Congenital diaphragmatic hernia (CDH) in the neonate: Clinical features and diagnosis

INTRODUCTION — Congenital diaphragmatic hernia (CDH) is a developmental defect of the diaphragm that allows abdominal viscera to herniate into the chest. Affected neonates usually present in the first few minutes to hours after birth with respiratory distress that can range from mild to life-threatening. With improvements in antenatal diagnosis and neonatal care, survival has improved. However, infants with CDH continue to have a considerable risk of mortality and morbidity.

The clinical manifestations and diagnosis of CDH in the newborn will be reviewed here. Related topics include:

●Pathogenesis, anatomy, prenatal detection, and prenatal management of CDH. (See "Congenital diaphragmatic hernia: Prenatal issues".)

●Postnatal management and outcome of CDH in the newborn. (See "Congenital diaphragmatic hernia (CDH) in the neonate: Management and outcome".)

PREVALENCE — Reported prevalence rates of CDH range from 2 to 3 cases per 10,000 live births [1,2]. It is more common in males than females, with a male-to-female ratio of 1.4 to 1 [2]. Approximately 5 to 10 percent of cases are associated with a chromosomal abnormality or genetic syndrome [2]. (See 'Associated conditions' below.)

PATHOGENESIS AND EMBRYOLOGY — CDH results from failure of normal closure of the pleuroperitoneal folds during the fourth to tenth weeks postfertilization, which allows herniation of viscera into the thoracic cavity. This interferes with normal lung development and has other adverse consequences. The reason for failure of normal diaphragmatic closure is not fully understood. The embryology, pathogenesis, and anatomy of CDH are discussed in greater detail separately. (See "Congenital diaphragmatic hernia: Prenatal issues", section on 'Pathogenesis' and "Congenital diaphragmatic hernia: Prenatal issues", section on 'Anatomic findings'.)

IMPACT ON CARDIOPULMONARY DEVELOPMENT — Because herniation occurs during a critical period of lung development, clinical manifestations of CDH result from the pathologic effects of the herniated viscera on lung development. With rising severity of lung compression, there are corresponding decreases in bronchial and pulmonary arterial branching, resulting in increasing degrees of pulmonary hypoplasia. Pulmonary hypoplasia is most severe on the ipsilateral side. However, pulmonary hypoplasia may develop on the contralateral side if the mediastinum shifts and compresses the lung. Arterial branching is reduced, resulting in muscular hyperplasia of the pulmonary arterial tree, which contributes to the increased risk of pulmonary hypertension (PH) [3].

In addition, hypoplasia of the left ventricle and other left heart structures (aortic valve, transverse aortic arch, aortic isthmus) contribute to adverse outcomes in CDH [4-7]. (See "Hypoplastic left heart syndrome: Anatomy, clinical features, and diagnosis".)

CLINICAL MANIFESTATIONS

Prenatal presentation — Many patients with CDH are identified through routine prenatal ultrasound. Prenatal ultrasound can also identify other associated anomalies (eg, cardiac abnormalities). Prenatal presentation and diagnosis are discussed in greater detail separately. (See "Congenital diaphragmatic hernia: Prenatal issues", section on 'Prenatal diagnosis'.)

Postnatal findings

Presentation — Postnatally, infants with CDH most often present with respiratory distress in the first few minutes after birth. Less commonly, a small subset of patients with CDH have minimal or no symptoms in the newborn period and present later in life. (See 'Late presentation' below.)

In patients who present as neonates, the degree of respiratory distress depends upon the severity of lung hypoplasia and the development of pulmonary hypertension (PH). Following delivery, hypoxemia, hypercarbia, and acidosis increase the risk of PH by inducing a reactive vasoconstrictive element to the preexisting fixed arterial muscular hyperplasia component. In some cases, pulmonary hypoplasia is so severe as to be incompatible with life. (See "Persistent pulmonary hypertension of the newborn (PPHN): Clinical features and diagnosis", section on 'Pathogenesis' and "Congenital diaphragmatic hernia (CDH) in the neonate: Management and outcome", section on 'Survival'.)

Physical findings — Physical findings in the newborn include a barrel-shaped chest, a scaphoid-appearing abdomen (because of loss of the abdominal contents into the chest), and absence of breath sounds on the ipsilateral side. In patients with a left-sided CDH, the heartbeat is displaced to the right because of a shift in the mediastinum.

Laterality — In most cases of CDH, herniation occurs on the left. Right-sided CDH occurs in approximately 15 percent of cases and bilateral herniation in 1 to 2 percent [8-10]. There may be a higher incidence of pulmonary complications associated with right- versus left-sided CDH [9]. Bilateral herniation is associated with a high mortality rate [10]. (See "Congenital diaphragmatic hernia (CDH) in the neonate: Management and outcome", section on 'Outcome'.)

Associated conditions — Associated congenital abnormalities are seen in approximately 50 percent of newborns with CDH. In some cases, the associated abnormalities are identified prenatally. However, in many cases, the full extent of associated abnormalities is not appreciated until after delivery. (See "Congenital diaphragmatic hernia: Prenatal issues", section on 'Associated fetal abnormalities'.)

