% of infected individuals 1
• Severe cardiac events: 1% of infected individuals 1
• Severe gastrointestinal involvement (megasyndrome): rare 1

Diagnostic Considerations

• The clinical diagnosis is based on a triad of positive epidemiology, positive serology, and characteristic clinical findings 3
• Suggestive electrocardiographic abnormalities include sinus bradycardia, right bundle branch block with or without left anterior hemiblock, T wave abnormalities, pathological Q waves, and ventricular premature beats 3
• Patients with dilated cardiomyopathy and risk factors (travel or residence in endemic areas) should be screened for Chagas disease 5

Treatment Implications

• Early diagnosis and treatment with benznidazole or nifurtimox can help prevent complications 5
• Treatment is most effective in the acute phase but may also be beneficial in early chronic phase 6
• Treatment can be challenging due to significant side effects of available medications 2

Key Prognostic Indicators

• Poor prognosis is associated with complete heart block, atrial fibrillation, left bundle branch block, and complex ventricular ectopy 1
• Cardiac involvement leads to a mortality rate of approximately 50% within 4 years 1

Healthcare providers should maintain a high index of suspicion for Chagas disease in patients from endemic areas presenting with cardiac symptoms, particularly conduction abnormalities or heart failure of unclear etiology 5.