Upper airways: children vs. adults
- 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)
Extrathoracic airway obstruction: dangerous signs
- usually presents with barking cough and stridor
- "4 Ds":
- dyspnea
- drooling
- dysphagia
- distress
Mild upper airway diseases + characteristics
- 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
- seen w/in first 6 weeks
- parainfluenza virus
- edema in subglottic space
- low-grade/absent fever
- neck image = steeple sign
- tx: supportive + sometimes: nebulized epinephrine, glucocoritcoids
Severe upper airway diseases + characteristics
- 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
- cause: usually H. influenzae
- supraglottic inflammation
- sudden onset high fever
- 4 Ds
- Tx: intubation + IV antibiotics
- cause: usually Staph aureus
- mucosal invasion of bacteria
- initially ~viral croup but w/out improvement ==> higher fever, toxicity
- Tx: intubation + suctioning secretions + IV antibiotics
Pediatric vs. Adult lower airway
-
Airways are smaller and the cross sectional area is lower
-
Infant chest walls have:
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Weak intercostal muscles
-
Ribs are horizontal (not slanted like in adults). This means that infants rely mostly on their diaphragm for increased tidal volume.
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Diaphragm is flat limiting the change in tidal volume and fatigues easily
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
Congenital disorders or intrathoracic airway obstruction
-
Tracheomalacia and bronchomalacia
-
Tracheoesophageal fistula
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Vascular Rings, Pulmonary slings, and other vascular anomalies that can cause airway compression
Tracheomalacia and bronchomalacia
Tracheoesophageal fistula
Vascular Rings, Pulmonary slings, and other vascular anomalies that can cause airway compression
Common acquired causes of intrathoracic airway obstruction
- bronchiolitis
- asthma
Bronchiolitis characteristics/dx/tx
- =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
Asthma characteristics/dx/tx
- 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
Bronchopulmonary dysplasia general characteristics + typical features
- 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.
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Required oxygen therapy or mechanical ventilation, with persistent oxygen requirement at 36 weeks gestational age or 28 days of life.
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Persistent respiratory abnormalities, including physical signs and radiographic findings.
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.
Pathogenesis of BPD
- 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
Risk factors for development of BPD
- pre-term infants
- full term w/: meconium aspiration, diaphragmatic hernia, pulmonary HTN
- prolonged ventilator support
BPD clinical course/prognosis
- 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
BPD sequelae/resulting conditions
-
persisent hypoxemia
-
airway hyperreactivity
-
exercise intolerance
-
pulmonary HTN
-
increased risk for COPD
- abnormal lung growth
- abnormal neurodevelopmental abnormalities
persisent hypoxemia
airway hyperreactivity
exercise intolerance
pulmonary HTN
increased risk for COPD
