Lennox-Gastaut Syndrome
Lennox-Gastaut Syndrome [LGS] is one of the more
severe forms of epilepsy. It usually develops
during preschool years and is characterised by
several seizure types and developmental delay.
Seizures are generally difficult to control due
to their resistance to antiepileptic drugs.
Often no specific cause is
identifiable: however, some of the known causes
include:
· developmental malformations of the brain
· genetic brain diseases, such as tuberous
sclerosis, and inherited metabolic brain
diseases
· brain injury due to problems associated with
pregnancy and birth including prematurity,
asphyxia [lack of oxygen] and/or low birth
weight
· severe brain infections including
encephalitis, meningitis, toxoplasmosis and
rubella.
In many instances, LGS is a sequel to infantile
spasms – sudden spasms or bending of the body,
either at the trunk or neck. These usually
commence at between three and eight months, and
may develop into the mixed seizure pattern,
which characterises LGS, at two to three years.
There are also a number of rare childhood
diseases that may lead to LGS.
It is estimated that LGS
occurs in between three to eleven per cent of
childhood epilepsies with slightly more males
than females affected. The average age of onset
is three years.
LGS is diagnosed by some or
all of the following:
· the presence of a mixed seizure pattern
· some degree of developmental delay or
intellectual disability.
· a typical electroencephalogram [EEG] pattern
of slow spike wave discharges may be present.
An EEG is a graphic chart that displays
electrical activity generated from the brain,
recorded at the skin surface of the head,
commonly referred to as a brain wave recording.
Seizures
Seizures are always of several types and a child
may experience some or all of these. The most
common seizure types associated with LGS are
tonic, atonic and atypical absence seizures.
Periods of frequent seizures may be interspersed
with periods of relative freedom from seizures.
The most common seizure types associated with
LGS are:
Behavioural disturbances
These include poor social skills and attention
seeking behaviour, and have at least four
possible causes:
· the underlying condition causing the epilepsy
· the effects of medication
· the electrical disturbance in the brain in
uncontrolled epilepsy
· difficulty in interpreting information and
understanding the world as others do.
Medication
Antiepileptic drugs [AEDs] are usually the best
treatment for seizures although complete seizure
control is rarely achieved. LGS often requires
frequent changes in dose and type of medication,
with some medications losing their initial
effectiveness. Unlike other childhood
epilepsies, the simultaneous use of more than
one type of medication is often necessary.
The AEDs most commonly prescribed for LGS are
listed in the table below. There are also a
number of new AEDs currently being trialed in
Australia and overseas.
Surgery
Rarely, corpus callosotomy can be considered for
very severe drop attacks.
Status epilepticus
Status epilepticus ['status'] occurs in about 50
per cent of people with LGS and is the term used
to describe prolonged seizures of 30 minutes or
more, or the occurrence of repeated seizures
without regaining consciousness between attacks.
Status can occur with any type of seizure and is
categorised as either convulsive or
non-convulsive Status can last from hours to
days or, in the case of non-convulsive status,
even weeks or months. Factors that may lead to
status include sudden withdrawal from
medication, illness, fever and infections.
Status in children with LGS is most often
non-convulsive It is characterised by severe
confusion, apathy or a 'flat' mood, stupor or,
at worst, apparent dementia. Inconspicuous
muscle spasms and greatly impaired balance and
coordination are usually evident.
Convulsive status may ultimately lead to brain
damage and death unless stopped quickly-usually
with the administration of rectal diazepam. Some
parents and carers learn to administer rectal
diazepam at home. This option would need to be
discussed with your doctor.
To date, little research has
been conducted into the prognosis of children
with LGS. It is clear, however, that prognosis
varies from child to child. Generally, this
syndrome is permanent. A few years after
diagnosis, the epilepsy, which was initially so
difficult to control, may become less of an
issue but impaired intellectual functioning and
behavioural problems frequently persist.
Complete recovery, with normal development and
freedom from seizures, is very unusual for the
child with LGS.