●Congenital heart disease – Congenital heart disease is the most common type of associated congenital abnormality in infants with CDH [11-13]. In a meta-analysis of 51 observational studies including >15,000 newborns with CDH, 17 percent of patients had associated congenital heart disease [12]. The most common defects were:

•Ventricular septal defects (accounting for 24 percent of all congenital heart defects in these reports) (see "Isolated ventricular septal defects (VSDs) in infants and children: Anatomy, clinical features, and diagnosis")

•Atrial septal defects (21 percent) (see "Isolated atrial septal defects (ASDs) in children: Classification, clinical features, and diagnosis")

•Single-ventricle defects, including hypoplastic left heart syndrome (12 percent) (see "Hypoplastic left heart syndrome: Anatomy, clinical features, and diagnosis")

•Coarctation of the aorta (9 percent) (see "Clinical manifestations and diagnosis of coarctation of the aorta")

•Tetralogy of Fallot (5 percent) (see "Tetralogy of Fallot (TOF): Pathophysiology, clinical features, and diagnosis")

Because of the strong association between CDH and congenital heart disease, all newborns with CDH should undergo postnatal echocardiography. (See 'Echocardiography' below.)

●Noncardiac abnormalities – A wide range of noncardiac abnormalities can be seen in newborns with CDH, including [14]:

•Neural tube defects (see "Neural tube defects: Overview of prenatal screening, evaluation, and pregnancy management")

•Central nervous system malformations (eg, agenesis of the corpus collosum, hydrocephalus)

•Genitourinary defects (eg, hydronephrosis, megaureter, hypospadias, solitary kidney, cystic kidneys) (see "Overview of congenital anomalies of the kidney and urinary tract (CAKUT)")

•Esophageal atresia (see "Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula", section on 'Tracheoesophageal fistula and esophageal atresia')

•Polysplenia

•Cryptorchidism (see "Undescended testes (cryptorchidism) in children: Clinical features and evaluation")

•Skeletal abnormalities (eg, supernumerary ribs, limb abnormalities, hemivertebrae)

●Genetic syndromes – Approximately 5 to 10 percent of newborns with CDH have an identified underlying genetic syndrome or chromosomal abnormality [2,15-17]. An underlying genetic syndrome is more likely if there are other associated malformations (eg, congenital heart disease) and/or the newborn has bilateral CDH. Examples include:

•Fryns syndrome, which is characterized by CDH, pulmonary hypoplasia, craniofacial abnormalities, and distal limb deformities. It is usually lethal in the neonatal period.

•Donnai-Barrow syndrome (LRP2 mutation), which is characterized by CDH, facial dysmorphisms (prominent brow, short nose, hypertelorism), ocular abnormalities, and sensorineural hearing loss.

•Others – Numerous other genetic syndromes are occasionally associated with CDH. Examples include the CHARGE association, Apert syndrome, Coffin-Siris syndrome, Emanuel syndrome, Cornelia De Lange syndrome, Goldenhar syndrome (also called hemifacial microsomia), Beckwith-Wiedemann syndrome, Pallister Killian syndrome, Stickler syndrome, Wolf-Hirschhorn syndrome, and others [15-17].

DIAGNOSIS

Prenatal — Many cases of CDH are diagnosed prenatally by routine antenatal ultrasound screening. This is discussed separately. (See "Congenital diaphragmatic hernia: Prenatal issues", section on 'Prenatal diagnosis' and 'Chest imaging' below.)

Postnatal — While most infants with CDH are diagnosed prenatally, a small subset present postnatally with respiratory distress. In these newborns, stabilization efforts in the delivery room take precedence over diagnostic testing. Once the newborn is stabilized, chest imaging and echocardiography are performed.

Initial stabilization — Postnatally, newborns with CDH often present with severe respiratory distress within the first few minutes after birth. Stabilization in the delivery room includes intubation, placement of a nasogastric tube, and other measures to support the newborn’s respiratory and hemodynamic status. These interventions are discussed in greater detail separately. (See "Congenital diaphragmatic hernia (CDH) in the neonate: Management and outcome", section on 'Initial interventions' and "Neonatal resuscitation in the delivery room".)

Chest imaging — Chest radiograph findings include:

●Herniation of abdominal contents (usually air- or fluid-containing bowel) into the hemithorax with little or no visible aerated lung on the affected side (image 1)

●Displacement of mediastinal structures (eg, heart) towards the contralateral lung

●Compression of the contralateral lung

●Reduced size of the abdomen with decreased or absent air-containing intra-abdominal bowel

●If the CDH is right sided, the liver may be the only herniated organ, appearing as a large thoracic soft tissue mass with absent intra-abdominal liver shadow

The diagnosis may be facilitated by placing a naso- or orogastric tube. Chest radiography will show deviation from the tube's expected anatomic course, typically showing the tube within the thoracic cavity [18].

Cross sectional imaging (eg, with computed tomography [CT]) is only necessary in rare cases when the diagnosis is uncertain.

