3 - Discussion
The diaphragm is the primary muscle used during inspiration. It acts as
a barrier between the thoracic and abdominal cavity and is innervated by
the phrenic nerve. DE is a condition where there is an abnormal
elevation of the diaphragm with maintained continuity and attachments to
the costal margin. The diaphragm can be partially or fully replaced with
fibroelastic tissue. (1, 2) DE can cause respiratory issues due to
reduced lung volume and impaired breathing mechanics. This could lead to
atelectasis, pneumonia as well as aspiration and respiratory
insufficiency requiring support. (2) Abdominal contents can be displaced
into the thoracic cavity, further compromising breathing by compressing
the lungs. Complications of eventration can also occur later in life
with case reports of volvulus and other issues with malpositioned
abdominal contents being the highest risk of morbidity.(3, 4) In
infants, DE can be congenital due to abnormal development or acquired
due to damage to the phrenic nerve. (5) In congenital diaphragmatic
eventration, there is inadequate development of the diaphragmatic muscle
or absence of the phrenic nerve. In acquired diaphragmatic eventration,
the most common cause is an injury to the phrenic nerve leading to
diaphragmatic paralysis. Damage to the phrenic nerve can be caused by
either trauma at the time of delivery or thoracic surgery.(5) In our
case, there was no history or exam findings suggestive of birth trauma
at the time of delivery suggesting a congenital etiology is the more
likely cause. Congenital DE constitutes only 5% of all diaphragmatic
defects including congenital diaphragmatic hernias (CDH) and is usually
unilateral with the left side more commonly affected than the right. (6)
It also has a higher male predominance. (7) The incidence and prevalence
of congenital DE in infants is unknown due to some lesions being
clinically silent. Some reports estimate this to be as low as 1 in
10,000 but the overall incidence is likely higher due to the number of
unreported cases. (8) DE can also be associated with many disorders and
infections. These include Spondylocostal dysostosis, Kabuki syndrome,
Beckwith-Wiedemann syndrome, Poland syndrome, chromosomal abnormalities
(trisomy 18), pulmonary hypoplasia, spinal muscular atrophy,
malrotation, and congenital heart disease. Infectious associations
include fetal rubella and cytomegalovirus infections.(9-12) In our case,
the infant appeared non-dysmorphic and there were no associated findings
on any investigation to suggest an associated syndrome or disorder.
The diagnosis of DE is usually made postnatally and can be delayed due
to the absence of symptoms.(13, 14). Chest X-ray can suggest the
diagnosis by showing the elevation of the hemi-diaphragm. Still, it can
be challenging to differentiate between DE and CDH due to the
similarities in imaging findings. Ultrasound can be used to confirm the
findings by demonstrating minimal or paradoxical diaphragmatic movement
although this is operator dependent. In our case, the final diagnosis
was made using MRI which was able to identify diaphragmatic eventration
on both sides of the diaphragm. With regards to management, the choice
between conservative management or surgical repair depends on several
factors including the presence or absence of symptoms, adequacy of
nutritional intake and growth, the need for respiratory support and the
presence of complications such as volvulus or recurrent pneumonia.
Surgical management is recommended for symptomatic cases, particularly
for bilateral eventration although there is no standardized approach
regarding the timing of surgical repair. Stabilization on non-invasive
ventilation before surgery is suggested, although with limited
literature support. Earlier intervention may also improve growth and
prevent lung injury (2) In this case, surgery was done closer to term as
the infant continued to be symptomatic with ongoing tachypnea and
bibasilar atelectasis despite interval growth. Complications after
abdominal plication of a diaphragmatic eventration commonly include
atelectasis and rarely, abdominal compartment syndrome and splenic
injury after mobilization of the left upper quadrant abdominal
structures. (15, 16) In our case, he developed findings suggestive of
NEC which was managed with bowel rest and antibiotics. Following
discharge, he will require routine monitoring and follow-up with a
multidisciplinary team including a Pediatrician, Pediatric Pulmonologist
and a Pediatric Surgeon as there is a possibility of relapse of
eventration. Overall, the prognosis of infants who undergo surgical
plication for DE is good. (14) The infant is currently doing well, not
requiring any respiratory support and growing appropriately. This case
is an excellent example of a multidisciplinary collaboration between
Neonatology, Pediatric Pulmonology, Radiology, and Pediatric Surgery
teams toward the management of a rare condition.