Bronchopulmonary Dysplasia (BPD) is a chronic lung condition that primarily affects premature infants. It develops when a baby’s lungs, which are still developing, become damaged after birth. This damage can lead to long-term breathing problems, making BPD a significant concern for families of preterm babies. While it is a serious condition, advancements in medical care have improved the outlook for many affected infants.
What is Bronchopulmonary Dysplasia?
BPD differs from acute respiratory distress in newborns because it involves ongoing damage and abnormal development of the lungs, rather than a temporary breathing issue. The condition usually manifests within the first four weeks after birth, affecting an estimated 10,000 to 15,000 babies in the United States annually. The disease can disrupt the normal formation of lung architecture, leading to fewer and larger air sacs (alveoli) and thickened tissue in between (interstitium). Additionally, the tiny blood vessels surrounding the alveoli may develop abnormally or be fewer in number, which can increase resistance in the pulmonary system and potentially lead to pulmonary hypertension. This abnormal lung development contributes to the breathing difficulties experienced by infants with BPD.
Causes and Risk Factors
Prematurity is the most significant risk factor for developing BPD, particularly for infants born more than two months early or weighing less than 2.2 pounds. Their underdeveloped lungs are more susceptible to inflammation and injury.
Mechanical ventilation, often necessary for these fragile infants, can contribute to BPD. The pressure and volume of air delivered by a ventilator can overstretch the delicate air sacs, causing inflammation and damage to lung tissue over time.
Supplemental oxygen therapy, while life-saving, also injures the underdeveloped lungs, especially when administered at high concentrations. Oxidative stress can lead to scarring and impaired lung growth.
Inflammation and infections, such as pneumonia or sepsis, worsen lung damage and increase BPD risk. Prenatal factors like lack of antenatal steroids, maternal smoking, or maternal infections (e.g., chorioamnionitis) are also associated with an increased risk.
Genetic predispositions can make some infants more vulnerable. The persistence of a patent ductus arteriosus (PDA), a blood vessel that normally closes shortly after birth, is also a risk factor. If the PDA remains open, it can lead to fluid overload in the lungs, contributing to inflammation and hindering lung development. Intermittent hypoxemia, or repeated drops in oxygen levels, is also linked to increased BPD risk with pulmonary hypertension.
Symptoms and Diagnosis
Infants with BPD often exhibit signs of respiratory distress. Symptoms include persistent rapid breathing (tachypnea) and visible retractions, where the skin pulls in between the ribs or at the base of the neck during inhalation. Wheezing, a soft whistling sound during exhalation, and a bluish discoloration around the mouth or lips (cyanosis) may also be present. Infants may also experience difficulty feeding and poor weight gain due to increased energy expenditure from breathing.
Diagnosis of BPD relies on a combination of clinical presentation and specific criteria related to oxygen dependence. A common diagnostic benchmark is the continued need for supplemental oxygen at 28 days of life, or at 36 weeks postmenstrual age for infants born before 32 weeks gestation. The severity of BPD is often graded based on the level of respiratory support required at these time points.
Diagnosis is confirmed through various methods. Chest X-rays can reveal characteristic changes in the lungs, such as a spongy appearance or hyperinflation. Blood gas analysis assesses oxygen and carbon dioxide levels. An echocardiogram, an ultrasound of the heart, is often performed to rule out underlying heart defects that could contribute to breathing issues.
Management and Outlook
BPD management focuses on supporting lung function and healthy development. Respiratory support is a primary component, including mechanical ventilation for severe cases, continuous positive airway pressure (CPAP), or supplemental oxygen. The goal is to gradually wean infants off support as their lungs mature.
Medications address specific symptoms. Diuretics remove excess fluid, bronchodilators relax airways, steroids reduce inflammation, and caffeine stimulates breathing. High-calorie nutritional support helps infants meet increased energy demands for growth and breathing.
Infection prevention is important, involving strict hygiene and timely vaccinations against respiratory illnesses like RSV and influenza. Physical therapy assists with motor development, which may be delayed due to prolonged hospitalization.
The outlook for infants with BPD varies. Many show improved lung function as they grow, though some face ongoing challenges like increased susceptibility to respiratory infections and potential developmental delays. Despite these hurdles, many children with BPD lead fulfilling lives with ongoing medical follow-up.