Epilepsy

Question 1

What is the mangement?

Answer 1

• A-E assessment - hypoglycaemia is an important cause of seizures
• Clear airway and administer oxygen by mask - prevents HIE
• Establish IV access
• Administer bolus injection of intravenous benzodiazepine (e.g. lorazepam 10mg) over 2 minutes

Question 2

The patient stops convulsing after Lorazepam 10mg IV and is now drowsy and probably post ictal. What do you do now?

Answer 2

• Check FBC, urea and electrolytes, glucose and calcium
• Blood gases
• ECG
• Take further history from husband
• Examine patient further
• Set up cardiac monitor and pulse oximetry

Blood screen is now needed (including calcium) once patient stabilised. History and further examination are essential.

Question 3

Define epilepsy.

Answer 3

>2 seizures

Epilepsy is a recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain, manifesting as seizures. Convulsions are the motor signs of electrical discharges.

Question 4

Define seizure.

Answer 4

Ictus - paroxysmal synchronised cortical electrical discharges

Question 5

How common is epilepsy?

Answer 5

Common affects 1% of population

Peak age of onset is in early childhood or in the elderly

Question 6

What are the two types of seizures?

Answer 6

1. Focal/Partial - localised to a specific cortical region. Used to be divided into simple partial and complex partial seizures which did not and did affect consciousness respectively.
2. Generalised - affect consciousness; usually split into 5 types.

Question 7

Describe the elements of a seizure (before/after).

Answer 7

Prodrome - experienced by some patients and may last hours to days; usually a change in mood/behaviour.

Aura - usually implies a focal seizure of the temporal lobe e.g

• strange feeling in gut
• deja vu
• strange smells
• flashing lights

Post ictally pt may experience

• headache
• confusion
• myalgia
• temporary weakness after focal seizure in motor cortex (Todd’s palsy)
• dysphasia

Question 8

What is the aetiology of epilepsy?

Answer 8

Majority idiopathic - 2/3 of cases

Primary epilepsy seizures e.g. idiopathic generalised epilepsy, temporal lobe epilepsy, junvenile myoclonic epilepsy

Secondary seizures (symptomatic epilepsy)

• tumour
• infection (e.g. meningitis, encephalitis, abscess)
• inflammation (vasculitis, rarely MS)
• toxic/metabolic (sodium imbalance, hyper/hypoglycaemia,hypocalcaemia, hypoxia, porphyria, liver failure)
• Drugs (and withdrawal e.g. alcohol, benzodiazepines)
• Vascular (haemorrhage, infarction)
• Congenital anomalies (e.g. cortical dysplasia)
• Neurodegenerative disease (e.g. Alzheimer’s disease)
• Malignant hypertension or eclampsia
• Trauma

Common seizure mimics

• syncope
• migraine
• non-epileptiform seizure disorder (e.g. dissociative disorder)

Question 9

What is the pathophysiology of epilepsy?

Answer 9

Seizures result from imbalance in the inhibitory and excitatory currents (e.g. Na+ or K+ ion channels) or neurotransmission (i.e. glutamate or GABA neurotransmitters) in the brain.

Precipitants include any trigger which promotes excitation of the cerebral cortex (e.g. flashing lights, drugs, sleep deprivation, metabolic) but often cryptogenic.

Question 10

What are the key questions to ask in an epilepsy history?

Answer 10

1. Rapidity of onset
2. Duration of episode
3. Any alteration of consciousness
4. Any tongue-biting or incontinence
5. Any rhythmic synchronous limb jerking
6. Any post-ictal period
7. Drug history (alcohol, recreational drugs)

Can be difficult to diagnose as there are 40 different types. All pts must be referred to specialist within 2 weeks if it’s a first seizure. Ask about previous funny turns/odd behaviour.

Question 11

What are the subtypes of partial/focal seizures and how do they differ?

Answer 11

NB partial seizures - originate within one hemisphere

1. W/o impaired consciousness (“simple”) - awareness N, with focal motor/sensory/autonomic/psychic symptoms. No post-ictal symptoms.
2. W/ impaired consciousness (“complex”) - awareness impaired; most commonly arise in temporal lobe and have post-ictal confusion
3. Evolving to bilateral, convulsive seizure (“secondary generalised”) - electrical disturbance of a partial seizure spreads widely causing gen seizure in 2/3 patients (typically convulsive)

Question 12

What are the subtypes of generalised seizures and how do they differ?

Answer 12

NB generalised = no localising features, spread bilaterally quickly.

1. Absence seizures(petit mal)- brief <10sec pauses LOC but maintained posture, present in childhood. Usually rolling eyes, staring or chewing.
2. Tonic-clonic seizures (grand mal) - LOC, limbs stiffen (tonic), then jerk (clonic), post-ictal confusion and drowsiness. Assoc with tongue biting and faecal/urinary incontinence.
3. Myoclonic seizures - sudden jerk of limb/face/trunk, may throw pt violently to the ground, or pt may have violently disobedient limb
4. Atonic (akinetic) seizures - sudden loss of muscle tone causing a fall, no LOC
5. Infantile spasms - common in tuberous sclerosis

??. Non-convulsive status epilepticus: Acute confusional state. Often fluctuating. Difficult to distinguish from dementia.

Question 13

What is the recurrence rate of provoked vs unprovoked seizures?

Answer 13

Provoked = 3-10% e.g. if caused by trauma, stroke, haemorrhage, alcohol.

Unprovoked = 30-50%

Question 14

What are the localising features of a focal seizure…

in the temporal lobe?

