Ch. 60 The Fetal Thorax Flashcards
what is the most important determinant for fetal viability?
pulmonary development
at birth fluid in the lungs is expelled through 3 routes. what are these routes?
- mouth and nose
- pulmonary capillaries
- lymphatics and pulmonary vessels
what 3 planes is the thorax examined in?
transverse, coronal, parasagittal
a fetus with a narrow chest diameter may have what?
asphyxiating thoracic dystrophy
the apex of the heart should be directed towards ___________ at an axis that is _____ degrees from midline
left chest wall
45
the base of the heart lies _______ to the diaphragm
horizontal
why is the location of the heart important?
to indicate presence of chest mass, pleural effusion, or cardiac malformation
when will fetal breathing become more prominent?
second and third trimesters
where can color doppler detect fetal breathing?
through the nostrils
4 reasons the lungs will not develop properly
- oligohydramnios
- small chest cavity
- balance between tracheal and airway pressure and fluid volume is inadequate
- fetus unable to practice breathing movements
what causes pulmonary hypoplasia?
decrease in lung cells, airways, and alveoli resulting in decreased organ size and weight
occurs from prolonged oligohydramnios or is secondary to a small thoracic cavity
pulmonary hypoplasia
4 masses that cause pulmonary hypoplasia
- pleural effusion
- diaphragmatic hernia
- cystic adenomatoid malformation
- bronchopulmonary sequestration
most common lung cyst detected prenatally
bronchogenic cyst
sonographic appearance of bronchogenic cyst
small circumscribed mass without mediastinal shift or heart failure
fluid within the pleural cavity that appears as an isolated lesion is called what?
pleural effusion or hydrothorax
sonographic appearance of pleural effusion
echo-free peripheral masses on one or both sides of fetal lung
compression of lung may cause what?
pulmonary hypoplasia (which leads to life-threatening consequences for neonate)
what is pulmonary sequestrian?
supernumerary lobe of lung separated from the normal tracheobronchial tree
sonographic appearance of pulmonary sequestrian
echo-dense solid mass resembling lung tissue
extralobar defects occur on the _____ side and are _______ or _______ shaped
left
cone
triangular
intralobar lesions are _____ shaped
spherical
what is congenital cystic adenomatoid malformation
multicystic mass within the lung consisting of primitive lung tissue and abnormal bronchial structures
what is the first form of cystic adenomatoid malformation?
CCAM type I: one or more large cysts replace normal lung tissue
what is the second form of cystic adenomatoid malformation?
CCAM type II: lesions consist of multiple small cysts
what is the third form of cystic adenomatoid malformation?
CCAM type III: bulky, large, noncystic lesions appearing echo-dense
what 6 sonographic findings should you attempt when you find a lung mass
Determine number and size of cystic structures
Check for presence or absence of a mediastinal shift
Identify and assess lung size
Look for fetal hydrops
Exclude cardiac masses
Search for other fetal anomalies
what is congenital bronchial atresia
rare pulmonary anomaly that results from obliteration of a segment of the bronchial lumen
where is congenital bronchial atresia commonly found?
left upper lobe
when does the diaphragm form
between 6th and 14th week
the fusion of what 4 structures causes the diaphragm to form
- septum transversum
- pleuroperitoneal membranes
- dorsal mesentery of esophagus
- body wall
congenital diaphragmatic hernia is
a herniation of the abdominal viscera into the chest that results from a congenital defect in the fetal diaphragm
the most common type of diaphragmatic defect occurs through
the foramen of Bochdalek posteriorly and laterally
if a diaphragmatic hernia occurs anteriorly and medially it goes through
the foramen of Morgagni and may communicate with the pericardial sac
prognosis for fetus is poor with diaphragmatic hernia is (4)
- hernia is detected before birth
- stomach is found in chest
- left heart is underdeveloped
- congenital heart disease is present
6 associated abnormalities of diaphragmatic hernia
- cardiac malformations
- CNS malformations
- renal anomalies
- vertebral defects
- pulmonary hypoplasia/ face clefts
- chromosomal abnormalities
what is the mortality rate for diaphragmatic hernia and why?
75% because of increased frequency of coexisting anomalies
