Ch. 61 Flashcards
(120 cards)
1
Q
__ is the single most important determine for fetal viability
A
Adequacy of pulmonary development
2
Q
__ is the major reason fetuses younger than 24 weeks are generally considered nonviable
A
Pulmonary immaturity
3
Q
Breathing movements that occur before birth results in _
A
Aspiration of fluid into the lungs
4
Q
The lungs at birth are about half filled with
A
Fluid from the amniotic cavity
5
Q
The fluid in the lungs at birth clears via 3 routes:
A
Nose and mouth
Into pulmonary capillaries
Into lymphatic and pulmonary vessels
6
Q
Normally the thoracic cavity is
A
Symmetric and bell shaped
7
Q
The lungs serve as __ for the heart, and lie __ to the diaphragm
A
Lateral borders
Superior
8
Q
The diaphragm can be seen as __ between the fetal liver and lungs
A
A smooth hypoechoic muscular curvilinear margin
9
Q
Normally the fetal thorax is slightly __ than the abdominal cavity
A
Smaller
10
Q
The ratio [TC:AC] __ throughout pregnancy
A
Remains constant
11
Q
Extreme variations in thoracic size should signal
A
Further investigation for other anomalies
12
Q
___ can result in pulmonary hypoplasia, which may cause __
A
Oligohydramnios
Overall reduction in the thoracic size
13
Q
Thoracic circumference measurements are made in the __ plane at the level of __
A
Transverse
4 chamber heart
14
Q
A fetus that has significantly narrower chest diameter may have
A
Asphyxiating thoracic dystrophy
15
Q
Sever syndromes are associated with asphyxiating thoracic dystrophy including
A
Dwarfism
16
Q
The majority of the heart is positioned in the
A
Midline and left chest
17
Q
The apex of the heart should be directed
A
Toward the spleen (left)
18
Q
It is important to document sonographically the position of the
A
the heart
19
Q
Detection for abnormal position of the heart may indicate the presence of
A
Chest mass
Pleural effusion
Cardiac malformation
20
Q
Fetal lungs appear
A
Homogeneous with moderate echogenicity
21
Q
Echogenicity of the fetal lungs __ as pregnancy progresses
A
Increases
22
Q
Fetal breathing becomes ___ in the 2nd & 3rd trimesters
A
More prominent
23
Q
A mature fetus spends almost __ of its time “breathing”
A
1/3
24
Q
Color doppler may be used to detect __, however it is not a well-recognized practice
A
fetal breathing through the nostrils
25
When evaluating the fetus for a lung mass the following should be assessed
Position of the fetal heart
Orientation of the cardiac axis (normal is 45 degree angle pointing left)
Measurement of the thoracic circmference
26
Deviation from the normal cardiac axis may suggest the presence of
an intrathoracic mass
27
Thoracic circumference measurements estimate ___& may predict ___
the size of the thoracic cavity
| secondary pulmonary hypoplasia
28
When the heart position & axis vary from the normal position:
look closely for any abnormalities that may be causing the displacement such as pleural effusion or diaphragmatic hernia
29
Lungs may not grow or develop properly with
oligohydramnios
30
A mass within the throacic cavity may have ___ on lung development. The heart may be displaced & the lungs may be __. These effects may lead to __
detrimental effects
compressed and destroyed
pulmonary hypoplasia
31
Pulmonary hypoplasia is caused by __ and results in __
a decrese in the number of lung cells, airways, and alveoli
| decrease in organ size and weight
32
Reduction in lung volume results in __
small inadequately developed lungs
33
Pulmonary hypoplasia most commonly ocurs from __ or secondary to __
prolonged oligohydramnios
| small thoracic cavity as a result of structural or chromosomal abnormality
34
Kidney abnormalities may result in __
lethal pulmonary hypoplasia
35
Kindey abnormalities that may result in lethal pulmonary hypoplasia
```
▪Bilateral renal agenesis
▪Bilateral multicystic kidney disease
▪Severe renal obstruction
▪Unilateral renal agenesis with contralateral multicystic kidney development
▪Severe obstruction
▪Infantile polycystic kidney disease
```
36
Pulmonary hypoplasia may occur in fetuses with
severe IUGR & early rupture of membranes
37
Masses within the thoracic cavity may lead to
Pulmonary hypoplasia
38
Abnormalities that can cause pulmonary hypoplasia are
▪Cardiac defects
▪Some skeletal dysplasias
▪CNS disorders
▪Chromosomal Trisomies
39
A small percentage of infants have pulmonary hypoplasia without
any fetal or uterine problems
40
_ pulmonary agenesis or hypoplasia is rare, often associated with __
Unilateral
| other fetal abnormalities
41
An absent lung should be considered a differential diagnosis of every fetus with
mediastinal shift and apparent chest mass
42
Prognosis of pulmonary hypoplasia
grave
| 80% die after birth
43
Severity of pulmonary hypoplasia depends on
```
▪when pulmonary hypoplasia occured during pregnancy
▪severity
▪duration
Other contributing factors:
