Congenital Diaphragmatic Hernia 

Updated: Oct 08, 2019
Author: Daniel S Schwartz, MD, MBA, FACS; Chief Editor: Jeffrey C Milliken, MD 

Overview

Practice Essentials

The diaphragm is the major muscle of respiration and the second most important muscle within the body after the heart. Because the body relies so much on the diaphragm for respiratory function, understanding how many different diseases processes ultimately result in dysfunction of the diaphragm is vitally important.

When a decrease in diaphragmatic function occurs, a concomitant respiratory dysfunction occurs. The body has many mechanisms in place to compensate for decreased diaphragmatic function. However, no compensatory mechanisms are in place to prevent respiratory compromise in the setting of decreased diaphragmatic excursion.

Diaphragmatic hernias can be divided into two broad categories: congenital and acquired.[1]  A congenital diaphragmatic hernia (CDH) occurs through embryologic defects in the diaphragm, and most patients present early in life rather than later. However, a subset of adults may present with a smaller CDH that was undetected during childhood.[2]

CDH was first described in 1679 by Riverius, who incidentally noted a CDH during a postmortem examination of a 24-year-old person.[3]  In 1701, Holt described the classical clinical and postmortem findings of an infant with CDH. In 1761, Morgagni described the classical anterior diaphragmatic hernia, which today bears his name—Morgagni hernia. In 1848, Bochdalek described both right and left posterolateral CDH. To this day, these CDHs are commonly referred to as Bochdalek hernias.

In 1828, Laënnec described the numerous causes of diaphragmatic hernias, as well as an auscultatory mechanism by which to diagnose them; he also discussed the potential for surgical repair of a diaphragmatic hernia. In 1888, Nauman proposed a two-cavity approach to repair diaphragmatic hernias. In 1889, O'Dwyer attempted the first reported repair of a CDH in an infant. At that time, O'Dwyer discovered the loss of "right of domain" commonly encountered during attempts to repair CDH. In 1929, the first successful CDH repair was performed in an infant, a 3.5-month-old girl.

In 1977, extracorporeal membrane oxygenation (ECMO) was introduced as a treatment for neonates with respiratory failure refractory to conventional care,[4]  and its application to CDH increased the survival rate of infants born with CDH from around 20% to 55-75%. ECMO provides a modality by which blood can be withdrawn, oxygenated, and finally returned to the body for circulation. With ECMO, infants are medically stabilized before surgery; surgical intervention after stabilization produces better outcomes.

Since the time of the first successful repair, great strides have been made in the field of CDH. However, until 1982, when ECMO was first used in the treatment of CDH, mortality remained extremely high for infants born with CDH and severe pulmonary hypoplasia. The field of CDH continues to grow as knowledge of the disease entity increases and progress is made with newer treatment modalities.

Anatomy

The diaphragm is a modified half-dome of musculofibrous tissue that separates the thorax from the abdomen. Four embryologic components make up the formation of the diaphragm, as follows:

  • Septum transversum
  • Two pleuroperitoneal folds
  • Cervical myotomes
  • Dorsal mesentery

Development begins during week 3 of gestation and is completed by week 8. Failure of the development of the pleuroperitoneal folds and subsequent muscle migration results in congenital defects.

The muscular origin of the diaphragm is from the lower six ribs bilaterally, the posterior xiphoid process, and from the external and internal arcuate ligaments. A number of different structures traverse the diaphragm, including three distinct apertures that allow the passage of the aorta, the esophagus, and the vena cava.

The aortic aperture is the lowest and most posterior of the openings, lying at the level of T12. The aortic opening also transmits the thoracic duct and sometimes the azygos and hemiazygos veins. The esophageal aperture is surrounded by diaphragmatic muscle and lies at the level of T10. The vena caval aperture is the highest of the three openings and lies level with the disc space between T8 and T9.

