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Trypanosomiasis (Chagas Disease Acute)
Cardiovascular Presentations
Abdominal aortic aneurysm
Acute coronary syndrome (NSTEMI)
Acute coronary syndrome (STEMI)
Acute decompensated heart failure
Acute limb ischemia
Acute mesenteric ischemia
Aortic dissection
Aortic stenosis
Atrial fibrillation and flutter
Bradyarrhythmia and heart block
Cardiac arrest
Deep vein thrombosis
Myocarditis
Pericarditis
Pulmonary embolism
Stable angina
Superficial thrombophlebitis
Superior vena cava syndrome
Supraventricular tachycardia
Syncope (cardiogenic)
Unstable angina
Ventricular tachycardia
Respiratory Presentations
Acute bronchitis
Acute respiratory failure
Aspiration pneumonia
Asthma exacerbation
Bronchiolitis
Community-acquired pneumonia
COVID-19 pneumonia
COPD exacerbation
Croup
Croup (laryngotracheobronchitis)
Epiglottitis
Hemothorax
Hospital-acquired pneumonia
Pleural effusion
Pneumothorax (traumatic)
Pulmonary contusion
Spontaneous pneumothorax
Neurological Presentations
Bell's palsy
Benign paroxysmal positional vertigo
Brain abscess
Cauda equina syndrome
Cervical radiculopathy
Concussion (mild traumatic brain injury)
Encephalitis
Guillain-Barré syndrome
Hemorrhagic stroke (intracerebral)
Ischemic stroke
Lumbar radiculopathy
Malignant spinal cord compression
Migraine
Peripheral neuropathy (acute)
Retropharyngeal abscess
Schizophrenia (acute exacerbation)
Seizure (breakthrough:known epilepsy)
Seizure (first-time)
Spinal cord injury
Status epilepticus
Subarachnoid hemorrhage
Tension headache
Transient ischemic attack
Traumatic brain injury (moderate-severe)
Vestibular neuritis
Viral meningitis
Gastrointestinal Presentations
Acute appendicitis
Acute cholecystitis
Acute diverticulitis
Acute pancreatitis
Anal fissure
Choledocholithiasis and cholangitis
Clostridioides difficile colitis
Gastritis
Gastroenteritis (viral and bacterial)
Gastroesophageal reflux disease
Incarcerated or strangulated hernia
Inflammatory bowel disease flare
Large bowel obstruction
Lower GI hemorrhage
Peptic ulcer disease
Perforated viscus
Small bowel obstruction
Upper GI hemorrhage
Genitourinary and Reproductive Presentations
Acute prostatitis
Acute urinary retention
Ectopic pregnancy
Epididymitis
Orchitis
Ovarian torsion
Paraphimosis
Pelvic inflammatory disease
Priapism
Pyelonephritis
Renal laceration
Ruptured ovarian cyst
Testicular torsion
Tubo-ovarian abscess
Urinary tract infection (uncomplicated)
Urolithiasis (renal colic)
Vaginal bleeding (non-pregnant)
Infectious Disease Presentations
Acute sinusitis
Acute tonsillitis
Acute upper respiratory infection
Animal bite
Bacterial meningitis
Cellulitis
Conjunctivitis (bacterial)
Dental abscess
Endocarditis
Febrile neutropenia
Fournier gangrene
Hand-foot-mouth disease
Hepatitis (acute)
Herpes zoster
HIV-related illness
Human bite
Impetigo
Infected diabetic foot ulcer
Infectious mononucleosis
Influenza
Necrotizing fasciitis
Osteomyelitis
Otitis externa
Parasitic infection
Periorbital cellulitis
Peritonsillar abscess
Scabies
Sepsis
Septic arthritis
Spontaneous bacterial peritonitis
Tick-borne illness (Lyme disease)
Tinea infection
Tuberculosis
Viral exanthem
Wound infection
Trauma Presentations
Achilles tendon rupture
ACL and mceniscus tear
Ankle fracture
Ankle sprain
Burn
Calcaneus fracture
Cervical spine fracture
Clavicle fracture
Dental avulsion
Distal radius fracture
Drowning
Elbow fracture and dislocation
Electrical injury
Facial bone fracture
Facial laceration
Femur fracture
Fingertip amputation
Forearm fracture (radius and ulna)
Frostbite
Hand:finger laceration
Heat exhaustion
Heat stroke
Hip fracture
Humeral shaft fracture
Knee dislocation
Knee sprain
Lightning injury
Mandible fracture
Metacarpal fracture
Metatarsal fracture
Muscle strain
Nasal fracture
Non-accidental trauma
Orbital fracture
Patella fracture
Phalanx fracture (finger)
Proximal humerus fracture
Pulmonary contusion
Rib fracture
Rotator cuff tear (acute traumatic)
Scalp laceration
Scaphoid fracture
Shoulder dislocation
Skull fracture
Splenic laceration
Sternal fracture
Supracondylar pediatric fracture
Tendon laceration (hand:wrist)
Thoracic and lumbar spine fracture
Tibia:fibula fracture
Tibial plateau fracture
Toe fracture
Traumatic epistaxis
Traumatic hyphema
Toxicologic Presentations
Acetaminophen toxicity
Alcohol intoxication
Alcohol withdrawal
Anticholinergic toxicity
Anticoagulant overdose
Benzodiazepine overdose
Benzodiazepine:sedative overdose
Beta-blocker and calcium channel blocker toxicity
Carbon monoxide poisoning
Caustic ingestion
Digoxin toxicity
Drug eruption
Foreign body ingestion
Opioid intoxication
Opioid overdose
Opioid withdrawal
Organophosphate
Salicylate toxicity
Serotonin syndrome
Stimulant intoxication (cocaine, methamphetamine)
Tricyclic antidepressant overdose
Psychiatric Presentations
Acute anxiety
Acute psychosis
Agitation:behavioral emergency
Bipolar disorder
Conversion disorder
Major depressive episode
Neuroleptic malignant syndrome
Suicidal ideation and attempt
Musculoskeletal and Rheumatologic Presentations
Acute low back pain (mechanical)
Bursitis
Cervical radiculopathy
Costochondritis
Gout (acute)
Lumbar radiculopathy
Pseudogout
Tendinitis
Dermatology Presentations
Acute eczema (Eczema acute flare)
Allergic contact dermatitis
Erythema multiforme
Henoch-Schönlein purpura
Pressure injury
Psoriasis (acute flare)
Stevens-Johnson syndrome
Toxic epidermal necrolysis
Urticaria (acute)
Environmental and Exposure Presentations
Envenomation (snake, spider, insect)
High-altitude illness
Hypothermia
Hematologic and Oncologic Presentations
Acute chest syndrome
Coagulopathy
Hyperviscosity syndrome
Sickle cell crisis (vaso-occlusive)
Symptomatic anemia
Thrombocytopenia (severe)
Tumor lysis syndrome
Pediatric-Specific Presentations
Bronchiolitis
Croup
