Chagas disease history and symptoms
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
History and Symptoms
The symptoms of Chagas' disease vary over the course of the infection. In the early, acute stage symptoms are mild and are usually no more than local swelling at the site of infection. As the disease progresses, over as much as twenty years, the serious chronic symptoms appear, such as heart disease and malformation of the intestines. If untreated, the chronic disease is often fatal.
The human disease occurs in two stages: the acute stage shortly after the infection, and the chronic stage that may develop over 10 years. In the acute phase, a local skin nodule called a chagoma can appear at the site of inoculation. When the inoculation site is the conjunctival mucous membranes, the patient may develop unilateral periorbital edema, conjunctivitis, and preauricular lymphadenitis. This constellation of symptoms is referred to as Romaña's sign. The acute phase is usually asymptomatic, but may present symptoms of fever, anorexia, lymphadenopathy, mild hepatosplenomegaly, and myocarditis. Even if symptoms develop during the acute phase, they usually fade away on their own within a few weeks or months. Although the symptoms resolve, the infection, if untreated, persists. Rarely, young children (<5%) die from severe inflammation/infection of the heart muscle (myocarditis) or brain (meningoencephalitis).
Some acute cases (10 to 20%) resolve over a period of 2 to 3 months into an asymptomatic chronic stage (called “chronic indeterminate”) during which few or no parasites are found in the blood. During this time, most people are unaware of their infection. Many people may remain asymptomatic for life and never develop Chagas-related symptoms. However, an estimated 30% of infected people will develop debilitating and sometimes life-threatening medical problems over the course of their lives.
The symptomatic chronic stage may not occur for years or even decades after initial infection. The disease affects the nervous system, digestive system and heart. Chronic infections result in various neurological disorders, including dementia, damage to the heart muscle (cardiomyopathy, the most serious manifestation), and sometimes dilation of the digestive tract (megacolon and megaesophagus), as well as weight loss. Swallowing difficulties may be the first symptom of digestive disturbances and may lead to malnutrition. After several years of an asymptomatic period, 27% of those infected develop cardiac damage, 6% develop digestive damage, and 3% present peripheral nervous involvement. Left untreated, Chagas' disease can be fatal, in most cases due to the cardiomyopathy component.
In people who have suppressed immune systems (for example, due to AIDS or chemotherapy), Chagas disease can reactivate with parasites found in the circulating blood. This occurrence can potentially cause severe disease.