Arterial supply to the diaphragm comes from the right and left phrenic arteries, the intercostal arteries, and the musculophrenic branches of the internal thoracic arteries. Some arterial blood is provided from small branches of the pericardiophrenic arteries that run with the phrenic nerve mainly where the nerves penetrate the diaphragm. Venous drainage is via the inferior vena cava and azygos vein on the right and the adrenal/renal and hemiazygos veins on the left.

The diaphragm receives its sole muscular neurologic impulse from the phrenic nerve, which originates primarily from the fourth cervical ramus but also has contributions from the third and fifth rami.[5] Originating around the level of the scalenus anterior, the phrenic nerve courses inferiorly through the neck and thorax before reaching its terminus, the diaphragm. Because the phrenic nerve has such a long course before reaching its final destination, any processes that disrupt the transmission of neurologic impulse through it directly affect the diaphragm.

Etiology

CDH occurs when the muscular entities of the diaphragm fail to develop normally, resulting in displacement of abdominal components into the thorax.

Bochdalek hernia

Bochdalek hernias[6] make up the majority of cases of CDH. The major problem in these hernias is posterolateral defects of the diaphragm, which results in either failure in the development of the pleuroperitoneal folds or improper or absent migration of the diaphragmatic musculature.

As many as 90% of patients with CDH present in the neonatal period or within the first year of life. These cases have a mortality of 45-50%. Most of the morbidity and mortality of CDH relates to hypoplasia of the lung and pulmonary hypertension on the affected side. Thus, timely diagnosis and proper management remain the keys to survival.

Morgagni hernia

Morgagni hernia[7, 8, 9] is a less common CDH, accounting for only 5-10% of CDH cases. The foramen of a Morgagni hernia occurs in the anterior midline through the sternocostal hiatus of the diaphragm, with 90% of cases occurring on the right side.

Epidemiology

CDH occurs in 1 in 3000 newborns. Mortality and morbidity are due to the amount of pulmonary hypoplasia (PH), the response on artificial ventilation, and the presence of therapy-resistant pulmonary hypertension. The survival rate is 55-65%.[10]

International data are available from the registry maintained by the Congenital Diaphragmatic Hernia Study Group (CDHSG), a consortium that includes 66 centers from 13 countries and that has amassed data on more than 8000 children with CDH to date.[11]

Prognosis

With the development of newer treatment techniques (see Treatment), including high-frequency oscillatory ventilation (HFOV) and more sophisticated extracorporeal oxygenation equipment, the mortality associated with CDH has continually decreased.[12, 13, 14, 15] However, long-term morbidity includes such entities as gastroesophageal reflux disease (GERD),[16] neurologic and developmental disorders,[17] and musculoskeletal disorders.[18]

Partridge et al analyzed outcomes in right-side CDH as compared with left-side CDH and found that whereas the former did not have a higher mortality, it was associated with increased need for pulmonary vasodilatory therapy and need for tracheostomy.[19]

Collin et al found that patients with right-side CDH required patch repair more often than those with left-side CDH did.[20] The only morbidity that was signnificantly more frequent in the former was the rate of recurrent herniation. There were no significant differences in neurodevelopmental outcome between the two groups: Both groups exhibited normal median Griffiths general quotient scores at the age of 1 year.

 

Presentation

History and Physical Examination

Clinical manifestations of congenital diaphragmatic hernia (CDH) include the following:

  • Early diagnosis - Right-side heart; decreased breath sounds on the affected side; scaphoid abdomen; bowel sounds in the thorax, respiratory distress, and/or cyanosis on auscultation; CDH can often be diagnosed in utero with ultrasonography (US), magnetic resonance imaging (MRI), or both
  • Late diagnosis - Chest mass on chest radiography, gastric volvulus, splenic volvulus, or large-bowel obstruction
  • Congenital hernias (neonatal onset) - Respiratory distress and/or cyanosis occurs within the first 24 hours of life; CDH may not be diagnosed for several years if the defect is small enough that it does not cause significant pulmonary dysfunction
  • Congenital hernias (childhood or adult onset) - Obstructive symptoms from protrusion of the colon, chest pain, tightness or fullness the in chest, sepsis following strangulation or perforation, and many respiratory symptoms occur
 

Workup

Laboratory Studies

Low levels of maternal serum alpha-fetoprotein (AFP) have been associated with congenital diaphragmatic hernia (CDH). However, decreased AFP also is observed with trisomy 18 and trisomy 21; thus, a low AFP level, by itself, is not diagnostic of CDH.

