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Flashcards in Pediatric Pulmonary Disorders Overview Deck (28)
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embryonic stage of lung development

3-6 weeks

i. Outpouching of the foregut into the mesoderm and begin to branch - trachea, main stem, lobar and segmental bronchi are formed, lacking cartilage, smooth muscle or nerves

ii. Epithelium remains undifferentiated

iii. Mesenchyme tissue is important to guide this branching morphogenesis

iv. Vascular connections with the atria are established, pulmonary and bronchial vessels are not well formed


pseudoglandular stage of lung development

6-16 weeks

i. Continued branching of airways - Terminal bronchioles and primitive acinar structure are formed

ii. Epithelial cells start to differentiate

iii. Pulmonary vasculature develops parallel to bronchi and bronchioles


canalicular stage of lung development

16-26 weeks

i. Continued branching to the level of primitive alveolar ducts and acinar tubules

ii. Epithelial cell differentiation becomes increasingly complex

iii. Capillaries surround distal acinar tubules to form gas exchange region of the lung

iv. By end of stage, gas exchange can be supported after birth


saccular stage of lung development

26-36 weeks

i. Further growth of lung acini

ii. Continued capillary development

iii. Epithelial cells differentiated - Type I and II alveolar cells


alveolar stage of lung development

36 weeks onward

continued development of alveoli, can persist up until adolescent age


respiratory distress syndrome (RDS)

diagnosis progressive respiratory failure, characteristic chest radiograph, which demonstrates low lung volme and diffuse reticulogranular ground-glass appearance with air bronchograms

most often seen in premature infants

due to inadequate production of surfactant


bronchopulmonary dysplasia (BPD) or chronic lung disease of infancy

term given to infants who had RDS and continue to have airway and parenchymal abnormalities

if an infant is on oxygen at day 28, need to reassess oxygen need later in infancy


mild BPD

if < 32 weeks gestational age, breathing room air at 36 weeks post birth

if >/= 32 weeks gestational age, breathing room air at 56 days of life


moderate BPD

if <32 weeks gestational age, breathing <30% FIO2 at 36 age post birth

if >/= weeks gestational age, breathing <30% FIO2 at 56 days post birth


severe BPD

if < 32 weeks gestation, >30% FIO2 or positive pressure ventilation at 36 weeks post birth

if >/= 32 weeks gestation, >30% FIO2 or positive ventilation at 56 days post birth


factors that increase the risk of BPD

lower birth weight

lower gestational age

infections (both maternal and infant)

positive pressure ventilation, oxygen toxicity



antenatal steroids

accelearate morphologic development of Type I and II pneumocytes

recommended for women at risk of preterm delivery prior to 34 weeks gestation


congenital airway abnormalities



tracheoesphageal fistula


congenital parenchymal abnormalities

pulmonary sequestration

congenital pulmonary airway malformation

congenital lobar emphysema


congenital vascular abnormalities

cascular ring/slings

pulmonary arteriovenous malformations



clinical presentation - stridor

omega shaped epiglottis

short aryepiglottic folds

prolapse arytenoids

diagnosis with bronchoscopy

surgical treatment if severe



noisy breathing

etiology not ocmpletely known, but likely to be alterations of structural support

diagnose with bronchoscopy or expert oopinion

treatmen tis primarily supportive, but surgery can be done for more severe cases


tracheoesophageal fistula

drooling due to inability to swallow secretions

choking when attemting feeds, usually within the first 24 hours of life

caused by incomplete separation of the esophagus from the laryngotracheal tube

diagnose because of inability to pass gastric tube, also can use a radiographic evaluation

treatment involves surgical means


pulmonary sequestration

normal, non-functioning lung tissue with no connection to the bronchial tree

blood supply for sequestration is from the systemic circulation and most often the descending thoracic aorta or the abdominal aorta

three different types:




intralobar:extralobar is 3:1


intralobar pulmonary sequestration

can be acquired through bronchial obstruction, pneumonia, parasitzation of pulmonary arteries

no lobar predominance

completely covered by normal lung tissue or by a segment of the visceral pleura of the lung lobe within which the sequestration occurs

equal among males and females

venous drainage via pulmonary veins


extralobar pulmonary sequestration

an accessory lung forms - covered in visceral pleura and spearated from the functioning lung

generally in the left lower lobe (80%)

about 10% below diaphragm

venous drainage is via systemic venous system (azygous or portal vein)


bronchopulmonary pulmonary sequestration

forgut malformation occurs when the abnormal lung tissue is connected to the gastrointestinal tract


congenital pulmonary airway malformation (CPAM)

previously called CCAM (cystic adenomatoid malformation of the lung)

heterogeneous group of congenital cystic and non-cystic lung masses characterized by extensive overgrowth of the primary bronchioles which are in communication with the abnormal bronchial tree lacking cartilage

25-30% of all congenital lung malformations 

no lobar or side predominance - most frequently in lower lobes, and 85-90% in only one lobe


congenital lobar emphysema

overinflation and distention of one or more pulmonary lobes

caused by intrinsic or extrinsic bronchial narrowing with subsequent air trapping

hypoalveolar (< expected number of alveoli)

polyalveolar (> number of expected alveoli)

left upper lobe most frequently affected (rarely bilateral or multifocal)


vascular rings/slings

presents with trouble swallowing, stridor, respiratory distress, recurrent pneumonia, or apnea

caused by developmental abnormality of the aortic arch system, which leads to the compression of the esophagus and trachea

diagnosed using barium swallow

types include sling (aberrant left pulmonary artery, aberrant right subclavian artery), ring (double aortic arch), or things (other variants)


pulmonary artery malformations

abnormal connection between arteries and veins

clinical presentation of pulmonary hemorrhage or hemoptysis or hypoxia

diagnosis is chest radiograph and angiography

treatment is embolization


hereditary hemorrhagic telangectasia (HHT)

genetic illness associated with AVMs caused by mutations in the genes for activin receptor like kinase (ALK1), endoglin (ENG), or SMAD4

patients can have telangectasias of the nose, mouth, and hands, and AVMs can be found in the lung, gastrointestinal tract, and brain


factors that decrease risk of BPD

antenatal steroids

surfactant treatment

nutritional support

ventilator management