Overview
Definition:
Bronchopulmonary dysplasia (BPD) is a chronic lung disease that develops in premature infants as a result of lung injury from mechanical ventilation and oxygen therapy
It is characterized by inflammation and scarring in the lungs, leading to impaired gas exchange and persistent respiratory symptoms
The severity of BPD is graded based on the need for respiratory support at 36 weeks corrected gestational age.
Epidemiology:
BPD affects approximately 20-30% of infants born before 28 weeks gestation
The incidence is inversely proportional to gestational age and birth weight
Factors contributing to BPD include prematurity, prolonged mechanical ventilation, high oxygen concentrations, antenatal infections, chorioamnionitis, and maternal smoking.
Clinical Significance:
BPD is a major cause of morbidity and mortality in premature infants, leading to prolonged hospitalizations, increased risk of respiratory infections, neurodevelopmental delays, and impaired growth
Understanding its management is crucial for optimizing outcomes in this vulnerable population, a key aspect for DNB and NEET SS preparation.
Clinical Presentation
Symptoms:
Persistent tachypnea
Increased work of breathing (retractions, nasal flaring)
Wheezing
Grunting
Retractions
Intermittent cyanosis
Poor feeding leading to poor weight gain
Frequent lower respiratory tract infections.
Signs:
Crackles on auscultation
Diffuse wheezing
Intermittent hypoxemia
Hypercapnia
Failure to thrive
Chest X-ray showing hyperinflation, thickened bronchial walls, and cystic changes.
Diagnostic Criteria:
Diagnosis is primarily clinical and radiographic
The most common definition requires supplemental oxygen for at least 28 days of life and the presence of respiratory support at 36 weeks postmenstrual age, with specific criteria for oxygen requirement and the need for ventilatory support (nasal cannula, CPAP, or mechanical ventilation).
Diagnostic Approach
History Taking:
Gestational age at birth
Duration and type of mechanical ventilation
Oxygen requirements
History of antenatal infections
Maternal factors like smoking
Previous episodes of pneumonia or other respiratory issues.
Physical Examination:
Assessment of respiratory rate, effort, and oxygen saturation
Auscultation for adventitious sounds (crackles, wheezes)
Evaluation of growth parameters
Assessment for signs of fluid overload.
Investigations:
Chest X-ray: characteristic findings include hyperinflation, thickened airway walls, patchy infiltrates, and later, cystic changes
Arterial blood gas (ABG): to assess for hypoxemia and hypercapnia
Echocardiogram: to rule out pulmonary hypertension and congenital heart disease
Pulmonary function tests (PFTs): generally not feasible in infants but may be used in older children.
Differential Diagnosis:
Congenital heart disease (e.g., VSD, PDA)
Pneumonia
Meconium aspiration syndrome
Transient tachypnea of the newborn
Congenital lung malformations (e.g., CCAM)
Gastroesophageal reflux disease causing aspiration.
Management
Initial Management:
Minimize lung injury: use of appropriate ventilator settings (low tidal volumes, appropriate PEEP)
Adequate hydration and nutrition
Bronchodilator therapy (e.g., albuterol) may be considered for reversible bronchospasm, though efficacy is debated.
Medical Management:
Diuretics: often used to reduce pulmonary edema and improve lung compliance
Common agents include furosemide and hydrochlorothiazide, administered orally or intravenously
Growth Optimization: focus on adequate caloric intake through enteral feeding, often supplemented with nasogastric or orogastric tubes, and consider high-calorie formulas or parenteral nutrition if oral intake is insufficient
Vitamin D supplementation is important
Hormonal therapy (e.g., recombinant human growth hormone) is generally not recommended for routine BPD management but may be considered in select cases of severe growth failure under specialist guidance.
Supportive Care:
Strict fluid management to prevent overload
Respiratory support: ranging from supplemental oxygen to non-invasive ventilation (CPAP, BiPAP) or mechanical ventilation as needed
Chest physiotherapy
Immunizations (especially RSV prophylaxis with palivizumab)
Nutritional support to promote catch-up growth
Close monitoring of respiratory status and oxygen saturation.
Surfactant Therapy:
Administered in the early neonatal period for infants with respiratory distress syndrome (RDS) to prevent lung injury that can lead to BPD
It is not a direct treatment for established BPD but is crucial in its prevention.
Complications
Early Complications:
Pneumothorax
Bronchiolitis
Pneumonia
Pulmonary hypertension
Fluid overload.
Late Complications:
Chronic respiratory failure
Recurrent lower respiratory tract infections
Pulmonary hypertension
Failure to thrive
Neurodevelopmental impairments
Hearing and vision deficits
Gastroesophageal reflux
Increased risk of asthma in later childhood.
Prevention Strategies:
Minimizing exposure to high oxygen concentrations and mechanical ventilation
Use of non-invasive respiratory support when possible
Antenatal corticosteroids
Avoiding maternal smoking
Prompt treatment of chorioamnionitis
Early surfactant administration.
Prognosis
Factors Affecting Prognosis:
Gestational age at birth
Severity of BPD at diagnosis
Presence of comorbidities (e.g., cardiac anomalies, neurological deficits)
Response to therapy
Adequacy of nutritional support.
Outcomes:
Prognosis varies widely
Mild BPD often resolves with minimal long-term sequelae
Severe BPD can lead to chronic respiratory insufficiency requiring ongoing medical support
Many survivors experience improved respiratory status over time but may have persistent limitations.
Follow Up:
Regular follow-up with pulmonologists, cardiologists, and developmental pediatricians is essential
This includes monitoring respiratory status, growth, neurodevelopment, and managing recurrent infections
Pulmonary function tests may be used for older children to assess lung function.
Key Points
Exam Focus:
The debate between diuretics and growth optimization in BPD management is a critical area
Diuretics aim to reduce lung fluid and improve compliance, while growth optimization focuses on supporting overall infant development and lung repair
Evidence supporting routine diuretic use is mixed, with a trend towards more judicious use
Growth optimization is universally accepted as crucial.
Clinical Pearls:
When considering diuretics for BPD, assess for signs of fluid overload and response
Discontinue if no clear benefit is observed
Aggressive nutritional support is paramount
focus on achieving appropriate caloric intake to support lung healing and growth
Consider RSV prophylaxis in infants with BPD.
Common Mistakes:
Over-reliance on diuretics without clear indications
Underestimating the importance of nutritional support for recovery
Inadequate follow-up care for infants with BPD, leading to missed opportunities for intervention
Failing to consider differential diagnoses when respiratory symptoms persist.