Emergency delivery
Febrile seizure
Kawasaki disease
Neonatal jaundice
Neonatal sepsis
Nursemaid's elbow
Pediatric fever 0 to 28 days
Pediatric fever 29 to 60 days
Pediatric fever 61 to 90 days
Pyloric stenosis
Slipped capital femoral epiphysis
Intussusception
Endocrine and Metabolic Presentations
Adrenal crisis
Diabetic ketoacidosis
Hypercalcemia
Hyperosmolar hyperglycemic state
Hypertensive emergency
Hypertensive urgency
Hypoglycemia
Myasthenia gravis crisis
Myxedema coma
Severe hyperkalemia
Severe hyponatremia
Thyroid storm
ENT and Maxillofacial Presentations
Acute laryngitis
Acute otitis media
Acute pharyngitis
Cerumen impaction
Epistaxis (anterior)
Nasal foreign body
Otitis externa
Tympanic membrane perforation
Ophthalmologic Presentations
Acute angle-closure glaucoma
Central retinal artery occlusion
Chemical eye injury
Corneal abrasion
Corneal ulcer
Globe rupture
Ocular foreign body
Orbital cellulitis
Retinal detachment
Obstetric Presentations
Hyperemesis gravidarum
Painful vaginal bleeding in pregnancy
Placenta previa
Placental abruption
Preeclampsia:eclampsia
Preterm labor
Threatened:inevitable:incomplete abortion
Systemic and Miscellaneous Presentations
Anaphylaxis
Angioedema
Cannabis-induced hyperemesis
Trypanosomiasis (Chagas Disease Acute)
POCUS
Procedures
Calculators
Resuscitation
ECG Guide
Back
Clinical Assessment Checklist
Browse categories and answer follow-up questions to refine your symptom profile.
Approach to the Critical Patient
Immediate priorities
Life-threatening presentations
▶
Acute myocarditis or cardiogenic shock
▶
Chest pain with tachycardia out of proportion to fever
Hypotension with signs of low cardiac output
Occurs in fewer than 5% of acute cases but carries significant mortality
Meningoencephalitis
▶
Altered mental status, seizures, or focal neurologic deficits
Approximately 1% of acute cases; higher mortality in infants and immunocompromised
Pericardial effusion with tamponade physiology
▶
Muffled heart sounds
Pulsus paradoxus
If hemodynamically unstable, immediate resuscitation bay activation
▶
IV access x2 large bore
Continuous cardiac monitoring and 12-lead ECG
Hemodynamic goals and monitoring
Stabilization targets
▶
MAP >= 65 mmHg
▶
IV fluid resuscitation for hypotension
Norepinephrine if vasopressor required
SpO2 >= 92% on supplemental oxygen
▶
HFNC or mechanical ventilation if respiratory compromise from cardiogenic pulmonary edema
Continuous telemetry
▶
AV block, RBBB, or ventricular arrhythmia triggers escalation
Atrial fibrillation management per ACLS protocol
Escalation triggers
▶
Worsening cardiac function on bedside echo
▶
Cardiology and cardiac ICU consultation
Rising lactate despite resuscitation
▶
Reassess for cardiogenic vs septic contribution
New CNS signs in febrile patient
▶
Urgent CT head followed by LP
Key early decisions
Confirm diagnosis before antiparasitic initiation when possible
▶
Thick and thin blood smear for trypomastigotes
▶
Standard first test in acute phase
PCR for T. cruzi DNA if smear negative but high suspicion
Contact CDC Parasitic Diseases Hotline 404-718-4745 for drug access and guidance
Antiparasitic therapy initiation
▶
Benznidazole first-line once diagnosis confirmed
▶
5 to 8 mg/kg/day PO divided BID x 60 days
80 to 100% cure rate with acute phase treatment
▶
Untreated, 30% risk of progression to chronic cardiomyopathy
History
Exposure and travel history
Geographic exposure
▶
Prolonged stay (more than 6 months) in Mexico, Central America, or South America
▶
Single most important screening question for Chagas disease
21 endemic countries, primarily rural areas
Rural dwelling in adobe or thatch-walled housing
▶
Triatomine kissing bug habitat
Sub-peridomestic infestation patterns
Immigration history from endemic region
▶
Country of origin and housing conditions
Transmission route
Vector-borne exposure
▶
Triatomine bug bite during sleep
▶
Bug defecates near bite; scratching inoculates wound
Symptoms appear 1 to 2 weeks after exposure
Oral transmission
▶
Contaminated fresh fruit juices (acai, sugarcane, guava)
Associated with more severe disease and higher case-fatality rates
Outbreak setting consideration
Non-vector transmission
▶
Blood transfusion from endemic-area donor
▶
Symptoms up to 3 to 4 months after transfusion
Organ transplant from seropositive donor
Congenital transmission
▶
Maternal history of T. cruzi infection
1 to 10% vertical transmission rate in seropositive mothers
Laboratory accident (rare, occupational exposure)
Symptoms
Febrile illness features
▶
Fever (often intermittent or low-grade)
Malaise, fatigue, headache, myalgia
Anorexia, nausea, diarrhea, abdominal pain
Duration 4 to 12 weeks; asymptomatic or undetected in more than 98% of cases
Pathognomonic features when present
▶
Romaña sign (unilateral painless periorbital edema)
▶
Conjunctival portal of entry
Present in approximately 50% of symptomatic cases
Chagoma (erythematous indurated nodule at bite site)
▶
Present in approximately 25% of symptomatic cases
Facial or limb edema
Alarm symptoms
▶
Chest pain, palpitations, dyspnea (myocarditis)
Confusion, seizures, focal neurologic deficits (meningoencephalitis)
Syncope or near-syncope
Risk factors
Host factors
▶
Age younger than 5 years or infancy
▶
Higher risk for severe acute disease and meningoencephalitis
HIV infection with CD4 count below 200 cells/mm3
▶
Risk for fulminant reactivation with CNS chagomas
CNS chagomas mimic toxoplasmosis but tend to be larger
Organ transplant recipient or on immunosuppressive therapy
Pregnancy (risk of congenital transmission, treatment contraindicated)
Social and environmental risk factors
▶
Poverty and poor housing conditions
Agricultural or outdoor work in endemic areas
No insecticide spraying history in home
Past medical history
Prior residence in endemic area even decades prior
▶
