Epilepsy Flashcards

1
Q

Define: Seizure, Epilepsy, Status Epilepticus

A

Seizure - sudden surge of electrical activity in the brain (sensory disturbance, loss of consciousness, convulsions, abnormal brain activity)
Epilepsy - neurological disorder characterised by recurrent episodes of seizures
Status Epilepticus - continuous seizure activity or repetitive seizures without regaining consciousness

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2
Q

What’re Jacksonian seizures?

A

Abnormal electrical activity in localised area of the brain - type of partial seizure

Motor: begins in one group of muscles and progresses to adjacent muscle groups usually distal -> proximal
Sensory: again short lasting activity that spreads

Typically through limbs and trunk

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3
Q

How is epileptiform activity characterised?

A

Prolonged large amplitude, synchronous cortical activity (ictal) with interspersed low-activity periods (inter-ictal)

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4
Q

What are the symptoms of epilepsy?

A

Varied according to focus and spread

May be preceded by auras/hallucinations and often followed by drowsiness

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5
Q

Where would the focal site be of seizures preceded by auras/deja vu or motor disturbances?

A

Temporal lobe

Frontal lobe

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6
Q

How are the different types of epilepsy newly classified?

A

Based on where seizures begin, the level of awareness and other features eg motor or auras

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7
Q

What are the classifications of epilepsy?

A

FOCAL: Aware / Impaired awareness / Motor / Non-Motor
FOCAL TO BILATERAL
GENERALISED: Motor / Non-Motor (impaired awareness assumed)
UNKNOWN ONSET - can still describe where motor/non-motor
+ Auras ?

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8
Q

What’s antiepileptic hypersensitivity syndrome?

A

Major side effect of AEDs usually 1-8 weeks after treatment
Need to withdraw AED immediately but beware of rebound seizures, and use topical steroid + antihistamines

Initial signs: fever, rash, lymph node swelling
Severe signs: blood, liver, kidney, respiratory abnormalities, vasculitis and organ failure

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9
Q

What’s NEAD and in what ways is it different to normal seizures?

A

Non epileptiform attack disorder (psychogenic seizures) = no physical reason or changes in brain activity but similar symptoms

Diagnose by EEG

Differences in tongue biting (usually tip of tongue whereas general seizures bite sides), eye opening (usually held shut), duration, recollection

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10
Q

What’s the basis of an EEG?

A

Records voltage deflections relative to ground electrode, usually the ear

Focus of activity easy to pinpoint and may correlate to symptoms/auras

Records levels of synchrony between neurones - those firing together will show larger amplitude oscillations

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11
Q

What are the 5 different types of rhythms seen on EEG?

A

Delta <3.5 Hz deep sleep/coma
Theta 4-7 Hz parietal and temporal lobes, alertness
Alpha 8-13 Hz occipital lobes, quietness, eyes shut
Beta >14 Hz parietal and frontal lobes, activity, tension, sleep spindles
Gamma >40 Hz learning and memory

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12
Q

What changes in neuronal excitability occur in epileptiform activity?

A

Reduction in GABA
Reduction in K+ channel activity
Increase in ACh transmission
Increase in Na+ channel activity

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13
Q

What channelopathies can occur in epilepsy?

A

Mutations often linked to congenital forms
K+, Na+, ACh, GABA receptors

GABA mutations in idiopathic generalised and juvenile myoclonic
SCN1B/1A in severe myoclonic infancy
CHRNA4/B2 in ACh receptors in autosomal dominant nocturnal frontal lobe epilepsy

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14
Q

Outline the treatment for epilepsy (pharmacological, surgical, implants)

A

Pharmacological AEDs: Na+ channel blockers, Ca2+ channel blockers, GABA modulation/mimetics

Surgical: removal of aberrant areas

Impants: DBS or VNS (vagal nerve stimulation)

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15
Q

What are routes to achieve GABA activity enhancement?

A

Co-agonist sites
Inhibition of GABA breakdown
Inhibition of GABA reuptake
GABAmimetics

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16
Q

What drugs are GABA mimetics, how do they work?

A

Gabapentin and Pregabalin

Indirectly enhance activity of GABA channel by voltage dependent Ca2+ block

17
Q

What are side effects of benzodiazepines and barbiturates?

A
Short term use only <12 weeks
Tolerance and dependency 
Withdrawal on termination
Reduced motor tone - impaired coordination
Impaired cognitive performance
Sedation
Retrogade amnesia
Disturbance sleep pattern
18
Q

How do barbiturates and benzodiazepines differ?

A

Barbiturates act on GABA-A B subunit
BDZ act on GABA-A y subunit

Both co-agonists to enhance GABAergic inhibition = reduce neuronal transmission

19
Q

What’s the emergency treatment for status epileptics?

A

IV Lorazepam
+ buccal midazolam/rectal diazepam

After 25 mins: IV Phenobarbital Sodium
After 45 mins: GA by non-barbiturate (propofol), Midazolam or Thiopental

20
Q

What are side effects of Na+ channel blockers?

A
CNS effects: cognitive/visual impairment 
Peripheral neuropathy
Skin problems
Gum hyperplasia
Anaemia
TERATOGENICITY