11 Congenital pathology

Question 1

When during embryogenesis do most heart anomalies arise? What are the usual causes?

Answer 1

3-8 weeks

**90%= idiopathic (can be genetic causes like trisomies/turner syndrome, or environmental causes as well)

Question 2

Describe the fetal circulation

Answer 2

• placenta -> umbilical vein -> liver/ductus venosus -> IVC
  
  • IVC -> RA -> RV -> pulmonary trunk -> ductus arteriosus -> aorta
  • IVC -> RA -> LA -> LV -> aorta
• aorta -> organs (gut/kidneys/legs/etc) -> umbilical arteries

Question 3

Describe a structural versus functional shunt

Answer 3

Structural= actual physical connection

Functional= abnormal pressures alter flow

Question 4

What are 4 examples of L->R shunt CHD?

Answer 4

1. ASD
2. VSD
3. AVSD
4. PDA

**notice late cyanosis

Question 5

What are 3 examples of obstructive CHD?

Answer 5

1. pulmonary stenosis
2. aortic stenosis
3. coarctation

**NO cyanosis

Question 6

What are 5 examples of R->L shunt CHD?

Answer 6

1. tetralogy of fallot
2. transposition of the great arteries
3. truncus arteriosus
4. TV atresia
5. TAPVR

**notice cyanosis (right away)

Question 7

What is an example of valvular regurg CHD?

Answer 7

Ebstein’s anomaly

Question 8

Describe the etiology of late cyanosis in L->R shunts

Answer 8

• initially oxygenated blood flows to the right sided circulation (no cyanosis)
  
  • however this increases pulmonary flow beyond its capacity
• results in pulmonary HTN and RV hypertrophy
• increased right sided pressure reverses the blood flow
  
  • becomes a R->L shunt
  • causes late cyanosis

Question 9

Describe plexogenic pulmonary HTN

Answer 9

• medial hypertrophy
• intimal proliferation
• plexiform lesions (irreversible damage)
• VSD>PDA>>ASD
  
  • increased flow (ASD) better tolerated than increased pressure (VSD)

Question 10

Describe an ASD

Answer 10

• may be asymptomatic until adulthood
• allows paradoxical embolism
• <10% lead to pulmonary HTN
• location
  
  • 90% secundum (at fossa ovalis)
  • 5% primum (adjacent to AV valves)
  • 5% sinus venosum (near SVC entrance)

Question 11

Contrast an ASD and PFO

Answer 11

Question 12

What are the long term effects of an ASD?

Answer 12

Right ventricular hypertrophy and dilation

AND

Dilated RA and LA

Question 13

Describe a VSD

Answer 13

• most common congenital heart anomaly
• 90% at septum (membranous VSD)
• usually associated with other anomalies

Question 14

Contrast membranous and muscular VSDs

Answer 14

• membranous
  
  • usually large
  • <10% spontaneously close by septal TV leaflet
  • requires surgery
• muscular
  
  • usually small
  • spontaneous closure by fibrosis >60% by 1 yo (most don’t require surgery)
  • less common than membranous

Question 15

Describe a PDA

Answer 15

• normal closure:
  
  • functional ~12hr
  • structural ~3mo
  • delayed by prostaglandin E
• causes harsh, continuous “machinery like” murmur
• usually in isolation (90%)

Question 16

Describe an AVSD

Answer 16

• deficient AV septum, associated with MV and TV anomalies
• two types
  
  • partial= primum ASD + cleft MV (w/ mitral regurg)
  • complete= AVSD + common AV valve
• down syndrome 40% with complete AVSD
• needs early surgical correction

Question 17

What are some clinical symptoms of R->L shunting?

Answer 17

• early cyanosis
• digital clubbing
• polycythemia
• paradoxical emboli
• decompression sickness (gas not filtered by lungs)

Question 18

Describe tetralogy of fallot

Answer 18

• most common form of cyanotic CHD
• anteriosuperior displacement of the infundibular septum leads to…
  
  • VSD
  • subpulmonary stenosis (protects lungs, but results in small pulmonary outlet)
  • overriding aorta
  • RVH (heart may appear “boot shaped” on xray)

Question 19

What determines the clinical outcome of tetralogy of fallot?