Chronic infection may reactivate under immunosuppression
Previous blood transfusions or organ transplants
Baseline cardiac history and prior ECG abnormalities
HIV/AIDS status and most recent CD4 count
Immunosuppressive medications
Pregnancy status
Physical Exam
Vital signs
Hemodynamic status
▶
Temperature (often low-grade fever)
▶
High fever may indicate oral-route transmission (more severe disease)
Heart rate
▶
Tachycardia out of proportion to fever suggests cardiac involvement
Bradycardia or irregular rhythm suggests conduction disease
Blood pressure
▶
SBP below 90 mmHg indicates hemodynamic compromise
MAP below 65 mmHg triggers resuscitation
Respiratory rate
▶
Elevated rate in cardiogenic pulmonary edema or meningoencephalitis
Head and neck exam
Pathognomonic signs
▶
Romaña sign
▶
Unilateral painless periorbital edema
Conjunctival injection with regional lymphadenopathy
Present in approximately 50% of recognized vector-borne acute cases
Chagoma at inoculation site
▶
Erythematous indurated subcutaneous nodule
Any skin surface; often extremities
Lymphadenopathy
▶
Generalized lymphadenopathy
▶
Mononucleosis-like clinical syndrome
Absence of posterior cervical lymphadenopathy distinguishes from African trypanosomiasis
Cardiovascular exam
Cardiac findings
▶
Tachycardia or irregular rhythm
▶
AV block or premature beats
Muffled heart sounds
▶
Pericardial effusion
Elevated JVP, peripheral edema, and pulmonary crackles
▶
Signs of congestive heart failure from myocarditis
Murmur
▶
Dilated cardiomyopathy with functional regurgitation
Abdominal exam
Organomegaly
▶
Hepatomegaly
▶
Mild to moderate tenderness
Splenomegaly
▶
Mild to moderate
Hepatosplenomegaly combination common in acute phase
Neurologic exam
CNS assessment
▶
Mental status changes
▶
Confusion, agitation, or reduced GCS
Meningismus
▶
Neck stiffness and photophobia
Focal neurologic deficits
▶
Motor weakness, cranial nerve palsies
Seizures
▶
New onset in febrile traveler requires urgent evaluation
Skin and edema
Cutaneous findings
▶
Facial and periorbital edema (Romaña sign as noted)
Limb edema
▶
Inflammatory response to T. cruzi dissemination
Rash absence distinguishes from dengue
Bite site erythema or induration at chagoma
Differential Diagnosis
Life-threatening mimics
Acute viral myocarditis
▶
ICD-10 I40.9
Travel history and blood smear or PCR differentiates
Endomyocardial biopsy may be needed if diagnosis unclear
Bacterial meningitis
▶
ICD-10 G00.9
CSF analysis with differential cell count and culture distinguishes
Chagas meningoencephalitis CSF may show predominantly mononuclear pleocytosis
Septic shock from bacteremia
▶
ICD-10 A41.9
Blood cultures and response to antibiotics differentiating
Infectious disease mimics
Malaria
▶
ICD-10 B54
Febrile illness in returning traveler; thick and thin smear shows Plasmodium not trypomastigotes
Cyclic fever pattern more prominent; no periorbital edema
Dengue fever
▶
ICD-10 A90
Rash and arthralgias more prominent; thrombocytopenia common
No trypomastigotes on smear; dengue NS1 antigen or PCR positive
Infectious mononucleosis (EBV)
▶
ICD-10 B27.00
Mononucleosis-like syndrome overlap; atypical lymphocytes on smear
Monospot or EBV serology positive; no trypomastigotes
Visceral leishmaniasis (Kala-azar)
▶
ICD-10 B55.0
Fever, hepatosplenomegaly, pancytopenia; different vector (sandfly) and geography
Leishmania amastigotes in bone marrow or spleen aspirate
African trypanosomiasis (sleeping sickness)
▶
ICD-10 B56.9
Sub-Saharan Africa geography; tsetse fly vector
Posterior cervical lymphadenopathy (Winterbottom sign)
T. brucei trypomastigote with small kinetoplast distinguishes from T. cruzi C-shaped form
Toxoplasmosis
▶
ICD-10 B58.9
CNS lesions in immunocompromised; Chagas brain chagomas tend to be larger
Toxoplasma serology and response to empiric therapy may guide
Typhoid fever
▶
ICD-10 A01.0
Prolonged fever in returning traveler; rose spots; blood culture positive
Zika and chikungunya
▶
ICD-10 A92.5 and A92.0 respectively
Arthralgia more prominent; specific PCR or serology
Non-infectious mimics
Periorbital cellulitis or preseptal cellulitis
▶
ICD-10 H05.01
Usually bilateral or bilateral risk; pain present; no systemic febrile illness
Distinguishes Romaña sign (painless, unilateral)
Allergic angioedema
▶
ICD-10 T78.3
Rapid onset with allergen exposure; urticaria common; no fever or systemic illness
Heart failure exacerbation
▶
ICD-10 I50.9
Prior cardiac history; responds to diuretics; no parasitemia
Laboratory Tests
Diagnostic parasitology
Blood smear microscopy
▶
Giemsa-stained thick and thin blood smear
▶
Standard first-line test in acute phase
Look for trypomastigotes with large posterior kinetoplast and C-shaped morphology
High sensitivity in acute phase when parasitemia is high
IDSA/ASM 2024 guideline recommended (Class I)
Buffy coat preparation
▶
Concentrates parasites; increases sensitivity
Useful when smear is negative in symptomatic patient
Fresh wet mount of anticoagulated blood
▶
May show motile trypomastigotes
Not routinely available in US labs
Molecular diagnostics
PCR for T. cruzi DNA
▶
Higher sensitivity than microscopy as adjunct
▶
Useful when parasitemia low (congenital, reactivation, chronic)
IDSA/ASM 2024 guideline recommended
Quantitative PCR useful for monitoring treatment response
▶
Parasitemia should clear within weeks of effective treatment
Reference laboratory testing required in most US institutions
▶
CDC can facilitate
Serologic testing
Acute phase serology
▶
Not reliable in acute phase (antibodies may be absent for 4 to 8 weeks)
▶
IgM anti-T. cruzi may be detectable earlier but not widely available
Two-test algorithm required for chronic infection diagnosis
▶
Two different antigen or format tests required; one positive is insufficient
Useful for confirming exposure history in patients with chronic or reactivation disease
