Handbook of Genetic Counseling/Congenital Diaphragmatic Hernia

Congenital Diaphragmatic Hernia

Definition

The presence of a hole in the diaphragm (the muscle that separates the thoracic and abdominal cavities) allows abdominal organs and intestines to enter the thoracic cavity.
The most common type (36%) is on the left side of the diaphragm towards the back of the body (Bochdalek hernia). A hernia on the left side is more likely to allow organs to protrude. On the right side, the liver blocks the hole and therefore there is less chance of severe organ herniation.
A less common hernia is located near the front of the body near the breastbone (Morgagni hernia).

Incidence

1/3000- 1/5000 live births
1/2200 including stillbirths, spontaneous miscarriages, and neonatal deaths before reaching treatment facility

Cause

Multifactorial

Maternal exposures

THE CAUSE OF CDH IS NOT YET KNOWN.

Studies have been done on the following:

Thalidomide
Bendectin
Quinine
Anti-epileptic drugs.

Embryological cause

At 9-10 weeks the peritoneal canals close creating the diaphragm and the separation between the thoracic and abdominal cavities is complete. If the closure does not occur properly, when the midgut returns to the abdomen, the abdominal viscera herniated through the opening. This causes compression on the developing lung, resulting in a decreased number of bronchial branches and mild to severe lung hypoplasia. There can also be compression on the heart causing cardiac deformities.

Associated anomalies/conditions

10-20% of CDH have chromosome anomalies
Trisomy 21, 13, 18 most common
Tetrasomy 12p has been noted)
Other anomalies occur in 25-57% of all cases of CDH (suspected 95% in stillborns with CDH)
Congenital heart defects (16-23%)
Hydronephrosis or renal agenesis
Intestinal atresia
Neurological defects (spina bifida, anencephaly, hydrocephalus)
Bronchial anomalies (18-40%)
Also seen to be associated with genetic conditions
Fryns syndrome (RARE - 25 cases reported. Autosomal recessive condition that is usually fatal. Includes cleft palate, hypoplastic nails, cystic kidneys, genital malformations, CNS malformations, and dysmorphic features)
Beckwith-Weidemann (usually sporadic. Macroglossia, large kidneys, macrosomia, other abnormalities)
Pierre-Robin syndromes
Outcome of pregnancies with CHD
The extent of pulmonary hypoplasia at birth is the single most important factor to predict morbidity and mortality.
Isolated CHD = 60-78% mortality rate
Death usually caused by complications of prematurity and pulmonary hypoplasia
Variation in outcome is dependent upon the timing, volume, and duration of the herniation
No CHD on US at 20-38 weeks but present at birth = 100% survival
Thought to be caused by a small herniation or "sliding" herniation.
Prenatal Diagnosis
Polyhydramnios caused by the obstruction in the herniated stomach.
Polyhydramnios is an indication for poor prognosis (only 11% of 94 cases survived compared to 55% survival when no polyhydramnios was present)

Ultrasound markers

Abdominal viscera at the level of the scapula or heart
Liver herniation into chest area
Herniation or misplacement the gallbladder
Ultrasound measurements
Lung to thorax ratio (L:T ratio) : a study found fetuses with CHD had a L:T ratio 2 SD below that in normal controls.
Right-lung: head circumference ratio (LHR) in those with left-sided CHD: predictive of outcome
LHR <0.6 = no survival with postnatal treatment
LHR <1.0 = survival 11%
LHR >0.6 and <1.35 = survival 61%
LHR >1.35 = 100% survival
Pregnancy Management (Depends on gestational age and degree of herniation)

All gestational ages

Level II ultrasound to identify any other anomalies
Serial ultrasounds to watch progression of pregnancy
Fetal karyotyping offered
Fetal echocardiogram
Large volume herniation (LHR<1.35, L:T ratio<0.5, dilated misplaced fetal stomach, and polyhydramnios):
Counseling for very poor outcome and possible termination
Option of delivery at term with conventional management
Option of surgical repair or tracheal clip procedure in utero (<26 weeks)
Smaller volume herniation (LHR>1.35, L:T ratio>0.5):
Serial ultrasounds
Discuss options of prenatal repair (inclusion criteria specific)
Delivery at high-risk center with postnatal repair
Recurrence risks
Sporadic in most cases
Recurrence risk for siblings ~2% (Fetology)
Females more commonly affected 3:2
AD familial cases have been reported (higher chance of bilateral hernias)
Fetal Treatment

