Clinical manifestations of Chagas disease
Chagas disease occurs in 2 stages, acute and chronic.1,2,4 In patients who are infected via an insect vector, the acute stage typically begins 1 to 2 weeks after the insect bite. This phase of the illness usually lasts 4 to 8 weeks and almost always resolves without treatment.
Some infected patients will be completely free of symptoms. Others will have manifestations such as:
- fever
- malaise
- headache
- hepatosplenomegaly
- lymphadenopathy
- swollen nodule at the site of infection
—Romaña’s sign, when the lesion is on the eyelid
—Chagoma, when the lesion is elsewhere on the skin.
Fortunately, less than 5% of patients will have severe illness, manifested by myocarditis, pericarditis, encephalitis, or meningitis.
People infected by ingestion of the parasite in food or drink often become more severely ill within 3 weeks. Their clinical manifestations include fever, vomiting, dyspnea, cough, chest pain, abdominal pain, and myalgias. Individuals infected through organ transplant or blood transfusion present more like those infected by the insect vector, but their illness may not develop until several weeks to 5 months after exposure.
In the absence of effective treatment, approximately 40% of patients with acute infection will develop chronic infection, often several decades later. The most common, and most ominous, feature of chronic illness is cardiac disease, experienced by about 30% of patients. Cardiac disease may be manifested as a serious arrhythmia, chest pain, congestive heart failure, or thromboembolism.
The other organ system that is likely to be adversely affected in patients with chronic disease is the gastrointestinal (GI) system, and approximately 10% of chronically infected patients experience this complication. Patients may develop a dilated esophagus, which leads to odynophagia and dysphagia. Diminished motility in other areas of the GI tract also may result in chronic constipation and even bowel obstruction. Chronically infected patients who are immunosuppressed due to HIV infection may become gravely ill as a result of encephalitis and brain abscesses. Cardiac and GI dysfunction is due to the parasite’s massive destruction of nerve endings.
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