B4.034 Development of the Respiratory System

Question 1

physical exam findings consistent with TEF

Answer 1

excessive oral secretions/mucous
feeding difficulty
gagging/choking
hyperventilation, dyspnea, tachypnea
cyanosis
rales on auscultation
VACTERL

Question 2

what is VACTERL

Answer 2

vertebral abnormalities
anal atresia
cardiac abnormalities
trachea-esophageal fistula
renal/radial issues
limb dysfunction

Question 3

why is abdominal distention present in TEF?

Answer 3

caused by swallowing air during feeding

Question 4

what physical exam finding with TEF helps rule out other congenital abnormalities with similar presentation?

Answer 4

mucous secretions from both nose and mouth suggest and interconnecting GI and trachea

Question 5

how to evaluate suspicion of TEF?

Answer 5

CXR with NG tube
KUB (plain supine film of the abdomen) to identify air in GI tract
bronchoscopy confirms narrowing or fistula in esophagus

Question 6

treatment of TEF?

Answer 6

emergency surgical repair

prognosis good following surgery

Question 7

what conditions may a mother have experienced during pregnancy if she gives birth to a baby w TEF?

Answer 7

polyhydramnios

inhibited swallowing of amniotic fluid

Question 8

complications of TEF surgery

Answer 8

aspiration pneumonia
pneumonitis
choking
reflux or esophageal stricture post op

Question 9

what is the first step in the respiratory system development?

Answer 9

respiratory diverticulum

Question 10

when do the esophagus and trachea split?

Answer 10

tracheoesophageal septum forms from the tracheoesophageal ridges

Question 11

etiology of TEF

Answer 11

1/3000 births
90% blind esophagus and developed trachea with a TEF attaching from just below the bifurcation to the distal part of the esophagus
4% common communication between trachea and esophagus at bifurcation
4% isolated esophageal atresia

Question 12

what is the hallmark of hypertrophic pyloric stenosis

Answer 12

normal feeding with a sudden change after 4-8 weeks

non-bilious projectile vomiting following feeding

Question 13

why is there an alkaline pH and low potassium levels?

Answer 13

starvation leads to altered metabolism, regurgitation/emesis causes progressive loss of fluids, kidneys retain H+ ions in favor of K+

Question 14

what is hypertrophic pyloric stenosis

Answer 14

narrowing of the pylorus region of the stomach (where the stomach meets the duodenum)

Question 15

etiology of hypertrophic pyloric stenosis

Answer 15

more common in males
4x more frequent in firstborn males
2.4/1000 Caucasian births

Question 16

key findings in a child w a congenital diaphragmatic hernia

Answer 16

scaphoid abdomen
carrel shaped chest
respiratory distress (retractions, cyanosis, grunting respiration)

Question 17

findings in left sided posterolateral CDH?

Answer 17

poor air entry on the left
shift of cardiac sounds over the right chest
signs of pneumothorax if severe

Question 18

downstream pathophysiology of CDH

Answer 18

pulmonary hypoplasia
fewer dichotomous branches of respiratory tree
increased muscularization of pulmonary arteries leading to pulmonary hypertension

Question 19

what leads to the increased muscularization of pulmonary arteries in CDH?

Answer 19

attempting to provide more air exchange

Question 20

what is the most/least common place for a CDH?

Answer 20

80-90% on left side

uncommonly in center

Question 21

what is neonatal respiratory distress syndrome

Answer 21

caused by surfactant deficiency in premature infants
surfactant deficiency causes the lungs to collapse (atelectacic lung) with each successive breath
lack of O2 impairs surfactant synthesis

Question 22

when is surfactant typically synthesized?

Answer 22

made by type 2 alveolar cells after the 35th week of gestation
corticosteroids induce this synthesis

Question 23

appearance of RDS on CXR

Answer 23

ground glass with air brochograms (darker bronchi due to opacity to alveoli)

Question 24

treatment for RDS

Answer 24

early admin os surfactant
CPAP for alveolar recruitment
diagnosis of patent ductus arteriosus 
fluid and electrolyte management
trophic feeding and nutrition
use of prophylactic fluconazole

Question 25

preventative steps to avoid RDS

Answer 25

antenatal steroid to enhance pulmonary maturity in utero

Question 26

what are the dangers of O2 administration in treatment of RDS?

Answer 26

retinopathy of prematurity

Question 27

stages in lung maturation

Answer 27

embryonic (26 days to 6 weeks) - formation of respiratory diverticulum
pseudoglandular (6 to 16 weeks) - formation of terminal bronchioles
canalicular phase (16 to 28 weeks)- formation of respiratory bronchioles
saccular (28 to 36 weeks)- terminal sacs form
alveolar (36 weeks to term) - alveoli mature, epithelium becomes squamous throughout and there is an intimate association with capillaries allowing gas exchange

Question 28

what is hyaline membrane?

Answer 28

debris of fibrin and serum proteins that collect in alveoli of babies with RDS

Question 29

discuss aeration at birth

Answer 29

replacement of liquid with air

resorption of liquid primarily into pulmonary capillaries, but also into lymphatics

Question 30

amniotic fluid pathway

Answer 30

fetus swallows and urinates fluid

Question 31

oligohydramnios

Answer 31

AFI<5 cm
less urine output = less fluid
restricts fetal breathing

Question 32

poluhydramnios

Answer 32

AFI > 24cm

less swallowing = more fluid

Question 33

what leads to oligohydramnios

Answer 33

early leaking of amniotic fluid due to premature rupture of the membranes that surround the fetus