In this section
Our bodies have many automatic functions that
are controlled by the brain. After a severe brain injury, our
ability to control these automatic functions can be reduced.
Automatic functions include breathing, body-temperature control, heart rate and blood pressure. There is a
delicate balance between all of these functions, and they are
usually adjusted automatically. We are only aware of it when
something unusual happens (e.g. when we are sick we can get a high
Sometimes, after a severe brain injury, our
ability to control these automatic functions is disturbed. There
can be under- or overactivity. The brain can respond to a gentle
stimulus, like being touched or hearing a noise, with an
exaggerated reaction (e.g. lots of body movements, high temperature,
high blood pressure or severe sweating). This may occur 'out of
the blue' without any obvious cause. This is called dysautonomia,
meaning disordered automatic function.
Quite often the signs of dysautonomia may not
show until after ventilation in intensive care has been ceased and
sedation such as morphine has been stopped. Sedatives can help
treat the syndrome, but often other treatment is needed. Children
cannot stay heavily sedated for very long periods or other
complications will also develop.
The overactivity often occurs in episodes or
'bursts'. There may be an obvious trigger to start the episode, such as
a painful stimulus like taking blood tests, or there may be no
trigger at all that we can identify. These episodes usually start
suddenly and stop suddenly, like turning a tap on and off. Several
or many episodes may occur in one day (this is sometimes called
'storming'). The bedside charts and parents' observations may help
to work out some triggers.
What are the features?
A variety of actions may be useful in treating
children with dysautonomia. You can:
One or more drugs are often needed. It takes
quite a long time to achieve the right combination of drug
treatments before the dysautonomia is controlled. With time,
the body will again learn to control the automatic responses. Medicines
usually have to be reduced slowly once control seems reasonably
good, because stopping too quickly may lead to a relapse.
During this time, careful fluid and nutrition balance are very
Medications that help include:
All drugs have some side effects and the
effects of any drug combination must be carefully checked by
looking at blood test results. Dysautonomia usually settles with
time, as the symptoms of the child's brain injury settle. This can take
a few days or many weeks. The problem does not recur later in the
The Royal Children's HospitalPaediatric Rehabilitation Service
T: (03) 93455283
Developed by the RCH Paediatric
Rehabilitation Service. First published Feb 2007. Updated November
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