Module 7: Fetal Chest Pathology Flashcards
How does the diaphragm appear in a fetus?
Hypoechoic because everything else is hyperechoic, easier to see in later gestations
What scan is the diaphragm seen best in?
Parasagittal (midline sagittal).
How do the fetal lungs appear?
Homogenous and isoechoic or hyperechoic to the liver.
How much of the chest does the fetal heart occupy?
1/3
What is levocardia?
The apex of the heart points to the left with a 45 degree axis
What is pulmonary hypoplasia?
When one of both lungs are underdeveloped (can be lethal).
Why are fetuses born under 24 weeks not considered viable?
Due to pulmonary immaturity
What are causes of pulmonary hypoplasia at term? (4)
- Restricted chest cage (due to some skeletal dysplasia’s)
- Decreased amniotic fluid
- Chest masses
- Pleural effusion
What is the most frequent cause of pulmonary hypoplasia?
The lack of fluid caused by PROM or GU abnormalities.
What is PROM?
Premature rupture of membranes
What are GU anomalies?
Genitourinary
What is amniotic fluid produced by?
Membranes until the fetal kidneys begin to produce urine from the swallowed fluid.
What causes polyhydramnios?
Any high GI obstruction/swallowing deficits will cause more fluid outside by preventing the fetus from swallowing the fluid.
What causes oligohydramnios?
Bilateral GU obstruction/renal agenesis
How can we predict pulmonary hypoplasia sonographically?
Thoracic circumferance
How is thoracic circumference measured?
Outer to outer at the level of the 4 chamber heart view in trans.
When is the thoracic circumference NOT measured outer to outer?
In cases of skin edema/hydrops
What is CCAM and what is it now called?
Congenital Cystic Adenomatoid Malformation
Now called:
CPAM: Congenital Pulmonary Airway Malformation
How many classifications of CCAM/CPAM are there?
Three types (I, II, III)
What is CCAM/CPAM?
A non-cancerous mass of abnormal lung tissue, usually located in one part (lobe) of a lung.
What does CCAM/CPAM communicate with?
Tracheobronchial tree
What may happen with a large CCAM/CPAM?
A Mediastinal shift
What is CCAM/CPAM associated with? (3)
- Hydrops
- Pulmonary hypoplasia
- Polyhydramnios
What is type one CCAM?
Macrosystic >2cm
What is type two CCAM?
Macro and microcystic smaller than 1.5 cm
What is type 3 CCAM?
Microcystic and sonographically very hyperechoic
What is the prognosis of CCAM/CPAM?
Depends on the mediastinal shift and hydrops but it may regress on its own or intervention may be necessary if hydrops is noted.
What is the treatment of CCAM/CPAM?
MAy drain cyst or surgically resect the mass
What is the DDx of CCAM/CPAM? (3)
- Pulmonary Sequestration
- Bronchogenic cyst
- Congenital Diaphragmatic Hernia (CDH)
What is pulmonary sequestration?
A mass of ectopic pulmonary tissue covered by it’s own pleura that does not communicate with the bronchial tree or pulmonary veins.
What supplies a pulmonary sequestration?
An ectopic arterial supply off of the descending aorta.
Where is 80% of pulmonary Sequestration located?
Left lung base
What is the US appearance of Pulmonary Sequestration?
A uniform hypoechoic mass with a feeding artery.
What is Pulmonary Sequestration associated with?
Hydrops and polyhyramnios
What is the prognosis of Pulmonary Sequestration?
Good, often resolves on its own unless associated with hydrops.
What is the DDX of Pulmonary Sequestration and how can you differentiate the two on US?
CCAM III
Use doppler to find a feeding artery off of aorta to support Pulmonary Sequestration diagnosis.
What is a cyst in the lung lined with bronchial epithelium called?
Bronchogenic cyst
What are bronchogenic cysts associated with?
Foregut anomalies (TE fistula, lung sequestration)
What is the US appearance of a bronchogenic cyst?
Uni/multilocular cyst in the lung causing a mediastinal shift.
What is a diaphragmatic hernia?
A defect in the diaphragm that allows abd contents to herniate up into the chest (intestines, stomach, liver).
What are the major types of diaphragmatic hernias?
- Foramen of Bochdalek
2. Foramen of Maorgagni
What is foramen of Bochdalek?
A posterior lateral defect of the diaphragm that allows herniation of abdomen contents into the chest.
What side is the foramen of Bochdalek on?
Either side but more commonly on the left.
What are the characteristics of a left hernia through foramen of Bochdalek?
- May see stomach/intestine in chest
- Lung with absence of diaphragm
- Mediastinal shift
What are the characteristics of a right hernia through foramen of Bochdalek?
- May see liver in chest
- Difficult to recognize liver from lung
- Less of a mediastinal shift
What is the foramen of morgani?
A complete or partial absence of the central diaphragm allowing herniation of the abdominal organs into the chest.
What are the characteristics of a herniation through the foramen of Morgagni? (2)
- Liver in chest (may see portal flow in chest)
- Mediastinal shift where heart is still on left side but the axis is shifted
What is the key sonographic sign of a congenital diaphragmatic Hernia?
Mediastinal shift
What are the US appearances of congenital diaphragmatic hernia? (4)
- Mediastinal shift
- Cystic component in fetal chest
- Diaphragm not intact on sagittal scans
- Stomach not seen in abdomen
What condition does congenital diaphragmatic hernia cause?
Pulmonary hypoplasia
What is it called when the diaphragm lacks muscle and therefore the abdominal contents push into the chest area?
Eventration of the diaphragm
What may Eventration of the diaphragm cause?
Pulmonary hypoplasia
What is a pleural effusion and is it abnormal in a fetus?
Fluid surrounding the lungs is abnormal at any gestation.
What can a large pleural effusion cause?
Pulmonary hypoplasia
What are the two types of pleural effusions?
- Serous
2. Chylous (lymphatic fluid)
What is serous pleural effusions a sign of?
Hydrops
What are serous and chylous pleural effusions associated with?
Serous = Downs, Turner’s
Chylous = Polyhydramnios
How do pleural effusions appear on US?
- Sonolucent fluid collections above diaphragm
- Unilateral may cause mediastinal shift
- May invert the diaphragms
What are other names for serous and chylous pleural effusions?
Hydrothorax and chylothorax
What is the treatment for hydrothorax and chylothorax?
- Thoracentesis
- Shunt to abdomen or amniotic fluid
- None (may resolve on its own)
What is tracheal atresia?
A congenitally non-patent airway
What is the US appearance of tracheal atresia?
- Bilaterally enlarged lungs with distended airways
- Flat diaphrams
- Ascites and polyhydamnios
Why is ascites and distended airways a sign of tracheal atresia?
Because a small amount of amniotic fluid is produced in the lungs and atresia prevents it from getting out.
What is esophageal atresia?
A congenitally non-patent esophagus
What is esophageal atresia associated with?
- TE fistula
- Down Syndrome
- VACTERL
What abnormalities can occur with the chest wall shape?
- Narrow
- Long
- Bell-shaped
- Dwarfism (from skeletal dysplasia)
What an an abnormal chest shape cause?
Pulmonary hypoplasia
What is the term for when the heart is outside the chest cavity?
Ectopia cordis
What is ectopia cordis due to?
An anterior chest wall fusion defect
What is Pentalogy of cantrell? (5)
A rare syndrome causing defects of the:
- Sternum
- Anterior diaphragm
- Pericardium
- Ectopia cordis with heart defects
- Omphalocele