Supportive laboratory tests
Complete blood count
▶
Leukocytosis with lymphocyte predominance common
▶
Atypical lymphocytes may be seen (mononucleosis-like)
Anemia in severe or prolonged infection
Thrombocytopenia uncommon; consider dengue if present
Liver function tests
▶
Transaminase elevation from hepatic involvement
▶
Baseline before benznidazole initiation (hepatotoxicity monitoring)
Alkaline phosphatase and bilirubin
Renal function and electrolytes
▶
Baseline before antiparasitic initiation
▶
Benznidazole and nifurtimox require dose adjustment in severe renal insufficiency
Hydration status assessment
Cardiac biomarkers
▶
Troponin I or T
▶
Elevated in acute myocarditis
Prognostic significance in acute Chagas myocarditis
BNP or NT-proBNP
▶
Elevated with myocarditis-associated heart failure
Lumbar puncture (if meningoencephalitis suspected)
▶
Opening pressure
CSF cell count, protein, glucose
▶
Mononuclear pleocytosis typical
CSF PCR for T. cruzi DNA
▶
Highest sensitivity for CNS involvement
Gram stain and culture to exclude bacterial meningitis
HIV testing
▶
All patients with suspected Chagas disease
▶
HIV coinfection dramatically increases severity and reactivation risk
CD4 count if HIV positive
Blood cultures (if bacterial co-infection suspected)
▶
Before antibiotics when feasible
Diagnostic Tests
Scoring Systems
Chagas disease severity staging
▶
WHO/PAHO staging classification
▶
Acute phase: parasitemia detectable, nonspecific febrile illness
Indeterminate chronic phase: seropositive, normal ECG and imaging
Chronic cardiac phase: ECG abnormalities, cardiomegaly, arrhythmia
Chronic digestive phase: megaesophagus or megacolon
Rassi score (chronic cardiomyopathy risk stratification)
▶
Not for acute phase; used for chronic phase prognosis
Variables include NYHA class, cardiomegaly, LV dysfunction, non-sustained VT, QRS low voltage, male sex
Sepsis screening tools
▶
qSOFA
▶
RR >= 22 per minute
SBP <= 100 mmHg
Altered mental status
Screening tool; clinical judgment required
SOFA score
▶
Full organ dysfunction assessment for ICU disposition
Limitations of scoring systems
▶
No validated acute Chagas-specific score
Clinical trajectory and cardiac involvement supersede scoring
MRI
Cardiac MRI
▶
Role in acute Chagas myocarditis
▶
Late gadolinium enhancement identifies myocardial inflammation and fibrosis
Characteristic pattern: subepicardial and midmyocardial enhancement, often involving lateral and inferior walls
Superior tissue characterization compared to echocardiography alone
Indications in acute setting
▶
Myocarditis with normal or borderline echo but ongoing clinical concern
Differentiating Chagas myocarditis from other cardiomyopathies
Pericardial disease characterization
Contraindications and limitations
▶
Hemodynamically unstable patient — echocardiography preferred
Non-MRI-compatible implants or pacemakers
Availability constraint in emergency setting
Brain MRI for meningoencephalitis
▶
Indications
▶
CNS symptoms in confirmed or suspected acute Chagas
Immunocompromised patient with focal neurologic signs
Expected findings
▶
Brain chagomas: ring-enhancing lesions, typically larger than toxoplasmosis
Diffuse meningoencephalitic changes
FLAIR signal abnormalities in white matter
Differentiating from toxoplasmosis
▶
Chagas CNS lesions often larger and fewer
T. cruzi PCR on CSF distinguishes
CT
CT chest
▶
Indications in acute Chagas
▶
Cardiomegaly evaluation when CXR equivocal
Pericardial effusion size quantification
Pulmonary edema assessment in acute myocarditis
Findings
▶
Cardiomegaly with globular cardiac silhouette (pericardial effusion or dilated cardiomyopathy)
Pulmonary vascular congestion pattern
Pleural effusions in heart failure
Contrast considerations
▶
Renal function assessment before contrast administration
Allergy history
CT brain
▶
Indications
▶
Altered mental status or new focal deficit
Seizure in febrile patient with suspected Chagas
Before lumbar puncture to exclude mass effect
Findings with CNS Chagas
▶
Hypodense lesions corresponding to chagomas
Ring-enhancing lesions with contrast (may mimic toxoplasmosis)
Mass effect with large chagomas
Evidence
▶
CT brain recommended before LP when focal deficits or papilledema present
ACEP Level C recommendation for neuroimaging before LP in this setting
Ultrasound
Echocardiography
▶
Indications in acute Chagas
▶
Any suspicion of cardiac involvement
All patients with ECG abnormalities, chest pain, or dyspnea
American Society of Echocardiography recommends multimodality cardiac imaging in Chagas disease (2018 Guideline)
Key echocardiographic findings in acute myocarditis
▶
Regional or global wall motion abnormalities
Reduced LV ejection fraction (below 50%)
Pericardial effusion
Intracardiac thrombus (risk of embolism)
ASE/ECOSIAC guideline recommendations
▶
Baseline echo for all confirmed Chagas cases
Repeat echo at 6 months to assess for progression to chronic cardiomyopathy
Point-of-care ultrasound (POCUS)
▶
Cardiac POCUS in ED
▶
Pericardial effusion rapid identification
Gross LV function assessment
IVC size for fluid responsiveness guidance
Abdominal POCUS
▶
Hepatosplenomegaly confirmation
Ascites detection if severe disease
Lung POCUS
▶
B-lines for pulmonary edema from myocarditis
Pleural effusion detection
Disposition
Admission indications
Cardiac involvement
▶
ECG abnormalities
▶
AV block (any degree)
Right bundle branch block (RBBB)
Ventricular arrhythmias or non-sustained VT
Atrial fibrillation or flutter
ST changes or QTc prolongation
Clinical myocarditis
▶
Elevated troponin with symptoms
LV dysfunction on echo
Pericardial effusion (any size with tamponade physiology; moderate or large)
Hemodynamic instability
▶
SBP below 90 mmHg
MAP below 65 mmHg despite initial resuscitation
Neurologic involvement
▶
