CARDIOPATIA CHAGASICA FISIOPATOLOGIA PDF

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Chagas disease is infection with Trypanosoma cruzi , transmitted by Triatominae bug bites or, less commonly, via ingestion of sugar cane juice or foods contaminated with infected Triatominae bugs or their feces, transplacentally from an infected mother to her fetus, or via blood transfusion or an organ transplant from an infected donor. In patients with AIDS, the skin or brain may be affected. Diagnosis is by detecting trypanosomes in peripheral blood or aspirates from infected organs.

Antibody tests are sensitive and can be helpful. Treatment is with nifurtimox or benznidazole; however, antiparasitic drugs do not reverse the course of cardiac or intestinal disease that has developed. Supportive treatment may be helpful. Nonhuman reservoirs include domestic dogs, opossums, armadillos, rats, raccoons, and many other animals. Less commonly, T. Worldwide, an estimated 8 million people are chronically infected with T. Most reside in Latin America, but about , of those infected in Latin America now live in the US; others live in Europe or elsewhere.

The incidence of T. Chagas disease is spread when a kissing bug bites an infected person or animal, then bites another person. While biting, infected bugs deposit feces containing metacyclic trypomastigotes on the skin. These infective forms enter through the bite wound or penetrate the conjunctivae or mucous membranes. The parasites invade macrophages at the site of entry and transform into amastigotes that multiply by binary fission; the amastigotes develop into trypomastigotes, enter the bloodstream and tissue spaces, and infect other cells.

Cells of the reticuloendothelial system, myocardium, muscles, and nervous system are most commonly involved. Acute infection is followed by a latent indeterminate period, which may remain asymptomatic or progress to chronic disease.

Immunosuppression may reactivate latent infection, with high parasitemia and a 2nd acute stage, skin lesions, or brain abscesses. Acute Chagas disease in endemic areas usually occurs in childhood and can be asymptomatic.

When present, symptoms start 1 to 2 weeks after exposure. An indurated, erythematous skin lesion a chagoma appears at the site of parasite entry. Acute Chagas disease is fatal in a small percentage of patients; death results from acute myocarditis with heart failure or meningoencephalitis. In the remainder, symptoms subside without treatment.

Primary acute Chagas disease in immunocompromised patients, such as those with AIDS, may be severe and atypical, with skin lesions and, rarely, brain abscesses. Many infected patients are identified by screening enzyme-linked immunosorbent blood assay ELISA and confirmatory radioimmunoprecipitation assay RIPA when they donate blood.

The parasites are probably present in chronic disease; an autoimmune reaction also may contribute to organ damage. The main effects are. Cardiac disease usually manifests with conduction abnormalities including right bundle branch block or left anterior fascicular block. Chronic cardiomyopathy often follows with flaccid enlargement of all chambers, apical aneurysms, and progression of lesions in the conduction system.

Patients may present with heart failure, syncope, sudden death due to heart block or ventricular arrhythmia, or thromboembolism. ECG may show right bundle branch or complete heart block. Gastrointestinal disease manifests with symptoms resembling achalasia or Hirschsprung disease. Chagas megaesophagus manifests as dysphagia and may lead to pulmonary infections caused by aspiration or to severe undernutrition.

Megacolon may result in long periods of obstipation and intestinal volvulus. The number of trypanosomes in peripheral blood is large during the acute phase of Chagas disease and can be readily detected by examining thin or thick smears. In contrast, few parasites are present in blood during latent infection or chronic disease.

Definitive diagnosis of acute-stage Chagas disease may also be made by examining tissue from lymph nodes or heart. Serologic tests are sensitive but may yield false-positive results in patients with leishmaniasis or other diseases. Thus, an initial positive test is followed by one or more different tests typically, radioimmunoprecipitation assay [RIPA] in the US or sometimes light microscopy of blood smears or a tissue sample to confirm the diagnosis.

Serologic tests are also used to screen blood donors for T. Polymerase chain reaction PCR -based tests are used when the level of parasitemia is likely to be high, as occurs in acute Chagas disease, in transplacentally transmitted congenital Chagas disease, or after transmission via blood transfusion, transplantation, or laboratory exposure. In endemic areas, xenodiagnosis has been used; it involves examining the intestinal contents of Triatominae bugs raised in a laboratory after they took a blood meal from a person thought to have Chagas disease.

No symptoms but documented T. Potential cardiac abnormalities on a screening test or symptoms suggesting heart disease: Echocardiography. Antiparasitic treatment is indicated for all cases of acute, congenital, or reactivated Chagas disease and for indeterminate infection in children up to age 18 years.

The younger the patient and the earlier treatment is started, the more likely that treatment will result in parasitologic cure. The efficacy of treatment decreases as the duration of infection lengthens, and side effects are more likely in adults. Treatment is recommended up to age 50 unless there is evidence of advanced cardiac or GI damage. Once signs of advanced cardiac or GI manifestations of chronic Chagas disease appear, antiparasitic drugs are not recommended.

