Chagas disease
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Etiology
Epidemiology
- United States, Central & South America
- rarely, cases orginate in United States
- one of top 5 neglected parasitic infections in the U.S.
- 5.7 million persons infected in Latin America
- transmitted by kissing bugs of the family Reduviidae, so named because it often bites the face
- bug defecates at the time of biting
- bug feces contain infective trypomastigotes that penetrate the skin as a result of scratching or rubbing or through intact mucosa
- bug urine is also infective[11]
- infection may be transmitted by blood transfusion
- vertical transmission from mother to baby
- dogs, rodents, armadillos, & other domestic & wild animals serve as reservoirs
Pathology
- after gaining access to tissues, typomastigotes transform into dividing amastigotes
- when the infected cell is full of amastigotes, transformation to trypomastigotes occurs, followed by cell rupture
- trypomastigotes are released into the peripheral blood where they reach distant tissues & begin the replicative cycle again
- cross-reactivity of Trypanosoma cruzi antigens with human protein(s) <see serology>
Clinical manifestations
- may cause acute or chronic infection
- most persons remain asymptomatic but are infected for life[8]
- acute infection:
- generally lasts 2-3 months
- fever/chills, malaise, hepatosplenomegaly, myocarditis
- swelling of the tissue around the eye may be present if bite occurred on face (Romana's sign)
- swelling of the tissues around the bite at other sites is called a chagoma
- acute disease is more common in children under 5
- in older individuals, infection is generally mild or asymptomatic
- vast majority of patients are asymptomatic[8]
- chronic infection
- achalasia, megaesophagus
- megacolon
- cardiac disease
- autoimmune destruction of parasympathetic innervation of heart
- bundle branch block, heart block
- ventricular tachycardia
- segmental ventricular wall abnormalities & apical aneurysm
- ventricular thrombus resulting in thromboembolism
- dilated cardiomyopathy with congestive heart failure
- quiescent infections may be exacerbated by immunosuppression
- most patients remain asymptomatic but are infected for life[8]
Laboratory
- diagnosis is made by demonstration of trypomastigotes in
- trypomastigotes
- curved with S & C shapes
- measure up to 20 um in length
- kinetoplast larger than that of T brucei
- culture
- xenodiagnosis in endemic areas
- examination of the gut contents of laboratory-raised rejuviid bugs that have been allowed to feed on the victim
- serology:
- EIA, IFA & ELISA are available
- false positives may occur in patients with Leishmaniasis
- antibodies against TCFL5 (nuclear antigen)
- see ARUP consult[5]
Complications
- cardiac & gastrointestinal complications dominate
- occur in 30% of infected individuals
- heart failure, 45% within 10 years of onset
- complete heart block
- ventricular arrhythmias, including sudden death[10]
- stroke[10]
- pulmonary embolism[10]
- dysphagia from esophageal dilation
- reactivation of dormant disease in immunosuppressed patients[10] images)
Management
- treatment is unsatisfactory
- benznidazole
- 5 mg/kg/day PO for 60 days
- delays progression to heart failure (10% vs 45&)[4]
- used for reactivation in brain (case report)[10]
- recommended as first-line therapy (only FDA-approved drug for treatment of Chagas disease)[11]
- nifurtimox
- markedly reduces duration of symptoms, parasitemia & mortality
- 50% of infections are cured by a full course of therapy
- may be useful in exposure from laboratory accidents
- treatment should be begun as soon as possible
- 8-10 mg/kg/day for adults
- 12.5-15 mg/kg/day for adolescents
- 15-20 mg/kg/day for children ages 1-10 years
- doses given orally, divided QID
- therapy should be continued to 90-120 days
- available from CDC (707 639-3670)
- referral to cardiologist for cardiac involvement
- referral to gastroenterologist for GI manifestations
- no vaccine available
Notes
- known Chagas disease is a contraindication for organ domation of
- heart (absolute), liver or kidney (relative)
More general terms
Additional terms
References
- ↑ Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 1266
- ↑ Stedman's Medical Dictionary 26th ed, Williams & Wilkins, Baltimore, 1995
- ↑ Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, 1193-94
- ↑ 4.0 4.1 Viotti R, Vigliano C, Lococo B, Bertocchi G, Petti M, Alvarez MG, Postan M, Armenti A. Long-term cardiac outcomes of treating chronic Chagas disease with benznidazole versus no treatment: a nonrandomized trial. Ann Intern Med. 2006 May 16;144(10):724-34. PMID: https://www.ncbi.nlm.nih.gov/pubmed/16702588
Pinto Dias JC. The treatment of Chagas disease (South American trypanosomiasis). Ann Intern Med. 2006 May 16;144(10):772-4. No abstract available. PMID: https://www.ncbi.nlm.nih.gov/pubmed/16702594 - ↑ 5.0 5.1 ARUP Consult: Trypanosoma cruzi - Chagas Disease The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/trypanosoma-cruzi
- ↑ 6.0 6.1 Jones SL et al Special Section on Neglected Parasitic Infections. American Journal of Tropical Medicine and Hygiene special section on neglected parasitic infections. http://www.ajtmh.org/content/90/5.toc#SpecialSectiononNeglectedParasiticInfections
Parise ME et al Neglected Parasitic Infections in the United States: Needs and Opportunities. Am J Trop Med Hyg 2014 90(5):783-785 http://www.ajtmh.org/content/90/5/783.full
Centers for Disease Control and Prevention (CDC) Press Release. May 8, 2012 Parasitic Infections also occur in the United States. http://www.cdc.gov/media/releases/2014/p0508-npi.html - ↑ 7.0 7.1 Blevins SM, Greenfield RA, Bronze MS Blood smear analysis in babesiosis, ehrlichiosis, relapsing fever, malaria, and Chagas disease. Cleve Clin J Med. 2008 Jul;75(7):521-30 PMID: https://www.ncbi.nlm.nih.gov/pubmed/18646588
- ↑ 8.0 8.1 8.2 8.3 Rothaus C Chagas' Disease Now@NEJM. July 31, 2015 http://blogs.nejm.org/now/index.php/chagas-disease-2/2015/07/31/
- ↑ Gomez CA, Banaei N Trypanosoma cruzi Reactivation in the Brain. N Engl J Med 2018; 378:1824. May 10, 2018 PMID: https://www.ncbi.nlm.nih.gov/pubmed/29742366 https://www.nejm.org/doi/full/10.1056/NEJMicm1703763
- ↑ 10.0 10.1 10.2 10.3 10.4 10.5 10.6 Pereira Nunes MC, Beaton A, Acquatella H Chagas Cardiomyopathy: An Update of Current Clinical Knowledge and Management: A Scientific Statement From the American Heart Association. Circulation. Aug 20, 2018 PMID: https://www.ncbi.nlm.nih.gov/pubmed/30354432 https://www.ahajournals.org/doi/10.1161/CIR.0000000000000599
- ↑ 11.0 11.1 11.2 Rothaus C Under Our Very Eyes. NEJM REsident 360. March 4, 2020 https://resident360.nejm.org/clinical-pearls/under-our-very-eyes
- ↑ GARD Genetic and Rare Diseases Information Center Chagas Disease (not a rare disease) https://rarediseases.info.nih.gov/diseases/6030/chagas-disease
Centers for Disease Control and Prevention http://www.cdc.gov/ncidod/dpd/parasites/chagasdisease Division of Parasitic diseases (physicians) 770-488-7775
Centers for Disease Control & Prevention (CDC) Parasites - American Trypanosomiasis (also known as Chagas disease) Triatomine Bug FAQs https://www.cdc.gov/parasites/chagas/gen_info/vectors/index.html