Meningoencephalitis or altered mental status
Seizures
Focal neurologic deficits
High-risk host
▶
Immunocompromised with suspected reactivation
▶
HIV with low CD4 count
Transplant recipient
Neonates with symptomatic congenital infection
Infants with acute disease (higher mortality risk)
Inability to initiate outpatient treatment
▶
Severe nausea or vomiting precluding oral antiparasitic therapy
No access to infectious disease follow-up
ICU-level indications
Cardiogenic shock
▶
Vasopressor requirement
▶
Norepinephrine initiated
Mechanical circulatory support consideration (IABP or impella)
Continuous arrhythmia monitoring and treatment
Respiratory failure
▶
Mechanical ventilation requirement
Severe pulmonary edema from myocarditis
Neurologic emergency
▶
Refractory seizures
Rapidly declining GCS
Discharge criteria and consults
Copy
Outpatient management criteria
▶
Mild febrile illness without cardiac or neurologic involvement
Normal ECG and stable vital signs
Tolerating oral medications
Reliable follow-up with infectious disease specialist arranged
Mandatory consults
▶
Infectious disease for all confirmed or suspected cases
▶
CDC Parasitic Diseases Hotline 404-718-4745 for drug access
Cardiology if any cardiac involvement on ECG or echo
Neurology if CNS symptoms present
Obstetrics/Maternal-fetal medicine if pregnant
Transfer criteria
▶
Transfer to tertiary center with infectious disease and cardiology expertise if local resources unavailable
Treatment
Antiparasitic therapy — first-line
Benznidazole
▶
Mechanism
▶
Nitroreductase-mediated formation of toxic metabolites
Direct trypanocidal activity
First-line preference due to better tolerability and tissue penetration
Dosing — adults
▶
5 to 8 mg/kg/day PO divided in 2 doses (BID)
Maximum 300 mg/day per expert recommendation
Duration 60 days
Take with food to reduce GI side effects
Dosing — children 2 to 12 years (FDA-approved)
▶
Same weight-based dosing: 5 to 8 mg/kg/day divided BID
Duration 60 days
Meningoencephalitis dosing
▶
Up to 15 mg/kg/day recommended
Specialist guidance required
Cure rate in acute phase
▶
76 to 100% when initiated early
Near 100% in congenital Chagas when treated in first year of life
Adverse effects
▶
Dermatitis and photosensitivity rash (approximately 30% of patients)
Peripheral neuropathy (approximately 30% with prolonged use)
GI intolerance (nausea, anorexia)
Bone marrow suppression (rare)
Management of adverse effects
▶
Mild rash: antihistamines or short-course corticosteroids
Discontinue immediately for severe or exfoliative dermatitis
Discontinue for dermatitis with fever and lymphadenopathy
Contraindications
▶
Pregnancy (teratogenic)
Breastfeeding
Severe hepatic or renal insufficiency
Advanced chagasic cardiomyopathy
Antiparasitic therapy — alternative
Nifurtimox
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Role
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Alternative when benznidazole not tolerated or contraindicated
FDA-approved for children birth to under 18 years (weight >= 2.5 kg)
Adult use off-label but standard practice
Dosing — adults
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8 to 10 mg/kg/day PO divided in 3 doses (TID)
Duration 60 days
Take with food
Dosing — pediatric (per kg)
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Children 1 to 10 years: 15 to 20 mg/kg/day in 4 divided doses
Adolescents 11 to 16 years: 12.5 to 15 mg/kg/day in 4 divided doses
Duration 60 to 90 days
Adverse effects
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Anorexia and weight loss
Neuropsychiatric symptoms: irritability, insomnia, restlessness
Nausea and vomiting
Peripheral neuropathy with prolonged use
Discontinuation rates reported 14.5 to 75%
Contraindications
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Pregnancy
Severe neuropsychiatric disease
Severe hepatic or renal insufficiency
Cardiac management
Acute myocarditis
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Standard heart failure therapy as needed
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Diuretics (furosemide IV 40 mg initially; titrate to urine output)
ACE inhibitor or ARB initiation with cardiologist guidance
Vasodilators for afterload reduction
Arrhythmia management
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Continuous telemetry
ACLS protocol for ventricular tachycardia or fibrillation
Amiodarone for refractory ventricular arrhythmia
Temporary pacing for high-degree AV block
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Transcutaneous pacing as bridge
Transvenous pacing if persistent
Anticoagulation
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Anticoagulation for LV thrombus detected on echo
Anticoagulation for atrial fibrillation per CHA2DS2-VASc score
Pericardial effusion
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Pericardiocentesis if tamponade physiology present
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Emergent if hemodynamic compromise
Echocardiography-guided preferred
Cardiology consultation for all pericardial effusions
Meningoencephalitis management
Antiparasitic at higher dose
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Benznidazole up to 15 mg/kg/day
Duration extended to 60 days minimum; specialist guidance
Supportive CNS care
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Seizure management: lorazepam IV 0.1 mg/kg (max 4 mg) for active seizure
Levetiracetam for seizure prophylaxis consideration
Dexamethasone 0.15 mg/kg IV q6h for vasogenic edema (specialist guidance)
Neurology and infectious disease co-management required
Immunocompromised and HIV management
HIV-coinfected patients
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Initiate or optimize antiretroviral therapy (ART)
Same antiparasitic regimen as immunocompetent
