00:00
Hi. Welcome to our lecture on Pediatric Meningitis. We're
going to start by talking
about some terms and concepts; review the risk factors and
causes of pediatric
meningitis; talk about the signs and symptoms you might see
in a neonate, infant
or child; talk about how it's diagnosed, and the basics on
how it's treated and
prevented. Let's start with terms and concepts. Meningitis
is a word that combines
the words meninges and itis. The meninges are the protective
covering of the brain
and spinal cord. There are actually 3 layers within them.
The dura is the outermost
layer of the meninges. Itis means it's a suffix that means
inflammation and it's
usually associated with some sort of disease process. So
meningitis is basically an
inflammation of that protective membrane, the meninges that
cover the brain and
spinal cord. It's usually caused by a virus or a bacterial
infection of the
cerebrospinal fluid which is the fluid that's in your brain
and spinal cord that's
protecting it, that's delivering nutrients to it, and that's
helping it rid it from some
waste and toxins. Meningitis is a global public health
challenge. It's still endemic
in some of the underdeveloped countries especially those
with low vaccination
rates. There are several forms of it and we're going to
actually talk just a tiny bit
about each one, but we're going to focus on the main 2 which
are bacterial and
viral. The signs and symptoms of meningitis are similar
regardless of form, but
they're more pronounced in the bacterial form which is very
very high risk and can
be very often fatal compared to the other types.
01:52
Let's review some risk
factors and causes of meningitis. Age is a risk factor, so
the very young and the
very old are going to be at higher risk than the rest of the
population except for the
adolescent population. The older adolescent, so around age
17 to age 23 or so
or the college age population as they're sometimes referred
to are also at a higher
risk for meningitis to some strains of meningitis due to the
group settings that they
often live in and because they usually hang out a lot with
big groups of their peers
so they're just more likely to swap germs and be exposed to
more illness especially
if there's somebody in their group of peers that is
unvaccinated. Certain medical
procedures as well as certain craniofacial deformities might
put somebody at risk
for meningitis due to a device or an abnormality that is
near the brain or has access
to the brain. An example is a cochlear implant. Also, the
various forms of
meningitis have their own risk factors. So for example,
somebody who goes
swimming a lot in warm fresh water, such as a pond, might be
at a slightly higher
risk than the general population for an amoebic meningitis.
Somebody who lives in
underdeveloped country where they may not pasteurize their
food, they may eat
meat that is raw or is not well cooked may be at higher risk
for parasitic
meningitis. Those are both very rare forms but that's just
an example of how
pathogen specific transmission has its own set of risk
factors. And finally, and even
if it's not vaccinated especially against the major forms of
meningitis that have
vaccines is definitely at higher risk for meningitis of all
types.
03:45
Despite what many people might
realize, there's actually 6 forms of meningitis.
03:52
We often just talk about bacterial
and viral because they are much more common than the others,
but we're going to
talk about all of them a little bit. Let's start with
bacterial.
04:05
Bacterial is definitely most often serious and quite a bit
more serious than viral.
04:11
Vaccines protect against many forms of it and it also can
turn into sepsis fairly easily
and fairly quickly. It's seen more often in children under
age 1 than in older
children and this is because first of all they do have less
developed immune system
but also because they often get it from either birth from
their mother through the
birth canal, from group B strep, or they can get it
sometimes even from E. coli
especially sometimes an E. coli bacteria which comes from
poop can contribute to
urinary tract infections in young infants and that is
another fairly common cause of
meningitis that has a bacterial cause. Again, we talked
about another pecan
incidents for around age 16 to 23 which is that college age
or adolescent
population. Let's go over some of the bacteria that cause
meningitis in children.
05:11
The first one is Streptococcus agalactiae. This is also
known as beta strep. Some
infants when they're born get this form of bacteria from the
mother's birth canal.
05:24
That's why pregnant mothers are tested for beta strep and
they're given antibiotics
usually during the birth to help prevent transmission.
Streptococcus pneumonia
or pneumococcus is another bacteria that can cause bacterial
meningitis. And
Haemophilus influenza or HIB. E. coli or Escherichia coli is
a pretty well-known
bacteria found in both human and animal poop. And the
dreaded Neisseria
meningitides otherwise known as meningococcemia. This is one
of the most,
probably the most serious form of bacterial meningitis. It
is the only type
transmitted by droplets from nasopharyngeal secretions. This
bacteria actually
lives in the throats and noses of some people and never
causes any problem, but
that's the case with many different organisms. Sometimes we
have no idea why
but they just all of a sudden cause an infection and this is
one of them. So it's most
common under age 12 months of age and then it has that
secondary peak in that
adolescent population and college age population.
Meningococcemia is something
that causes meningitis in this population and fortunately
there is a vaccination
for it that the adolescents are supposed to get during that
age to try to prevent it.
06:52
Neisseria meningitides or meningococcus is the most dreaded
form of bacterial
meningitis. It's also known as meningococcal disease. When
bacteria from
meningococcus infects the CSF, it causes meningitis. When
the bacteria from
meningococcus infect the bloodstream, it's considered
meningococcemia or
or meningococcus in the blood, emia is a suffix for blood or
in the blood.
07:22
Sometimes it can infect both the CSF and the bloodstream.
This is the hallmark
sign of meningococcal disease. It's a purpuric rash and
purpura are basically like
really big petechia so it's a rash that's caused by
bleeding, not by the typical
inflammation inflammatory processes that caused some other
rashes. Meningococcal
disease is definitely a very severe disease in anybody that
has a purpuric rash
especially one that is all over their body needs to be taken
very seriously and
precautions need to be taken assuming they have this disease
until it's ruled out.
08:03
Alright, now let's talk about viral meningitis. Viral
meningitis is usually much less
serious than bacterial. Most people will recover from it
without any treatment at
all. Some don't even come to the doctor's office or to the
hospital when they have it
because they don't realize they have it. If they do present
to a hospital for
treatment or for identification of it and if they get a
lumbar puncture to check the
cerebrospinal fluid, it will not show any bacteria in the
fluid. Now, let's go over
some of the pathogens that are known to cause viral
meningitis. Some of these are
pretty benign most of the time but cause problems in other
types of patients or in
other situations where they just happen to invade. Herpes
simplex virus is a virus
that the infant can get during birth from the mother.
Cytomegalovirus is a virus that
causes some viruses of childhood that can be fairly benign
usually but can also
cause infection and cause viral meningitis as well. The HIV
virus is another virus
that can cause viral meningitis and the enterovirus which is
another virus that
causes fairly benign childhood illnesses can be spread
through respiratory droplets
and sometimes found in the GI tract. Alright, let's go over
the less common forms
of meningitis. Fungal meningitis is a pretty rare form and
it usually just affects
people who are immunocompromised for some reason or at
higher risk for
contracting it such as people who might have cancer or HIV.
Parasitic meningitis is
quite rare. It's usually only seen in underdeveloped
countries where people might
be eating food that has some sort of parasite in it. Amoebic
meningitis is a very
rare and devastating form of meningitis that's almost always
fatal, is caused by an
ameba that lives in warm fresh water and soil. It's only
contracted when this water
rushes up somebody's nose. Usually, fairly forcefully. Not
many people have
contracted this, but those who have have often either been
jumping in water that
meets this criteria or they're at a water park and they may
go down a slide or some
other type of ride that propels them into this water at a
high rate of speed and then
that water rushes up their nose. And if it has this amoeba
in it, it can infect their
brain. Finally, there's a few other types of meningitis that
we won't go into that
maybe caused, for example, by some forms of cancer.