Imaging Studies

On chest radiography,[21] CDH may be signaled at an early stage by a finding of bowel and stomach in the chest cavity and shifting of the mediastinum (usually to the right). (See the image below.) At a later stage, CDH may be signaled by a suspicious mass incidentally found on a chest radiograph.

Anteroposterior view of chest in patient with cong Anteroposterior view of chest in patient with congenital diaphragmatic hernia shows herniation of bowel loops into left hemithorax, with right shift of heart and mediastinum.

For reaching a diagnosis of CDH in utero, a level 3 ultrasound examination is the criterion standard. Features indicative of CDH are as follows:

  • Polyhydramnios
  • Absent or intrathoracic stomach bubble
  • Mediastinal and cardiac shift away from the side of herniation
  • Fetal hydrops (rare)

Magnetic resonance imaging (MRI) can be utilized to show a fetal lung volume and, in some instances, to help determine postnatal mortality.[22]

 

Treatment

Approach Considerations

The diaphragm is the major muscle of respiration and the second most important muscle after the heart. When a decrease in diaphragmatic function occurs, a concomitant respiratory dysfunction generally always accompanies the functional decrease. Although the body has many compensatory mechanisms in the setting of decreased diaphragmatic function, little can be done to prevent respiratory compromise if excursion of the diaphragm is moderately diminished or simply absent. Appropriate treatment is essential in cases of congenital diaphragmatic hernia (CDH).

Some reports exist of increases in mortality with early surgical intervention for CDH in infants. Many authors suggest that the patient be stabilized (often with the use of extracorporeal membrane oxygenation [ECMO]) and that repair be delayed until the infant is better prepared to survive the operation.

Research is under way into the use of inhaled nitric oxide (iNO) or partial liquid ventilation and the possibility of lung transplantation for infants born with severe hypoplasia.[18]  Minimally invasive repair techniques for latent CDH are being explored at a number of institutions.

Guidelines for the management of CDH have been published.[23]

Medical Therapy

Resuscitation with ventilatory support is of prime importance in patients born with a CDH. There has been a trend toward switching from conventional mechanical ventilation to high-frequency oscillatory ventilation (HFOV). HFOV serves to minimize airway pressure and, in conjunction with permissive hypercapnia, helps those with CDH suffer less traumatic lung injury and fewer long-term complications. Mortality has been shown to decrease from 49% to 20% when HFOV is used early in the treatment course.[24]

ECMO has been shown to decrease the mortality of CDH significantly but is currently reserved for individuals whose condition fails to improve with both HFOV and conventional mechanical ventilation. The decision to utilize ECMO is made early in the disease process, usually within 24 hours of birth.

With the addition of HFOV, more reports exist of decreased morbidity and mortality with early surgical intervention. However, there remains some controversy regarding this practice. The classical teaching is that patients need to be stabilized (often with the use of ECMO) and that repair should be delayed until the infant is better prepared to survive the operation.[25]

Maternal antenatal corticosteroid administration has also been employed in an effort to improve fetal lung growrth and maturity, but the available evidence is insufficient to support its routine use.[26]

Prostaglandin E1 (PGE1) has been used to treat severe pulmonary hypertension in patients with CDH; a study by Lawrence et al found it to be well tolerated in this setting and to be associated with improvements in B-type natriuretic peptide (BNP) and echocardiographic indices of pulmonary hypertension.[27]

Surgical Therapy

With regard to treatment of CDH in the perinatal period, significant issues remain, and many questions are yet to be answered. However, the possibility of maternal-fetal surgical treatment of CDH is on the horizon.[28, 29]

For treatment of CDH in the neonatal period, a subcostal incision is used. An attempt should be made to carry out a primary repair of the hernia. The abdominal contents are reduced, and the edges of the diaphragm are then approximated with nonabsorbable suture. In some cases, such as when the defect is large or the repair is being made while the patient is on ECMO, a prosthetic material such as expanded polytetrafluoroethylene (ePTFE) or polypropylene is used.

