chapter 62 reverse Flashcards
1
Q
bile formation by hepatic cells begin when
A
12 wks
2
Q
the midgut is suspended by
A
elongated dorsal mesentery
3
Q
The Hindgut is supplied by
A
inferior mesenteric artery
4
Q
Stomach should be seen by
A
14 to 16 weeks
5
Q
Echogenic debris may sometimes be seen along dependent wall of stomach
A
Vernix
6
Q
If stomach seen in right upper quadrant, condition is called
A
situs inversus
7
Q
If fetus is in vertex presentation with spine up, both aorta and stomach should be seen to left of spine
A
Stomach
8
Q
can be visualized in thorax during second and third trimesters as two or more parallel echogenic lines (“multilayered” pattern)
A
Normal esophagus
9
Q
Measured at level of portal sinus and umbilical portion of left portal vein (“hockey stick” appearance on sonogram)
A
Abdominal Circumference
10
Q
Abdominal circumference should be round, not oval.
A
Abdominal Circumference
11
Q
Joins umbilical portion of left portal vein at caudal margin of left intersegmental fissure of liver
A
Umbilical Cord Insertion
12
Q
Visualization of insertion site must be made to rule out presence of omphalocele, gastroschisis, hernia, and mass formation.
A
Umbilical Cord Insertion
13
Q
Movement of gastric musculature begins in
A
approximately fourth to fifth month of gestation
14
Q
After 15th to 16th week, meconium begins to accumulate in distal part of small intestine
A
Bowel
15
Q
Appears as ill-defined area of increased echogenicity in mid to lower abdomen
A
Bowel
16
Q
Hyperechoic appearance could be secondary to reflections from walls of collapsed loops of small bowel or from mesenteric fat between loops
A
Bowel
17
Q
As pregnancy progresses: Hyperechoic area becomes less prominent Small bowel located more centrally in abdomen than colon
A
Bowel
18
Q
Normal diameter of small bowel lumen ≤5 mm, with length of 15 mm near term
A
bowel
19
Q
Haustral folds of colon help to differentiate it from small bowel
A
Bowel
20
Q
In early gestation, haustral folds appear as thin linear echoes within lumen of colon Later, colon diameter increases and folds become longer and thicker
A
Bowel
21
Q
Colon seen near end of second trimester as long tubular hypoechoic structure with well-defined walls
A
Bowel
22
Q
Normal measurements of colon diameter range from 3 to 5 mm at 20 weeks to 23 mm or larger at term
A
Bowel
23
Q
does not have peristalsis like small bowel
A
Colon
24
Q
more peripheral than small bowel
A
Colon
25
After 14 weeks of gestation, lipid absorbed from fetal colon and remaining contents collect in colon as meconium
Bowel
26
hypoechoic relative to fetal liver and in comparison with bowel wall
Meconium within lumen of colon
27
Accounts for 10% of total weight of fetus at 11 weeks and 5% of total weight at term
Liver
28
Left lobe of liver larger than right in utero secondary to greater supply of oxygenated blood Reverses after birth
Liver
29
Distinguished by location to right of portal-umbilical vein and as oblong, more oval structure than “tubular” intrahepatic umbilical vein
Gallbladder
30
Lies in the retroperitoneal cavity anterior to the superior mesenteric vessels, aorta, and inferior vena cava (IVC)
Pancreas
31
Normal fetal pancreas has been seen in utero but is more difficult to routinely visualize because of the lack of fatty tissue within the gland
Pancreas
32
Homogeneous in texture Similar in echogenicity to kidney Slightly less echogenic than liver Increases in size during gestation Imaged on transverse plane posterior and to left of fetal stomach
Spleen
33
Is involved in several congenital anomalies but rarely affected by isolated hepatic lesions
Abnormalities of the Hepatobiliary System
34
Liver parenchymal cysts and hemangiomas of liver have been reported. Enlarges in fetuses with Rh-immune disease in response to increased hematopoiesis
Abnormalities of the Hepatobiliary System
35
Liver tumors, hamartoma, hepatoblastoma uncommon but may be seen
Liver
36
Hemangioendothelioma Most common symptomatic, vascular hepatic tumor of infancy (although rare) May cause nonimmune hydrops in fetus
Liver
37
Sonographic Findings of the liver
Most liver tumors appear as hypoechoic solid masses; cystic components have also been reported as mixed with solid masses
38
Partial situs divided into asplenia and polysplenia
Situs Inversus
39
Choledochal cyst (dilation of CBD) may be diagnosed when
cystic mass identified adjacent to fetal stomach and gallbladder
40
Agenesis of gallbladder occurs in approximately
20% of patients with biliary atresia
41
Absence of gallbladder can occur in association with
polysplenia and rare multiple anomaly syndromes
42
Combination of polyhydramnios and absent stomach over repeated studies may be suggestive of
esophageal atresia
43
In \>50% of cases, stomach present because fistula usually present that leads to fluid filling stomach
Esophageal Atresia
44
About 30% of fetuses with duodenal atresia have
trisomy 21 (Down syndrome)
45
Anomalies occur in approximately with duodenal atresia
50%
46
Occurs in 1 in 3000 to 5000 live births; thought to be secondary to vascular accident, volvulus or gastroschisis or be sporadic
Bowel Intestinal Obstructions
47
Meconium begins to accumulate in the fetal bowel in the second trimester, at which time it can be seen sonographically as tiny echogenic reflections within the peristaltic small bowel.
