Neuro - seizures

Question 1

What causes seizures?

Answer 1

Neurones are excitable cells and can depolarise
When the excitatory state is not balanced with the inhibitory state then can get seizures

Question 2

What is a seizure threshold?

Answer 2

Brain activity fluctuates between excitatory and inhibitory stimulation
Threshold where excitatory stimulation is enough to start synchronous activation of neurones

Question 3

What is the definition of a seizure?

Answer 3

Fit=episode=moment
Change in mentation and autonomic function over a period of time

Question 4

What is the definition of an epileptic seizure?

Answer 4

Abnormal uncontrollable hypersynchronous activation of a large group of neurones

Question 5

What is epilepsy?

Answer 5

Recurrent epileptic seizures - always forebrain neurolocalisation

Question 6

What is status epilepticus?

Answer 6

Seizure for longer than 5 mins
Or 2 seizures without complete recovery in between
Emergency action required - seizure longer than 5 mins lead to brain damage

Question 7

What are cluster seizures?

Answer 7

2 or more seizures in 24hr period with complete recovery in between

Question 8

What are the different types of seizures?

Answer 8

Partial/focal seizure
Generalised seizures
Partial with secondary generalisation

Question 9

What is a partial/focal seizure?

Answer 9

Affects a well defined area
May not have loss of consciousness/awareness

Question 10

What is the most common type of seizure?

Answer 10

Generalised seizure - tonic-clonic
Change in behaviour/consciousness/absence

Question 11

What does tonic-clonic mean?

Answer 11

Tonic - prolonged extension
Clonic - alternating flexion and extension

Question 12

What are the phases of the classic generalised tonic-clonic seizure?

Answer 12

Pre-ictal phase - period before the seizure, behaviour changes
Ictus - seizure, non responsive, tonic clonic movements, autonomic signs
Post ictal phase - mins to days afterwards, disorientation, polyphagia, ataxia, blindness

Question 13

What can trigger seizures?

Answer 13

Stress
Excitement
Flashing lights
Noises

Question 14

What are some seizure mimics?

Answer 14

Narcolepsy/cataplexy - conscious, quick loss of muscle tone
Fly catching - dog doesnt look consciousness
Movement disorder
Syncope - very quick, dog immediately back to normal
3rd degree AV block - not enough blood to brain

Question 15

What are the features of movement disorders that distinguish them from seizures?

Answer 15

Responsive/conscious
Often longer than 5 mins - sometimes hours
No autonomic signs - salivating, defecating

Question 16

What is an example of a movement disorder?

Answer 16

Border terrier epileptoid cramping syndrome (spikes disease) - running along skipping occasionally with leg lifting into the air

Question 17

What are the differentials for seizures? Use localisation to help

Answer 17

Extra-cranial - toxins, metabolic
Intra-cranial - structural, functional

Question 18

What are the signs of toxin induced seizures?

Answer 18

Often accompanied by GI signs - vomiting and seizures

Question 19

What are common toxins causing seizures?

Answer 19

Ethylene glycol - antifreeze
Permethrin spot on in cats
Ivermectins in collies

Question 20

What are 3 causes of metabolic induced seizures?

Answer 20

Portosystemic shunt/liver failure - causing hepatic encephalopathy
Hypoglycaemia - liver dysfunction, toy breeds, insulinoma
Hypocalcaemia

Question 21

What are 3 structural intracranial causes of seizures?

Answer 21

Brain tumour
Inflammation
Hydrocephalus

Question 22

What is a functional intracranial cause of seizures?

Answer 22

Idiopathic epilepsy

Question 23

How is idiopathic epilepsy diagnosed?

Answer 23

Rule out all other options first
Recurrent seizures in animal between 6 months and 6 years
Normal inter-icteral neurological exam
Normal metabolic investigation

Question 24

What is the minimum database following an isolated seizure?

Answer 24

Haem
Biochem
Fasted blood glucose
Isolated bile acids test - pre and post prandial

Question 25

What are the goals of seizure management?

Answer 25

Stop patient seizuring in emergency management
Reduce seizure frequency
Reduce severity
With acceptable side effects and costs for owner, and is practical

Question 26

When do you start treatment in a seizuring animal?

Answer 26

If more than 1 seizure per month
Increasing frequency
Cluster seizures or status epilepticus
If there is underlying structural or metabolic cause

Question 27

When is just monitoring appropriate for a seizuring animal?

Answer 27

Single seizure
Long interictal period - more than 3 months
Known toxic trigger

Question 28

What type of drug can you use as emergency management to treat seizures?

Answer 28

Anti-convulsants - very short half life, short acting rapid onset of action
Stops a seizure when it is occuring

Question 29

What are some examples of anti-convulsants?

Answer 29

Diazepam - first line IV/rectally (not IM)
Midazolam
Propofol

Question 30

How often can you give anti-convulsants in an emergency?

Answer 30

Can repeat diazepan/midazolam dose up to 3 times or until seizure stops

Question 31

What type of drug do you use for long term management of seizures?

Answer 31

Anti-epileptic - longer half life, slow onset of action, long acting

Question 32

What are some examples of anti-epileptic drugs?

Answer 32

Phenobarbitone - first choice
Imepitoin - second choice (doesnt treat status epilepticus or cluster seizures)
Adjunct - potassium bromide (not in cats)

Question 33

When should you consider referral for advanced imaging in seizure cases?

Answer 33

Very young or old dog
Not normal between episodes
Status epilepticus

Question 34

What is the mechanism of action of an anticonvulsant?

Answer 34

Reduces excitation and promotes inhibition - act on GABA

Question 35

When do you add a second antiepileptic drug?

Answer 35

Improper seizure control
Causes side effects
if increasing first line drug means reaching toxic blood level
(best to use one drug though)

Question 36

When should you monitor seizure drug control?

Answer 36

At steady state - 3 weeks after starting, then every 6-12 months
If seizure control is lost
If signs of toxicity

Question 37

What is uncontrolled epilepsy? What percentage of patients have this?

Answer 37

When still seizure the same amount even after treatment - 20-30% of patients

Question 38

What are the 5 steps of managing acute seizures?

Answer 38

Check vital parameters
Time it
Protect patient
Try to get IV access
Check blood glucose/get blood sample
Givve anticonvulsant - IV, rectally