TRUNCUS ARTERIOSUS | Embryology, Etiology, Hemodynamics, Symptoms, Diagnosis, Management, Prognosis

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TRUNCUS ARTERIOSUS
CONTENT
Introduction
Embryology
Etiology
Types
Hemodynamics
Clinical features
Diagnosis
Management
Complication
Prognosis

NORMAL HUMAN HEART
PA - Deoxygenated blood from RV
Aorta - Oxygenated blood from LV

TRUNCUS ARTERIOSUSINTRODUCTION
The anomaly consists of a single arterial trunk exiting from the heart through a common valve, giving origin to Aorta, pulmonary artery, & coronary arteries
It is also called as
Truncus arteriosus communis
Common arterial trunk

INCIDENCE
It affects males & females equally.
1% of all CHD cases
Almost always associated with VSD.

ETIOLOGY
Diabetic mother
Retinoic acid exposure
Siblings of a child born with truncus
Association with
CHARGE syndrome,
DiGeorge syndrome
-Deletion of 22q11

EMBRYOLOGY
At 4 weeks of gestation, two spiral ridges appear which separate common Truncus into the aorta & pulmonary artery.
Failure of septation of the conotruncal segment gives rise to truncus arteriosus
Mixing of blood
Desaturation & hypoxemia.

HEMODYNAMICS
-Aorta & PA arises from a common trunk
-VSD present
-Oxygenated &deoxygenated blood - mixed.
-Systolic pressure: ventricles= aorta= PA
-Blood ejected from Rt & Lt ventricles enters the common trunk
-Blood flow is distributed to each system.
-Cyanosis - mild/negligible

-Soon after the birth :
-SVR increased & PVR decreased
-Increased pulmonary flow, if the pulmonary flow is adequate, systemic saturations become normal.
-But later because of increased pulmonary blood flow Increased pulmonary venous return to LA & LV
CCF within 1st week of birth.

-Truncal regurgitation
-Volume overload in ventricles
& pulmonary circulation
-obstructive changes of the pulmonary vasculature
-increased PVR
-pulmonary hypertension
-eisenmenger’s complex.

CLINICAL FEATURES
Minimal Cyanosis
Dyspnea
Tachypnea
Increase respiratory rate
Edema
Cold sweating
CCF
FTT ,
Growth failure,
Feeding difficulties,
Recurrent respiratory infection
Cardiomegaly,
Hepatomegaly,
Biventricular hypertrophy
Increase pulmonary vascularity

HEART SOUND
Auscultation: loud single 2nd heart sound
Loud – Dilation of trunk
Single–closure of onset of Single valves.
Loud ejection systolic murmur – increase blood flow through the Truncal orifice
DIAGNOSIS
RADIOGRAPHY:
Cardiomegaly,
Waterfall sign ,
Hilar Comma sign in CXR - Dilated Lt PA
ECG:
Tall peaked P wave in lead II III aVF shows RAE,
Right axis deviation - RVH
ECHO: A most helpful diagnostic tool
CARDIAC CATHETERIZATION: Used to clarify doubts about a cardiac anatomy

MEDICAL MANAGEMENT
Control of CCF with diuretics & digoxin
Correction of acidosis
Treatment of respiratory infections

SURGICAL MANAGEMENT
DEFINITIVE: Surgical repair Early surgery is necessary for definite repair using conduit (RV - PA conduit)& closure of VSD

SURGICAL MANAGEMENT
Optimum age: Before 3 months.
As children grow this conduit tends to degenerate & calcify. So it needs replacement in future.

COMPLICATION
CCF
Recurrent respiratory infection
Increased cyanotic and hypoxemia
Brain abscess
CVA
Infective endocarditis
Complication of surgery
Truncus valve dysfunction
RV Conduit obstruction

PROGNOSIS
Mortality is high if not corrected early
75% die within 1st month of life
The average lifespan is 5 week
Survival up to 1 year is seen at only 15%
If survived,
Features of pulmonary vascular obstructive disease &
Develops Eisenmenger’s syndrome

DIFFERENTIAL DIAGNOSIS
Tetrology of Fallot
Univentricular heart
Large vsd
Pulmonary atresia with vsd
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