▪Pulmonary fluid dynamics
▪Fetal breathing movements
▪Hormonal influences
```
44
Various methods are used to determine the presence of pulmonary hypoplasia
```
▪thoracic measurements
▪Various lung measurements
▪Estimation of lung volume
▪Doppler studies of pulmonary arteries
▪Assessment of fetal breathing activity
```
45
A thoracic circumference below the _____percentile suggests the possibility of pulmonary hypoplasia
5th
46
Cystic Lung Masses
Echo free masses that replace normal lung parenchyma
47
Cystic lung masses vary in __
size, ranging from small isolated lesions to large cystic masses
48
Cystic lung masses may cause
notable shifts of intrathoracic structures
49
Simple cysts may be
surgically removed after delivery
50
Most common lung cyst detected prenatally
Bronchogenic cysts
51
Bronchogenic cysts occur as a result of
abnormal budding of the foregut
52
Brochogenic cysts lack
any communication with the trachea or bronchial tree
| Isolated
53
Bronchogenic cysts typically occur within the
mediastinum or lung
54
Bronchogenic cysts infrequently found
inferior to the diagram
55
Sono appearance of bronchogenic cysts
* Appear as small circumscribed masses
* No evidence of mediastinal shift or heart failure
* Amniotic fluid within normal range
56
Accumulation of fluid within the pleural cavity
Pleural effusion
57
Pleural effusion may appear as
an isolated lesion or secondary to multiple fetal anomalies
58
Most common reason for pleural effusion
Chylothorax
59
Chylothorax
* Occurring as a right sided unilateral collection of fluid secondary to malformed thoracic duct
* Hydramnios often accompanies chylothorax resulting from esophageal compression
60
Pleural effusion can be
unilateral or bilateral
61
Pleural eeffusion may result from
immune [Rh isoimmunization] or nonimmune causes or from congestive heart failure
62
Effusions may also occur in fetuses with:
Chromosomal abnormalities (21) & cardiac mass
63
Other reasons for pleural effusions
```
▪Lymphangietctasia
▪Cystic adenomatoid malformations
▪Bronchopulmonary sequestration
▪Diaphragmatic hernia
▪Hamartoma
▪Atresia of pulmonary vein
▪Unknown causes
```
64
Sono findings of pleural effusion
▪Echo-free peripheral masses on one or both sides of the fetal heart
▪Conform to the thoracic cavity & often compress the lung tissue
▪Lung appears to float in the fluid
65
Pleural effusions are rarely seen before _, except when __
15 weeks gestation associated with Down or Turner syndrome
66
With pleural effusion, Compression of lung parenchyma may cause __, often represents __
pulmonary hypoplasia
| life threatening consequences for neonate
67
The presence of pleural effusion may cause:
▪a shift in medistinal structure
▪Compression of the heart
▪Inversion of the diaphragm
68
Mortality rate of pleural effusion
approx. 50%
69
Prognosis of pleural effusion
poorer with associated hydrops
70
When pleural effusion is large
▪Lung development is impaired
| ▪Pulmonary hypoplasia may result
71
Solid lung masses appear as
echo-dense (hyperechoic) masses in the lung tissue
72
Pulmonary sequestration and certain types of cystic adenomatoid malformations (CCAMs) appear as
solid masses
73
Pulmonary sequestration
supernumerary lobe of the lung (extra lung tissue) separated from the normal tracheobronchial tree
74
Intralobar pulmonary sequestration
There is extra lung tissue present within the pleural lung sac
75
Extralobar pulmonary sequestration
Lung tissue is connected to the inferior border of the lung within its own pleural sac
76
Pulmonary sequestration most likely develops from either
A separate outpuching of foregut
| Separation of a segment of developing lung from the tracheobronchial tree
77
with pulmonary sequestration the extra lung tissue is
non-functional & receives blood supply from systemic circulation
78
Sono findings of pulmonary sequestration
▪Echogenic solid mass resembling lung tissue, usually in the lower lobe of the lung
▪Usually on the left side
▪Rarely occurs below the diaphragm
79
Pulmonary sequestration is associated with
```
▪Hydrops
▪Polyhydramnios
▪Diaphragmatic hernia
▪Gastrointestinal anomalies
▪Lung anomalies [pulmonary hypoplasia]
```
80
Prognosis of pulmonary sequestration
▪Intralobar sequestration has a highly favorable prognosis
▪Extralobar sequestration carries a poor prognosis
Becuase of associated anomalies and hydrops
81
Congenital Cystic Adenomatoid Malformation([CCAM)
multicystic mass within the lung Consists of primitive lung tissue & abnormal bronchial and bronchial-like structures
82
CCAM is one of the
bronchopulmonary foregut malformations
83
CCAM lesions may involv
▪One or more lobes of lung
▪Entire lung
▪Be bilateral
84
CCAM malformations may
communicate with the bronchial tree
85
With CCAM, cysts within the mass may be
large or small
86
Texture of CCAMs
Varies:
solid
cystic
mixed
87
