Pediatric Lung Disease

Question 1

Upper airways: children vs. adults

Answer 1

• Child airway anatomy is smaller: 4mm vs. 8mm (adult)
• larynx is higher, more anterior
• epiglottis is floppy
• Cricoid is narrowest part of airway (just below vocal cords vs. adult is @ vocal cords)

Question 2

Extrathoracic airway obstruction: dangerous signs

Answer 2

• usually presents with barking cough and stridor
• “4 Ds”:
• dyspnea
• drooling
• dysphagia
• distress

Question 3

Mild upper airway diseases + characteristics

Answer 3

• laryngomalacia = congenital disorder; most common cause of persistent stridor (some variable severity)
  
  • seen w/in first 6 weeks
• Viral croup (some variable severity)
  
  • parainfluenza virus
  • edema in subglottic space
  • low-grade/absent fever
  • neck image = steeple sign
  • tx: supportive + sometimes: nebulized epinephrine, glucocoritcoids

Question 4

Severe upper airway diseases + characteristics

Answer 4

• Epiglottitis
  
  • cause: usually H. influenzae
  • supraglottic inflammation
  • sudden onset high fever
  • 4 Ds
  • Tx: intubation + IV antibiotics
• Bacterial Tracheitis
  
  • cause: usually Staph aureus
    
    • mucosal invasion of bacteria
  • initially ~viral croup but w/out improvement ==> higher fever, toxicity
  • Tx: intubation + suctioning secretions + IV antibiotics

Question 5

Pediatric vs. Adult lower airway

Answer 5

• Airways are smaller and the cross sectional area is lower
• Infant chest walls have:
  
  • Weak intercostal muscles
  • Ribs are horizontal (not slanted like in adults). This means that infants rely mostly on their diaphragm for increased tidal volume.
  • Diaphragm is flat limiting the change in tidal volume and fatigues easily

Question 6

Congenital disorders or intrathoracic airway obstruction

Answer 6

• Tracheomalacia and bronchomalacia
• Tracheoesophageal fistula
• Vascular Rings, Pulmonary slings, and other vascular anomalies that can cause airway compression

Question 7

Common acquired causes of intrathoracic airway obstruction

Answer 7

• bronchiolitis
• asthma

Question 8

Bronchiolitis characteristics/dx/tx

Answer 8

• =most common serious acute respiratory illness in infants/young children
• Characterized by acute onset tachypnea, labored breathing, and/or hypoxia.
• Irritability, poor feeding.
• Wheezing and crackles on chest auscultation.
• common cause: RSV (respiratory syncytial virus)
• Tx: prevention (hand-washing, monoclonal Ab in high-risk), supplemental O₂, some hospitalization

Question 9

Asthma characteristics/dx/tx

Answer 9

• Most common chronic pediatric condition
• Recurrent symptoms of airway obstruction: cough, shortness of breath, chest tightness, wheezing
• At least partial reversal of bronchospasm and symptom relief with a bronchodilator (e.g. a beta agonist such as albuterol)
• All other diagnoses ruled out
• cause: airway inflammation ==> increased mucous production, bronchial hyperreactivity, airway edema
• Dx usually clinical, occasionally PFTs
• Tx: inhaled beta-agonist; inhaled corticosteroids

Question 10

Bronchopulmonary dysplasia general characteristics + typical features

Answer 10

• BPD = most significant sequelae of acute respiratory distress @ NICU
• disorder characterized by decreased SA for gas exchange, reduced inflammation, dysmorphic vascular structure
• Acute respiratory distress in the first week of life.
• Required oxygen therapy or mechanical ventilation, with persistent oxygen requirement at 36 weeks gestational age or 28 days of life.
• Persistent respiratory abnormalities, including physical signs and radiographic findings.

Question 11

Pathogenesis of BPD

Answer 11

• premature lung rpduces insufficient functional surfactant + reduced antioxidant defense
• early inflammation and hypercellularity ==> fibrosis
• structural immaturity, surfactant deficiency, atelectasis, and pulmonary edema—as well as lung injury secondary to hyperoxia and mechanical ventilation—lead to further abnormalities of lung function

Question 12

Risk factors for development of BPD

Answer 12

• pre-term infants
• full term w/: meconium aspiration, diaphragmatic hernia, pulmonary HTN
• prolonged ventilator support

Question 13

BPD clinical course/prognosis

Answer 13

• variable course: mild increased O₂ requirement w/resolution ==> tracheostomy + mechanical ventilation X 2yrs
• generally favorable long-term outlook
• lung fxn may be altered for life

Question 14

BPD sequelae/resulting conditions

Answer 14

• persisent hypoxemia
• airway hyperreactivity
• exercise intolerance
• pulmonary HTN
• increased risk for COPD
• abnormal lung growth
• abnormal neurodevelopmental abnormalities