Clinical Reference Systems: Pediatric Advisor 10.0
Infection of the Newborn
Definition
Newborn babies can get infections easily because their
defenses against infections are not well developed. The
more premature a baby is, the more likely she is to get an
infection.
When a baby first develops an infection, the baby might:
- not feed well
- be very sleepy, not wake up for feedings
- be irritable, not settle down after feedings
- breathe fast (over 60 breaths a minute)
- have trouble keeping a normal temperature (a normal
rectal temperature is 99.8ƒF, or 37.5ƒC)
- not act right, have a change in behavior.
Many healthy newborns have these symptoms occasionally.
However, if a baby keeps having these symptoms, she needs to
be checked.
As the infection gets worse, a baby might:
- have pale or greyish skin
- work hard to breathe
- have a bluish color around the lips and mouth
- have a low body temperature despite normal wrapping with
clothes or blankets (a rectal temperature under
98ƒF, or under 36ƒC)
- have a high body temperature (a rectal temperature over
100ƒF, or over 38ƒC).
Some newborns may have an infection in one specific part of
their body. In these cases you might see:
- redness or swelling of skin, particularly around the
umbilical cord or circumcision
- redness, swelling, or yellowish discharge from the eyes
- blisters on the skin.
Cause
Most newborn infections are caused by bacteria. Bacteria
normally live in the birth canal, and the baby is exposed to
them during birth. The baby may swallow or breathe in the
fluid in the birth canal and then the bacteria may get into
the baby's lungs and bloodstream.
A baby may be sick at the time of birth or become sick any
time during the first week. The first symptoms may be
subtle, but as the bacteria multiply the baby can become
quite sick very fast. If an infection is found and
treated early, the baby will do very well. If the baby is
not treated until the later stages of the infection, the
baby may be very sick and need intensive care to recover.
Sometimes newborns catch a viral infection. Viruses cause
colds, flu, and some diseases such as herpes and chickenpox.
A virus may travel from the placenta into a baby's
bloodstream before birth. Or the baby may be exposed to a
virus in the birth canal during delivery. Occasionally, a
newborn catches a viral infection after birth by being
exposed to someone with a cold.
Treatment
- Philosophy of treatment
Many newborns are tested and treated for infection, even
when their doctors are not yet sure that they have an
infection, for the following reasons:
- Infection is a common problem for newborns.
- Newborns can get sick very fast.
- Babies respond very quickly to antibiotics. They do
extremely well if they start getting antibiotics when
an infection has just begun.
The early signs of infection are subtle and not specific.
For example, at first it may not be known whether a baby's
fast breathing is caused by an infection or by fluid in
the lungs. If treatment is not given until it is certain
the baby has an infection, the baby may become quite sick
and require intensive care. So, if a baby has one or two
signs of infection, the baby is often tested for infection
and antibiotics are given until the results of the tests
come back (usually 48 to 72 hours).
- The special care nursery (SCN)
If a baby has signs of infection, she is taken to the
special care nursery (SCN) for evaluation and treatment.
The baby is placed on a warming bed. She is attached to
a cardiorespiratory monitor, which continuously measures
her heart rate and breathing rate. If the baby is having
trouble breathing, she is attached to a monitor that
records the amount of oxygen in her skin. This monitor is
called a pulse oximeter.
- Laboratory tests
Certain laboratory tests will show if a baby has an
infection and where it is located.
Samples of the baby's blood are taken for a blood count
(CBC) and blood culture. The CBC counts the different
types of cells in the blood. The blood culture is a
test to see if bacteria can be grown from the blood. A
sample of the baby's urine is tested for signs of
infection.
Several other tests may be done. If there is an obvious
site of infection, a sample of secretions may be
cultured (for example, pus from around the umbilical
cord or eye). If a baby is having trouble breathing, a
chest x-ray may be taken to look for signs of pneumonia.
If the doctor suspects the baby has meningitis, a sample
of cerebrospinal fluid (also called spinal fluid, or
CSF) may be tested.