Answer 14

• Automatisms - complex motor phenomena with impaired awareness, varying from primitive oral (lip smacking, chewing, swallowing) or manual movements (fumbling, fiddling, grabbing), to complex actions.
• Dysphasias
• Deja vu (when everything seems strangely familiar) or jamais vu (strangely unfamiliar)
• Emotional disturbance e.g. sudden terror, panic, anger, elation, derealisation (out-of-body experiences)
• Hallucinations of smell, taste or sound
• Delusional behaviour
• Bizzare associations

Question 15

What are the localising features of a focal seizure starting in the…

frontal lobe?

Answer 15

• Motor features such as posturing/peddling movements of legs
• Jacksonian march - spreading focal motor seizure with retained awareness, often starting with the face or a thumb
• Motor arrest
• Subtle behavioural disturbances (often diagnosed as psychogenic)
• Dysphasia or speech arrest
• Post-ictal Todd’s palsy

Question 16

What is Todd’s palsy?

Answer 16

Transient neurological deficit (paresis) after a seizure.

There may be face, arm, or leg weakness, aphasia, or gaze palsy, lasting from ~30min–36h.

The aetiology is unclear.

Question 17

What are the localising features of a focal seizure startring in ..

the parietal lobe?

Answer 17

• Sensory disturbances - tingling, numbness, pain (rare)
• Motor symptoms (due to spread to the pre-central gyrus)

Question 18

What are the localising features of a focal seizure startring in ..

the occipital lobe?

Answer 18

Visual phenomena such as spots, lines and flashing.

Question 19

What investigations would you do for epilepsy?

Answer 19

Look for provoking causes

• EEG - cannot exclude epilepsy and can be falsely +ve so don’t do one if simple syncope is the likely diagnosis
• MRI - look for structural lesions
• Toxicology screen + levels- check if patient is compliant on anti-epilectics?
• LP - if infection suspected

Question 20

Describe the conservative management of epilepsy.

Answer 20

• After any “fit” avoid swimming, driving, heights until diagnosis is known
• Inform DVLA and avoid driving until >1yr seizure-free
• Individualised counselling on employment, sport, insurance, conceptions.
• Only one doctor should be in charge of one patient when prescribing AEDs

Psychological therapies - relaxation/CBT may be of mild benefit but do not improve seizure frequency so only used as adjunct to medication.

Question 21

When should you start anti-epilepsy medication?

Answer 21

Only after >2 seizures or if there is a high risk of another seizure - only started by specialists.

Question 22

What anti-epileptic drugs are 1st and 2nd line for

• partial seizures?
• tonic-clonic (generalised) seizures?

Answer 22

Focal (partial)

• 1st line: lamotrigine or levetiracetam
• 2nd line: carbamazepine, oxcarbazepine or zonisamide

Tonic-clonic

• males: sodium valproate
• females: lamotrigine or levetiracetam

Question 23

What anti-epileptic drugs are 1st and 2nd line for

• absence seizures?
• myoclonic seziures?
• tonic/atonic seizures?

Answer 23

Absence:

• 1st line: ethosuximide
• 2nd line:
  
  • male: sodium valproate
  • female: lamotrigine or levetiracetam

Myoclonic:

• males: sodium valproate
• females: levetiracetam

Tonic/atonic:

• males: sodium valproate
• females: lamotrigine

Question 24

Which drugs can worsen myoclonic seizures?

Answer 24

Avoid carbamazepine and oxcarbazepine—may worsen seizures.

Question 25

What is status epilepticus and how is it managed?

Answer 25

**Status epilepticus -** seizure lasting \>30min and failure to regain consciousness. Treatment is often initiated after **5-10min** of seizure starting as early treatment has higher treatment success. IV lorazepam or PR diazepam and repeat once after 15min if needed. Then IV phenytoin under ECG if unresolved. *NB to protect airway, breathing, circulation. Always look for a cause.*

Question 26

Name 2 side effects of these anti-epileptic drugs: * carbamazepine * lamotrigine * levetiracetam * sodium valproate * phenytoin

Answer 26

* carbamazepine - **leucopenia**, diplopia, drowsiness, erythematous rash, SIADH * lamotrigine - maculopapular rash (can--\> SJ syndrome), photosensitivity, blurred vision, tremor, **aplastic anaemia** * levetiracetam - depression, agitation, dyspepsia, blood dyscrasias * sodium valproate - liver failure, pancreatitis, hair loss, oedema, ataxia, tremor, encephalopathy * phenytoin - no longer used as much due to toxicity --\> nystagmus, tremor, dysarthria, ataxia. SE: reduced intellect, depression, coarse facial features, acne, gum hypertrophy ## Footnote *Carbamazepine, phenytoin and barbiturates are liver enzyme inducing.*

Question 27

What is a possible surgical management of epilepsy?

Answer 27

Considered if there is a single epileptogenic focus which can be identified (e.g. hippocampal sclerosis, small grade tumour) Neurosurgical resection offers up to 70% chance of seizure resolution but can cause focal neurological deficits _Alternatives_: vagal nerve stimulation, DBS (deep brain stimulation)

Question 28

What is the prognosis with epilepsy?

Answer 28

* 3x mortality risk * \>700 epilepsy related deaths in UK each year (17% are "sudden unexpected death in epilepsy" or SUDEP) * Epilepsy carries 5% risk of fetal abnormalities in pregnancy - good seizure control is essential in pregnancy

Question 29

What are the complications of epilepsy?

Answer 29

* Fractures with tonic-clonic * Behavioural problems * SUDEP * AEDs SEs and complications

Question 30

Which drug exacerbates absence seizures?

Answer 30

* Carbamazepine