EPILEPSY SURGERY

WORKSHOP

K.B.Das

Master Class July 2012

Young Epilepsy

Aim

To discuss presurgical evaluation through some

illustrative case studies

To highlight practical issues

The dilemma

The removal of or modification of a part of the

brain with the aim of alleviating seizures

Epilepsy Surgery

Case 1

The jerking girl

History

15.6 yr girl

Normal birth, development

Well until 9 yrs of age

Mainstream school

9yrs

1st seizure: aged 9 yrs, x 1hr GTC

Admitted to local hospital

Rx Lorazepam, Phenytoin,

intubated, Thiopentone

No definite fever, rash

Few days before-episode of staring, fidgeting of

hands, confusion

Course in hospital

? Encephalitis

CT normal

CSF 17 WBC

Rx –Aciclovir,Antibiotics

Seizures controlled on carbamazepine

Stable when discharged, ? behaviour not normal

Progress

9 - 10 yrs : Recurrent attacks

Left arm posturing,staring,dysphasia,

tachycardia lasting 30-90 secs x 12/hr

Repeated episodes of status

No focal deficits on examination

MRI- Normal

What is the problem?

?Sequelae of encephalitis

?Neurodegenerative disease

?Seizure disorder

?

What is the next step?

EEG right slow

Sz onset right hemisphere

History (contd.)

Recurrent focal sz

At times transient weakness of left face & leg,speech disturbances

Frequent jerking of left leg

Resistant to various drugs (valproate,clobazam,lorazepam,

phenytoin,steroids)

Repeat CSF-normal

Progress

Left side clumsy

Dysphasia

Struggling in school

Uninhibited behaviour, aggressive,

hyperactive

What next ?

MRI

?

Rasmussen’s Encephalitis (Rt)

April 2006

Right functional Hemispherotomy

Dense Lt hemiplegia

Weaning Phenobarbitone

Reducing steroids gradually

July 2006

Recurrence of sz post op

‘Stretches’

Rt sided jerking – several /day

Any thoughts?

Rasmussen’s encephalitis (Kozhevnikov-Rasmussen Syndrome)

“A severe, probably acquired, neurological

neocortical disorder characterized by intractable

mainly motor focal seizures, epilepsia partialis

continua and progressive neuropsychiatric

deterioration with hemiparesis and mental deficits.” (Panayiotopoulos)

Rasmussen’s encephalitis

Peak onset around 5 - 6 years

Sex incidence equal

Rare

Progressive initially and then gradually burns out

Rasmussen’s encephalitis

Aetiology:

Unknown

?Chronic viral infection

?Autoimmune - T cell mediated

Pathology:

Inflammatory process – initially localized then spreading

Mainly a cortical process

Rasmussen’s encephalitis

EEG:

May be normal initially

Later unilateral, focal slow activity

Often progresses to bilateral slowing

Progressive loss of normal rhythms over affected

hemisphere

Interictal spikes/sharp waves common

– unilateral/bilateral

Imaging

Progressive hemi-atrophy

Commonly starts in temporo-insular region with

enlargement of temporal horn and sylvian fissure

Temporal & Frontal lobes chiefly affected

Involvement of Caudate nucleus

Management

Immunomodulation

IVIG

Methylprednisolone

Prednisolone

Azathioprine

Anticonvulsants

Definitive therapy

Hemispherotomy

Timing critical

Case 2

The baby who wouldn't leave hospital !

11 wk boy

Forceps delivery, no AN problems

Sz from D1

Twitching of right arm, leg ,few secs x multiple

Eye flickering, pupillary dilatation, cycling of arms

D6 : Rt sided jerking – left , bilateral convulsive sz

Frequent attacks, needing rescue meds

Never left hospital from birth

PICU X 2 for iv clonazepam at 5 wk , 10 wk

11 wk

Subtle behavioural changes, eye flickering and

deviation to right and sometime right upper limb

jerking and stiffening.

It may involve right leg and left hand

Duration: 20 to 60 seconds

Frequency: 50 to100 / day

Medications

Previous

Phenobarbitone

Sodium Valproate

Phenytoin

Carbamazepine

Clobazam

Clonazepam infusion: partial

control

Midazolam (rescue)

Paraldehyde (rescue)

Current

Vigabatrin 150 mg/kg/day

Levetiracetam 50 mg/kg/d

Clonazepam

Paraldehyde 5 ml (50:50mix)

Development : fixing and following at 10 wks (when well)

Family History : Nil relevant

O/E:

OFC 47.5 cms

No dysmorphic features

No neurocutaneous markers

Spontaneous movements Lt> Rt

Brisk reflexes Rt UL & both LL

Truncal and axial hypotonia

Ophthalmology -normal

EEG (Local)

Numerous seizures have been documented.

All have a stereotyped appearance though the clinical onset and termination are difficult to define precisely.

There is increased rhythmic jerking of the eyelids and deviation of the eyes (with a slightly dysconjugate gaze) to one or other side or often downwards. No jerking of the limbs is seen.

All are associated with epileptiform rhythmic activity appearing over the left centro-temporal and posterior temporal region with slightly variable emphasis between these two electrode locations.

EEG (GOSH )

Prolonged EEG recording (15 hours) with 78 electro-clinical seizures captured:

Asymmetry in the background with excess of slow activity over the left.

