Differentials
Transient tachypnea of the newborn
SIGNS / SYMPTOMS
May be seen in infants of any gestational age. History of maternal diabetes may be present. Most infants of diabetic mothers are macrosomic. Tachypnea is the main feature with no hypoxia or cyanosis. History of meconium-stained amniotic fluid may or may not be present.
INVESTIGATIONS
CXR is the most important distinguishing test. Findings include perihilar markings and presence of fluid in the transverse fissure on the right side (sail sign). Absence of atelectasis.
ABG measurement shows no evidence of hypoxemia or acidosis.
Surfactant deficiency
SIGNS / SYMPTOMS
Respiratory distress secondary to surfactant deficiency is more common in preterm and late preterm infants. A variant of surfactant protein B deficiency may be present as severe respiratory distress in late preterm and term infants, leading to typical clinical presentation of respiratory distress syndrome/hyaline membrane disease; absence of history of meconium-stained amniotic fluid.
INVESTIGATIONS
Demonstration of absence of surfactant protein B deficiency by molecular testing.
ABG measurement shows severe hypoxemia and acidosis.
CXR is indistinguishable from MAS.
Persistent pulmonary hypertension
SIGNS / SYMPTOMS
May be present in association with MAS. Characterized by elevated pulmonary vascular resistance, resulting in right-to-left shunting of blood and hypoxemia.[52]
INVESTIGATIONS
Pulse oximetry demonstrates differential oxygenation between preductal and postductal sites with low oxygen saturation as measured by pulse oximetry. A difference of >5% to 10% in saturation or PaO₂ differences of 10 to 20 mmHg between right upper limb and lower limbs are considered significant. In neonates with persistent pulmonary hypertension (PPHN) and atrial level right-to-left shunting without a significant ductal shunt, saturations will be low in both right arm and right leg.[52] Hypoxemia is often labile.
CXR may show no severe parenchymal disease.
Echocardiography reveals tricuspid regurgitation, elevated pulmonary artery pressure, and right-to-left shunt through patent ductus arteriosus and patent foramen ovale.
Cyanotic congenital heart disease
SIGNS / SYMPTOMS
Infants are usually term. Minimal respiratory disease but severe cyanosis that does not respond to giving 100% oxygen. No history of meconium-stained amniotic fluid or birth asphyxia.
INVESTIGATIONS
Echocardiography helps to establish the correct diagnosis of cyanotic heart disease in the newborn.
Lung hypoplasia
SIGNS / SYMPTOMS
History of chronic leakage of amniotic fluid and oligohydramnios; history of difficult resuscitation in the delivery room. Severe hypoxemia is present. There may be a history of meconium-stained amniotic fluid with thick or thin meconium.
INVESTIGATIONS
CXR shows small lung volumes.
ABG measurement shows severe hypoxemia.
Echocardiography shows absence of congenital cyanotic heart disease and presence of severe persistent pulmonary hypertension.
B streptococcus infection/pneumonia
SIGNS / SYMPTOMS
History of B streptococcus sepsis in a sibling or positive B streptococcus culture in the mother before delivery without intrapartum antibiotics; history of prolonged rupture of membranes. It is usually associated with hypotension. Signs of shock may be present.
INVESTIGATIONS
CBC findings include severe leukopenia and thrombocytopenia.
ABG shows persistent metabolic acidosis.
Blood culture is positive for B streptococcus infections.
Amniotic fluid aspiration
SIGNS / SYMPTOMS
Aspiration of amniotic fluid before birth with hypoxia or asphyxia. No differentiating signs or symptoms.
INVESTIGATIONS
Diagnosis is by history, clinical observation, and a positive blood culture for infection.
Blood aspiration
SIGNS / SYMPTOMS
Stomach contents may be aspirated during vaginal or cesarean birth. Occurs at birth in the presence of placental abruption or placenta previa.
No differentiating signs or symptoms.
INVESTIGATIONS
Diagnosis is by history, clinical observation, and a positive blood culture for infection.
Aspiration pneumonia
SIGNS / SYMPTOMS
Usually occurs after birth and involves aspiration of gastric contents. It can occur with gastroesophageal reflux or swallowing dysfunction.
No differentiating signs or symptoms.
INVESTIGATIONS
Diagnosis is by history, clinical observation, and a positive blood culture for infection.
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