Flashcards in Pulmonary Embryology/Pediatric Lung disorders Deck (44):
lung tissue is derived from..
embryonic endoderm in the yolk sac
Pulmonary circualtion vessels is derived from
Lung bud moves ventrally into mesoderm "respiration diverticulum"
(primitive foregut epithelial cells invade splanchnic mesenchyme)
what happens Day 32?
laryngotracheal groove - out pouching between 4th and 6th brachial arch
R and L lung buds push into the primordial pleural cavity
Descent into the thorax (lung and heart) until pleuroperitoneal foramen close
descent halted by liver
Major events of Months 3-9
lungs grow (glandular)
respiratory bronchioles proliferate and alveolar ducts and sacs form
Outline of the stages
embryonic --> pseudoglandular --> Canalicular --> Saccular/terminal --> alveolar/postnatal
Formation of the proximal tracheobronchial tree by branching of the foregut endoderm.
Formation from main --> lobar --> segmental (tertiary) --> subsegmental.
Occurs assymetrically and dichotomous
Disorders associated with embryonic stage dvmt issues
Vascular malformation to cause airway compression
Formation until terminal bronchioles (but not alveoli).
Differentiation of conducting airway epitheilum
Splancnic mesoderm forms cartilage, Smooth muscle and mucus glands.
Formation of the respiratory bronchioles
Delineation of pulmonary acinus and initial development of pulmonary capillaries.
Beginning of fetal breating.
Survival is possible - but limited.
Diseases associated with canalicular stage
Pulmonary hypoplasia, potter's syndrome (decreased renal function), diaphragmatic hernia, RDS
26-36 weeks, or to term
growth and branching of sacs to increase in number. (alveolar ducts and terminal sacs)
Increase in vascularization! and epithelial differentiation to cause surfactant production increases
37 weeks to 3 yr
secondary septal formation and True Alveoli (90% occur after birth).
Continued formation of Type I from type II with lengthening of capillaries.
Pulmonary Arch and capillaries forms from..
6th aortic arch
Pulmonary veins form from
outgrowth of left atrium
Lungs/airways/chest in children vs. adults
Children have smaller airways - decreased radiance so larger resistance.
Larynx is more anterior and higher, large tongue, floppy epiglottis (for suck and swallow).
Smallest part is cricoid cartilage (adults is vocal cords)
Intercostal muscles are weaker
Diaphram is flat and easily fatigued due to type I muscles.
Increased compliant thorax (due to flat diaphragm)
what does a increased compliant thorax mean for infants?
- decreased negative intrathoracic pressure and outward recoil
- decreased tidal volume -- prone to atelactasis.
ultimately cause less effective pump and easily fatigued.
PE signs of upper airway obstruction
Stridor, dysphagia, (drooling to avoid swallowing), dypsnea and distress.
No hypoxemia - that is a lower airway problem.
Most common cause of stridor in kids.
Ineffective cartalaginous support of supraglottic structures.
Early presentation (before 6 months), worse with increase airflow or supine.
Outgrowth by 1 (female) or 2 (male)
abnormal cartilage of trachea and bronchi to cause problems with exhalation.
increased secretion, recurrent wheeze, hoarse cough, and recurrent pneumonia.
Causes of Acute Stridor
Croup, Foreign Body, Epiglottitis, Bacterial Trachilitis
Most common cause of acute stridor.
Viral and mild symptoms due to virus
Cough, low grade or no fever, NO drooling.
Treatment with steroids
A medical emergency cause of acute stridor.
Not seen often due to immunization of H influenza B.
Also with strep A and N. Gonnorhea or Hot liquid aspiration.
Occurs in older 2-7 year olds.
Associated with HIgher fever, drooling, dysphagia and low saturation
Tx: intubation and IV antibiotics
Acute stridor due to viral croup that progresses or staph aurea to cause edema and purulence.
High fever, normal epiglottis, in older kids.
recovery is longer than with epiglotitis.
Tx: intubation, debrdiement, suctioning, IV antibiotics.
Physical exam for lower airway disease
Hypoxemia, Wheeze, crackles
decreased number of alveoli due to thickened interstitum and simplification of lung structure.
Defined as any baby that needs O2 after due date.
RDS vs BPD
RDS is a description of what happens when you are born. - whether at 27 weeks or 40.
BPD - use of oxygen after due date (40 wks).
causes of hypoxemia
VQ mismatch, hypoventilation, shunt, diffusion, extreme altitude, hemoglobinopathy
Causes of acute polyphonic wheeze
Bronchioloitis, viral pneumonia, CF, Heart disease, aspiration pneumonia, asthma
are you likely to grow out of asthma
no if you have eczema or allergies
Pneumonia causes for birth to one month
strep agulactiae and staph aureus
Pneumonia 1month - 5 years causes
Pneumonia 5 y - 18 y
Tx for Px 1 -5 yrs
what do babies do to prevent atelactasis and maintain minute ventilation
increase TV (retractions)
increase respiratory rate (tachypnea)
grunt to keep oxygen in lungs longer
Differentials for recurrent Px
immunodeficient, Aspiration Px, CF, airway anomalies, foreign body, TB, neuromucocilliary dysfunction
Poor growth is due to..
decreased absorption, decreased intake, increased WOB to cause increased metabolic demand
CF effects on lungs
Endobronchitis, bronchiectasis, fibrosis, inflammation, mucus plugging