🧑‍⚕️ Chagas disease was first described in 1909 by Carlos Chagas in Brazil. It is caused by the protozoan Trypanosoma cruzi, transmitted by the faeces of the triatomine (reduviid) bug.

📖 About

🌎 Endemic in South America, causing >50,000 deaths annually.
🦠 Caused by infection with T. cruzi.

🏚️ Triatomine bugs thrive in cracks of poorly built houses (mud, thatch, adobe). 🌙 They feed at night → people in endemic areas should avoid sleeping in such dwellings or outdoors.

🧬 Aetiology

🦟 Vector: reduviid “kissing bug”.
Acquires parasite from infected host → transmits via faeces.
Parasite enters through mucous membranes or skin breaks.
Other routes: 💉 blood transfusion, 👶 vertical transmission.

🩺 Clinical Features

⚡ Acute phase: fever, rash, lymphadenopathy, hepatosplenomegaly, myalgia, myocarditis. • Chagoma: swelling at entry site. • Romana’s sign: periorbital oedema (classic).
⌛ Chronic phase: often silent for years → complications: ❤️ dilated cardiomyopathy, arrhythmias, cardiac arrest. 🍽️ Mega-oesophagus → dysphagia. 🚽 Megacolon → constipation, obstruction.

🔎 Investigations

🩸 Blood smear: parasites in acute phase.
🧪 Serology: IgG antibodies in chronic phase.
📈 FBC, U&E, ESR.
🫀 ECG, Echo: assess cardiomyopathy.
📷 Barium swallow/Endoscopy: GI involvement.
🖥️ CT/MRI if CNS involvement suspected.

💊 Management

Antiparasitic: Benznidazole or Nifurtimox → best in acute/early chronic or reactivation (e.g. immunosuppression).
❤️ Cardiomyopathy: arrhythmia control, anticoagulation, heart failure therapy.
🍽️ Mega-oesophagus: dietary modification, balloon dilation.
🚽 Megacolon: fibre, fluids, enemas.
Note: antiparasitic drugs do not reverse established organ damage.

🛡️ Prevention

🏠 Improve housing → reduce bug infestations.
🦟 Use bed nets, insecticide, repellents, protective clothing.
💉 Screen blood transfusions & organ donors.
🚫 Avoid contaminated food in endemic regions.

🧪 Screening for Blood Donors

❌ Exclude donors from South/Central America (including southern Mexico) unless seronegative after ≥6 months of no exposure.

🤰 Pregnancy

Offer serology to at-risk women; refer positives to specialist centres.
👶 Infants born to seropositive mothers require follow-up for congenital infection.

💡 Exam tip: Think Chagas if you see Romana’s sign (eyelid swelling) in acute disease, or unexplained dilated cardiomyopathy in a South American patient.

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American Trypanosomiasis (Chagas Disease)