Icterícia neonatal

What is jaundice?

Jaundice is due to a build-up of a chemical called bilirubin in the tissues of the body. Bilirubin is a chemical which is normally found in the body within red blood cells. It is broken down and processed by the liver. There are many different causes of jaundice and they can occur at different times in a life - from birth to old age.

This leaflet will only discuss the types of jaundice that can occur when a baby is first born.

What does jaundice look like?

Jaundice can mostly be noticed in the skin and in the whites of the eyes. The whites of the eyes are often the first tissues that are noticed to be turning yellow. If the bilirubin level is only mildly high then the eyes might be the only part of the body where you can detect a yellow colour. Yellowing of the skin can be seen when there are higher levels of bilirubin.

Why do babies get jaundice?

Newborn babies have more red blood cells than adults have and the red blood cells don't last as long. When the red blood cells are broken down, a substance called bilirubin is made. The bilirubin is made too quickly for the liver to break it all down, so the level of bilirubin increases. It is the increased level of bilirubin that causes jaundice.

Within a few weeks the number of red cells broken down decreases. The liver is also able to break down the bilirubin more quickly. Therefore, for most babies the jaundice disappears by the time they are 2 weeks old.

The most common cause of jaundice in newborn babies is harmless and is called physiological jaundice. This type of jaundice occurs between day 2 and day 4 of life, increases to a peak at day 7 and then fades and disappears by day 14.

Jaundice may also be caused by a serious problem. There is more likely to be a serious cause if:

• It starts in the first day of life

• It is severe (the bilirubin level is very high).

• Your baby is also unwell (for example, irritable or not feeding well).

• It is still present at two weeks after the birth, or your baby has pale stools (faeces which look chalky) or the urine causes dark stains in the nappy. This may be caused by a liver problem.

Icterícia fisiológica

It is common for newborn babies to develop mild jaundice, which starts when they are 2 days old. This is due to a mild increase in the breakdown of red blood cells combined with a liver that is not quite fully functioning. The level of jaundice usually reaches a peak by day 4 of life. The liver soon fully develops and the jaundice usually disappears between 7 and 10 days of age. The baby is well and has no other problems.

Outras causas

The are various other causes of jaundice in newborn babies. Some are due to serious blood or problems with the liver (such as liver disease) or to other problems. As a rule, the jaundice is not likely to be physiological jaundice if the baby is unwell, or the jaundice is present in the first 24 hours after birth.

Serious causes of jaundice in babies include infections and blood group incompatibility. Blood group incompatibility occurs when the mother's blood group reacts with the baby's blood and this destroys some or many of the baby's red blood cells. When red cells are broken down then more bilirubin is made and the baby becomes more jaundiced.

Neonatal jaundice may also rarely be caused by problems with a baby's liver. One example is called biliary atresia which means an obstruction of the normal flow of bile from your baby's liver into the gut.

Icterícia prolongada

Jaundice that lasts until and after 14 days after birth (or 21 days for premature babies) is called prolonged jaundice. Prolonged jaundice may indicate a serious problem but is most often caused by breast-feeding. Breast-feeding can cause a baby to be jaundiced but this is harmless and is not a problem for the baby.

What should you do if your baby is jaundiced?

If your baby develops jaundice then contact your midwife or GP for advice. Jaundice is not usually a serious problem but it is very important to get it checked to see if your baby needs any treatment. Your baby will usually be routinely checked for jaundice by a midwife within 72 hours of birth.

Contact a GP immediately if your baby becomes jaundiced in the first 24 hours of life or is still jaundiced at 14 days of life. Also contact a GP immediately if your baby is unwell in any way as well as being jaundiced.

How long does neonatal jaundice last?

This depends on the cause of the jaundice. The most common cause of neonatal jaundice is physiological and this has usually disappeared by 10 to 14 days after birth.

What tests are needed for neonatal jaundice?

The level of bilirubin can often be measured by a special meter that is placed against your baby's skin (called a transcutaneous bilirubinometer). This can be used for babies born at 35 weeks or more and if they are more than 24 hours old. Otherwise a blood test is needed to measure the level of bilirubin.

Other tests are essential for any baby who is also unwell, has jaundice in the first 24 hours, or has prolonged jaundice. These babies must be seen by a doctor straightaway. Your GP will refer your baby to hospital for further tests. These other tests may include further blood tests, tests for any infection and an ultrasound scan of your baby's liver.

How to treat neonatal jaundice

Increasing your baby's fluid intake is very important. Treatment will also be needed for any cause of the jaundice such as an infection.

Phototherapy

Light treatment (phototherapy) uses light to help reduce the amount of bilirubin and so treat the jaundice. Your baby's skin and blood absorb the light waves. The light waves change bilirubin into harmless substances. Phototherapy is safe and effective. It is used if the bilirubin level goes too high and it is often the main treatment for jaundice in a baby.

A chart is used to see if the bilirubin level is high enough to need treatment. For some babies phototherapy may be started very soon after birth, such as for premature babies or when jaundice starts in the first 24 hours.

Babies receiving phototherapy need as much skin exposed to the light as possible. Your baby will need eye pads to protect their eyes. Phototherapy is otherwise safe.

The main problem with phototherapy is that your baby has to stay under the lights and you will have less chance to hold your baby. There are times when the phototherapy can be stopped for a short time. It is then very important to take every chance to hold your baby.

If your baby is treated with phototherapy they will need to drink more fluids. Your baby may also need to have fluids from a drip into a vein (intravenous fluids). Phototherapy may also cause your baby to have loose stools (faeces).

Exchange transfusion

If the bilirubin level becomes very high then an exchange transfusion may be needed. This involves replacing some of your baby's blood with a blood transfusion to bring the bilirubin level down more quickly.

Other treatments may be needed for any underlying cause of the jaundice.

Are there any complications of neonatal jaundice?

If the level of bilirubin goes very high then this can cause brain damage in your baby and cause problems like paralisia cerebral, learning difficulties and hearing problems. Damage to the brain caused by high bilirubin levels is called kernicterus.

Kernicterus is very serious but it is also very rare in developed countries like the UK. Kernicterus affects about 1 in every 100,000 babies.

Qual é a perspectiva (prognóstico)?

The outlook for physiological jaundice and breast-feeding jaundice is excellent and the jaundice will not cause any long-term problems.

The outlook will otherwise depend on the nature of any serious cause of the jaundice.