With CCAM, most lesions are
unilateral and do not favor either lung
88
3 forms of CCAM
Type 1- macrocystic
Type 2- macrocystic w/ microcystic components
Type 3- Microcystic
89
CCAM type 1
Macrocystic
•One or more large cyst replaces normal lung tissue
•Single or multiple cysts measuring 2cm up to 10 cm
90
CCAM type 2:
| Anomalies may include:
Macrocystic with microcystic components
•Lesions consist of multiple small cysts <1cm
•Associated with fetal &/or chromosomal abnormalities in 25% of cases:
Renal agenesis
Pulmonary anomalies
Diaphragmatic hernia
91
CCAM Type 3
```
Micocystic
•Bulky, large, noncystic lesions
•Appear as echo-dense [hyperechoic] masses of the entire lung lobe
•When mediastinal structures shift
oLung compression may occur
oHydrops may develop
•Hydramnios may be seen secondary to esophageal compression
oPreventing normal fetal swallowing
```
92
When a cystic or solid lung mass is identified the sonographer should attempt to
▪Determine the number & size(s) of the cystic structure(s)
▪Check for presence or absence of a mediastinal shift
▪Identify & assess the size of the lungs
▪Look for fetal hydrops
▪Exclude cardiac masses
▪Search for other fetal anomalies
93
Progsis of CCAM
the type of lesion
type 1- favorable outcome
type 2 &3- poor prognosis
94
Smaller cysts= _ prognosis
poorer
95
Congenital Bronchial Atresia
Rare
Results from focal obliteration of a segment of the bronchial lumen
Most common in left upper lobe
Appears as an echogenic pulmonary mass lesion
96
Normally, the diaphragm should appear as a
curvilinear hypoechoic structure coursing anteriorly to posteriorly
97
The fetal stomach & liver should be identified _to the diaphragm
caudal/ inferior
98
The fetal lungs and heart should be identified _to the diaphragm
Cephalad/ superior
99
Failure to see normal relationships to the diaphragm indicates
diaphragmatic defects
100
Congenital Diaphragmatic Hernia [CDH]
Herniation of the abdominal viscera into the chest
101
CDH results from
congenital defect in the fetal diaphragm
102
Most posterior aspect of the diaphragm:
forms last
| most commonly defective
103
Hernia permits abdominal organs to
enter the chest
104
Herniation through Foramen of Bochdalek
Most common type of diaphragmatic defect
▪*Occurs posteriorly & laterally in the diaphragm
•This abnormality positions the heart & mediastinal structures to the right side of the chest
•Look for stomach, portions of small & large intestines, left lobe of liver & spleen in thoracic cavity
•*bowel loops may be seen within the thoracic cavity
105
How would you distinguish loops of bowel vs a mass
bowel has peristalsis
106
Herniation through foramen bochdalek accounts for more than
90% of diaphragmatic defects
107
Herniation through foramen bochdalek usually occurs on the
left side of the diaphragm
108
Diaphragmatic herniation through the foramen of Morgagni
Anteriorly & medially
May communicate with the pericardial sac
The heart & stomach may be normally positioned
109
With Diaphragmatic herniation through the foramen of Morgagni, herniation is on the _, allowing
right side of the diaphragm
| the right sided abdominal viscera to enter the chest (liver, GB, intestines)
110
Herniated abdominal organs cause
lung compression
111
With Diaphragmatic herniation through the foramen of Morgagni Size of defects can vary. Range from
small to large to complete absence of both diaphragms
| Smaller defects are more difficult to diagnose in utero
112
Hydrops is usually not present with _ CDH
left sided unless associated fetal malformations are present
113
with hernias, Pulmonary arteries become _
Results in_
After birth, _
hypertrophied & thickened
Results in pulmonary HTN
After birth, leads to persistent fetal circulation
114
B/L hernias are
very unusual
more difficult to detect
Cardio-mediastinal shift may not be present
115
Sonographically:
| Left-sided CDH
* Intrathoracic stomach
* Displaced cardiac apex
* Cardio-mediastinal shift [critical in making diagnosis]
* Intrathoracic liver
* Small right lung
* Small left ventricle of heart
* Evaluate for chromosomal abnormalities
116
Sonographically:
| Right-sided CDH
```
•Liver appears in the chest
•Possibly collapsed bowel
•Heart deviated to the left
•Abnormal stomach alignment
•Respirations may be severely compromised
•May result in death
of the newborn
```
117
CDH prognosis
```
Poor prognosis if:
•Detected before birth
•Stomach is found in the ches
•Left side of heart is undeveloped
•Congenital heart disease is present
```
▪
118
With CDH, Primary cause of death is
pulmonary hypoplasia
119
With CDH, if __Survival rate is low
diagnosis is made before 25 weeks & polyhydramnios is present
120
Anomalies associated with CDH
```
▪Cardiac malfomations
▪CNS malformations
▪Renal anomalies
▪Vertebral defects
▪Pulmonary hypoplasia
▪Facial clefts
▪Trisomy 18 & 21
```
