Hi welcome to Nursing School Explained! Today's topic is hydrocephalus, so let's
take a look here. So hydrocephalus is an imbalance in
production and absorption of cerebrospinal fluid and, remember that
cerebrospinal fluid is in the brain and also flows all the way down into the
spinal cord and it's usually contained within the ventricles of the brain. But
when there's too much cerebrospinal fluid, the ventricles inside the brain
will dilate, and when that happens the brain gets compressed. And I wrote down
these three terms: so basically in our cranial cavity we have three components:
we have the brain, we have blood inside the blood vessels, and we have
cerebrospinal fluid. And usually that's all contained in our skull so this is a
nice protective mechanism to protect the brain, blood and cerebrospinal
fluid. But when there is now increased production of cerebrospinal fluid,
there's an imbalance between these three structures or compartments within the
brain, and so then something has to give. And if the cerebrospinal fluid gets
larger and larger, the brain gets compressed against the skull. Now
hydrocephalus is usually something that occurs in infants or children and the
good thing about infants is that their skull is not completely fused yet so
they have their anterior and posterior fontanelles open still and so when the
cerebrospinal fluid, there's an increased production, then the skull, there's
basically room for that to expand. And so then you will see fontanelles that are
bulging because now the cerebral spinal fluid is causing
increased intracranial pressure and these fontanelles will kind of allow
the expansion of the cerebral spinal fluid. So when there's open fontanelles,
then the skull will basically enlarge, you will see the bulging
fontanelles but in overtime, because the skull, the bones of the skull are still
kind of formable, pliable, it will result in hydrocephalus. So their skull cavity,
their whole head will get bigger. Now that's the advantage of having open fontanelles
but if the fontanelles are closed, there's no way for the skull to expand, everything
is already set and then the patient will exhibit signs and symptoms of increased
intracranial pressure, which will be all kinds of neurological signs. So what
causes hydrocephalus? It's either congenital, so that can be either by tumors that are
causing increased cerebrospinal fluid production, or Chiari malformation. And
Chiari malformation is a complication of spina bifida cystica, or
myelomeningocele, which is a neural tube defect. And keep in mind that in
embryonic development the embryo is basically just a tube that eventually
starts to develop and elongate and develop into the different parts. And
this neural tube can have a defect called spina bifida or myelomeningocele
where there is then at the level of L5/S1 kind of like a sac-like
protrusion and if this protrusion happens, the the brain kind of gets
sucked down into the spinal cord and this is called a Chiari malformation. And
in turn, cerebral spinal fluid will increase causing the increased pressure
in the cranial cavity and then the enlargement of the skull with all those
complications. Now another cause is acquired
hydrocephalus and this might be due to neonatal meningitis as well as
subarachnoid hemorrhage, so bleeding in the intracranial cavity. So in this case
the cause would be the actual blood taking up more space here rather than
the cerebral spinal fluid, but nonetheless the cerebral cavity will
expand. Now, how do we diagnose this? That's why we measure head circumference
in infants at every visit and sometimes it's pretty obvious already if the
patient has spina bifida that is detected during the prenatal checkups or
some other abnormalities that occur, but head circumference is number one. And
then certainly a cat scan or an MRI to have get some pictures of the exact
structures of the brain to see what's what might be causing it, or
an ultrasound can also be helpful, an transcranial ultrasound as
well as a lumbar puncture, which will help to detect the subarachnoid
hemorrhage. Now the treatment goal for hydrocephalus is to decrease
that CSF accumulation so that the skull cavity doesn't
get enlarged, which helps to decrease disability and death. And the way this is
accomplished is by a the ventriculoperitoneal shunt, or also
called a VP shunt, and bear with me here, I'm not the greatest drawer there is,
but I drew out of a child here. And the VP shunt basically means there's
a tube placed inside the ventricle of the brain that's then threaded down through
one of the blood vessels of the neck all the way down into the abdomen. And
basically the contents are just emptied into the abdominal cavity and then
the body just reabsorbs that CSF, allowing it to drain and not
accumulate in the brain. And that's usually done in smaller children. If
children need a shunt for hydrocephalus and they're a little bit older, this
might be a ventricular-atrial shunt. So basically again stemming from the
ventricles of the brain and that shunt now ends up inside the right atrium, where
a CSF just enters the brain, I'm sorry, the blood stream, and then is circulated
throughout the blood and then reabsorbed by the body. Now, as you can imagine,
anytime you have a surgical procedure that involves placing a shunt inside the
brain there's a high risk for infection. So complications of either one of
these shunts are infection or blockage, and keep in mind these shunts are
usually there for a lifetime. So you might even see adults that have a VP
shunt or VA shunt implanted and now they are being brought to the hospital
for altered level of consciousness and then your thought should be: maybe there's
a blockage or an infection of that shunt. And if the shunt is now blocked that CSF
again is accumulating causing the brain to be
compressed causing altered level of consciousness and neurological deficits.
And the shunt also might need to be changed, which means that there's a
surgical procedure involved and, again whenever we have a surgical procedure
involved in the central nervous system, we always have to be concerned about
infection. So thank you for watching this video on hydrocephalus. If you would like
more information on spina bifida, there's a separate video about that. Thanks for
watching Nursing School Explained.