Seizures lecture

Question 1

What is our normal neurobiology?

Answer 1

Electrical activity: non-synchronous

Neurons: can maintain resting potential, depolarise and repolarise

Ion channels/pumps: maintain gradient and have adequate energy to work

Neurotransmitters: balance between inhibitory (GABA) and excitatory (glutamate)

Question 2

Neurobiology in seizures?

Answer 2

Cortical neurons are hypersynchronous

Develop paroxysmal depolarising shift: leading to increased firing rate and sustained NETWORK of firing

Spreading wave of electrical activity
Refractory period reduced
Loss of surrounding neuronal inhibition
Neurotransmitter imbalance may be found

Question 3

Summary of neurobiology in seizures

Answer 3

Initial trigger = high frequency action potential and hyperpolarisation

Often seen in astrocytes with calcium signalling

Leading to a NETWORK ISSUE (‘epileptic aggregate’)

Question 4

Clinical definition of seizure

Answer 4

Transient occurrence of signs/symptoms associated with abnormal excessive/synchronous neuronal activity in the brain

Question 5

ILAE 2014 epilepsy definition

Answer 5

1. at least 2 unprovoked seizures more than 24 hours apart
2. 1 unprovoked seizure with probability of further seizure is more than 60% occurring in the next 10 years
3. diagnosis of epilepsy syndrome

Question 6

Day to day epilepsy definition

Answer 6

At least one unprovoked seizure with high risk of another

Question 7

Resolved epilepsy

Answer 7

1. age-dependent epilepsy syndrome - now past applicable age

2. seizure free for 10 years and off anti-seizure meds for 5 years

Question 8

How are seizures classified?

Answer 8

1/ generalised
2/ focal
3/ unknown

Question 9

What is a generalised seizure?

Answer 9

rapid onset
bilateral
loss of consciousness
convulsive/non convulsive (brainz monitoring if LOC and non-convulsive)

Question 10

Examples of generalised seizure

Answer 10

Tonic/clonic
Absence (typical/atypical/with myoclonic changes)
Clonic
Tonic
Atonic
Myoclonic

Question 11

What is a focal seizure?

Answer 11

onset in 1 hemisphere
often involves: aura/MOTOR/autonomic sx
awareness: retained/altered
often progresses to both hemispheres:
BILATERAL CONVULSIVE SEIZURE

Question 12

What is an irritative lesion? Where would they look?

Answer 12

Epilepsy/minor stroke

look AWAY from focus

Question 13

What is a destructive lesion? Where would they look?

Answer 13

Massive MCA infarct

look TOWARDS the focus

Question 14

How are absence seizures caused? (most of time)

Answer 14

hyperventilating (decreased calcium ions)

Question 15

What are the causes of a seizure?

Answer 15

PROVOKED:
fever
toxin/drug/withdrawal
metabolic
catamenial
reflex epilepsys

ACQUIRED:
trauma
stroke
tumour
infection
autoimmune

Question 16

What are the causes of epilepsy?

Answer 16

GENETIC
abnormal syndromes
channelopathies
GLUT1 deficiency

STRUCTURAL/METABOLIC
tuberous sclerosis (neurocutaneous disorder)
epilepsy syndrome
structural development disorders

Question 17

What is a febrile convulsion?

Answer 17

Short generalised seizure with increase in temperature in children (6months - 6 years)
Rapid recovery

Treat:
gently cool
refer if first
refer if no source of infection found

Question 18

What is reflex anoxic seizure?

Answer 18

Noxious stimuli -> reflex cardiac standstill and seizure in children (under 2)

cyanosis
pallor
tonic clonic
downbent nystagmus

BENIGN
short latency from stimuli (differentiate between vasovagal)

Question 19

What is eclampsia?

Answer 19

life threatening condition in pregnancy
confusion, headache, tremour -> gen tonic clonic

primips
young women

Question 20

What conditions predispose to eclampsia?

Answer 20

pre-eclampsia (proteinuria, hypertension)

HELLP

Question 21

How do you treat eclampsia?

Answer 21

oxygen
magnesium sulphate (4g IV)
manage BP with labetalol or hydralazine
deliver baba
treat complications

Question 22

Management of post traumatic seizure?