Very frequent epileptiform discharges seen over the left central and posterior temporal regions

Infrequent independent discharges over the right central region

Stereotypical electrographic seizures arising from the left centro-temporal regions and

spreading to the right central region. These are associated with rapid bilateral eye blinking, head turn to the right and reduced right arm movements. The seizures vary in duration from 20-60seconds with the shortest interval between seizures being 20seconds.

When compared to the previous EEG (20/05/2011), the site of seizure onset has not changed. There is slight improvement in the background activity over the left hemisphere however this could be partially state (sleep/wake) related.

What next ?

Any thoughts?

?

Echo: cardiac rhabdomyomas

Summary

11 week old infant with clinical diagnosis of Tuberous sclerosis

He has symptomatic focal refractory epilepsy onset from

Day 1 of life

Seizure semiology: stereotypical, left hemisphere origin

Focal deficit right upper limb (frequent seizures)

MRI Brain: Bilateral changes with possible dominant tuber /

area of cortical abnormality in left parietal region

Telemetry: left centro-temporal region

Outcome

12 wks:

Urgent discussion at MDT

Resection of left parietal cortical tuber with ECoG

(Electrocorticography)

Seizure free post-op

Recently: ? Recurrence of events ,for re-evaluation

Case 3

Sz from the wrong side !

8 yr old boy

Birth History: Born 42 weeks

15 hours of age, apnoeic. SCBU

Blood sugar of 1.2 mmol /L

Responded to a bolus of Glucose but had 2 further right sided fits, within 24 hrs

Early Development : Normal

History

First seizure: <1 year old

Subsequent seizures: Age 5 years, complaining of ‘sore head’ Then started to see animals and dinosaurs Subsequently, would wander, laugh inappropriately, staring Drowsy or hyperactive afterwards x 10/day Current seizures: With hallucinations Parents alerted by shouting Often sees dinosaurs Shouts “Dynamite” Is found pale, staring and looking afraid

Where is the seizure coming from ?

Hypothesis

What next ?

?

Invasive Monitoring

Conclusion

Sz onset over left hemisphere

Rapid spread to right

Progress

Left occipital resection done

Post-op sz free

In quest of the holy grail ! (Lesion)

Case 4

The Jigsaw puzzle !

History :

7 yr old boy

Seizure onset at 3 years

Head turning to left

Drooling

Trance-like

Quickly evolved to clusters of multiple seizure types

including tonic seizures, drop attacks and jerks

x 20/ a day lasting 30 seconds

No response to medications

Current seizures

Type 1 (aura) - says “Mum seizure feeling”, buries his head/face

for a couple of seconds. Sometimes associated with repeated

blinking

Frequent events every day, some not recognised completely.

No loss of consciousness

Type 2 (Drop attacks): grabs on to nearby persons/furniture for

support, takes a gasping breath

Suddenly loses tone, drops to the floor, rubs his nose on the floor

and retains partial awareness

Hyper-motor, repetitive movements arms/legs. Day and night.

There can be facial flushing

Whole episode 10-15 seconds x 9-14 per day

Previous

Medication:

Carbamazepine, sodium valproate, clonazepam,

phenytoin, phenobarbitone, topiramate.

Current Medication: Lamotrigine 5mg bd

Schooling/

behaviour:

Mainstream primary school, no learning difficulties

identified

Family: No significant illnesses. No history of nocturnal

seizures.

Examination: Normal examination. Right handed.

Past medical history Normal birth history. No meningitis or prolonged febrile

seizures.

Seizures fairly stereotyped

Short events

Behavioural arrest

Leans to side and grabs parents

Long events

Behavioural arrest

Rubbing nose in the pillow

Flipping over

Thrashing movements

Imaging

1.5 T x 2 epilepsy protocol

3T MRI

All negative

Any ideas?

?

MEG

Synchronous neuronal

currents produce weak

magnetic fields

Analogous to EEG

Good for convexity

Mainly inter-ictal

Clusters of dipoles

Able right handed 6-year-old boy with high average intellect.

Some difficulties with attention and concentration.

Neuropsychiatry Concerns about impact of epilepsy on school life.

Neuropsychology

Summary Seizure semiology Frontal, not clinically lateralising

Temporal - significance of aura?

Examination Normal ,Right handed

MRI March 2011

SPECT March 2010

PET July 2010

MEG Feb 2011

Negative (3T)

Lateralises to the right but does not localise (short seizure)

right mid frontal / right anterior temporal region.

Right frontal

Right frontal

Telemetry March 2010 Inter-ictal: right frontal

Ictal: Right frontal and anterior temporal slowing (F8, F10)

Neuropsychology Able right handed 6-year-old boy with high average intellect. Some

difficulties with attention and concentration

Neuropsychiatry Concerns about impact of epilepsy on school life

Reasons for

Invasive/ECoG

Hypothesis

Localise ictal onset. Map motor cortex

Depth into MEG lesion

Conclusion

Sz onset from DA03-04 and surrounding grid contacts (G34-

35).

Functional stimulation mapped sensory (hand) and motor

function (hand and mouth) to areas posterior to seizure onset

zone.

Puzzle complete ! Quest ?

Semiology

EEG

PET

SPECT

MEG

Invasive monitoring

- concordant

Plan

Focal resection of gyrus underlying contacts

G34/35/42/45

Follow depth electrode down with further resection.

Prognosis given:

Seizure freedom: 50-60%

Significant seizure reduction: further 20%

Risk of neurological deficit: 2-5%

The end of the journey?

Well post-operatively, no deficit

Seizure free