Echocardiography — All neonates with CDH should undergo echocardiography early in the postnatal course to detect any associated cardiac anomalies, evaluate ventricular function, assess the size of the patent ductus arteriosus, assess the degree and direction of ductal and intracardiac shunting, and to assess for pulmonary hypertension (PH) (image 2A-B).

●Congenital heart disease – Approximately 15 to 20 percent of patients with CDH have associated congenital heart defects [12]. (See 'Associated conditions' above.)

Infants with associated severe cardiac anomalies are at considerably higher risk for morbidity and mortality, and these findings may have an impact on management decisions [11,19-21]. The prognosis is particularly poor for infants with comorbid hypoplastic left heart syndrome (HLHS). (See "Hypoplastic left heart syndrome: Management and outcome", section on 'Outcome'.)

●PH and ventricular function – In addition to evaluating cardiac anatomy, the echocardiogram assesses ventricular function and estimates the right ventricular pressure to establish if there is evidence of PH (image 2B). The echocardiographic assessment for determining the presence and severity of PH in neonates is discussed separately. (See "Persistent pulmonary hypertension of the newborn (PPHN): Clinical features and diagnosis", section on 'Severity of PH'.)

Neonates with severe biventricular dysfunction often require extracorporeal membrane oxygenation (ECMO) support and have a high risk of morbidity and mortality [22,23]. (See "Congenital diaphragmatic hernia (CDH) in the neonate: Management and outcome", section on 'Extracorporeal membrane oxygenation'.)

LATE PRESENTATION — Infrequently, mild CDH defects present after the neonatal period. In a case series of 15 children who presented late with CDH, the mean age at presentation was 18 months (range 38 days to 10 years) [24]. The main presenting symptoms were respiratory complaints in 40 percent of patients, gastrointestinal (GI) symptoms in 40 percent, and both respiratory and GI symptoms in 20 percent. One-third of the patients had failure to thrive. The diagnosis was made by chest radiography in six patients, and the other patients were diagnosed by gastrointestinal contrast series or computed tomography (CT). Primary repair was successful in all patients, and all patients were alive and clinically well at an average follow-up of two years.

DIFFERENTIAL DIAGNOSIS — The differential diagnosis of neonatal CDH includes other causes of neonatal respiratory distress, including infections (sepsis, pneumonia) and noninfectious etiologies (table 1). CDH is differentiated from these conditions by the characteristic chest radiograph finding of herniated abdominal contents into the thorax (image 1). (See "Overview of neonatal respiratory distress and disorders of transition".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Pulmonary hypertension in children".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Congenital diaphragmatic hernia (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Pathophysiology – CDH is a developmental defect in the diaphragm that allows abdominal viscera to herniate into the chest, thereby compressing the lung and interfering with normal fetal lung development. With increased compression of the developing lung by the herniated abdominal contents, there are corresponding decreases in bronchial and pulmonary arterial branching, resulting in increasing degrees of lung hypoplasia and pulmonary arterial muscle hyperplasia (pulmonary hypertension). (See 'Pathogenesis and embryology' above and 'Impact on cardiopulmonary development' above.)

●Epidemiology – Reported prevalence rates of CDH range from 2 to 3 cases per 10,000 live births. It is slightly more common in males than females. (See 'Prevalence' above.)

●Presentation – In many cases, the diagnosis of CDH is known at the time of birth based upon the prenatal ultrasound. Patients not diagnosed prenatally generally present with respiratory distress in the first few hours or days after birth. Physical examination may reveal a barrel-shaped chest, a scaphoid-appearing abdomen because of loss of the abdominal contents into the chest, and the absence of breath sounds on the ipsilateral side. (See 'Postnatal findings' above.)

Less commonly, a small subset of patients with CDH have minimal or no symptoms in the newborn period and present later in life. (See 'Late presentation' above.)

●Associated conditions – Associated congenital abnormalities are seen in approximately 50 percent of newborns with CDH. The most common associated condition is congenital heart disease, which occurs in 15 to 20 percent of cases and can be severe. A wide range of noncardiac abnormalities can also be seen. Approximately 5 to 10 percent of newborns with CDH have an identified underlying genetic syndrome or chromosomal abnormality. (See 'Associated conditions' above.)

●Diagnosis – The diagnosis is often made prenatally with ultrasound examination. Among infants in whom CDH is not diagnosed in utero, the diagnosis is made by chest radiography showing herniation of abdominal contents (image 1). (See "Congenital diaphragmatic hernia: Prenatal issues", section on 'Prenatal diagnosis'.)

All neonates with CDH should undergo echocardiography early in the postnatal course to detect any associated cardiac anomalies, evaluate ventricular function, and to assess for pulmonary hypertension (PH) (image 2A-B). (See 'Echocardiography' above.)

●Differential diagnosis – The differential diagnosis of neonatal CDH includes other causes of neonatal respiratory distress, including infections (sepsis, pneumonia) and noninfectious etiologies (table 1). CDH is differentiated from these conditions by the characteristic chest radiograph finding of herniated abdominal contents into the thorax (image 1). (See "Overview of neonatal respiratory distress and disorders of transition".)