Supportive measures include treatment for heart failure , pacemakers for heart block, antiarrhythmic drugs , cardiac transplantation, esophageal dilation, botulinum toxin injection into the lower esophageal sphincter, and GI tract surgery for megacolon.

They have substantial toxicity, which increases with age. Contraindications for treatment include severe liver or kidney disease. Common adverse effects of benznidazole include allergic dermatitis, peripheral neuropathy, anorexia, weight loss, and insomnia.

Common adverse effects of nifurtimox are anorexia, weight loss, polyneuropathy, nausea, vomiting, headache, dizziness, and vertigo. Plastering walls and replacing thatched roofs or repeated spraying of houses with residual insecticides those that have prolonged duration of action can control Triatominae bugs.

Infection in travelers is rare and can be avoided by not sleeping in adobe dwellings or by using bed nets if sleeping in such dwellings is unavoidable. Blood and organ donors are screened in many endemic areas and, since , in the US to prevent transfusion- and organ transplant—related Chagas disease. Chagas disease is caused by Trypanosoma cruzi , which is transmitted by Triatominae reduviid, kissing, or assassin bugs.

Infection is endemic in South and Central America and Mexico; an estimated 8 million people worldwide, including an estimated , people in the US primarily immigrants , are infected.

Diagnose acute Chagas using light microscopy of blood smears thin or thick or a tissue sample or PCR-based assays. Diagnose chronic T. Use PCR-based tests to evaluate cases potentially transmitted transplacentally or via transfusion, transplantation, or laboratory exposure.

To detect chronic Chagas disease, do echocardiography if patients have symptoms suggesting heart disease or potential cardiac abnormalities on a chest x-ray, ECG, or rhythm strip; do GI contrast studies or endoscopy if they have dysphagia or other GI symptoms. Treat patients in the acute stage and many in the indeterminate stage with benznidazole or nifurtimox. Antiparasitic drugs are not effective in chronic Chagas disease, but supportive measures eg, treatment of heart failure, pacemakers for heart block, antiarrhythmic drugs, cardiac transplantation, esophageal dilation, botulinum toxin injection into the lower esophageal sphincter, GI tract surgery are often helpful.

CDC: Resources for health professionals: Chagas disease. From developing new therapies that treat and prevent disease to helping people in need, we are committed to improving health and well-being around the world. The Manual was first published in as a service to the community. Learn more about our commitment to Global Medical Knowledge. This site complies with the HONcode standard for trustworthy health information: verify here. Common Health Topics.

Videos Figures Images Quizzes. Symptoms and Signs. Acute Indeterminate Chronic. Ancillary testing in patients with chronic Chagas disease.

Key Points. More Information. Extraintestinal Protozoa. Test your knowledge. In developed countries, Salmonella typhi is most likely transmitted via which of the following pathways? More Content. Click here for Patient Education. Chagas disease can occur in 3 stages:. Light microscopy of blood smears thin or thick or tissue acute Chagas disease.

After Chagas disease is diagnosed, the following tests should be done, depending on findings:. Benznidazole or nifurtimox. Treatment of acute-stage Chagas disease with antiparasitic drugs does the following:. Rapidly reduces parasitemia. For children aged 11 to 16 years, 3 to 3. It is recommended that these drugs not be used in pregnant women or in breastfeeding mothers. Was This Page Helpful? Yes No. Granulomatous Amebic Encephalitis. Blood Collection. Complications of Transfusion. Esophageal Motility Disorders.

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Chagas Disease

Chagas disease is infection with Trypanosoma cruzi , transmitted by Triatominae bug bites or, less commonly, via ingestion of sugar cane juice or foods contaminated with infected Triatominae bugs or their feces, transplacentally from an infected mother to her fetus, or via blood transfusion or an organ transplant from an infected donor. In patients with AIDS, the skin or brain may be affected. Diagnosis is by detecting trypanosomes in peripheral blood or aspirates from infected organs. Antibody tests are sensitive and can be helpful. Treatment is with nifurtimox or benznidazole; however, antiparasitic drugs do not reverse the course of cardiac or intestinal disease that has developed. Supportive treatment may be helpful. Nonhuman reservoirs include domestic dogs, opossums, armadillos, rats, raccoons, and many other animals.

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General Information - Chagas Disease

Chagas disease is a neglected chronic condition that presents high morbidity and mortality burden, with considerable psychological, social, and economic impact. The disease represents a significant public health issue in Brazil, with different regional patterns. This document presents the evidence that resulted in the Brazilian Consensus on Chagas Disease. The objective was to review and standardize strategies for diagnosis, treatment, prevention, and control of Chagas disease in the country, based on the available scientific evidence.

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