Hypoplasia

A developmental disorder of the lungs

Overview

Pulmonary hypoplasia in a newborn

Pulmonary hypoplasia is a developmental disorder characterized by incomplete development of the lungs. It results in a reduced number of alveoli and bronchioles, leading to impaired respiratory function. This condition can occur as an isolated anomaly or as part of a syndrome involving other organ systems.

Etiology

Pulmonary hypoplasia can be caused by a variety of factors that restrict lung growth during fetal development. These include:

• Oligohydramnios, a condition where there is insufficient amniotic fluid surrounding the fetus, often due to renal agenesis or premature rupture of membranes.
• Congenital diaphragmatic hernia, where abdominal organs herniate into the thoracic cavity, compressing the developing lungs.
• Skeletal dysplasias that restrict thoracic cavity size, such as thanatophoric dysplasia.
• Chromosomal abnormalities and genetic syndromes, such as trisomy 18 and trisomy 21.

Pathophysiology

The pathophysiology of pulmonary hypoplasia involves a reduction in the number of airway branches and alveoli, leading to decreased lung volume and surface area for gas exchange. This results in respiratory insufficiency and can lead to neonatal respiratory distress syndrome.

Clinical Presentation

Infants with pulmonary hypoplasia often present with:

• Tachypnea and cyanosis shortly after birth.
• Poor oxygenation and ventilation requiring respiratory support.
• Associated anomalies depending on the underlying cause, such as renal anomalies or skeletal deformities.

Diagnosis

Diagnosis of pulmonary hypoplasia is typically made through:

• Prenatal ultrasound showing reduced lung size or associated anomalies.
• Postnatal imaging, such as chest X-ray or CT scan, revealing small lung volumes.
• Histopathological examination of lung tissue, if available, showing reduced alveolar development.

Management

Management of pulmonary hypoplasia focuses on supportive care and addressing the underlying cause. This may include:

• Mechanical ventilation and oxygen therapy to support breathing.
• Surgical correction of associated anomalies, such as repair of a congenital diaphragmatic hernia.
• Long-term follow-up for chronic lung disease and associated conditions.

Prognosis

The prognosis of pulmonary hypoplasia varies depending on the severity of the lung underdevelopment and the presence of other anomalies. Isolated cases with mild hypoplasia may have a better outcome, while severe cases or those associated with other significant anomalies may have a poor prognosis.

Related pages

• Congenital diaphragmatic hernia
• Oligohydramnios
• Neonatal respiratory distress syndrome