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Seizures and brain tumours
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Contents
1. What is a seizure?
Types of seizure
Presentation in your Pt
2. Pathogenesis of brain tumour seizures
Location of tumour and seizure symptoms
3. Tumour type and location
4. Management and medication5. Physiotherapy and your Pt
6. Summary
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1. What is a seizure?
Do you know the difference betweenseizures and epilepsy?
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Seizures vs epilepsy
A seizure is defined as: by burst of electrical impulses in the brain escape their
normal limits (past threshold)
they spread to neighbouring areas and create an uncontrolled
storm of cortical nerve cell electrical activity the electrical impulses can be transmitted to the muscles,
causing twitches or convulsions
Seizures are not a disease, they are an event
Epilepsy (seizure disorder) is a neurological condition,that in different times produce brief disturbances in theelectrical functions of the brain
Seizures are a symptom of epilepsy
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Types of seizure
Partial
begin locally in one part of the brain
Generalised
bilaterally symmetric
no local onset and although they involve theentire brain, physical control is rarely lost
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Partial and generalised seizures
Partial seizure with secondary
generalization
Primary
generalised
seizurePartial seizure
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Partial seizures
Simple partial seizure
consciousness not impaired
Complex partial seizure
consciousness impaired
Secondary generalised seizure
begins as partial and transitions into a generalised
seizure
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Generalised seizures
i. Absence seizures (petit mal)- staring, slightbody movement and short periods ofunawareness
ii. Myoclonic seizures- sudden jerks of arms andlegs
iii. Atonic seizures (drop attacks)- suddenlycollapse or fall down
iv. Tonic-clonic seizures (grand mal)- most
severe type of seizure; characterized by lossof consciousness, body stiffening, shakingand sometimes tongue biting or bladderincontinence
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Seizure presentation in your
patient
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Simple Partial Seizures
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Complex Partial Seizures
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2. Pathogenesis of seizures
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Pathogenesis of brain tumour-
associated seizures Pathogenesis is poorly understood
Slow-growing benign tumours cause more seizureproblems than malignant tumours which rapidly destroy
nearby neurones instead of stimulating them4
Slow-growing tumours may cause seizures by focal orremote cell changes3
Alteration in peritumoural amino acids
Regional cell metabolism pH
Protein expression
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3. Tumour type and location
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Tumour type
Seizure risk is associated with grade of
primary brain tumour
Higher risk of having seizures in low-gradeprimary brain tumour, astrocytoma,
oligodendroglioma, meningioma
Lower risk of having seizures in high-grade
primary brain tumour, anaplastic astrocytoma,glioblastoma
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Tumour location
Most important predictor of seizures
Seizures more common with supratentorial than
infratentorial tumours
Cortical tumour main predictor for development of
epilepsy
Tumours affecting frontal, temporal and parietal lobes
more commonly associated with seizures than occipital5
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Seizure prevalence
Any type of brain tumor can cause seizures
Seizures are the presenting sign in 30-50% of Pt with
a brain tumour
10-30% of Pts will develop seizures later in diseasecourse1
25% of Pts with meningioma present with
seizures2
20% of Pts with meningioma, without a history of
seizure, will develop seizures post-surgery2
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Prognosis
Large studies have found no effect of seizures on
survival WHAT KIND OF STUDY?
Presentation with a seizure is a favourable prognosticsign
Earlier diagnosis
Surgically accessible
Over-representation of Pts with lower grade tumours
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4. Management and
medication
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Medication
Antiepileptic drugs (AEDs)
Drug therapy goal: to prevent seizures with the lowest effective doses of AEDs with
the least side effects
Commonly used AEDs: Carbamazepine (Tegretol)
Gabapentin (Neurontin) Oxycarbazepine (Trileptal )
Phenobarbital (Luminal)
Phenytoin (Dilantin )
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AESs: The first line of defence
36%
4%
13%
47%
ha ac es s a e e sy e e- ee w h multiple drugs
eizure- reewith sec d or third drug Seizure- reewith first drug
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AEDs first line of defence
Wen (2002)
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Side effects of AEDs
Side effects are more frequent in Pts with brain tumours
compared with people with epilepsy6
Some AEDs can interfere with chemotherapeutic agentsand corticosteroids eg, dexamethasone reducing their
efficacy7
Drowsiness/dizziness
Ataxia
Cognitive impairment
Dermatological reactions
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Surgery
Focal area of brain causing the seizures
area may be removed without producing new problem
Resection of tumour not always sufficient to stop the seizures (seizures do
not arise from tumour tissue, but from damaged or
malfunctioning adjacent tissue)
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Vagal nerve stimulator (VNS)
VNS is implanted to control
seizures by delivering
electrical stimulation to the
Xth cranial nerve in the
neck, which relays impulsesto widespread areas of the
brain
Used to treat partial
seizures when medication
does not work
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VNS and quality of life
Less severe or shorter seizures
Improved post-ictal period
Better mood Improved alertness
Improved memory/cognition
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5. Physiotherapy treatment
and seizures
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Your Pt may
Have experienced seizures prior to Dx-what is theirpresenting sign?
Develop seizures during tumour Rx at any stage
Have communication problems
Focal facial seizures Have communcation problems
Be receiving AEDs to control seizures
Affecting their attention, cognition, balance
Check your Pts notes thoroughly prior to considering Rx plan Ensure you choose your Rx environment carefully
Ensure that if there is a bone-flap deficit that head protectionis worn continuously
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Summary
Seizures can be the first sign of a brain tumour
Seizures can develop at any stage during treatment
Seizures can have a profound affect on a Pts quality oflife
Seizures and subsequent AED medication may affect
how you treat
where you send your Pt for post-surgery rehabilitation
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References
1. Van Vellen et al. J Neurol Neurosurg Psychiatry1998;64: 581-7
2. Lieu & Howng (2000). Epilepsy Res 38:45-52
3. Herman. Neurology 2002;59(suppl):S21-26
4. Riva. Neurol Sci2005;26(suppl) S40-42
5. Sirven et al. Mayo Clin Proc2004;79:1489-946. Wen & Marks. Curr Opin Oncol2002;14:299-307
7. Hauser et al. Epilepsia 1993;34:453-68