Answer 19

**based on severity of subpulmonary stenosis:

• pink tetralogy (less cyanotic)
  
  • less severe stenosis
  • BAD; doesn’t protect the lungs from high pressures
• classic tetralogy
  
  • more cyanotic
  • subpulmonary stenosis protects lungs

Question 20

Describe TGA

Answer 20

• transposition of the great arteries
  
  • aorta from the RV
  • pulmonary artery from the LV
• RVH and pulmonary HTN develop
• two types
  
  • intact ventricular septum (65%); unstable, need prompt surgery
  • with VSD (35%); stable

Question 21

Describe truncus arteriosus

Answer 21

• origin of aorta and pulmonary artery from common truncal artery
• most have large VSD
• mixing of blood= cyanosis
• increased pulmonary flow -> pulmonary HTN

Question 22

Describe tricuspid atresia

Answer 22

• complete occlusion of the tricuspid orifice (from unequal division of the AV canal; mitral valve is enlarged)
• needs ASD/PFO and VSD for survival
• causes right ventricular hypoplasia

Question 23

Describe TAPVR

Answer 23

• total anomalous pulmonary venous return (pulmonary veins don’t directly drain into LA -> LA hypoplasia)
• pulmonary veins connect with left innominate/brachiocephalic or coronary sinus
• ASD/PFO allows oxygenated blood to enter systemic circulation

Question 24

Describe aortic coarctation

Answer 24

• constriction/narrowing of aorta
• 2 types
  
  • preductal/infantile (tubular hypoplasia with PDA)
  • postductal/adult (ridgelike infolding at ligament without PDA)

Question 25

Describe the clinical presentation of aortic coarctation

Answer 25

* 50% bicuspid AV * preductal * lower body cyanosis * requires neonatal surgery * postductal * symptoms depend on narrowing * surgically treatable HTN (presents as upper BP \> lower BP) * rib notching on xray (collaterals develop)

Question 26

Describe isolated pulmonary stenosis

Answer 26

* pulmonary valve obstruction from hypoplasia, dysplasia, or abnormal number of cusps * RV dilation and hypertrophy * post-stenotic injury to PA * may be asymptomatic until adulthood

Question 27

How does pulmonary stenosis differ with an intact ventricular septum?

Answer 27

* hypoplastic RV and TV * PDA needed to get blood to lungs

Question 28

Describe aortic stenosis

Answer 28

* aortic valve obstruction due to hypoplasia, dysplasea, or abnormal number of cusps * 80% isolated (mild to critical) * LV hypertrophy and LA dilation * systolic murmur

Question 29

How does aortic stenosis differ with an intact VS?

Answer 29

* results in hypoplastic left heart syndrome (left ventricle and mitral valve) * dependent on PDA for survival * requires staged surgical correction

Question 30

Describe Ebstein anomaly

Answer 30

* inferiorly displaced tricuspic valve with... * adherent septal/posterior leaflets * redundant anterior leaflet * dilated annulus (regurgitation!) * secondarily results in * **RV and RA dilation** * arrhythmias (WPW)

Question 31

Describe dextrocardia

Answer 31

* right sided "mirror image" heart * usually associated with situs inversus * 5-10% have other anomalies, usually TGA

Question 32

Describe ectopia cordis

Answer 32

* very rare * anterior throacic wall fails to close properly * "pentalogy of Cantrell": * ectopia cordis * VSD * sternal cleft * diaphragmatic hernia * omphlocele

Question 33

What are some late effects of CHD?

Answer 33

* endocarditis * hyperviscosity (cyanosis increases RBCs) * pulmonary HTN/shunt reversal * childbearing risk * residual post-surgical pathology (e.g. scarring)