What investigation is typically conducted to rule out other causes of respiratory distress in cases of IRDS?

In cases of infant respiratory distress syndrome (IRDS), a chest X-ray is a common investigation performed to rule out other causes of respiratory distress. The chest X-ray provides crucial information about the lung structures and can help identify conditions such as pneumonia, pneumothorax, or congenital anomalies that may present with similar respiratory distress symptoms.

IRDS is typically characterized by the presence of neonatal atelectasis and lung opacities due to surfactant deficiency. The X-ray findings in IRDS often show a "ground-glass" appearance of the lungs, which is indicative of the condition. This imaging modality is readily available, fast, and non-invasive, making it an appropriate choice for initial assessment.

Other investigations, such as a CT scan, while providing detailed images, involve higher radiation exposure and are not usually required for immediate assessment in neonates. Ultrasound has limited utility for evaluating respiratory distress directly in this context, and blood tests would not provide the necessary visual information about the lungs to rule out anatomical or structural problems. Hence, the use of a chest X-ray is essential in quickly assessing and ruling out alternative diagnoses in cases of respiratory distress in newborns.