For treatment of latent CDH, the typical surgical approach has been through a thoracotomy or laparotomy. Most surgeons approach via a laparotomy so that abdominal contents can be inspected adequately. In children, prosthetic mesh is typically used; in adults, direct suture technique using nonabsorbable suture material is commonly employed.

For CDH related to traumatic rupture,[30, 31, 32]  the surgical approach depends on the timing of the diagnosis with the surgical intervention.[29]

Minimally invasive approaches (eg, involving video-assisted thoracoscopy

[33]

or laparoscopy

[34]

) are being explored. Putnam et al found that a minimally invasive approach was associated with a shorter hospital stay and reduced small-bowel obstruction but with higher recurrence rates.

[35]

Criss et al found that in low-risk patients born with small or moderate-sized defects, a thoracoscopic approach was associated with a shorter hospital stay, reduced mechanical ventilation days, and decreased time to feeding but also with a trend toward higher recurrence rates.

[36]

 Robotic approaches are being explored as well.

[37]

Fetoscopy

Some centers use intrauterine fetal surgery (fetoscopy) to repair diaphragmatic defects in an attempt to prevent the hypoplastic lung problems encountered with large hernias.[18]  (See Fetal Surgery for Congenital Diaphragmatic Hernia.)

Because the number of cases performed is still relatively small and very few centers are capable of performing intrauterine surgery, this practice has been controversial. A 2015 Cochrane review concluded that there was not sufficient evidence to recommend in-utero intervention for fetuses with CDH (including both maternal antenatal corticosteroid administration and fetoscopic tracheal occlusion) as a part of routine clinical practice.[26]  

Preterm rupture of membranes remains the weak link of fetoscopy. Refinement of the technique of fetoscopy and technologic advances such as partial amniotic carbon dioxide insufflation will help correct this problem and may allow the application of fetoscopy to other pathologies in the future.[38, 29, 28]

Complications

It is extremely important to keep in mind that there is an increased risk of concomitant congenital defects in an infant with CDH. If a diaphragmatic hernia is diagnosed in utero, a high index of suspicion for concomitant abnormalities must be maintained. It should always be remembered that infants with CDH are at increased risk for postnatal respiratory failure, incarceration or strangulation of bowel, and pulmonary hypoplasia.[39]

In cases of traumatic or adult repaired CDH, recurrence of the hernia is possible; thus, follow-up with chest radiography is important.

Long-Term Monitoring

Once an anatomic defect has been corrected, periodically assessing pulmonary function and obtaining chest radiographs is important. Although spontaneous recurrence of a repaired diaphragmatic hernia is low, small defects in the repair site have been reported; accordingly, surveillance is essential.

 

Guidelines

Canadian CDH Collaborative Guidelines for Congenital Diaphragmatic Hernia

In 2018, the Canadian Congenital Diaphragmatic Hernia Collaborative issued guidelines for diagnosis and management of congenital diaphragmatic hernia (CDH).[23]

Recommendations for antenatal diagnosis included the following:

  • Ultrasonographic measurement of observed-to-expected (O/E) lung-head ratio (LHR) should be done between 22 and 32 weeks of gestational age to predict the severity of pulmonary hypoplasia in isolated CDH.
  • In left-side CDH, an O/E LHR < 25% predicts poor outcome. In right-side CDH, an O/E LHR < 45% may predict poor outcome. 
  • Fetal magnetic resonance imaging (MRI) should be used (where available) for the assessment of lung volume and liver herniation in moderate and severe CDH.