Meconium Ileus
48
True ascites in fetal abdomen always
abnormal
49
Other conditions that may cause ascites to develop include bowel perforation or urinary ascites secondary to bladder rupture.
Ascites
50
Pharynx Lower respiratory system Esophagus Stomach Part of the duodenum Liver and biliary apparatus Pancreas
foregut
51
Results from abnormal deviation of tracheoesophageal septum in posterior direction
Esophageal atresia
52
Appears as fusiform dilation of caudal part of foregut During fifth and sixth weeks, dorsal border (greater curvature) grows faster than ventral border (lesser curvature)
Stomach
53
Develops from caudal part of foregut and cranial part of midgut Comes to lie primarily in retroperitoneum
Duodenum
54
Liver, gallbladder, biliary ducts arise as bud from most caudal part of foregut in fourth week
Liver and Biliary System
55
(blood formation) begins during sixth week
Hemopoiesis
56
Blockage of bile ducts results from failure to recanalize following solid stage of development
Extrahepatic biliary atresia
57
Develops from dorsal and ventral pancreatic buds of endodermal cells that arise from caudal part of foregut
Pancreas
58
Lymphatic organ derived from mass of mesenchymal cells located between layers of dorsal mesogastrium
Spleen
59
Small intestines Cecum and cloaca exstrophy Ascending colon Most of transverse colon
The Midgut
60
All structures supplied by superior mesenteric artery
The Midgut
61
Usually by 10th or 11th week, midgut herniation returns to abdomen
The Midgut
62
Is usually located to right of umbilical cord
Gastroschisis
63
Forms when: Intestines return normally to abdominal cavity Herniate either prenatally or postnatally through inadequately closed umbilicus
Umbilical Hernia
64
Is the most common malformation of midgut Remnant of proximal part of yolk stalk that fails to degenerate and disappear during early fetal period
Meckel’s Diverticulum
65
Derivatives of hindgut: Left part of transverse colon Descending colon Sigmoid colon Rectum Superior portion of anal canal Epithelium of urinary bladder Most of urethra
The Hindgut
66
Central nervous system problem (swallowing disorders) Obstruction Oligohydramnios Atresia
if stomach is not seen RO
67
Distinction of large bowel from small bowel possible after 20 menstrual weeks
Bowel
68
After 27 weeks
peristalsis occurs
69
Relatively large compared with other intraabdominal organs Occupies most of upper abdomen in fetus
Liver
70
Hepatic veins and fissures formed by end of first trimester
Liver
71
May be seen sonographically after 20 weeks of gestation
Gallbladder
72
Normal fetal pancreas has been seen in utero but is more difficult to routinely visualize because of the lack of fatty tissue within the gland
Pancreas
73
Is more severe disorder May develop in two different combinations of organ reversals Thoracic viscera usually reversed Abdominal viscera may or may not be reversed
Partial situs inversus
74
At least two spleens present along greater curvature of stomach Heart block common in polysplenia syndrome
Polysplenia
75
Cardiac malformations common (99%) in asplenia syndrome; are seen with less frequency in polysplenia syndrome (90%)
Situs Inversus
76
Endocardial cushion defects Hypoplastic left heart Transposition of great vessels
Cardiac defects of situs inversus
77
usually has normal outcome
total situs inversus
78
extremely high; death occurs in 90% to 95% with asplenia syndrome and 80% with polysplenia syndrome
Mortality rate for partial situs inversus
79
right-sided heart axis and aorta; transposition of liver, stomach, spleen; left-sided gallbladder)
Total situs inversus
80
(right-sided stomach, left-sided liver); dextrocardia with normal stomach position (see previous section)
Partial situs inversus
81
Genitourinary Gastrointestinal Liver Cardiac Infections Metabolic storage disorders Idiopathic
Causes of Ascites
82
Cholelithiasis (gallstones)
identified in fetus when calcifications are found within gallbladder.
