Embryology and CLD/CHD Flashcards
3rd aortic arch develops into…
L common carotid and part of internal and external carotid
4th aortic arch develops into…
R = subclavian L = arch of aorta
6th aortic arch develops into…
part of pulmonary aa and ligamentum arteriosum
Double aortic arch
Right dorsal aorta remains intact below 7th intersegmental artery > forms around esophagus and trachea > pt often present with difficulty swallowing > may present with signs of intrathoracic compression of trachea (i.e. wheezing)
Subclavian sling
Right dorsal aorta remains intact below 7th intersegmental artery but disappears more superiorly > doesn’t compress esophagus and trachea as severely > R subclavian comes off left side and crosses posterior to esophagus and trachea
Sinus venosus becomes
Smooth wall of RA
Coronary sinus
Primordial atrium becomes
R and L auricles and LA
Primordial ventricle becomes
LV
Bulbus cordis becomes…
Proximal 1/3
Conus cordis
Truncus arteriosus
Muscular RV
Smooth outflow of RV and LV
ascending aorta and pulmonary trunk
Aortic sac becomes…
Aorta and pulmonary a.
Endocardial cushions become…
Atrial septum, membranous IVS, AV and semilunar valves
Early pulmonary vv become…
Smooth wall of LA
Conotruncal ridges become…
Septum b/w aorta and pulmonary a.
RDS MCC of…
respiratory failure in newborns
Most common CHD lesion
VSD
Most common congenital anomaly of the upper airway
Laryngomalacia
Structural differences between infant and adult lungs
- Infant airways not as complex
- Type I alveoli not completely flat > gas exchange less efficient
- Alveolar pores (Kuhn) and canals of Lambert not well developed
What phase of the fetal period is surfactant starting to be made?
Saccular ~26 weeks
Ground glass x-ray
RDS
Boot shaped heart x-ray
TOF
Egg on a string x-ray
TGA
Snowman x-ray
TAPVR
Tetralogy of Fallot Criteria
- Pulmonary stenosis
- RV hypertrophy
- Overriding aorta
- VSD
Associated with hypocalcemia, VSD
Truncus arteriosus
Associated with strong UE pulses and weak LE pulses
Coarctation of aorta
Why are infants prone to RDS?
- Lower # alveoli > decreased SA, lower elastin and collagen, bronchi more collapsible
- Ribs horizontal, not ossified, less muscle > much more compliant chest wall, much less outward recoil
How does MAS lead to disruption of NML lung function?
- Airway obstruction
- Surfactant dysfunction
- Direct chemical pneumonitis
- Resultant persistent pulmonary HTN
Septum transversum
Splits intraembryonic cavity into pericardial and peritoneal cavities > makes up part of diaphragm
Space that connects pericardial and peritoneal cavities
Pericardioperitoneal canals
Pleuroperitoneal folds
Connect with septum transversum to close pericardioperitoneal canals and form diaphragm
CDH
Abdominal viscera herniate into thorax
- Mostly L sided d/t liver
- Ipsilateral lung hypoplastic
Most common hernia
Esophageal
CDH clinical presentation
Antenatally - large can be dx
Neonatal - severe resp distress
Infancy/childhood - chronic resp symptoms, feeding difficulty, can be asymptomatic and noted incidentally
CDH Management
Antenatally - surgery
Neonatal - supportive care > vent, ECMO
Childhood - surgical closure
Eventration of diaphragm
Similar to hernia, but no hole just weakened diaphragm
-correct by pushing back into thorax > still not functional but not impinging on lung
Pleuropericardial fold
Folds anterior to lungs and posterior to heart
- As lungs move anterior > bring folds with them > eventually form fibrous tissue of heart and parietal pleura
- Contains phrenic n. and cardinal vv
How is the pediatric upper airway different from adults?
- Smaller diameter
- More anterior
- Floppier epiglottis
- Larger tongue
- Larger occiput
- Narrowest portion of airway is cricoid
Buccopharyngeal membrane
Thins and ruptures posteriorly to create an opening from nasal cavity into pharynx > choana
Choanal atresia
Failure in resorption of bucco-pharyngeal membrane
-suspect if unable to pass catheter through nares
Pierre Robin
Micrognathis
Glossoptosis
Cleft palate
Macroglossia
Laryngeal cleft
Split like opening b/w posterior larynx and esophagus > zipper
Recurrent aspiration or cyanotic spells with feeding
Developmental failure of tracheoesophageal septum
Laryngomalacia
Floppy larynx > poor epiglottis cartilaginous development or abnormal muscular tone
- Typically present with inspiratory stridor w/i first few weeks
- Supine worse than prone
Subglottic stenosis
- Narrowing of subglottic airway at cricoid
- Congenital results from incomplete recanalization of laryngotracheal tube
- severe = resp distress; milder = stridor; recurrent croup in older kids
Tracheoesophageal fistula
Connection between esophagus and trachea maintained
Tracheomalacia
- Weakness in tracheal wall
- recurrent wheezing, barking cough with illness or activity
- recurrent lower airway infections d/t impaired airway clearance
- coarse, low-pitch, monophonic wheeze
- beta-agonist worse
Bronchomalacia
- Monophonic wheezing
- Typically not symptomatic past school age kids
- Impaired mucous clearance > recurrent PNA
- beta-agonist worsen
Bronchial isomerism
- increased risk of ciliary dyskinesia
- associated with CHD
- heterotaxi syndrome
Tracheal bronchus
- associated with impaired airway clearance
- increased risk of other associated anomalies
Bronchial stenosis/atresia
Can both cause and result from recurrent infection
Bronchogenic cysts
- Abnormal budding of ventral foregut endoderm
- Most mediastinal
- Often asymptomatic
- typically resected d/t risk of malignancy
Cystic adenomatoid malformation
- defect in development of terminal bronchioles leading to structure that resembles cystic collection of small airways
- may cause polyhydraminos or even hydrops fetalis
Congenital large hyperlucent lobe
Massive overinflation of one or more lobes > postnatally following initiation of respiration (some sort of malacia leaves bronchi to collapse when baby tries to exhale after their first inhale)
-MC in LUL
ASD
- Ostium secundum (more common, more sporadic)
- primum, or sinus venosus (less common, more associated with other defects)
ASD/VSD presentation
- Small often asymptomatic
- Murmur may be heard
- Large cause L-R shunt leading to R atrial enlargement, increased R pressure, and eventually HF if untreated
ASD/VSD Tx
- Small often close (for VSD location matters > membranous not as likely to close on their own)
- Small to medium > transcatheter device
- Large/complication > surgical patch
AV Canal defect / endocardial cushion defect
- Partial = severe low ASD or high VSD with AV valves affected but present
- Complete = AV valves not developed and all 4 chambers contiguous (trisomy 21 association)
LVOTO
- Milder = aortic stenosis
- Severe = HLHS (underdeveloped LV > cyanotic newborn; can be caused by mitral atresia)
RVOTO
- Milder = pulmonary stenosis
- Severe = TOF
- Very severe = HRHS (underdeveloped RV)
Tricuspid atresia
- PFO or ASD
- VSD
Truncus arteriosis
Often associated with other cardiac anomalies, DiGeorge syndrome (hypocalcemia)
Vitelline veins
Deoxygenated blood from yolk sac
Cardinal vv
Deoxygenated blood from embryo
Umbilical vv
Oxygenated blood from placenta
TAPVR
Pulmonary vv carry oxygenated blood to SVC > mixed blood