Mortality remains high even with treatment in fulminant reactivation
Screen for CNS involvement aggressively
Transplant recipients with reactivation
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Reduction in immunosuppression if feasible (discuss with transplant team)
Antiparasitic therapy initiated immediately
Monitoring with PCR during treatment
Supportive care
Fever management
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Antipyretics (acetaminophen preferred)
IV hydration for dehydration from fever and poor oral intake
Drug monitoring during treatment
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CBC every 2 weeks during therapy
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Monitor for bone marrow suppression (benznidazole)
LFTs every 2 weeks during therapy
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Monitor for hepatotoxicity
Renal function at baseline and monthly
Prevention of oral transmission reinfection
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Counsel on avoiding raw or untreated fruit juices from endemic areas
Special Populations
Pregnancy
Treatment considerations
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Benznidazole and nifurtimox both contraindicated in pregnancy
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Teratogenic in animal studies
Antiparasitic treatment deferred until after delivery and cessation of breastfeeding
Supportive therapy for acute illness
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Antipyretics (acetaminophen; avoid NSAIDs in third trimester)
IV hydration for severe dehydration
Congenital transmission risk
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Occurs in 1 to 10% of pregnancies in seropositive mothers
Screening of all neonates born to seropositive mothers
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PCR or microscopy at birth and 4 to 8 weeks
Serology not valid before 9 months of age (maternal antibody interference)
Congenital transmission associated with stillbirth, prematurity, and low birth weight
Delivery and postpartum
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Mode of delivery not changed by Chagas status
Breastfeeding generally considered safe if no breast wounds or cracked nipples
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Treatment may be initiated after cessation of breastfeeding
Maternal-fetal medicine and infectious disease co-management
Cardiac monitoring in pregnancy
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Baseline ECG and echo for seropositive pregnant women
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Increased cardiac demand of pregnancy may unmask latent cardiomyopathy
Geriatric
Reactivation in older adults
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Immunosenescence increases reactivation risk
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Consider reactivation in older Latin American immigrants with new cardiac symptoms
Chronic infection may have been acquired decades prior
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Serologic screening in at-risk older adults from endemic regions
Medication tolerability
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Benznidazole neuropathy risk higher in elderly
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Lower starting dose and gradual uptitration may be considered
Close monitoring for peripheral neuropathy (symptom diary)
Renal function decline affects drug clearance
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Creatinine clearance calculation before initiation
Dose reduction for CrCl below 30 mL/min
Polypharmacy drug interaction review
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Bone marrow suppression additive with other myelosuppressants
Cardiac disease overlap
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Pre-existing arrhythmias may complicate Chagas cardiac involvement
Pacemaker or ICD threshold lower in geriatric Chagas cardiomyopathy
Heart failure management adjusted for reduced renal reserve
Atypical presentation
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Confusion or delirium as presenting symptom without classic fever
Lower temperature response to infection
Pediatrics
Congenital Chagas disease
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Presentation
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Low birth weight, prematurity, hepatosplenomegaly
Meningoencephalitis in severe congenital cases
Hydrops fetalis (rare)
Diagnosis in neonates
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PCR or blood smear in first month of life
Serology unreliable before 9 months (maternal IgG)
Retest with serology at 9 months if PCR negative
Treatment in congenital infection
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Near 100% cure rate when treated in first year of life
Benznidazole FDA-approved for ages 2 to 12 years
Nifurtimox FDA-approved from birth to under 18 years
Acute vector-borne disease in children
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Higher risk for meningoencephalitis compared to adults
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CNS involvement up to 3 to 5% in young children
Romaña sign more commonly recognized in children
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Higher rate of periorbital presentation in pediatric series
Weight-based dosing
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Benznidazole 5 to 8 mg/kg/day PO divided BID x 60 days
Nifurtimox 15 to 20 mg/kg/day PO divided q6h for ages 1 to 10 years
Oral transmission outbreaks in children
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School-based outbreaks from contaminated juice reported in Brazil
More severe disease and higher rates of myocarditis
Public health reporting and outbreak investigation required
