Pathology- congenital defects Flashcards
What are the 5 right to left congenital shunts
5 T’s
- Truncus arteriosus (1 vessel)
- Transposition (2 vessels switched)
- Tricuspid Atresia (3= tri)
- Tetralogy of Fallot (4= tetra)
- TAPVR (total anomalous pulmonary venous return) (5 letters in name)
What is persitent truncus arteriosus?
when the truncus arteriosus fails to divide into the pulmonary/aortic trunk due to lack of aorticopulmonary septum formation
Most patients also have an accompaning ventricular septal defect
What is D-Transposition of great vessels?
Aorta leaves right ventrical anteriorly and the pulmonary trunk leaves the left ventricle posteriorly.
this causes separation of the pulmonary/systemic circulations and is not compatable with life unless a shunt is present to allow mixing of blood (ventricular septal defect, patent ductus arteriosus, patent foramen ovale)
This is due to failure of the aorticopulmonary septum to spiral
What is tricuspid atresia?
absence of the tricuspid valve and hypoplastic Right ventricle requires both Atrial septal defect and ventricular septal defect for viability
What is a tetralogy of Fallot?
Caused by anterosuperior displacement of the infundibular septum - most common cause of early childhood cyanosis
- pulmonary infundibular stenosis- most important determinant of prognosis
- right ventricular hypertrophy ( boot shaped heart)
- overriding aorta
- ventricular septal defect
*pulmonary stenosis forces right to left flow
*squatting increases systemic venous return, decreases right to left shunting and improves cyanosis
What is total anomalous pulmonary venous return?
pulmonary veins drain into right heart circulation (superior vena cava, coronary sinus etc), associated with Atrial septal defect and sometimes patent ductus arteriousus to allow for right-left shunting maintaining cardiac output
What is Ebstein Anomaly?
characterized by displacement of tricuspid valve leaflets downward into Right ventrical causing atrializing of the ventricle- this is associatedd with tricuspid regurgitation and right heart failure -
*can be caused by lithium exposure in utero*
What is the presentation of a left to right shunt in the heart?
acyanotic at presentation, but cyanosis may occur years later
How are the left to right heart shunts ordered according to frequency?
most common = ventricular septal defect
- atrial septal defect
least common = patent ductus arteriosus
How does a ventricular septal defect present?
asymptomatic at birth but may manifest weeks later or remain asymptomatic throughout life.
- most self resolve, but larger ones may lead to left ventricular overload and left sided heart failure
What is the presentation of an atrial septal defect?
defect in interatrial septum, loud S1 with wide/fixed split S2.
*not the same as a patent foramen ovale because in this case, the septa are missing tissue rather than failing to fuse*
How does a patent ductus arteriosus present?
in fetal period, shunt is right to left -
in neonatal period, decreased pulmonary vascular resistance, shunt becomes left to right, progressive Right ventricular hypertrophy and or left ventricular hypertrophy and heart failure.
- associated with a machine like murmer-
How is patency maintained in a patent ductus arteriosus?
maintained by PGE synthesis and low O2 tension
What is the effect of Indomethacin?
it ‘end’omethacins
Ends patentcy of PDA
What is Eisenmenger Syndrome?
Uncorrected left to right shunt
leads to
- increased pulmonary blood flow
- pathologic remodeling of vasculature
- pulmonary arterial hypertension
- Right ventricular hypertrophy occurs to compensate
- shunt becomes right to left
- causes late cyanosis, clubbing and polycythemica
