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SEVENTH FRAMEWORK PROGRAMME


Educational tools for parents

NEONATAL SEIZURES

BACKGROUND INFORMATION

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  What is a seizure?
Each of our brains consists of millions of nerve cells all connected together. Each of these nerve cells (called neurons) create and receive tiny electrical signals which control many aspects of our body function. All neurons work together in a very complex but highly organised and coordinated manner. As the baby grows up and develops new skills, so the organisation of the neurons develops to make it all work

A seizure – sometimes called a ‘fit’ or a ‘convulsion’ – may occur when the brain becomes disturbed in some way (see “what causes seizures”). The communication between individual neurons is altered and many neurons send out impulses at the same time. This simultaneous ‘discharge’ produces the symptoms we recognise,ú although many of the seizures we can record using an EEG may not be obvious – we discuss this further on in the website.

So – a seizure may occur together with changes in the conscious level, with a pattern of movements we can recognise or with no obvious findings – we describe this further in the next section
  How do we recognize a seizure

Recognising that a baby is having a seizure may be quite difficult even for experienced doctors. Seizures in babies are very different compared to seizures that occur as part of Epilepsy in older children and adults.

The most common sign that a seizure is happening is a run of repeated “jerky” or “twitching” movements of the arms or legs that continue when we gently hold one of the limbs to see if the movements stop. This can be seen on the video here

Other babies have changes in their behaviour – such as repeated hiccoughs, jerky movements of the eye or lip-smacking/chewing movements – although all these we see in babies that are not having seizures. Some examples of this can be seen on the video here

Because seizures can be very difficult to identify or diagnose it is really important to check whether the movements occur with changes in the function of the neurons in the brain – we do this by making a recording of the brain waves – called an electroencephalogram or EEG

  How do we tell whether a baby’s movements are normal or a seizure?
Once you are discharged from hospital you might find yourself in a situation where you are not sure if some of your baby’s movements are due to seizures or not. Newborn babies can show a variety of movements that might be misinterpreted as seizures.

For example:
  • Many babies can show some degree of jitteriness when they are crying or when they are asleep. This jitteriness diminishes during the first weeks after birth and is less frequent in quietly wakeful infants. It should get less noticeable once you pick your baby up.
  • Other babies have repeated single jerks of the limbs during sleep (usually when they are dropping off or waking up). We call this “benign neonatal sleep myoclonus” and it stops when the baby wakes up. Neither of these need any treatment.


So how can you recognise seizures? Your doctor will look for repetitive movements that are not triggered by touch or noise, particularly if your baby looks “distant” when they are happening. These movements tend to occur in a cluster or group, which means you will see more than one seizure in a row. Each seizure will most probably look very much like the others. Some seizures only involve a part of the brain (focal seizures) and you might see one arm or one leg twitching or getting stiffer for a short period. Other seizures might involve the whole brain (generalized seizures): With these your baby can show changes in breathing rate and the skin colour can turn slightly pale or bluish.

If you observe repeatedly abnormal movements and are not sure about their significance, try to video them (a smart phone is usually sufficient) so your doctor can have a look at them.

Most seizures end after a very short time (some seconds to a minute). Very few babies develop longer lasting seizures where urgent treatment is needed (see separate section below). When your baby is discharged from the hospital your doctors will tell you what to do in case of a seizure. In general for a short seizure of only a few seconds no immediate interventions are needed whereas for a longer seizure you might be asked to give a medication and call an ambulance. Most of the times when a seizure occurs and you are not familiar with this situation it is reasonable to seek the advice of a doctor.

  What is epilepsy?

Epilepsy refers to more than one seizure, usually a run of seizures, occurring usually in an older child or adult.  We do not refer to seizures occurring in newborn baby (neonatal seizures) as Epilepsy.  Less than 1-in-5 babies who have neonatal seizures go on to have seizures of some type later in life, but many fewer go on to develop Epilepsy

 

Epilepsy consists of a group of conditions, taken together these are termed the Epilepsies, which differ widely in the age of onset, types of seizures, response to treatment, and underlying and concomitant disorders.

 

Most neonatal seizures either settle spontaneously or respond well to treatment.  To a large extent this depends on the reason the seizures are happening (see why do babies have seizures)

  How often do babies have seizures?
Seizures are more common in the newborn period than during any other time throughout life (see graphic). Between one and three in 1000 develop seizures (0.1%-0.3%), even so they are relatively rare events – jitteriness and myoclonus are much more common. Seizures may occur more frequently in babies born prematurely, when the brain is still more sensitive to disturbances. Most seizures happen during the first days after birth and are much less frequent after the first week.
  Why do babies have seizures
We know that the immature brain is more susceptible to seizures and the underlying mechanisms for this are still a field of intense medical research. Nerve cells are connected through connectors called synapses, where chemicals called “neurotransmitters” interact with the nerve cell to pass on electrical signals. These substances and structures change as the baby develops. For example an important neurotransmitter called gamma-aminobutyric acid (GABA) increases transmission in babies whereas in older children or adults it decreases it (we call this excitation and inhibition). This might be a reason why babies have more frequent seizures, which usually stop as the child gets older.