Background
Epidemiology
Global burden
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Estimated 6 to 7 million people infected worldwide
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GBD 2023 study confirms ongoing high disease burden in Latin America
21 endemic countries primarily in Central and South America
Approximately 300,000 to 400,000 people with T. cruzi infection in the United States
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Primarily immigrants from endemic regions
Congenital transmission occurring in US among seropositive immigrant mothers
Annual deaths estimated at 7,000 to 10,000 (predominantly from chronic cardiomyopathy)
Acute phase epidemiology
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More than 98% of acute infections asymptomatic or unrecognized
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Symptomatic acute disease skewed toward children in endemic areas
Oral transmission outbreaks increasingly recognized
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Higher case-fatality rates than vector-borne infection
Brazil, Venezuela, and Colombia most reported
Congenital transmission: 1 to 10% rate in seropositive mothers
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Up to 14,000 infected neonates born annually in Latin America
Mortality
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Acute phase mortality less than 5% overall
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Higher in infants, young children, and immunocompromised
Without antiparasitic treatment: 20 to 30% progress to chronic cardiomyopathy over decades
Pathophysiology
Causative organism
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Trypanosoma cruzi
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Protozoan parasite, Kinetoplastida order
Discrete typing units (DTUs) TcI through TcVI with geographic and host variation
Kinetoplast (mitochondrial DNA) is large and posterior; C-shaped morphology on smear
Transmission cycle
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Vector-borne route (most common historically)
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Triatomine bug (Rhodnius prolixus, Triatoma infestans, others)
Fecal contamination of bite wound or mucosal surface
Oral route
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Ingestion of triatomine feces or crushed bugs in fruit juices
Highly efficient transmission route (higher inoculum)
Other routes: blood transfusion, organ transplant, congenital, laboratory accident
Acute phase pathogenesis
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Local inflammation at inoculation site (chagoma or Romaña sign)
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Leishmanoid amastigotes proliferate locally before entering bloodstream
Parasitemia
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Trypomastigotes circulate and invade multiple cell types
Cardiac myocytes, macrophages, neurons preferentially parasitized
Innate and adaptive immune response
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TNF-alpha, IFN-gamma, IL-12 mediate inflammatory myocarditis
Inflammatory response responsible for much of acute cardiac damage
Resolution
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Parasitemia controlled by immune response over 4 to 12 weeks
Parasite persists at low levels in tissue (chronic infection established)
Acute cardiac pathology
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Myocarditis
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Direct myocardial invasion and inflammatory infiltrate
Focal necrosis and edema
Conduction system involvement
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Inflammation of sinus node and AV conduction
RBBB most common acute ECG abnormality
Pericarditis
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Inflammatory pericardial involvement
Therapeutic Considerations
Timing of treatment
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Acute phase antiparasitic treatment has best efficacy
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76 to 100% cure rate in acute phase
Cure rate declines significantly in chronic phase (less than 30%)
Treatment in chronic phase (indeterminate or cardiac): reduces seroreversion but evidence for clinical benefit is less established
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BENEFIT trial (Lancet 2015): no significant reduction in cardiac clinical events with benznidazole in chronic cardiomyopathy
Drug access in the United States
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Benznidazole and nifurtimox not routinely stocked in US pharmacies
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Contact CDC Parasitic Diseases Hotline 404-718-4745
Investigational drug protocols may apply for adult off-label use
FDA approved indications
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Benznidazole: ages 2 to 12 years
Nifurtimox: birth to under 18 years (weight >= 2.5 kg)
Monitoring strategy
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CBC and LFTs every 2 weeks during 60-day treatment course
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Bone marrow suppression and hepatotoxicity surveillance
Peripheral neuropathy symptom monitoring
Drug reaction monitoring
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Rash onset typically weeks 2 to 4
Post-treatment surveillance
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Serologic follow-up to document seroconversion
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May take months to years in adults; faster in children
PCR negativity as early marker of parasitological cure
Annual ECG for all confirmed T. cruzi infection even after acute treatment
