Chagas Disease Flashcards
What is Chagas disease caused by?
Chagas disease is caused by the protozoan parasite Trypanosoma cruzi.
How is Chagas disease transmitted to humans?
Chagas disease is transmitted by infected triatomine bugs, transfusion, organ transplant, from mother to infant, and ingestion of contaminated food or drink.
In which geographical area does vector-borne transmission of Chagas disease occur?
Vector-borne transmission occurs only in the Americas.
What is the estimated number of people with Chagas disease?
An estimated 6 million people have Chagas disease.
What is the characteristic sign of acute Chagas disease when the conjunctiva is infected?
Romaña’s sign, characterized by unilateral painless swelling of the upper and lower eyelids.
What are the common symptoms of acute Chagas disease?
Symptoms typically include a non-specific febrile illness, and in some cases, acute myocarditis or meningoencephalitis.
What happens at the end of the acute phase of Chagas disease?
Parasitemia falls below levels detectable by microscopy, and the infection passes into the chronic phase.
What is the indeterminate form of Chagas disease?
It is when most patients with chronic T. cruzi infection have no signs or symptoms.
What is the most common complication of chronic Chagas disease?
Cardiomyopathy.
What are the early manifestations of chronic Chagas disease?
Conduction system abnormalities, such as right bundle branch block.
How is T. cruzi reactivation characterized during the chronic phase?
By a return to high levels of parasite replication and parasitemia, detectable by microscopy.
What are common manifestations of reactivated Chagas disease in HIV patients?
- T. cruzi meningoencephalitis
- Acute myocarditis
- Skin lesions
- Erythema nodosum
- Parasitic invasion of the peritoneum, stomach, or intestine.
What screening is recommended for individuals who have lived in endemic areas?
Serological testing for Chagas disease.
What serological methods are used to diagnose chronic Chagas infection?
- Enzyme-linked immunosorbent assay (ELISA)
- Immunofluorescent antibody assay (IFA).
What is required for a confirmed diagnosis of chronic T. cruzi infection?
Two serological tests based on different antigens and/or techniques.
What is the role of polymerase chain reaction (PCR) in diagnosing chronic Chagas disease?
PCR is generally not useful as its sensitivity is highly variable.
What should be considered in the differential diagnosis of CNS symptoms in patients with HIV?
Coinfection with T. cruzi and reactivation disease.
What is the primary method for identifying reactivation of Chagas disease?
Identification of the parasite or its products in tissue, such as blood or CSF.
What is the recommended treatment for individuals with T. cruzi infection living with HIV?
A single course of treatment with benznidazole or nifurtimox.
What is the FDA-approved age range for using benznidazole?
Children 2 to 12 years of age.
What is the recommended regimen for nifurtimox?
8 to 10 mg/kg/day in three divided doses with food for 60 days.
What is a significant risk factor for reactivation of Chagas disease in people with HIV?
Low CD4 T lymphocyte cell counts (<200 cells/mm3).
What is the recommended preventive measure for travelers to endemic areas of Chagas disease?
Avoid sleeping in rustic lodging and use insecticide-treated bed nets.
True or False: There are currently drugs or vaccines available to prevent T. cruzi infection.
False.
What is the typical presentation of reactivation in immunosuppressed patients compared to HIV patients?
Different; the most common in HIV patients is T. cruzi meningoencephalitis.
What should be done for individuals with high clinical suspicion of reactivation of chronic Chagas disease?
Testing to identify T. cruzi should be considered.
What must be carefully considered before initiating ART in people with HIV and reactivated T. cruzi infection involving the brain?
The decision to initiate ART must be carefully considered
There is no known contraindication to starting or optimizing ART in patients with CNS Chagas disease.
What is the recommendation regarding ART for patients with concomitant T. cruzi?
ART should be initiated in all patients with concomitant T. cruzi (AIII)
IRIS is not recognized as a common manifestation in the setting of coinfection.
What monitoring should be conducted for patients undergoing treatment with benznidazole?
Comprehensive metabolic panel (CMP) and complete blood count (CBC) should be monitored before initiation and during therapy
Benznidazole is associated with significant toxicities.
What are some benznidazole-associated adverse drug reactions?
Adverse reactions include:
* Abdominal symptoms (pain, nausea, vomiting, diarrhea)
* Reversible peripheral neuropathy
* Rash
* Granulocytopenia
Co-administration with disulfiram, alcohol, and products containing propylene glycol should be avoided.
What are the adverse drug reactions associated with nifurtimox?
Adverse reactions include:
* Anorexia
* Nausea
* Vomiting
* Abdominal pain
* Weight loss
* Rash
* Restlessness
* Tremors
* Dose-dependent peripheral neuropathy
Alcohol consumption should be avoided with nifurtimox.
How frequently should CMP and CBC be monitored during treatment?
Generally every 2 weeks
The frequency is not standardized.
What is the concern regarding treatment failure in people with HIV and chronic T. cruzi infection?
Benznidazole and nifurtimox are only partially effective and may be suppressive rather than curative
Expert advice should be sought due to the drugs’ toxicity.
What is unclear regarding secondary prophylaxis or chronic maintenance therapy in people with HIV with latent Chagas disease?
It is unclear whether secondary prophylaxis or chronic maintenance therapy should be used
Particularly when potent ART is used.
What should be considered for pregnant individuals with epidemiologic risk of Chagas disease?
Screening for maternal infection and possible risk of infection in offspring should be considered
See the CDC resource for congenital Chagas disease.
What percentage of infants born to mothers with T. cruzi have acute T. cruzi infection?
Between 1% to 10%
Congenital infections are often asymptomatic or cause non-specific signs.
What severe morbidities can congenital T. cruzi infection cause?
Severe morbidities include:
* Low birthweight
* Hepatosplenomegaly
* Anemia
* Meningoencephalitis
* Respiratory insufficiency
* High risk of mortality
Limited data suggest higher rates of congenital transmission for women with HIV.
What is the recommendation regarding treatment of acute T. cruzi infection in pregnant individuals?
Treatment should only be undertaken in consultation with a specialist
Treatment of chronic disease should be considered only after pregnancy and breastfeeding.
What is recommended for individuals with epidemiological risk factors for Chagas disease who test positive for antibody to T. cruzi?
They should be tested using at least two serological tests
Tests should be based on different antigens and/or techniques.
What is the recommended therapy for individuals with acute or reactivated T. cruzi infection?
Benznidazole 5–8 mg/kg/day PO in 2 divided doses for 60 days or Nifurtimox 8–10 mg/kg/day PO in 3 divided doses for 60 days
Initiation or optimization of ART is also recommended.
What is the indication for treating acute or reactivated T. cruzi infection?
Presence of parasitemia should be treated (AII)
Treatment is not recommended for patients with advanced chagasic cardiomyopathy.