In most babies with seizures an underlying disorder or cause for seizures is found. The range of conditions that causes neonatal seizures varies with gestational age. Whereas in extremely preterm infants bleeding into the immature brain is most frequent, in term infants it is usually a lack of oxygen around the time of birth or a “stroke” (see sections below), among many other conditions. Sometimes an infection or changes in blood sugar or blood salt levels may give rise to seizures and can be treated. In other cases babies are born with an abnormality of brain development, a disorder of the body’s chemistry or metabolism, and some babies carry a genetic change that makes them more likely to have seizures. Your doctor will explain if he or she thinks that one of these conditions is causing the seizure.

 What is hypoxic ischemic encephalopathy?
A small number of babies show signs of stress at delivery and need help to breathe. This could be a sign that the baby suffered lack of oxygen or blood supply before/during birth. Most do well once they have settled after birth, but some need extra care and support. The worry is that the brain has suffered from this period of poor oxygen or blood supply. If this period prolonged and injures the brain, we call this asphyxia. This can cause swelling of the baby’s brain leading to irritability or excessive sleepiness during the first few days. The medical term we use for this is ‘encephalopathy’. We can assess the degree of encephalopathy through a change of electrical brain activity by doing an EEG (see section below). Most babies with encephalopathy get better without treatment, although for those with more severe brain injuries we treat by reducing the baby’s body temperature to around 33.5oC for 72 hours (we refer to this as cooling or use the technical term therapeutic hypothermia). Your doctors will answer any questions you have about this.
 What is a stroke?
Sometimes seizures are the first sign of what is called a “stroke”. This happens when one of the brain’s blood vessels becomes blocked, usually with a clot. This leads to an area of the brain becoming injured in a similar fashion to what happens to the whole brain in asphyxia, as above. We think these happen in the newborn period because of changes in the system that allows blood to clot. Many strokes only affect small areas of the brain but some are more extensive.  Often we do not notice anything other than seizures in the period after birth. As the tissue responds to the injury it may trigger seizures.  Sometimes these are confined to one area but they also may spread.  There are many types of stroke and your doctor will explain what has happened to your baby. 

TESTS THAT WE DO TO DETECT SEIZURES

Working out whether seizures are happening

When a baby presents with a seizure, doctors will perform a thorough examination, focused on finding the underlying condition. The doctor will be looking for the level of consciousness, muscle tone, body-posture and reflexes as well as differences between movements on each side of the body. We also examine the skin carefully for birthmarks, changes in colour, rashes, bruises or bleeding, all of which are sometimes signs of the cause of seizures. All other body systems will also be checked.

 

The doctor will then perform some blood tests to work out if an immediate treatment needed. Imbalance in salts and chemicals in the body and infections will be ruled out first. Often the doctor will want to rule out an infection of the brain if suspected (meningitis is the infection of the tissue layers surrounding the brain, encephalitis is an infection of the brain itself) by doing a lumbar puncture - a test where your doctors will drain a little amount of cerebrospinal fluid - the fluid surrounding the brain and the spinal cord – with a small needle from the lower part of your baby’s back. In most cases antibiotics will be started, as it takes a few days to be sure there is no infection.  

Next the doctor will perform an electroencephalogram (EEG) - this is used to record the brain activity by picking up the very low intensity electrical signals from the brain cells with the help of electrodes which stick to the scalp with the help of some gel.  We only record the brain signals and do not transmit anything to it.

 On the computer the doctors can analyse the recording and detect the typical pattern of seizures. We use several electrodes so we can look for seizures in different parts of the brain. During a seizure we see rhythmic activity (sometimes called waves or spikes) in some or all areas of the brain.  When we give medicine to stop fits (antiepileptic drugs) these seizures may stop but sometimes they may start again and further medicine is needed.

 During an EEG recording you will notice a lot of different waves or rhythmic changes that do not represent abnormal brain activity. For example movements of your baby’s head but also movements of persons in the room or just the fact that you patted your baby while the EEG was running will result in changes of the EEG trace (we call them artefacts). An experienced EEG interpreter is trained to differentiate these from abnormalities arising from your baby’s brain activity and our EEG machine has a special programme to draw our attention to episodes when seizures may be happening so we can look at the recording closely.

Monitoring Seizures in Babies

As clinical features of neonatal seizures are variable and in many cases we cannot be sure that a baby has seizures, continuous monitoring of the electrical activity of the brain with EEG is necessary. At the same time we make a video recording of your baby; to detect very minimal changes with in behaviour that occur with seizures recorded on the EEG.

We also monitor heart rate and oxygen levels in your baby, as often a drop of oxygen saturation and an increase in heart rate can be seen with a seizure. 

EEG Example:

Above you can see a baby with applied EEG monitoring using an EEG cap.

A normal EEG trace in an awake newborn. You can see the mixture of different frequencies. The activity of right side of the brain is represented by red lines (channels) and the left side is represented by blue lines. The heart rate is registered at the same time and demonstrated in the last trace (in violet).