83
Develop when portion of bowel grows and infarcts Occurs anywhere in gastrointestinal tract Polyhydramnios evident on ultrasound
Atresias
84
back-up of amniotic fluid and hydramnios
Blockage results in
85
Most common form occurs in conjunction with a fistula, communicating between trachea and esophagus (tracheoesophageal fistula). allows passage of amniotic fluid into stomach
Esophageal Atresia
86
Gastric secretions may contribute to stomach fluid
Esophageal Atresia
87
Hydramnios may exist from impaired reabsorption of swallowed fluid and be associated with esophageal atresia; usually does not develop until third trimester
Esophageal Atresia
88
Growth restriction present in 40% of cases Chromosomal trisomies (18 and 21) reported Coexisting anomalies common in 50% to 70% of fetuses with esophageal atresia
Esophageal Atresia
89
Blockage of duodenal lumen by membrane that prohibits passage of swallowed amniotic fluid
Duodenal Atresia
90
Two echo-free communicating structures (stomach and duodenum) found in upper fetal abdomen Sonographic appearance termed “double bubble sign” Hydramnios almost always seen with duodenal atresias later in pregnancy
Duodenal Atresia Sonographic Findings
91
Duodenal atresia Duodenal stenosis Annular pancreas Ladd’s bands Proximal jejunal atresia Malrotation Diaphragmatic hernia
Causes of Double Bubble
92
Atresia or stenosis of jejunum or ileum, or both, and small bowel atresia slightly more common than duodenal atresia
Bowel Intestinal Obstructions
93
(jejunoileal atresia or stenosis) appears as multiple cystic structures (more than two) proximal to site of atresia within fetal abdomen
Blockage of jejunum and ileal bowel segments
94
General rule: The more distal the obstruction, the less severe the hydramnios, and the later it will develop.
Bowel Intestinal Obstructions
95
Malrotation Atresias Volvulus Peritoneal bands Cystic fibrosis Dilated bowel loops isolated or associated with other anomalies, ascites, or meconium peritonitis
Causes of fetal small-bowel obstruction include:
96
Intestinal obstructions appear as cystic bowel loops discontinuous with stomach Fetal intestinal obstruction should be suspected when clear cystic structures found in pelvis Vascular restriction may lead to obstruction secondary to gastroschisis
Sonographic Findings
97
Is a small-bowel disorder marked by presence of thick meconium in distal ileum
Meconium Ileus
98
10% to 15% of patients; is third most common form of neonatal bowel obstruction after atresia and malrotation
Earliest manifestation of cystic fibrosis occurring (%)
99
The anal sphincter prevents the passage of meconium (meconium plug) into the amniotic fluid, unless the fetus is stressed or traumatized.
Meconium Ileus
100
Ileum dilates because of impacted meconium (which appears echogenic) Increased production of mucus by GI organs and electrolyte imbalance explains overproduction of meconium (characteristic of cystic fibrosis)
Meconium Ileus Sonographic Findings
101
Presents as complex disorder of bowel and genitourinary tract Imperforate anus is disorder that occurs when membrane covers anus, prohibiting expulsion of meconium
Anorectal Atresia
102
Megacolon is congenital disorder in which there is abnormal innervation of large intestine
Hirschsprung’s Disease
103
Condition that may arise when fetus has sterile chemical peritonitis secondary to in utero bowel perforation Hydramnios present in 65% of fetuses
Meconium Peritonitis
104
Calcifications seen on peritoneal surfaces or in scrotum via processus vaginalis Ascitic fluid may be echogenic. Is unusual to see calcification in meconium ileus in fetus with cystic fibrosis
Sonographic FindingsMeconium Peritonitis
105
Grade 1: Mildly echogenic and typically diffuse Grade 2: Moderately echogenic and typically focal Grade 3: Very echogenic; similar to that of bone structures
Hyperechoic Bowel
106
poor in nonimmune hydrops
Prognosis is