Recommendations for ventilation included the following:

  • Newborns with CDH and immediate respiratory distress should be preferentially intubated at birth. Bag-valve-mask ventilation should be avoided.
  • Sedation should be provided to all mechanically ventilated newborns with CDH. Deep sedation and neuromuscular blockade should be provided selectively to those with greater ventilation or oxygen requirements. 
  • A T-piece should be used with the ventilator to avoid a peak inspiratory pressure (PIP) higher than 25 cm H 2O.
  • An arterial carbon dioxide tension (PaCO 2) between 45 and 60 mm Hg and a pH between 7.25 and 7.40 should be targeted in all newborns with CDH.
  • Supplemental oxygen should be titrated to achieve a preductal saturation of at least 85% but no greater than 95%.
  • Gentle intermittent mandatory ventilation (IMV) should be the initial ventilation mode for newborns with CDH who require respiratory support. High-frequency oscillatory ventilation (HFOV) or high-frequency jet ventilation (HFJV) should be used when the PIP required to control hypercapnia using IMV exceeds 25 cm H 2O.

Recommendations for hemodynamic support included the following:

  • Treatment of poor perfusion (capillary refill >3 s, lactate >3 mmol/L, urine output < 1 mL/kg/hr) and blood pressure below norms for age should include (1) judicious administration of crystalloid, generally not exceeding 20 mL/kg; (2) inotropic agents such as dopamine or epinephrine; and (3) hydrocortisone.
  • If poor perfusion continues, assessment of cardiac function (via echocardiography or central venous saturation) should be performed.

Recommendations for echocardiography included the following:

  • Two standardized echocardiograms, one within 48 hours of birth and one at 2-3 weeks of life, are needed to assess pulmonary vascular resistance, as well as left ventricular (LV) and right ventricular (RV) function. Additional studies may be conducted as clinically indicated.

Recommendations for management of pulmonary hypertension included the following:

  • Inhaled nitric oxide (iNO) is indicated for confirmed suprasystemic pulmonary arterial hypertension without LV dysfunction, provided that lung recruitment is adequate. In the absence of clinical or echocardiographic response, iNO should be stopped.
  • Sildenafil should be considered in patients with refractory pulmonary hypertension (ie, hypertension unresponsive to iNO) or as an adjunct in weaning iNO.
  • Milrinone should be used to treat cardiac dysfunction, particularly if it is associated with pulmonary hypertension.
  • Prostaglandin E1 can be used to maintain ductus arteriosus patency and reduce RV afterload in patients with pulmonary hypertension with RV failure or in the presence of a closing ductus. 

Recommendations for extracorporeal life support included the following:

  • The possibility of extracorporeal life support should be discussed during antenatal counselling for CDH, and the discussion should disclose that available evidence does not suggest a survival benefit to its use. 

Recommendations for surgery included the following:

  • The following physiologic criteria should be met before surgery: (1) urine output >1 mL/kg/hr, (2) fraction of inspired oxygen (FiO 2) < 0.5, (3) preductal oxygen saturation between 85% and 95%, (4) normal mean arterial pressure for gestational age, (5) lactate < 3 mmol/L, and (6) estimated pulmonary artery pressures less than systemic pressure.
  • Failure to meet these criteria within 2 weeks should prompt consideration of either attempted repair or a palliative approach. 
  • For diaphragmatic defects that are not amenable to primary repair, oversized tension-free polytetrafluoroethylene/GORE-TEX patches should be used. 
  • A minimally invasive surgical approach or technique should not be used in the repair of neonatal CDH, because of the high rates of recurrence. 
  • In patients on extracorporeal life support, surgery should be avoided until after decannulation. If the patient cannot be weaned off extracorporeal life support, consideration should be given to either surgery or palliation, as appropriate. 

Recommendations for long-term follow-up included the following:

  • Standardized multidisciplinary follow-up is recommended for children with CDH to provide surveillance and screening, optimal and timely diagnosis, and clinical care adjusted to the level of risk.
  • It is recommended to identify the subset of CDH survivors at high risk for long-term morbidity as comprising those infants and children who require extracorporeal life support, who have been repaired with a patch, or who required respiratory support at 30 days of life.