Answer 22

CT within 1 hour

hypoxic - ischaemia: myoclonic or focal and altered GCS

Question 23

Definition of post traumatic epilepsy

Answer 23

One or more unprovoked seizure 7 days after TBI with no other cause

Question 24

Predictions of PTE

Answer 24

skull fracture
severity of injury
haemorrhage
contusion FL>PL>TL

Question 25

Emergency management of seizure in trauma

Answer 25

Help
ABC (adjuncts?)
COMA

C-spine
Oxygen
Monitoring
Access (IV)

Question 26

Med ladder in emergency management of seizure

Answer 26

Oxygen
Benzos (max 2x dose)
Phenytoin
Phenobarbitone/thiopentone
GA (propofol/thiopentinol)
ITU for neuromonitoring

Question 27

What is the dose of lorazepam?

Answer 27

2-4 mg IV bolus

0.1mg/kg

Question 28

What is the dose of diazepam?

Answer 28

5-10mg PR

0.25mg/kg IV or 0.5mg/kg PR

Question 29

What is the dose of midazolam?

Answer 29

1-2mg bolus iv

0.5mg/kg buccal

Question 30

What is the dose of phenytoin?

Answer 30

1g IV slow over 30 mins
ECG monitoring (cause arrhythmias)
18mg/kg IV

Question 31

What is the dose of phenobarbitone/thiopentone?

Answer 31

4mg/kg

Question 32

What else do you need to think about giving in seizure?

Answer 32

glucose (0.5mg/kg IV)
thiamine
recatal paraldehyde (children)

DVLA post seizure

Question 33

Prophylaxis of seizure post head trauma?

Answer 33

phenytoin
levetiracetam
(topiramate)

Question 34

What should you avoid giving in absence seizures?

Answer 34

carbamazapine

Question 35

What can you do whilst wait for CT head in TBI?

Answer 35

1. optimal neuroprotection
2. bleeding status (meds/clotting)
3. prepare for theatre

Question 36

How can you optimise neuroprotection?

Answer 36

loosen c-spine immobilisation
hyperosmotic fluids (mannitol/HTS)
head up tilt 30 degs
sedation?
control CO2 (normal to low)
control O2 (avoid hypoxia and hyperoxia)
glucose and temp control
ensure have BP

Question 37

What is an ICP bolt?

Answer 37

intracranial device
screwed into brain with small port into part of brain with limited function
directly measures ICP -> continual assessment

(CPP=MAP-ICP)

Question 38

What are the indications for ICP bolt?

Answer 38

1. GCS <8 and abnorm CT
2. GCS <8, norm CT but 2 of:
   - age >40
   - BP <90
   - abnorm posturing

Question 39

What is an external ventricular drain?

Answer 39

temporary diversion of CSF due to:

• obstruction of csf flow
• failure of csf absorption (sah)
• overproduction of csf (rare)

intraventricular meds

often seen in diffuse injuries to avoid surgery and decrease icp

Question 40

pros of EVD?

Answer 40

monitor ICP

decrease ICP

Question 41

cons of EVD?

Answer 41

operative risk
risk of infection
difficult if ventricles displaced or small
if decompress ventricles could lead to expansion of haematoma
not difinitive

Question 42

When can you do burr holes?

Answer 42

frontal
suboccipital
parietal
temporal bones

Question 43

What are the pros of burr holes?

Answer 43

buys time - temporarily relieves pressure

Question 44

what are the cons of burr holes?

Answer 44

unlikely benefit to acute bleed (sticky wont come out)
operative risk
delay definitive treatment

Question 45

indications for surgery in EDH

Answer 45

> 30cm3 (regardless of GCS)

GCS <9 and anisocoria (unequal pupils)

Question 46

indications for conservative management of EDH

Answer 46

vol <30cm3
thickness <15mm
midline shift <5mm
GCS >8
No focal neuro deficit

Question 47

indications for surgery in acute SDH

Answer 47

thickness >10mm and MLS >5mm regardless of GCS
if thickness if <10mm and MLS <5mm but:
- GCS drops by 2
- pupils fixed and dilated or anisocoria
- ICP more than 20

Question 48

What is status epilepticus?

Answer 48

Seizure lasting 30 mins or more
or
cluster of shorter seizures without intervening and recovery continues for 30 mins or more

Question 49

what can prolonged seizures cause?

Answer 49

mesial temporal sclerosis (temporal lobe seizures) - CA1 and subiculum

seizures beget seizures (kindling)
- seizures induce more seizures?

risk of death