Pearls:
- Chagas disease is a parasitic disease carried by the kissing bug that can be passed via multiple routes (fecal-oral, mother-to-child, blood) that has become more prevalent even in non-endemic regions of the world.
- 70% of people who are infected are asymptomatic and if left untreated 30% may go on to develop chronic disease that often manifests as dilated cardiomyopathy and arrhythmias.
- Weight-based benznidazole, BID for 60 days is first-line treatment and quite effective.
- The CDC has a 24/7 consultation line to help sort through diagnoses, which can be tricky in the acute vs. chronic phases.
- Epidemiology:
- 1 in 5 most neglected parasitic infections in the US
- Affects hundreds of thousands of people across the country
- Spread across 40 states
- Growing in prevalence even in non-endemic areas
- Pathophysiology:
- Caused by protozoan parasite Trypanosoma cruzi
- Vector is “kissing bug” (Triatominae)
- Transmission: fecal-oral via ingestion of contaminated food products, mother-to-child transmission, blood transfusion, organ transplantation
- Endemic to south and central America
- In the US more common in immigrants from Mexico and El Salvador
- Vectors invade homes through adobe walls or thatched roofs
- Clinical Presentation:
- Acute phase lasts 8-12 weeks
- 70% asymptomatic
- For those with symptoms, nonspecific viral/flu-like symptoms like fever, malaise, splenomegaly
- Rarely may have inflammation at site of inoculation called Chagoma
- If inoculated through the conjunctiva, may see Romana’s sign – unilateral painless swelling of the upper and lower eyelid
- 1% may present with severe acute myocarditis
- Indeterminate phase lasts for years to decades
- No signs or symptoms
- Must have normal ECG →
- Pearl: as long as it remains normal, these patients have the same risk of death as the normal population
- Positive serology
- Progress to dilated cardiomyopathy at rate of 2-7% per year
- Chronic disease
- Develops in about 30% of patients
- May manifest as dilated cardiomyopathy, thromboembolic disease, arrhythmias
- Most common cause of death is sudden death 55-60%, heart failure 25-30% and thromboembolic event 10-15%
- Acute phase lasts 8-12 weeks
- Diagnosis:
- History: travel or living in endemic countries, blood transfusions, organ transplant
- Serologies:
- Acute phase: IgG antibody testing via ELISA and immunofluorescence
- Pearl: The CDC offers 24/7 assistance for consultation at 404-718-4745
- PCR helpful to monitor after potential exposure but not useful in the acute phase as it may be negative. It will remain positive even after treatment proportional to the time the patient was infected
- Acute phase: IgG antibody testing via ELISA and immunofluorescence
- Cardiac: dreaded complication is dilated cardiomyopathy
- ECG looking for any changes like interventricular blocks, diffuse ST or T wave changes, abnormal Q waves → may progress to AV blockage and QT prolongation
- Ambulatory ECG monitoring looking for more subtle changes
- Echo
- Stress test
- Treatment:
- Indeterminate phase
- Monitor ECG annually looking for any changes
- May also check chest x-ray for cardiomegaly every 3-5 years
- First-line drug: benznidazole, BID, 60 days of treatment (wt-based)
- Most common side effect is allergic dermatitis and some may have peripheral neuropathy and some anorexia
- Leads to sustained 12 month parasite response in 85-95% of adults who complete the full course
- Second-line drug: nifurtimox, BID, 90 days
- More side effects
- Treatment does not reverse cardiomyopathy once its occurred but it does reduce symptom severity and shortens the clinical course
- Indeterminate phase
- Prevention:
- Hand hygiene
- Counsel on risk of vertical transmission and transmission via breastfeeding
- Do not donate blood or organs if ever infected
Chief Residents' Blog 