Done at the following major centers

Columbia University Medical Center/Children's Hospital of NY - 1-877-THE-BABY
UCSF Fetal Treatment Center 1-800-RX-FETUS
CHOP Center for Fetal Diagnosis and Treatment 1-800-IN-UTERO
Florida Institute for Fetal Diagnosis and Therapy - limited no. of patients
Complete repair of CHD (no longer done) - studies done reported no significant increase in survival rate in cases that did not involve herniation of the left liver lobe (44% survival w/ surgery, 41% w/out surgery).
Tracheal occlusion surgery - theory behind surgery is that throughout gestation, the fetal lung produces fluid that leaves the body through the trachea. When this occurs in CHD, it causes a lung hypoplasia. However, when the trachea is blocked, the fluid becomes trapped causing a lung hyperplasia which forces the viscera back into the abdominal cavity.
This procedure requires a postnatal surgical procedure to remove the clip and may require postnatal repair of the diaphragm.
Studies have shown 90% mortality rate and have resulted in 50% of surviving fetuses to have vocal-cord paralysis requiring permanent tracheotomies.
Current recommendations are to do the surgery only in those with isolated CDH, an LHR<1.0 and a herniated liver.(Fetology) However, inclusion criteria at CHOP for tracheal clip is LHR<1.4 and liver herniation.

Newborn treatment

Immediate intubation
Neuromuscular blockade
Positive pressure ventilation
Nasogastric tube to avoid dilation of the bowel
Treatment with either high frequency oscillatory ventilation (HiFi) or traditional ventilation

Postnatal repair

WAIT UNTIL INFANT HAS STABILIZED
If necessary, place the infant on extracorporeal membrane oxygenation (ECMO)
65% require it.
Increased risk for neurological difficulties later on.
The defect is repaired primarily or by a patch
Surgery uses muscle biopsy or foreign substance to close the diaphragm
(If a foreign substance is used, it will not grow with the child and may require additional surgeries. When the muscles are sewn together, the diaphragm is not as flexible as normal. Can lead to respiratory dysfunction.)
Sometimes a silo is required if there is not enough room for the bowel in the stomach cavity.
Chest tube is inserted
Average intubation period of 20 days (Maratore et al. 2001)
Average length of stay in hospital of 60 days

Long-term outcome

Possibility of bronchopulmonary dysplasia from long-term ventilation
Increased risk for
Neurological problems regardless of exposure to ECMO
Developmental delay (20-30%)
Sensorineural hearing loss
Failure to thrive resulting from feeding difficulties
Gastroesophageal reflux (50-60%)
Musculoskeletal deformities (10-21%)
A study of 48 infants with postnatal repair (Chu et al. 2000) showed a 73% survival rate with leading causes of death being severe respiratory failure, pulmonary hypertension, pneumothorax, and anomalies.

.

CHERUBS - The Association of Congenital Diaphragmatic Hernia Research, Advocacy and Support Over 2100 families affected by CDH supporting and encouraging each other Message Boards, Research Library, Free Membership, Newsletters, Awareness Activities

http://www.cdhsupport.org

Breath of Hope, Inc., Congenital Diaphragmatic Hernia, Supporting all, together searching for a cure.

PO Box 6627

Charlottesville, VA 22906

http://www.breathofhopeinc.com

Adam.com website has details and pictures of a variety of conditions, the surgical procedures to repair them, and the follow-up from surgery. Very easy to understand.

http://www.adam.com

Each fetal surgery location has its own website

http://fetalsurgery.chop.edu

http://fetalsurgery.ucsf.edu

http://www.fetalmd.com/research

http://www.prenatalpediatrics.org - The Center for Prenatal Pediatrics at Columbia University

References

Bianchi et al. Fetology: Diagnosis & Management of the Fetal Patient (2000).
Chu et al. Treatment and outcome of congenital diaphragmatic hernia. L Formos Med Assoc. Nov 2000: 99 (11) p 844-7.
Muratore et al. Pulmonary morbidity in 100 survivors of congenital diaphragmatic hernia monitored in a multidisciplinary clinic. J Pediatr Surg. Jan 2001: 36(1) p133-40.
Nose et al. Airway anomalies in patients with congenital diaphragmatic hernia. J Pediatr Surg. Nov 2000: 35 (11) p1562-5.
Snijders RJM & Nicolaides KH. Ultrasound Markers for Fetal Chromosomal Defects.

Notes

The information in this outline was last updated in 2001.