The interpretation of a multichannel EEG requires special expertise and not all neonatal intensive care units (NICUs) have this available 24 hours a day, so we use a special display that makes it easier to detect seizures called the amplitude integrated EEG (aEEG).  This can be done with all the EEG electrodes in place, or sometimes only four or five are needed. The aEEG is relatively easy to interpret.

aEEG-example:

 

You can see the reduced set of electrodes on the head of the baby, attached with little white stickers. The sticker next to the nose is attaching the nasogastric tube to feed the baby and this is not part of the aEEG system.

 

 

The traces above give the multichannel EEG where you can see the rhythmic activity of a seizure (first two red channels). Below this the time-compressed, amplitude integrated EEG is projected, the time cursor in red indicates the position of the chosen time segment. In the upper aEEG trace you can see a change of the lower band limit with the seizure.

 

Neonatal intensive care unit:

Above you can see a baby ventilated on the intensive care unit with applied EEG monitoring.

 

The picture above gives an overview of a neonatal intensive care unit.

 What Other Tests Do We Do

It is helpful to have a test which shows us something about the brain structure by taking a picture. We use technologies that are not harmful to the baby or brain, magnetic fields or ultrasound avoid the use of radiation and are the safest, though sometimes x-rays are needed in a scan called a CT (or computerised tomogram). 

Cranial ultrasound is readily available in a modern neonatal intensive care unit and many of the doctors are skilled in its use. As your baby’s skull has not fully joined together in the first months after birth, we can use the soft spot or fontanel on top of the head to use ultrasound without bone making it very difficult to see anything. Ultrasound works like a submarine’s sonar, a sound wave is sent out (much too high pitch for us to hear) and we measure the reflection of echoes from the brain.  As the tissues of the brain reflect sound differently we can easily build up a picture of the brain. We can identify bleeding in or swelling of the brain quite easily. We can also get information about how fast the blood flows in the vessels inside the brain using a special type of ultrasound called Doppler ultrasound – this gives us really useful information about any swelling or blockages in blood vessels.

Magnetic resonance imaging (MRI) gives us the most information about the brain and is usually performed in most babies with seizures. MRI uses a magnet to detect very faint signals from the brain and then the computer builds up a very accurate picture.  The MRI takes between 30 minutes and an hour to complete and is best done when your baby is sleeping – e.g. after a feed or a small dose of a sedative. The MRI can identify many of the conditions that cause seizures and tell us how healthy the brain is.  Different hospitals do scans in different ways and your doctor will explain this procedure to you.

 

 

 

TREATMENT OF NEONATAL SEIZURES

When Do We Need To Treat?

We are always concerned that seizures may harm the developing brain of your baby. Therefore treatment is recommended even if seizures are only seen on the EEG and you do not see any behaviour changes in your baby (e.g. no rhythmic movements). In general treatment is started shortly after the seizure, even more so if seizures are occurring repetitively.

 
 Which Medication is Used?

Worldwide a drug called Phenobarbitone is the first drug of choice to treat seizures in the newborn baby. The drug has been used for half a century and about half of babies with seizures respond to it. It is a well understood drug and generally very safe. Sleepiness is one of its major side effects and you might observe this especially in the first days of the treatment (often this effect will diminish over the first weeks as your baby gets used to the medication should it continue). 

If your baby does not respond to this medication there are several drugs available with names like Midazolam, Lidocaine, Phenytoin and Levetiracetam all are used as second line drugs – this means when we know that Phenobarbitone was not effective. Which drug is preferentially used is dependent on the country where you are living and the experiences of the centres with the individual drugs.

In general we give the medication via intravenous line or drip in order to have a quick response. If we need a longer treatment the preparation might be given as a solution that your baby take in a feed.

Research into which are the most effective medicines to use is really difficult to do and we are part of a group of doctors trying for the first time to work this out using the best technology available.

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Are Vitimans Helpful?

In a small number of babies with seizures an disorder of their vitamin system is present and some babies respond to a large dose of vitamin B6, which is usually given with an EEG test running to see if it is effective.

 

 

 

 

OUTCOME FOR THE BABY WHO HAS HAD SEIZURES

Do Seizures Harm The Brain

A single seizure of a short duration does not cause appreciable harm. However we know that very frequent seizures can harm the brain and make it more likely to have further seizures. To protect your baby’s brain from further damage we also treat seizures only detected on the EEG.

 Will My Baby Always Need Medication?

Often newborns require medication for a short period after birth. Ongoing seizures are very uncommon in the newborn, compared to older children or adults and often settle after a few days.  When your baby is discharged from the hospital the medication might already have been stopped or reduced. For some babies seizures persist and medication needs to be continued and your baby monitored as an outpatient.

 Do These Medications Effect My Baby In The Long Term?

We know that in the neonatal brain numerous developmental changes occur (see section why do babies have seizures). And we also know that anti-seizure medications can have an impact on development. For example when a medication makes your baby sleepy it cannot discover the world in the same way and acquire new skills in the same speed. Because of this we always try to reduce medications (and therefore the risk of side effects) or stop them as soon as possible. It is thought that short periods of treatment do not affect long term development, but the underlying reason that the seizures occurred may also indicate problems – your doctor should discuss this with you.

 

 

 

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