Chagas disease
Chagas disease is chronic infection with Trypanosoma cruzi, transmitted by the triatomine (kissing bug) vector in Latin America, that after a mild acute phase and a long silent latency destroys the myenteric plexus and cardiac conduction system, producing megaesophagus, megacolon, and dilated cardiomyopathy decades later. Diagnosis is by blood smear or PCR in acute disease and two different serologic assays in chronic disease, and treatment is benznidazole or nifurtimox, most effective when given early, while established organ disease is managed symptomatically.
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What this article covers
- Overview
Definition: Chagas disease (American trypanosomiasis) is a chronic parasitic infection caused by the protozoan Trypanosoma cruzi, acquired mainly through the triatomine ("kissing") bug in Latin America.
- Epidemiology
Geographic distribution: endemic across rural Latin America, from Mexico to Argentina, where the triatomine vector infests poorly constructed adobe and thatch housing.
- Risk factors
Residence or long-term habitation in rural Latin America: the dominant risk factor, from exposure to triatomine-infested substandard housing (mud walls, thatched roofs) where the vector lives in wall cracks and bites at night.
- Pathophysiology
Vector inoculation: the triatomine bug bites, usually on the face, and defecates near the bite or mucosa; the person inoculates the feces into the wound or mucosa by scratching or rubbing.
- Clinical features
Acute phase, often mild or subclinical: fever, malaise, lymphadenopathy, and headache; most acute infections go unrecognized.
- Differential diagnosis
Idiopathic (primary) achalasia: identical dysphagia, regurgitation, and manometric picture but no endemic exposure history; distinguished by Chagas serology and epidemiologic history rather than manometry alone (Achalasia).
- Diagnosis
The approach differs by phase: acute infection is confirmed by direct parasite visualization or PCR, and chronic infection is confirmed by two positive serologic tests of different methods, because…
- Management
Treat all confirmed acute, congenital, reactivated (immunosuppressed), and early chronic infection with antitrypanosomal therapy, since efficacy is highest in these groups and in children and young adults.
- Complications
Chagasic dilated cardiomyopathy with heart failure and malignant arrhythmia: the leading cause of death, from progressive myocardial fibrosis, apical aneurysm, ventricular tachyarrhythmia, and…
- Prognosis
Most infected people never progress: roughly 70% remain in the asymptomatic indeterminate phase for life with normal life expectancy.
- Prevention
Vector control is the cornerstone of prevention: residual insecticide spraying of infested housing plus structural home improvement (replacing mud/thatch walls and roofs with plaster and metal/tile)…
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Achalasia is a primary esophageal motility disorder from myenteric plexus degeneration that causes failure of lower esophageal sphincter relaxation and aperistalsis, producing dysphagia to solids and liquids with regurgitation. Diagnosis requires endoscopy to exclude pseudoachalasia followed by esophageal manometry, and definitive treatment is pneumatic dilation, laparoscopic Heller myotomy, or POEM.
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