Today, Due to
environmental conditions, pre-pregnancy pulmonary infections, lifestyle
habits like Smoking, junk food, the ability to withstand the intra-uterine
and extrauterine turbulence is critically altered in the past couple of decades.
Accordingly, studies have revealed that almost 35% of neonates face breathing
difficulties, and need assisted ventilation. even above 28 weeks of gestation.
Surprisingly, the data excludes neonates who are born with congenital
abnormalities and other common conditions seen in infants. Enough
evidences gathered through several studies are also supporting the
fact that there has been an exponential increase in several neonatal
admission postpartum; due to increased respiratory complications in
mothers as well as due to increased rate of c-section deliveries.
Although, due to increased technological advancements and
contemporary diagnostic facilities, the mortality rate has severely
decreased over the period prompt administration of effective
treatment regimens is highly crucial for better clinical outcomes.
Accordingly, the present review specifies common respiratory conditions
in neonates, risk factors, and clinical aspects (symptoms and causes) of all
neonatal diseases. Here, we have summarized the genetic predisposition
in neonates responsible for respiratory illness and respiratory dysfunctional
attributes.
Common Neonatal Respiratory Challenges:
Respiratory Apnea
Respiratory apnea, also commonly known as respiratory distress syndrome
is mainly reported in neonates with a congenital functional deficiency in the
lungs. The deficiency is primarily associated with the lack of enough surfactant
in the lungs, and can also be referred to as hyaline membrane disease. Some
studies have also reported that infants born to pre-diabetic and/or diabetic
mothers are at higher risk of suffering from respiratory apnea.
Although, production of surfactant is initiated on the 24th week of
gestation by type 2 pneumocytes; the level can increase with increased
gestational age, susceptibility to respiratory illnesses, and genetic
predisposition associated with lung disease. The infant may start
displaying the early signs of respiratory disturbances soon after birth
and hence, will need immediate supportive ventilation. More in-depth
analysis of acute respiratory distress syndrome involves chest radiograph
with poorly inflated lungs along with ground grass appearance.
The condition may advance in the first 24-48 hours of assisted ventilation
stabilize after 24-48 hours followed by clinical improvement.
Transient Tachypnea
It is one of the most reported conditions of neonatal respiratory
distress syndrome; constituting more than 50% of the total neonatal
issues. The condition is commonly associated with reversal of
pulmonary residual fluid postpartum; which in ideal condition is
removed with the help of dilated lymphatic vessels, to increase
pulmonary circulation and retain breathing. Although, researchers
are not able to pinpoint the genetic cause of the lung disease many
commonly reported risk factors to include maternal asthma, maternal
diabetic, c-section delivery, macrosomia to be possibly responsible
for underlying condition. The clinical aspects include immediate
respiratory distress within 1-2 hrs of birth; which can last up to 48 hrs.
Fluid accumulation in the lung region can be confirmed through chest
radiography. Many reported cases can be managed through conservative
treatments along with supportive oxygen therapy.
However, in case of prolonged respiratory support or supplementary
oxygen intake; an alternative diagnosis is generally referred to with diuretics.
Persistent Pulmonary Hypertension
Persistent pulmonary hypertension is characterized by sudden failure
of neonatal respiratory vasculature to adapt to the changing environment
from intra-utero to ex-utero, following birth. Studies have indicated that
the sudden collapse is a secondary clinical sign of an associated lung disorder.
The reported prevalence of the condition so far is around 1 in 1000 births and
is found to be mainly connected with congenital birth abnormalities, congenital
diaphragmatic hernia, maladaptation, etc. Many of these maladaptations, i.e.
reported failure of infants to adapt to the external environment are observed
to be the complications of perinatal asphyxia, other known/unknown lung infections,
and/or lung parenchyma diseases. Other studies have also linked genetic predisposition
along with chromosomal abnormalities to be responsible for lung disorders.'
Researchers have also pinpointed the fact that maternal medications at the
time of pregnancy can also challenge the smooth lung functioning of the baby.
