Neonatal respiratory distress syndrome, also known as hyaline membrane disease, is a condition due to insufficient surfactant synthesis and secretion, that characterizes prematurely born infants. Consequences such as atelectasis, abnormal ventilation-perfusion ratio, decreased oxygenation with consecutive hypoxia and acidosis are seen.
Neonatal respiratory distress syndrome (NRDS) more frequently affects the Caucasian boys, especially born to diabetic mothers by cesarean section, second born twins and children with a positive family history. On the other hand, maternal hypertension, antenatal steroid administration and prolonged membrane rupture seem to act as protective factors. Keeping this in mind, mothers should be counseled upon discharge in case they ever want to have another child.
The more prematurely the baby is born, the higher the chances of suffering from this ailment are. However, late prematurity is also associated with this disease . The problem becomes apparent soon after birth, progressively worsens and its signs consist of tachypnea, increased respiratory effort with intercostal, suprasternal and substernal retractions, flaring of the nasal alae, expiratory grunting and cyanosis. In extreme situations, irregular breathing, apnea, and hypothermia are encountered. The consciousness state may be diminished and severe fatigability may be reported. In advanced cases, the patient requires ventilatory support and intensive care  .
The surfactant deficiency may be secondary to several pathological processes, such as infectious or meconium aspiration pneumonia or pulmonary hemorrhage, intrapartum asphyxia, pulmonary hypoplasia or oxygen toxicity. Furthermore, the newborn may have other associated diseases, such as congenital diaphragmatic hernia, necrotizing enterocolitis or patent ductus arteriosus.
An amniocentesis is able to predict if NRDS will occur after birth, based on the lecithin-to-sphingomyelin ratio the presence of phosphatidylglycerol in the amniotic fluid. If these tests are not available, birth is in progress at the time the mother comes to the hospital or fetal distress is seen and childbirth is required, the diagnosis is made after the delivery is done.
Once respiratory distress is noticed, the physician should determine its severity and arterial blood gases offer a good measurement tool. Central (umbilical) or peripheral arterial blood should be analyzed  and may show hypoxemia, hypercapnia and respiratory (caused by alveolar atelectasis) and metabolic (due to lactic acid accumulation) acidosis. If a congenital right to left shunt heart malformation coexists, hypoxia will be severe and the child is likely to be cyanotic. A patent ductus arteriosus can have the same results. Blood workup should include a blood glucose level, that is often low, a complete cell count, bilirubin level, renal and liver function and electrolytes.
Oxygenation may also be monitored using a less invasive method, pulse oximetry. Probes should be placed on the right wrist or palm in order to establish the preductal saturation and on either foot for postductal saturation. Saturation should be kept at 91-95% . This is a good screening technique for congenital heart disease, but the diagnosis should finally be evaluated by echocardiography in selected cases.
A thoracic radiography is done in order to observe the pulmonary aspect. Pleural effusion, atelectasis or air bronchograms, interstitial emphysema, pneumothorax, bronchogenic cyst or pulmonary sequestration may be described by this exam. Cardiomegaly is often found and further characterization by echocardiography is required. Doppler echocardiography is reliable in determining if pulmonary hypertension is present. Hyperinflation (in a non-ventilated patient) or a normal aspect at 6 hours of age exclude the NRDS.
Pulmonary ultrasonography may be a reliable method   that visualizes the existing pleural effusions . However, pneumothorax is harder to find by lung ultrasonography .
In situations where the outcome is unfavorable, a histology evaluation will describe the presence of hyaline membranes - an amorphous material, lining the alveolar spaces, collapsed alveoli alternating with hyper aerated ones and vascular congestion.