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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

  1. 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).

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.


Written by Patricia Bromberger, M.D., neonatologist, Kaiser Permamente, San Diego, CA
Copyright 1999 Clinical Reference Systems