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Monitor for late cardiac manifestations
Prevention
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Vector control with insecticide spraying in endemic housing
Housing improvement (replacing thatch and adobe)
Blood bank and organ donor screening (now universal in endemic countries and US)
Avoidance of untreated fresh fruit juices from endemic areas
No vaccine currently available
Patient Discharge Instructions
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Home care instructions for Chagas disease
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Take your antiparasitic medication exactly as prescribed
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Benznidazole or nifurtimox must be taken with food
Do not skip doses; full 60-day course is essential
Contact your doctor if you develop a rash, numbness or tingling in hands or feet, or severe stomach upset
Rest and hydration
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Drink plenty of fluids during the febrile illness
Rest as needed until fever resolves
Sun protection
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Benznidazole can cause photosensitivity rash
Use sunscreen and avoid prolonged sun exposure during treatment
Follow-up appointments
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Blood test (CBC and liver tests) every 2 weeks during treatment
First follow-up appointment within 1 week to check medication tolerance
Infectious disease specialist appointment arranged
Cardiology appointment if heart problems were identified
Warning signs — return to emergency department immediately for
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Chest pain, racing heart, irregular heartbeat, or fainting
Shortness of breath at rest or waking you from sleep
Severe rash especially with blistering, peeling, fever, or swollen lymph nodes
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Stop your medication and return immediately
Numbness, tingling, or weakness in arms or legs (new or worsening)
Confusion, severe headache, seizures, or difficulty speaking or moving limbs
Yellowing of skin or eyes (jaundice)
Fever returning or worsening after initial improvement
Important information for you and your family
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You cannot donate blood or organs
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Inform blood banks and your medical providers of your diagnosis
If you are a woman of childbearing age, Chagas can be passed to your baby during pregnancy
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Discuss family planning and pregnancy testing with your doctor
Any children born to seropositive mothers should be tested
Family members who lived with you in the same endemic area or housing should also be tested
Chagas disease is not spread by casual contact (shaking hands, hugging, coughing)
References
Guidelines and key sources
Primary clinical guidelines
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Bern C. Chagas Disease. New England Journal of Medicine 2015
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Comprehensive review of diagnosis and management across all phases
Nunes MCP et al. Chagas Cardiomyopathy: AHA Scientific Statement. Circulation 2018
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Cardiac management, imaging, and monitoring recommendations
Perez-Molina JA, Molina I. Chagas Disease. Lancet 2018
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Updated comprehensive clinical review
Acquatella H et al. ASE Recommendations for Multimodality Cardiac Imaging in Chagas Disease. J Am Soc Echocardiogr 2018
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Echocardiographic surveillance guidelines
Constance Benson et al. IDSA/OARAC Guidelines for Opportunistic Infections in HIV. 2025
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Chagas reactivation in HIV: management recommendations
Miller JM et al. IDSA/ASM Guide to Microbiology Laboratory for Infectious Disease Diagnosis. Clinical Infectious Diseases 2024
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Diagnostic testing guidance for T. cruzi
Cantey PT et al. Neglected Parasitic Infections: CDC Update. American Family Physician 2021
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US-focused management, drug access, and screening
Key research
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Rassi A et al. Chagas Disease. Lancet 2010
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Natural history and pathophysiology overview
Bern C et al. Evaluation and Treatment of Chagas Disease in the US. JAMA 2007
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Systematic review of US management and drug access
GBD 2023 Chagas Disease Collaborators. Global Burden of Chagas Disease 1990-2023. Lancet Infectious Diseases 2026
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Current epidemiologic burden data
Elkheir N et al. HIV and T. cruzi Co-Infection Systematic Review. PLoS Neglected Tropical Diseases 2026
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Reactivation risk and outcomes in HIV coinfection
ICD-10 codes
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B57.0 — Acute Chagas disease with heart involvement
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Use for acute myocarditis or cardiac complications
B57.1 — Acute Chagas disease without heart involvement
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Febrile illness without cardiac findings
B57.5 — Chagas disease (chronic) with other organ involvement
SNOMED CT concept: Acute Chagas disease (disorder)
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.
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Management Protocols
Trypanosomiasis (Chagas Disease Acute)