Atlas of Neonatal Pathology: Bronchopulmonary dysplasia (BPD)

+ Introduction

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+ Neonatal pathology

Bronchopulmonary dysplasia (BPD)

Introduction

BPD is a chronic lung disease that occurs in infants who received respiratory support with mechanical ventilation and prolonged oxygenation. It is seen in babies recovering form respiratory distress syndrome, sepsis or prolonged apnea and most babies who develop BPD nowadays have birthweights below 1000 g. BPD is defined as receiving supplemental oxygen or ventilatory support at 36 weeks of postmenstrual age.

Clinical signs

there is delayed resolution of RDS
classified as mild, moderate or severe depending on the need for supplemental oxygen and positive pressure ventilation
most patients with BPD survive
increased risk for repated and serious pulmonary infections and asthma during childhood
poor growth and psychomotoric delay is a frequent problem
severe BPD is complicated by cor pulmonale and secondary pulmonary hypertension

Etiology

extreme lung immaturity
hyperoxia injury
barotrauma
patent ductus arteriosus
fluid overload
fetal inflammatory response — antenatal exposure to proinflammatory cytokines as found in choriamnionitis or funisitis effects pulmonary developement and contributes to the developement of BPD. There is also strong association of BPD and postnatal sepsis.

Macroscopic appearance

Classic BPD

Originally described in 1967 as severe lung injury caused by oxygen toxicity and barotrauma with prolonged aggresive ventilation in the treatment of RDS. Its etiopathogenesis was abnormal reparative process in response to injury and inflammation. There was a progress from an acute exsudative phase of acinar injury to reparative and chronic fibroproliferative phase. The histopathologic findings originally reported were airway epithelial lesions, smooth muscular hyperplasia, extensive peribronchiolar and instersticial fibrosis, focal hemorrhage, areas of overdistension and atelectasis and hypertensive vascular disease.

New BPD

In recent years with gentler ventilation techniques, antental glucocoricoid therapy and surfactant therapy the histologic changes seen in infants differ.New BPD is characterised by decrease in alveolar number (enlarged simplified alveoli), abnormal microvasculature and intersticium with less prominent celularity and fibroproliferation. The current view is that new BPD is caused by interruption of normal developemental pathways for terminal maturation and alveolarization of lungs of very preterm infants. The maximum rate of accretion of alveoli is seen in a period from 25 weeks to 4 months after birth.

Pictures

Classic bronchopulmonary dysplasia in infant aged 3 months. Premature birth at 29 weeks with birth weight 970 g. The baby was dependent on ventilatory support from birth. Premature rupture of membranes which occured at 23 week's gestation was a significant risk factor as well as several episodes of sepsis. Death from pneumonia. Bronchopulmonary dysplasia, Macro, autopsy (73786)

Bronchopulmonary dysplasia in 11-week old infant. Premature birth at 26 weeks with birth weight 1100 g. The baby suffered from early onset neonatal sepsis, (Streptococcus agalactiae), RDS, repeated episodes of late sepsis and was operated on necrotizing enterocolitis. Death due to massive intracranial hemorrhage. Bronchopulmonary dysplasia, Macro, autopsy (73785)

Bronchopulmonary dysplasia: Bronchopulmonary dysplasia, Macro, autopsy (74363)