Switching gears, let’s talk a little
bit about pulmonary hypoplasia,
which is a slightly different
problem than surfactant deficiency.
In this case, the baby has not developed
the lungs appropriately while in utero.
And there’s a famous thing you
should know about that is
pretty high-yield on the test,
which is the Potter sequence.
I want to go through
this with you carefully.
Remember that the primary
source of amniotic fluid
inside the mother is
the baby’s urine.
There are other tissues that make some of
the fluid, such as skin and even lungs,
but the urine is the
So, if a child has agenesis of the kidneys
and they’re not making adequate urine,
this will result in
anuria in utero.
That lack of fluid or
amniotic fluid in the mother
will in turn result in a decreased pressure
of the fluid that is inside their lungs.
Remember, this is a closed system.
As a result of that decreased pressure,
the lungs will undergo agenesis
and this child will have poorly developed
lungs or pulmonary hypoplasia.
So before birth,
we can make the
diagnosis by noting
decreased amniotic fluid
levels or oligohydramnios
or we may notice decreased
because the baby is literally
pinned in place inside the uterus
and those are diagnosed
Flipside, after birth,
the baby may have apnea,
the baby may have severe
the baby may develop a pneumothorax
as they’re trying to open their lungs
but the lung is coming along with the
chest wall creating a pneumothorax,
the child may also have
the original problem,
the renal mass or the enlarged bladder from,
say, severe posterior urethral valves,
anything that’s causing the
urine from not coming out.
And there’s a typical
It’s easy to think of it as just
simply the baby is so constricted
that their facies are abnormal.
So this children may have
Potter’s facies as well
and skeletal abnormalities
having grown and developed
in this fluid deficient
Those are ways we can
diagnose this after birth.