Early diagnosis of persistent pulmonary hypertension is observed to be quite
difficult as the signs and symptoms are found to be quite in line with other
congenital disorders. However, certain clinical assessments like the right to
left shunting assessments are based on the pre and post ductal oxygen
saturation levels.
Persistant pulmonary hypertension studies have pinpointed the fact that
it can directly or indirectly impact neonatal survival rate with significant
neurodevelopmental disabilities by the age of 2.
Meconium Aspiration Syndrome
The full-term healthy fetus tends to pass meconium into the amniotic
fluid, before the delivery; if it experiences significant stress or discomfort
during delivery. Some studies have connected the phenomena of passing
meconium with fetal distress, while the fetus is trying to cope up with
respiratory attempts. Previous reports have suggested that during such
gasping process, there is a chance of fetal discomfort due to meconium
inhalation into the lungs which can further give rise to many adverse
conditions like chemical pneumonitis, lung infections, obstruction of
pulmonary airways, surfactant disturbance, etc.
Statistical analysis done on the same has demonstrated that almost
0.43 per 1000 live births can report meconium aspiration syndrome;
requiring immediate assisted respiratory support. Studies have also
proposed that male sex of the fetus, increased maternal age, reduced
APGAR score are some of the common risk factors assessed for the condition.
For effective clinical assessments routine hospital observation is advised
especially in infants who have passed the meconium in-utero. Some
neonates may display signs of respiratory distress including ischemic
encephalopathy due to hypoxia, convulsions, vomiting, etc. Further,
chest radiograph can display patchy lungs and lung inflammation.
Management of infants exhibiting signs of meconiuminduced lung distress
revolves around supportive therapeutic modules, including oscillatory
ventilation, Extra Corporeal Membrane Oxygenation (ECMO), antibiotic
therapy, exogenous surfactant therapy, etc. The preliminary aim of these
therapies is to reduce lung inflammation as well as decrease associated
lung infection.
Congenital Pneumonia
The condition is described as an early onset, mostly associated with
trans-placental infections, higher maternal age, rubella infections, etc.
Studies have reported Group B Streptococcus as one of the primary
factors responsible for the conditions. Some other investigations
have proposed that improperly done amniocentesis can be responsible
for initiating infections in the amniotic fluid; which further if inhaled by
a full-term fetus can result in pneumonia or other respiratory infections.
Accordingly, as per current guidelines proposed by regulatory authorities,
amniocentesis should be accompanied by the administration of intrapartum
antibiotics.
Apart from the above mentioned, multiple other risk factors have been
stated including pre-labor rupture of amniotic membrane for a prolonged
period, preterm birth, intrapartum fever higher than 38??C, along with
chronic bacterial infections to mother.
It should also be noted that there are cases of late-onset of pneumonia as
well, reported immediately after the birth. Infants who have been on
mechanical ventilation are more vulnerable to pneumonia or other
respiratory infections and are mostly considered to be hospitalacquired.
The clinical assessments are mostly dependent upon the signs of respiratory
distress in neonates, along with a chest radiograph showing multiple patches
in the lungs with inflammation. The immediate administration of antibiotics
is referred to as the mainstay treatment in the current condition; however,
other supportive treatments like oxygen therapy, etc., are also advised
depending upon the requirement to avoid dangerous consequences.
Experts believe that period immediately after birth is quite critical for the
future well-being of a baby as well as a mother, may it be pre-term delivery
or full term. The infant has to go through many physiological changes during
the process, and hence is quite vulnerable to range of respiratory challenges
in his extra-uterine life. Through proper clinical assessments, thorough
investigations, genetic testing for neonatal respiratory diseases, and other
appropriate investigations; these signs and conditions of respiratory illnesses
can surely be prevented. Further, accurate diagnosis is the key to correct
treatment applications, and hence, one should make sure that the clinicians
who are taking care of the infants have vast experience and wide knowledge
about these clinical manifestations, and further reducing the mortality rate.