- Antibiotics
Suspected bacterial infections are treated with
antibiotics. After the laboratory tests are begun, an
intravenous line (IV) is inserted into one of the baby's
veins. The IV is used to give antibiotics to newborns
to make sure that the right amount of antibiotic reaches
the baby's bloodstream. Antibiotics are not well
absorbed into the blood from a baby's stomach. If the
baby is given antibiotics by mouth, the concentration of
the medicine in the baby's blood will be too weak.
Treatment usually begins with two antibiotics. These
antibiotics treat all the bacteria that might cause
infection in a newborn. Ampicillin (a kind of penicillin)
and gentamicin are often used. Both antibiotics are very
safe and have been used for a long time in newborns. They
have very few side effects. In general, newborns do not
have allergic reactions to medications, even if other family
members are allergic. The gentamicin levels in the
bloodstream can be monitored and the dosage adjusted so that
the baby gets just the right amount.
- Supportive care
Antibiotics help a baby fight infection. Other
treatments help the baby's symptoms. If the baby is
breathing too fast to eat, he is given fluids through
the IV so he won't get dehydrated. If he is too sleepy
to eat, he may be given IV fluids or he may be fed by
dripping milk through a tube that passes through his
mouth and into the stomach (gavage feeding). If the
baby needs extra oxygen, he is placed in a plastic hood
into which extra oxygen is blown.
Some babies are relatively well and the only treatment
they need is antibiotics. These babies are able to
breast-feed or bottle-feed.
- Meningitis
Meningitis is a serious infection of the fluid
surrounding the brain. Any baby who is very sick from
infection or has bacteria in her blood could get
meningitis. Meningitis is diagnosed by doing a test
called a spinal tap. It may also be called a lumbar
puncture, or LP.
Spinal taps are safe procedures for babies. The baby is
curled on her side for the test. To make sure that she
is breathing OK during the test, the baby is attached to
a monitor and a nurse holds and watches the baby during
the spinal tap. A hollow needle is put into the space
in the baby's back below the spinal cord and a small
amount of spinal fluid is taken. The fluid is then
tested for infection. Most babies do not like to be
held in this position and will cry during the test, but
a spinal tap is no more painful than blood drawing. It
takes 5 to 10 minutes to perform a spinal tap.
If a baby is very unstable from breathing problems or
for other reasons, antibiotics may be started and the
spinal tap postponed until the baby is better able to
tolerate the test.
The baby's parents will be asked for their written or
verbal consent before the spinal tap is done. Some
parents worry that putting a needle so close to the
spinal cord will cause the baby to become paralyzed.
However, there is virtually no risk of paralysis because
the needle is inserted into the space below the end of
the spinal cord.
- Determining the cause and site of infection
Many babies are treated for the possibility of
infection. However, most of these babies turn out not
to have an infection. Whether a baby has an infection
can be determined by several factors:
- the nature and severity of symptoms
- whether laboratory tests show signs of infection
- the results of cultures.
If a baby does have an infection, bacteria usually grow
in a culture within 2 to 3 days. If cultures are
negative (no bacteria grew) and the baby's symptoms go
away quickly, or if some other cause is found for the
symptoms, the baby probably does not have an infection
and the antibiotics will probably be stopped. If the
cultures are positive (bacteria grew) or the baby's
symptoms strongly suggest infection, the baby will
continue to receive IV antibiotics for 7 to 14 days.
- Viral infections
If your baby has a viral infection, supportive care is
usually the most important part of the treatment (see
section 5). Generally, viral infections cannot be
treated with antibiotics, and most babies will be able
to fight the infection without medication. However,
there are now a few antiviral antibiotics that can be
used for specific viral infections, such as herpes and
chickenpox.
COMPLICATIONS
Nearly all babies who have infection when they are newborns
recover completely and do not suffer any long-term problems.
Babies who have meningitis are at risk for hearing loss and
will need to have their hearing checked several times during
their first year. They can also develop learning or other
developmental problems later on and will need to be followed
by their doctor for these problems.
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