Fetal Chest abnormalities

Normal fetal lung development occurs in these 5 stages:

Embryonic - 4-5 weeks, the larynx, trachea, and lung bud form

Pseudoglandular- 7-16 weeks, airways are created

Canalicular - completed by 25 weeks, development of gas exchange portion of lung

Saccular - From 26 weeks until term, last airspaces of bronchial tree evolve

Alveolar - From approximately 32 weeks into early childhood growth of more bronchioles

Coronal view is best to see

Diaphragm and both lungs

Gold star standard for assessing lung maturity

Amniocentesis

Lung maturation testing using the Lecithin/sphingomyelin ratio to determine

If fetal lungs are mature enough to deliver the fetus early

Predicts potential for fetal respiratory distress

L/S Ratio <2:1 ratio indicated…

High probability of FRD

Pulmonary hypoplasia is caused by

Restriction/compression of developing lung tissues and olioghydramnios/anhydramnios

Pulmonary hypoplasia

Incomplete development of lung tissue

Severe chest and lung hypoplasia are usually lethal to fetus

Measure thoracic circumference to confirm diagnosis

Bell/pear shaped chest

Most common cause of pulmonary hypoplasia

Diaphragmatic hernia

>50% of cases with pulmonary hypoplasia have…

Coexisting cardiac, GI, GU and skeletal dysplasias

Pulmonary hypoplasia is associated with

Potter syndrome (bilateral agenesis of kidneys reduces fluid)

Fetal thoracis circumference/abdominal circumference ratio <__ indicates significant thoracic hypoplasia

0.77

Severe chest and lung hypoplasia is suspected if thoracic circumference is <__ th percentile for GA

5

Pulmonary hypoplasia

When a chest mass is identified, it is important to evaluate the pregnancy for:

Mediastinal shift, AFI levels (poly), Signs of hydrops

Most common chest mass in a fetus

Congenital cystic adenomatoid malformation or CPAM/CCA

Congenital cystic adenomatoid malformation or CPAM/CCA

Usually unilateral but effects entire lung

Can cause mediastinal shift and cardiac malposition

Can lead to inversion of diaphragm; concave shape instead of convex

Prenatal administration of __________ is used to reverse the effects of hydrops or prevent hydrops

Corticosteroids

CCAM is associated with

Polyhydramnios and ascites

CCAM types

1. Macrocystic (2-10cm)

2. Medium cystic (0.5-2cm)

3. Microcystic (<0.5cm)

CCAM types 1 and 2 demonstrates…

Single or multiple cystic structures within chest cavity replacing normal lung tissue

CCAM type to demonstrates…

Microscopic cystic that cause an overall increase in echogenicity of affected lung

Type 3 is associated with…

Fetal hydrops and demise

CCAM Type 1

CCAM type 2

Type 3 CCAM

Bronchogenic cysts

Usually demonstrates a single unilocular cyst located centrally in lung parenchyma

Most are right sided, near midline, and adjacent to tracheobronchial tree

Location at midline and the lack of surrounding echogenic lung tissue differentiates this cyst from CCAM

Pulmonary sequestration

Mass of nonfunctional lung tissue that does not communicate with bronchial tree

Separate blood supply from AO

May regress

Appears as echogenic triangular-shaped mass in fetal chest

Pulmonary sequestration

CHAOS syndrome

Congenital high airway malformation

Complete atresia of airway is commonly associated with tracheoesophageal fistula

Lethal

CHAOS syndrome is caused by

Obstruction of fetal upper airway

CHAOS syndrome USA

Dilated, fluid-filled trachea

Bilateral symmetrically enlarged hyperechoic fetal lungs

Flattened or everted hemidiaphragms

May see polyhydramnios

Diaphragmatic hernia

Abdominal organs herniate into chest cavity through an opening in diaphragm

May see peristalsis in chest

Coronal view is best

Can be bilateral but usually on left side

Associated with polyhydramnios

Most common cause for pulmonary hypoplasia

Diaphragmatic hernia

Most common reason for shift of cardiac axis/position

Diaphragmatic hernia

Classic diaphragmatic hernia classic sign

Fetal stomach is visible at the same level of the heart in a trans or coronal view

Bochdalek hernia

Posterior left lateral defect

MOST COMMON

Morgagni hernia

Anterior to right medial defect

Lung-head ratio

lung AP x lung width/HC

• predicts outcome and plan treatment

Congenital diaphragmatic eventration

Developmental defect of muscular portion of diaphragm

Results in weakness of diaphragm

Can mimic diaphragmatic hernia

Easier to fix

Unilateral eventration is associated with

Beckwith-Weidemann syndrome and Trisomy 13 and 18

Bilateral eventration is associated with

Toxoplasmosis and cytomegalovirus

Hydrothorax

Pleural effusion or fluid in lung cavities

Bilateral or uni

“Bat wing” sign for unilat

Associated with hydrops, chromosomal anomalies and polydactyly

Hydrothorax is most commonly caused by

Chylothorax

Pleural effusion

Pericardial effusion

Anterior fluid collection

Can compress lungs against posterior chest wall

Associated with hydrops, heart failure and some cardiac tumors

Pericardial effusion

Fatal lung disorders

Type 3 CCAM

CHAOS syndrome

Pulmonary hypoplasia

Which of the following correctly describes a fetal diaphragmatic hernia?

Usually on right side

Associated with oligohydramnios

Decreased survival rate if fetal liver has herniated into thoracic cavity

Most common cause of pulmonary sequestration

Decreased survival rate if fetal liver has herniated into thoracic cavity

The 3 lung abnormalities associated with polyhydramnios

Diaphragmatic hernia, CHOAS, CCAM