Infant respiratory distress syndrome

Overview

Infant respiratory distress syndrome (IRDS), also known as neonatal respiratory distress syndrome or hyaline membrane disease, is a serious condition that affects premature newborns. It occurs due to insufficient production of surfactant—a substance that helps keep the lungs inflated—leading to collapsed air sacs (alveoli), impaired gas exchange, and breathing difficulties. IRDS most commonly affects babies born before 37 weeks of gestation and is a leading cause of morbidity and mortality in preterm infants.

Causes

The primary cause of infant respiratory distress syndrome is a deficiency of surfactant in the lungs. Surfactant is a lipoprotein substance produced by type II alveolar cells that reduces surface tension within the alveoli, preventing their collapse during exhalation. Contributing factors include:

• Prematurity: The most significant risk factor. Surfactant production typically begins around the 24th week of gestation and reaches adequate levels by 34–36 weeks.

• Maternal diabetes: Can delay fetal lung maturation and surfactant synthesis.

• Cesarean delivery without labor: May result in less hormonal stimulation for lung development.

• Perinatal asphyxia: Oxygen deprivation around the time of birth can impair surfactant production and lung function.

• Multiple births: Twins or higher-order multiples are at higher risk due to common prematurity.

Symptoms

Symptoms of IRDS usually appear within minutes to a few hours after birth and may include:

• Rapid, shallow breathing (tachypnea)

• Grunting: A sound made during exhalation to help keep air in the lungs.

• Nasal flaring: Widening of the nostrils during breathing as a sign of respiratory effort.

• Chest retractions: Visible pulling in of the chest muscles with each breath.

• Cyanosis: Bluish coloration of the skin or lips due to low oxygen levels.

• Lethargy or poor feeding

Diagnosis

Diagnosis of infant respiratory distress syndrome is based on clinical presentation and supported by laboratory and imaging tests:

• Physical examination: Observation of breathing difficulty, cyanosis, and abnormal chest movements.

• Chest X-ray: Shows a characteristic “ground-glass” appearance and air bronchograms consistent with underinflated lungs.

• Blood gas analysis: Reveals low oxygen (hypoxemia) and elevated carbon dioxide (hypercapnia) levels.

• Prenatal history: Premature birth and known risk factors support the diagnosis.

Treatment

Treatment of IRDS focuses on supporting breathing and improving oxygenation until the baby’s lungs mature and produce sufficient surfactant:

• Surfactant replacement therapy: Surfactant is administered directly into the lungs via an endotracheal tube shortly after birth or once symptoms appear.

• Oxygen therapy: Supplemental oxygen is provided via nasal cannula or hood to maintain adequate oxygen levels.

• Continuous Positive Airway Pressure (CPAP): Helps keep the airways open and improve lung expansion.

• Mechanical ventilation: Required in more severe cases where the infant cannot breathe adequately on their own.

• Supportive care: Includes fluid management, temperature regulation, and nutritional support in a neonatal intensive care unit (NICU).

• Antenatal corticosteroids: In cases of anticipated preterm delivery, corticosteroids given to the mother before birth can accelerate fetal lung development and reduce the risk of IRDS.

Prognosis

The prognosis for infants with respiratory distress syndrome has improved significantly with advances in neonatal care and surfactant therapy. Most infants recover fully with timely and appropriate treatment. However, complications can occur, particularly in very premature infants, including:

• Bronchopulmonary dysplasia (BPD): A chronic lung condition resulting from prolonged mechanical ventilation and oxygen therapy.

• Intraventricular hemorrhage: Bleeding in the brain due to fragile blood vessels in premature infants.

• Retinopathy of prematurity: Abnormal blood vessel growth in the eyes, potentially leading to vision problems.

With early detection, surfactant therapy, and supportive NICU care, the majority of infants with IRDS can survive and thrive, although close follow-up is necessary to monitor for developmental and respiratory complications.