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WHAT IS ENCEPHALITIS?

 

Encephalitis is inflammation of the brain, an extremely serious condition that can affect both children and adults.

 

• Encephalitis is the result of an infection, usually caused by a virus. 
• The brain tissue itself is inflamed, as opposed to the meninges (the membranes that surround the brain), which occurs in meningitis. 
• Sometimes, both the brain and the meninges become inflamed. This condition is known as encephalomyelitis. 

If encephalitis is suspected, a brain scan will be taken to detect swollen tissue. This is one of the main symptoms of the condition.

 

What are the causes?

 

A range of viruses can cause encephalitis and/or meningitis

 

The herpes simplex virus: this is the virus that causes genital herpes. It can be passed by a mother infected with genital herpes to her baby during a vaginal delivery, and therefore a Caesarean section is usually performed.

 

The measles virus: about one in 5000 children with measles have encephalitis as a complication. The condition usually develops a few days after the rash becomes obvious.

 

Mumps virus: this is another condition that can cause encephalitis as a complication.

 

The varicella virus (chickenpox virus): this is usually a comparatively mild form of the illness compared with the other types.

 

Encephalitis can be caused by the herpes simplex virus. A pregnant woman infected with genital herpes can pass it on to her child during a vaginal birth.

 

Recognising the symptoms

 

The symptoms of encephalitis in a child vary greatly; they may be mild or serious and can either appear suddenly or develop over a period of time. The symptoms also depend on the cause - for example, if encephalitis is a complication of measles, the symptoms of measles will be present as well. The symptoms outlined below may be present in affected children

 

• A raised temperature, above 37.2°C (99°F), or vomiting. 
• Headache - if a child is too young to explain that he has a headache, there may be obvious signs of distress, such as persistent crying or rubbing the head. 
• The child behaving strangely, or being consistently irritable or confused. 
• Weakness in one or more parts of the body. 
• Occasionally, the speech is affected and there may be blurred vision and poor balance.
• Decreased levels of consciousness ranging from unusual drowsiness to unconsciousness 
• Convulsions ­the child may have seizures. 

NOTE: fever and headache occur in lots of minor childhood illnesses but if a child also has any of the other symptoms listed above, or if you are worried, you should seek urgent medical advice.

 

Confirming the diagnosis

 

If a child has suspected encephalitis, admission to hospital is usually arranged straightaway. The problem is that the symptoms could apply to a range of diseases that affect the brain, for example an infection or a tumour, so investigations need to be carried out to exclude these.

 

Physical examination: a special series of tests will be carried out, such as testing reflex reactions, to assess the nervous system.

 

Blood samples: these are taken to look for infection, and specimens of the child's urine and faeces may also be sent to the laboratory for examination under the microscope.

 

Electroencephalography (HG): this shows the brain's activity as waves on a graph. In some types of encephalitis, particularly herpes simplex encephalitis, the results are abnormal.

 

Scans: both MRI (magnetic resonance imaging) and CT(computed tomography) scanning can show up any swelling of the brain tissue

 

Lumbar puncture: this will be carried out in most cases because it can distinguish between a viral and bacterial infection, and will therefore exclude bacterial meningitis as the cause of the symptoms. A lumbar puncture involves taking a small sample of fluid from around the spinal cord. The procedure is done using local anaesthetic, so it is not painful. A narrow needle is inserted into the space between the vertebrae in the lower back and fluid is withdrawn using a syringe. The sample is then examined for inflammation or infection.

 

Treatment

 

The treatment of encephalitis has two aims - to treat the cause of the inflammation and to treat the effects of the encephalitis. Most children with encephalitis improve once the cause is treated.

 

Affected children are usually nursed in a specialist unit. It is important to monitor a child's consciousness and, if he is drowsy, to make sure that his airway is kept clear and that he is breathing easily. 

Fluids are usually given directly into a vein to keep a child well hydrated, especially if he is unable to drink regularly if the illness persists for more than a few days, it maybe .necessary to feed the child with special liquid nutrition into nasogastric tube (a tube passed down the nose and into the stomach). 

Rarely if the brain inflammation is severe, a child may have increased. pressure within the skull. In the short term, artificial ventilation (a breathing machine) helps to reduce this pressure.                                           

Herpes simplex Encephalitis is treated by administering the anti-viral drug aciclovir directly into the bloodstream. 

Reye’s syndrome

This rare condition may follow a viral infection, typically chickenpox or influenza, and is associated with children under sixteen years taking aspirin. Reye's syndrome causes liver failure and this causes brain poisoning. The brain poisoning is called encephalopathy and, like encephalitis, it has brain swelling as a symptom.

 

• Symptoms initially include vomiting and signs of a chesty cold. The child becomes drowsy and has convulsions. 
• If doctors suspect Reye's syndrome from the symptoms, they will probably carry out a scan ­either a CT scan or an MRI scan ­which will show swelling of the brain. Blood tests will show that the liver is not functioning properly. 
• A child with Reye's syndrome will need to be looked after on a paediatric intensive care unit. There is no treatment, but doctors will provide medical 'support' - such as artificial ventilation to decrease the pressure in the brain - until there are signs of improvement.

 For  More  Information:  Please  consult  your  physician  on  your  next  visit.