Truncus arteriosus
Cyanotic CHD: a single arterial trunk overrides a VSD, giving rise to aorta + pulmonary + coronary arteries
Overview
A single common arterial trunk arises from the heart (overriding a VSD) and gives off the systemic, pulmonary and coronary arteries — mixed blood goes everywhere, causing cyanosis plus high pulmonary flow and early heart failure. Associated with 22q11 deletion (DiGeorge). Needs early surgical repair.
Recognise
- Cyanosis with EARLY heart failure (high pulmonary blood flow); a single S2; murmur of the VSD/truncal valve
- Bounding pulses, wide pulse pressure; associations: 22q11 deletion (DiGeorge — hypocalcaemia, immunodeficiency)
- Pulmonary overcirculation → failure and early pulmonary hypertension
Red flags
- Early heart failure and pulmonary hypertension → timely surgery
- DiGeorge associations (hypocalcaemia, immunodeficiency)
Differentials & how to tell them apart
Investigations
Echocardiography (single trunk over a VSD); CXR (cardiomegaly, increased pulmonary markings); 22q11 testing; calcium (DiGeorge).
Management
Heart-failure management + early surgical repair (separate the circulations)
- 1Echocardiography (single arterial trunk over a VSD). Manage heart failure; early surgical repair to separate systemic and pulmonary circulations.Gate: Strongly associated with 22q11 deletion (DiGeorge) — check calcium (hypocalcaemia) and immune function; early surgery prevents fixed pulmonary hypertension
- 2Surgical repair (VSD closure + RV-to-pulmonary conduit); manage DiGeorge; lifelong follow-up (conduit replacement).
Key points
Cyanosis + early heart failure + single S2 + single arterial trunk = truncus arteriosus → early surgery. Think 22q11/DiGeorge (hypocalcaemia, immunodeficiency).
Monitor & prognosis
Heart failure; pulmonary pressures; conduit.
Good with early repair; conduit revisions.
Source: RCPCH; paediatric cardiology