Practical suggestions to help carers support the
child with LGS
Consider using respite care schemes provided
by local councils and other organisations. These
schemes offer the services of a professional
carer to visit your home to look after the
child; or placement with another family or
residential centre. Respite care can be on a
regular or occasional basis.
· Keep a diary that details the child's
seizures, seizure triggers and any side effects
of current medications. This can be useful when
consulting with doctors and in identifying
seizure patterns and medication responses.
· Use an intercom in the child's bedroom to
monitor any changes in their condition.
· On outings, consider using a child-stroller
for school age children going through a phase of
frequent seizures.
· Question your doctor about all aspects of the
child's treatment, including medications and
their side effects, to ensure that you are
sufficiently informed to confidently coordinate
the day-to-day management of the condition.
· If you have any unanswered questions about
medications, contact your local pharmacist.
However, do not alter your child's medication
schedule without consulting your doctor.
· Consider a hand-held harness to help prevent
falls and a helmet to protect the face and head.
· Lower the temperature on the household's hot
water unit or install a thermostat to prevent
scalds and burns.
· Buy a dosette box and tablet cutter from your
local pharmacy to assist in preparing and
administering medication.
Diet
The ketogenic diet has been clinically effective
in reducing seizures. It is very high in fat,
often unpalatable and must be followed exactly.
The ketogenic diet elevates blood cholesterol
levels markedly and is expensive to implement.
It is not a long-term proposition. Some children
benefit from this diet.
Vagus nerve stimulation
The vagus nerve stimulator is a device, similar
in size to a heart pacemaker, which is implanted
in the chest with a lead that passes up to the
neck and is placed around the vagus nerve. This
device stimulates the vagus nerve for about 30
seconds every 5 minutes and has been shown to
improve seizure control in people with
uncontrolled seizures. The device may take up to
a year to show maximum benefit. This device
requires an operation for insertion as well as
for removal. The batteries require replacement
approximately every 5 years entailing further
surgery.
Attention to seizure triggers
It is recognised that the frequency of seizures
may be associated with the child's level of
alertness. The child who is overexcited for
example, or lacks sufficient stimulation, may
experience more seizures. A stimulating but
stable environment can therefore be important in
reducing the number of daily seizures. This may
include a strict routine of regular meals, sleep
and medication.
Illness may also trigger seizures. For example,
seizure activity may increase just before the
onset of high body temperature and fever.
Vomiting and diarrhoea can also effect the
body's ability to absorb medication.
Family support programs
Most state epilepsy associations run family
support programs that often involve daytime and
evening meetings, and usually include expert
speakers. The Epilepsy Foundation of Victoria
coordinates a group called the Uncontrolled
Epilepsy Parents Support Group (UEPSG) for
parents and carers of children with LGS and
other forms of uncontrolled epilepsy. If you are
unable to attend UEPSG meetings or you reside
outside Victoria, you can be included on their
mailing list which comprises many Australian
families, and others worldwide.
It is recognised that the
frequency of seizures may be associated with the
child's level of alertness. The child who is
overexcited for example, or lacks sufficient
stimulation, may experience more seizures. A
stimulating but stable environment can therefore
be important in reducing the number of daily
seizures. This may include a strict routine of
regular meals, sleep and medication.
Illness may also trigger seizures. For example,
seizure activity may increase just before the
onset of high body temperature and fever.
Vomiting and diarrhoea can also effect the
body's ability to absorb medication.
Family support programs
Most state epilepsy associations run family
support programs that often involve daytime and
evening meetings, and usually include expert
speakers. The Epilepsy Foundation of Victoria
coordinates a group called the Uncontrolled
Epilepsy Parents Support Group (UEPSG) for
parents and carers of children with LGS and
other forms of uncontrolled epilepsy. If you are
unable to attend UEPSG meetings or you reside
outside Victoria, you can be included on their
mailing list which comprises many Australian
families, and others worldwide.
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