Fetal Chest Flashcards
What are the stages of lung development?
embryonic pseudeoglandular canalicular saccular alveolar
Air-blood barrier is formed when?
16-24 wks
The heart occupies how much of the fetal chest
1/3 (25-30%)
What angle do we want to see the heart at
45
What can be the first clue of unilateral chest mass or diaphragmatic hernia?
cardiomediastinal shift
The lungs are what to the liver? (echogenicity)
echogenic
Echogenicity of the lung ________ as gestation advances
increases
Pulmonary hypoplasia:
reduction in the number of cells, airways and alveoli
Is pulmonary hypoplasia unilateral or bilateral?
can be both depending on the etiology and time of effect to the lungs
Primary pulmonary hypoplasia:
caused by a primary process that does not let the lungs form normally
uni- a/w other abnormalities
bilateral- incompatible with life
Secondary pulmonary hypoplasia:
masses, skeletal malformations, oligohydramnios can cause this
Majority of pulmonary hypoplasia cases are associated with:
major structural or chromosomal abnormalities
Congenital diaphragmatic hernia:
abdominal viscera in the thoracic cavity due to a defect in diaphragm
can be tiny opening to complete absence of hemidiaphragm
can be surgically repaired
Which side more common for congenital diaphragmatic hernia
Left
Left sided CDH:
small abdo circumference, stomach or bowel in left chest, and polyhydramnios
What’s associated with left sided CDH?
dextroposition of the heart
stomach may not be visualized in LUQ and bowel peristalsis can be seen
Right sided CDH:
liver herniates into chest and mediastinal is to the left
liver’s echogenicity is similar to lungs
can potentially see GB and hep vessels which can help confirm diagnosis
What can we see with right sided CDH:
bowel herniation, but stomach is below diaphragm
ascites and hydrops
absence of hypoechoic aspect of diaphragm on the right helps differentiate
What helps in differentiating CDH from other fetal chest masses?
absence of the hypoechoic aspect of the diaphragm on the right
What is associated with CDH?
structural chromosomal or syndromal anomalies
CHD (most common)
anecephaly, ventriculomegaly and neural tube
Tri18
Fryn, Beckwidth-Wiedemann,Simpson-Golabi-Behmel, Brachmann-de lange and Perlman syndromes
Is the prognosis good for CDH?
No. 80% mortality rate due to pulmonary hypoplasia or CHF
The most common defects occur on the _____ _____ ________ and involve the herniation of the stomach and small bowel in the chest. (90%)
left side posteriorly
Pleural effusion is also known as
hydrothorax
Pleural effusion is most often a manifestation of:
fetal hydrops, ascites and edema
How can pleural effusion be managed?
Depending on GA and detected fetal anomalies, a US thoraco-amniotic shunt can be put in
What is a thoraco-amniotic shunt?
a drainage tube with one end in the pleural space and the other in amniotic fluid
Congenital Cystic Adenomoid Malformation (CCAM):
rare
lung tissue is replaced by cysts of varying sizes
abnormal growth of lung tissue can compress normal lung tissue and affect development
CCAM is described as _______ _______ of the lungs.
focal dysplasia
What’s the most common congenital lung lesion?
CCAM
What are the 3 pathological types of CCAM?
Type 1: mainly cystic, single or multiple cysts (2-10cm in diameter)
Type 2: mainly solid w/ multiple small cysts <2cm
Type 3: mainly solid lesion with tiny cysts <0.5cm (hyperechoic without detectable cysts)
What causes CCAM?
pulmonary insult during embryonic development of the bronchial tree before 7th wk of gestation
What is the outcome of the cysts in CCAM?
may dimish in size and regress before/after birth
may require intervention/respiratory support
What are the pathological features of CCAM?
unilater
one part of lung (lower lobe most common)
complications- PH, heart compression, fetal hydrops and polyhydramnios
Bronchopulmonary sequestration:
presence of non-functioning pulmonary tissue (doesn’t have communication with bronchial tree)
Where does the non-functioning tissue in bronchopulmonary sequestion get its blood supply?
anomalous artery from aorta rather than pulmonary artery branch
What are the 2 major types of bronchopulmonary sequestration?
Intralobar
Extralobar
Intralobar sequestration:
abnormal tissue lies within normal lung, usually in posterior segment of lower lobe
Extralobar sequestration:
abnormal tissue is anatomically separated from the normal lung
most common location is left chest in basal region (near diaphragm)
Extralobar pulmonary sequestration appears as:
a homogenous echogenic chest mass with or without cardiac shift
Differential diagnosis of bronchopulmonary sequestration? (2)
Type 3 CCAM
CDH
(If the abdominal viscera appear normal (stomach, liver, and bowel identified in their normal locations), then CDH can be excluded)
Bronchogenic cysts:
rare
result from abnormal budding of the tracheobronchial tree (size is variable)
What’s the difference between a bronchogenic cyst and a CCAM?
CCAM has more than one cyst and an echogenic mass
Tracheoesophageal fistula:
abnormal connection b/w esophagus and trachea
common congenital abnormality
What causes a tracheoesophageal fistula?
failed fusion of the tracheoesophageal ridges during the 3rd week of embryological development
Can you see a tracheoesophageal fistula easily on US?
No
