Pediatric Pulmonary System

Key Differences: Smaller airways, fewer alveoli, more compliant chest wall, higher oxygen demands, immature immune systems.
Larynx: More anterior and superior in children.
Tongue: Larger in proportion to mouth in children.
Epiglottis: Floppier, U-shaped in children.
Vocal Cords: Upward slant in children.
Cricoid: Narrowest part of child's airway.
Trachea: Narrow and less rigid in children.
Lungs: Less capacity in children.

Definition: Lipoprotein made by lung cells.
Function: Reduces surface tension in alveoli, prevents lung collapse (atelectasis).
Production: Starts around 20-24 weeks gestation, usually adequate by 35-37 weeks.
Premature Infants (born before 34 weeks): Insufficient surfactant leads to Respiratory Distress Syndrome (RDS), atelectasis, and respiratory failure.

Also Known As: Chronic lung disease of prematurity.
Causes/Risk Factors: Premature infants (<32 weeks gestation), lung injury from mechanical ventilation, high oxygen exposure, lung infections (e.g., pneumonia) or sepsis.
Pathophysiology: Immature lungs damaged by oxygen/pressure → inflammation and fluid buildup → impaired alveolar development (fewer, larger alveoli) → poor gas exchange, lung stiffness, scarring.
Clinical Signs: Rapid breathing, retractions, wheezing, oxygen dependence past 28 days of life, poor feeding/growth.

Cause: Viral infection, most often RSV (Respiratory Syncytial Virus), common in infants under 2 years (<6 months).
Transmission: Respiratory droplets.
Risk Factors: Prematurity, chronic lung/heart disease, exposure to smoke.
Pathophysiology: Virus infects bronchioles → inflammation, swelling, mucus buildup → air trapping (difficulty exhaling).
Clinical Signs: Initally runny nose, mild cough, fever; progresses to wheezing, tachypnea, retractions, poor feeding; severe cases: apnea, cyanosis.

Cause: Most often parainfluenza virus.
Pathophysiology: Viral infection → inflammation and swelling of larynx, trachea, and sometimes bronchi → narrowed airway.
Age Group: Common in children 6 months to 3 years.
Classic Sign: Barking cough (seal-like), inspiratory stridor, worse at night.

Cause: Haemophilus influenzae type B (Hib).
Pathophysiology: Bacterial infection → rapid swelling of the epiglottis.
Age Group: Typically seen in older children (2-7 years).
Emergency: Can cause sudden airway obstruction.
Signs: High fever, drooling, difficulty swallowing, tripod position, muffled voice.

Cause: Often polymicrobial (e.g., Group A Strep, Staph aureus, anaerobes).
Pathophysiology: Infection spreads from tonsil → pus collects in peritonsillar space.

Definition: Genetic disease caused by mutations in the CFTR gene, affecting exocrine glands (lungs, pancreas, digestive system).
Respiratory Pathophysiology: Defective CFTR protein creates thick, sticky mucus in lungs → blocks airways, traps bacteria → recurrent infections, chronic inflammation, lung damage, respiratory failure.
Other Effects: Pancreatic enzyme deficiency (malabsorption), salty skin.
Symptoms: Persistent cough, frequent lung infections, poor weight gain, greasy stools.

Definition: Unexplained death of an apparently healthy infant under 1 year old, usually during sleep.
Prevention (ABC): Alone, Back, Crib.