What is the differential diagnosis for congenital diaphragmatic hernia (CDH) in a newborn?

Differential Diagnosis for Congenital Diaphragmatic Hernia in Newborns

The primary differential diagnoses for congenital diaphragmatic hernia (CDH) in a newborn presenting with respiratory distress include persistent pulmonary hypertension of the newborn (PPHN), primary pulmonary hypoplasia, pneumothorax, meconium aspiration syndrome, neonatal pneumonia, and congenital cystic lung lesions.

Critical Distinguishing Features

Persistent Pulmonary Hypertension of the Newborn (PPHN)

• PPHN coexists with CDH in 63% of cases, making differentiation essential but challenging 1
• Chest radiography in isolated PPHN shows lung fields without abdominal viscera in the thorax, which is the key distinguishing feature from CDH 1
• Echocardiography is mandatory to evaluate pulmonary hypertension severity in both conditions, as mortality reaches 45% when present 1
• Both conditions present with severe respiratory distress and cyanosis, but the radiographic absence of bowel gas pattern in the chest rules out CDH 1

Primary Pulmonary Hypoplasia

• Presents with severe respiratory distress similar to CDH but radiography does not show abdominal viscera in the thorax 1
• Consider evaluation for developmental disorders including congenital surfactant deficiency or alveolar-capillary dysplasia when CDH is ruled out 1
• May be associated with oligohydramnios, renal anomalies, or prolonged rupture of membranes 2

Pneumothorax and Tension Pneumothorax

• Can mimic CDH with absent breath sounds, hyperresonance, and mediastinal shift 3, 4
• Chest radiograph shows air in the pleural space without bowel gas pattern or solid organ herniation 4
• Requires immediate needle decompression if tension physiology present, unlike CDH which requires stabilization before surgery 1

Meconium Aspiration Syndrome

• Presents with respiratory distress in term or post-term infants with history of meconium-stained amniotic fluid 5
• Chest radiograph shows patchy infiltrates and hyperinflation, not bowel loops in thorax 5
• May be complicated by surfactant inactivation and secondary PPHN 5

Neonatal Pneumonia/Sepsis

• Presents with respiratory distress, often with maternal risk factors (prolonged rupture of membranes, chorioamnionitis) 5
• Chest radiograph shows infiltrates or consolidation without herniated abdominal contents 5
• May be associated with surfactant inactivation requiring rescue therapy 5

Diagnostic Approach

Immediate Radiographic Evaluation

• Plain chest radiograph with nasogastric tube in place is the initial diagnostic step 6
• Look for bowel gas pattern in the hemithorax, mediastinal shift to contralateral side, and absence of normal diaphragmatic contour 6, 3
• The presence of a nasogastric tube curling up into the chest confirms CDH 6

Advanced Imaging

• CT scan of chest and abdomen is the gold standard for confirming CDH diagnosis 1
• CT allows evaluation of defect size, herniated organs, degree of pulmonary hypoplasia, and associated anomalies 1
• Lung ultrasound at point-of-care may provide rapid diagnosis showing partial absence of diaphragmatic profile, absence of pleural line, and presence of multi-layered hyperechoic contents (bowel) in the affected hemithorax 7

Essential Cardiac Evaluation

• Echocardiography is obligatory to evaluate associated pulmonary hypertension and congenital heart disease 1
• This evaluation is critical as it determines survival, with mortality reaching 45% when pulmonary hypertension is present 1

Additional Differential Considerations in Older Presentations

Diaphragmatic Eventration

• Represents incomplete diaphragmatic muscle development rather than a true hernia 8
• Left-sided predominance (81.5-85% of cases) similar to CDH 8
• Can be easily missed due to nonspecific radiographic findings 8

Congenital Cystic Lung Lesions

• Include congenital pulmonary airway malformation (CPAM) and bronchogenic cysts 4
• May present with respiratory distress but show cystic lucencies rather than bowel gas pattern on imaging 4

Common Diagnostic Pitfalls

• The most frequent misdiagnoses include pneumonia, massive pleuropneumonia, empyema, pneumothorax, and lung cysts 4
• These errors occur because clinicians fail to consider CDH in the differential, particularly in late presentations 4
• Right-sided CDH (15-19% of cases) is particularly challenging as the liver may create a solid appearance mimicking pleural effusion or consolidation 8, 1, 3
• Bilateral CDH is extremely rare but has been reported and carries very high mortality 3

Age-Specific Presentation Patterns

• Neonatal presentation (most common): severe respiratory distress immediately after birth or within first hours of life 2
• Late presentation (13-14% of cases): may present with chronic respiratory infections, gastrointestinal symptoms (vomiting, failure to thrive), or be completely asymptomatic 6, 3, 4
• Children presenting with gastrointestinal symptoms are significantly older than those with respiratory symptoms 4