chapter 61 fetal thorax Flashcards
single most important determinant for fetal viability
adequacy of pulmonary development
the major reason why fetuses younger than 24 weeks gestation are generally nonviable
pulmonary immaturity
breathing movements that occur before birth result in
aspiration of fluid into the lungs
the lungs at birth are about ____ filled with fluid from amniotic cavity
half-way filled
the fluid in the lungs at birth clears via 3 routes:
- through the nose/mouth
- into pulmonary capillaries
- into the lymphatics and pulmonary vessels
normal thoracic cavity is symmetric and ____ shaped
bell shaped
the lungs serve as lateral borders for the hear and lie ____ to the diaphragm
superior
the diaphragm can be seen as a _______ curvilinear margin
smooth hypoechoic/sonolucent
normally the fetal thorax is slightly _____ than the abdominal cavity
smaller
the ratio of thoracic cavity(TC) and abdominal cavity(AC) is ______ throughout pregnancy
constant
oligohydramnios can result in _______
pulmonary hypoplasia
thoracic circenference is measured in the ____ plane at the level of the _____
transverse
4 chamber heart
a fetus that has a significantly narrower chest diameter may have _____
asphyxiating thoracic dystrophy
the majority of the heart is positioned in the midline and ____
left
the apex of the heart should be directed toward the ____
spleen(left)
detection of abnormal position of the heart may indicate:
- chest mass
- pleural effusion
- cardiac malformation
fetal lungs appear:
homogeneous with moderate echogenicity
fetal lungs: echogenicity _____ as pregnancy progresses
increases
fetal breathing becomes more prominent in the ____
2nd and 3rd trimesters
a matrue fetus spends almost _____ of its time breathing
1/3
color doppler may be used to detect fetal breathing through ___
the nostrils
when evaluating fetus for lung mass, you must note:
- position of heart
- orientation of cardiac axis
- measurement of thoracic circumference
deviation of heart from the normal axis may suggest presence of
intrathoracic mass
caused by a decrease in the number of lung cells, airways, and alveoli
pulmonary hypoplasia
pulmonary hypoplasia results in
decreased organ size and weight, small undeveloped lungs
pulmonary hypoplasia most commonly occurs from
prolonged oligohydramnios or secondary to small thoracic cavity resulting from structural/chromosomal abnormality
_____ abnormalities may result in lethal pulmonary hypoplasia
kidney
abnormalities that may cause pulmonary hypoplasia
- cardiac defects
- skeletal dysplasias
- CNS disorders
- Trisomy
________ pulmonary agenisis or hypoplasia is rare
unilateral
every fetus with mediastinal shift and chest mass, the differential should include
absent lung
prognosis for pulmonary hypoplasia: ____% die after birth
80%
severity of pulmonary hypoplasia depends on
when it occurred during pregnancy
thoracic circumference below the ____ percentile suggests pulmonary hypoplasia
5th
echo free masses that replace normal lung parenchyma
cystic lung masses
most common lung cyst
bronchogenic cyst
cyst that lacks any communication with the trachea or bronchial tree
bronchogenic cyst
bronchogenic cysts typically occur in the _____ and are ____ to the diaphragm
mediastinum or lung
inferior
accumulation of fluid in the pleural cavity
pleural effusion
most common reason for pleural effusion
chylothorax
occuring as a right-sided unilateral collection of fluid secondary to malformed thoracic duct
chylothorax
______ often accompanies chylothorax resulting from esophageal compression
hydramnios
pleural effusion is also known as
hydrothorax
pleural effusion rarely is seen before ___
15 weeks gestation
pleural effusion may be seen before 15 weeks when it is associated with
turner or downs syndrome
mortality rate of pleural effusion
50%
prognosis with pleural effusion is poorer when associated with
hydrops
echo-dense/hyperechoic masses in the lung tissue
solid lung masses
extra lobe of lung separated from the normal tracheobronchial tree
pulmonary sequestration
pulmonary sequestration most likely occurs from
separate outpouching of foregut
separation of a segment of developing lung from the tracheobroncial tree
pulmonary sequestration lung tissue is ___
nonfunctioning
pulmonary sequestration usually occurs on the ___ side
left
pulmonary sequestration rarely occurs ____
below diaphragm
intralobar sequestration has a ____ prognosis
highly favorable
extralobar sequestration has a ___ prognosis
poor
extralobar sequestration poor prognosis is because of
associated anomaies and hydrops
multicystic mass in lung that may communicate with bronchial tree
Congenital Cystic Adenomatoid Malformation (CCAM)
one of the bronchopulmonary foregut malformations
CCAM
most lesions in CCAM are ___
unilateral
Forms of CCAM
- type 1–Macrocystic
- type 2–Macrocystic with microcystic components
- microcystic
type 1 of CCAM cyst size:
single or multiple cysts measuring >2cm and up to 10cm
type 2 of CCAM cyst size:
2-10cm and multiple cysts >1cm
type 3 CCAM looks like
bulky, large, echo-dense masses of entire lung lobe
may cause mediastinal structures to shift
- lung compression
- hydrops
- hydramnios secondary to esophageal compression
type 1 CCAM has a ___ prognosis
favorable
type 2 and 3 CCAM have _____ prognosis
poor
Results from focal obliteration of a segment of the bronchial lumen
congenital bronchial atresia
congenital bronchial atresia is more common in the ____ lobe
left upper lobe
congenital bronchial atresia appears as:::
an echogenic pulmonary mass
herniation of abdominal viscera into the thoracic cavity/chest
Congenital diaphragmatic hernia(CDH)
congenital diaphragmatic hernia results from
congenital defect in fetal diaphragm
congenital diaphragmatic hernia occurs where?
posterior aspect of diaphragm
most common type of diaphragmatic defect
herniation through Foramen of Bochdalek
Foramen of Bochdalek occurs ____ and _____ in the diaphragm
posterior and lateral
foramen of bochdalek accounts for more than _____% of defects
90%
foramen of bochdalek usually occurs on the ____ side
left side of diaphragm
_____ may be seen in throacic cavity from foramen of bochdalek
bowel loops
how would you distinguish bowel vs mass?
peristalsis
Diaphragmatic herniation that is anterior and medial
foramen of Morgagni
hernias on the right side of the diaphragm allow ____ _____ ______ to enter the chest
liver, gallbladder, intenstines
hydrops is not usually present with ______ sided CDH
left sided
left-sided CDH sonographically appears:
- stomach in the chest
- small right lung
- small left ventricle of heart
right-sided CDH sonographically appears:
- liver appears in chest
- heart deviated to the left
poor prognosis in CDH if
detected before birth
- stomach in chest
- left side of heart undeveloped
- congenital heart disease present
primary cause of death with CDH
pulmonary hypopasia
associated anomalies with CDH:
- cardiac & CNS malformations
- renal anomalies
- vertebral defects
- pulmonary hypoplasia
- facial clefts
- trisomy 18 & 21
