Pediatrics (3)- Gomez Flashcards
Congenital Anomalies
Agenesis or hypoplasia
Tracheal and/or bronchial abnormalities
Vascular anomalies
Congenital overinflation (emphysema)
Congenital foregut cysts- bronchogenic, esophageal or enteric
Sequestrations of lung tissue - intralobar or extralobar
Congenital Cystic Adenomatoid Malformation = Congenital Pulmonary Airway Malformation = CPAM
Pulmonary Hypoplasia
Common (10% neonatal autopsy)
Seen with fetal compression and
with other anomalies
Congenital Foregut Cysts
Detached section of maldeveloped foregut
(lungs arise from ventral wall foregut as lung buds)
Presents as mass or incidental finding, possibly in adulthood
Mediastinal & hilar locations
Usually not connected to airways
Consists of cystic spaces up to ~5 cm
Usually Bronchogenic with respiratory epithelium
+/- cartilage +/- smooth muscle and filled with mucin
Some esophageal (squamous mucosa)
Some enteric (intestinal mucosa)
Congenital Cystic Adenomatoid Malformation
(Congenital Pulmonary Airway Malformation =‘CPAM’)
Hamartomatous lesion with abnormal bronchiolar tissue
Type I – Large cysts; good prognosis
Type II – Medium cysts; poorer prognosis since associated with other congenital malformations
Bronchopulmonary Sequestrations
1 - Areas of lung without normal connection to airways
2 - Blood supply is from systemic arteries (no pulmonary arteries)
Extralobar
- external to lung
(thorax or mediastinum)
- may have other congenital anomalies
Intralobar
- within lung
- associated with recurrent local infection and/or bronchiectasis
most likely an acquired lesion
Respiratory Distress In The Newborn
Hyaline membrane disease most common (think of this with retraction during breathing)
Excessive maternal sedation
Fetal head injury
Blood or amniotic fluid aspiration
Intrauterine hypoxia from nuchal cord (umb cord wrapped tightly around neck)
Neonatal Respiratory Distress Syndrome
(Hyaline Membrane Disease)
Can occur in term infants, but most are preterm and have adequate growth for gestational age
Rate inversely proportional to gestational age
Associated with male sex, maternal diabetes mellitus, multiple gestation and C- section before onset of labor
- High levels of insulin inhibit secretion
- Glucocorticoids (stress) and thyroxine induce surfactant secretion
Immaturity of lungs!!
Deficiency of pulmonary surfactant
- The first breath of life requires a large inspiratory effort but once inflated the lungs remain ~ 40% inflated
- If inadequate surfactant, lungs collapse back and every breath is as hard as the first
Surfactant
Secreted by Type II pneumocytes
“Mature” levels at about 35 weeks gestation\
- Lecithin to Sphingomyelin ratio:
L/S ratio > 2 Lungs mature (except with some maternal diabetes)
less than 1 Lungs are immature
Methods to determine L/S: thin layer chromatography *
or fluorescence polarization, foam stability index, lamellar body count
lack of surfactant –>
increased surface tension–>
atelectasis –>
uneven perfusion and/or hypoventilation –>
hypoxemia and CO2 renention
–> acidosis–> pulmonary vasoconstriction –> pulmonary hypoperfusion –>
endothelial and epithelial damage –>
plasma leak into alveoli –>
fibrin and necrotic cells (* hyaline membrane)
–> increased diffusion gradient and worsening hypoxemia
Respiratory Distress Syndrome
Clinical Presentation
Preterm and AGA Male sex, maternal DM, C-section Low 1 minute Apgar score May need resuscitation Then may do well for short time (less than 1 hour) Become cyanotic Fine pulmonary rales (crackles) Reticulonodular/ground glass chest x-ray Oxygen therapy needed Death or recovery in 3 – 4 days
Not seen in stillborns (need to exude protein rich fluid into alveolar space to make a hyaline membrane)
Respiratory Distress Syndrome
Clinical Course
Outlook much more favorable today
Administration of surfactant (less than 28 weeks)
Antenatal treatment with steroids (24-34 weeks)
Monitor amniotic fluid surfactant for lung maturity
Death now unusual
Recovery begins at about 4 days
Therapy with O2 carries risks
– Retinopathy of prematurity
– Bronchopulmonary dysplasia
Bronchopulmonary Dysplasia
> 28 days of O2 therapy in infant > 36 weeks post-menstrual age
Now infrequent in infants >1200g and 30 weeks
Gentler ventilation, steroids, and surfactant therapy reduced rates
Mild, moderate, or severe based on need for positive pressure O2 therapy
Alveolar hypoplasia & thickened walls
O2 thought to decrease lung maturation
Dysmorphic capillaries and decreased VEGF
Cytokines (TNF, Il-8, etc) increased and may have a role
Developmental arrest at saccular stage
alveolar developmental stages
20 Weeks - glandular
32 weeks - saccular
Full term - alveolar
Cystic Fibrosis
(Mucoviscidosis)
Widespread disorder in epithelial transport affecting fluid secretion in exocrine glands and the epithelial lining of the respiratory, gastrointestinal, and reproductive tracts
Autosomal recessive transmission
Primarily due to abnormal function of an epithelial chloride channel protein encoded by the cystic fibrosis transmembrane conductance regulator (CFTR) gene
Diagnostic Criteria for Cystic Fibrosis
One or more characteristic phenotypic features
Or A history of cystic fibrosis in a sibling
Or A positive newborn screening test result
AND
An increased sweat chloride concentration on two or more occasions
Or Identification of two cystic fibrosis (CFTR) mutations
Or Demonstration of abnormal epithelial nasal ion transport
