Neuro 6.02 - Epilepsy, Spina Bifida

Front 1

Back 1

A. Third ventricle
B. Fourth ventricle

Front 2

Where are the choroid plexuses located?

Back 2

1. Lateral ventricles
– floor of body, also extending into
temporal horns
2. Third ventricle - roof
3. Fourth ventricle - roof

Front 3

What difference in the capillary endothelium of the brain allows it to form the blood brain barrier?

Back 3

- Brain Capillary endothelium: tight junctions
- Other capillary endothelium: gap junctions

Therefore only:
- Low molecular weight substances
- Lipid-soluble substances
can cross

Front 4

What are the symptoms and signs of acute hydrocephalus?

Back 4

Symptoms
- Headache, nausea and vomiting
- Lethargy, drowsiness, stupor and coma
Signs
- Papilledema, Diplopia
- Setting sun sign
- False localising signs – 6th nerve signs
- Decreased level of consciousness

Front 5

What is the characteristic triad of normal pressure hydrocephalus?

Back 5

- Gait disturbance (short shuffling, poor balance)
- Dementia
- Urinary incontinence

Front 6

Back 6

Chiari II Malformation

Front 7

What action do benzodiazepines (diazepam) have on GABA receptors?

Back 7

› Enhances the actions of GABA
› Increases the frequency of channel opening
› Act on GABAA receptors containing α1, α2, α3, α5 and γ subunits
› Binds at the interface between α and γ subunits

Front 8

What actions do barbituates have on GABA transmission?

Back 8

› May act alone or enhance actions of GABA
› Prolongs the open time of the channel by slowing the dissociation of GABA from the receptor
› Act on all GABAA receptors

Front 9

What action does ethanol have on GABA transmission?

Back 9

› Enhance the actions of GABA, prolongs the open time of the channel, Binds within the transmembrane domain

Front 10

What action do general anaesthetics have on GABA transmission?

Back 10

› Enhance the actions of GABA, may directly stimulate receptors at high conc., Bind at the interface between α and β subunits within the transmembrane region of the channel

Front 11

What type of seizure is described?

- Activation of neurons in a relatively small, discrete region
- Clinical manifestation reflects region of brain in which they occur
- Sensory or motor
- Complex X – impairment of consciousness
ie. Familiarity (déjà vu) or strangeness (jamais vu), automatisms, hallucinations (auditory and visual), temporal lobe epilepsy

Back 11

Partial Seizure (and Complex partial seizure)

Front 12

What type of seizure is characterised by initial involvement of both hemispheres and widespread neuronal activation?

Back 12

Generalised seizure

Front 13

What are the 5 types of generalised seizures?

Back 13

1. Tonic – extension of the extremities, rigid stretching
2. Atonic – sudden loss of muscle tone
3. Clonic (Myoclonic) – repetitive muscle twitching
4. Tonic-clonic (grand mal) – distinct tonic phase followed by a clonic phase (full body spasms with intermittent relaxation)
- Generalised absence seizures (petit mal) –brief lapse of consciousness

Front 14

What are the 6 types/categories of anticonvulsant medications?

Back 14

1. Enhance Na+ channel inactivation – reduce firing frequency of neurons
2. Inhibit excitatory amino acid release – block Ca2+ channels
3. Block excitatory amino acid action
4. Enhance GABA action
5. Inhibit GABA breakdown
6. Inhibit GABA uptake

Front 15

What is the mechanism of action of Phenytoin, Carbamazepine and Lamotrigine?

Back 15

› Enhance voltage gated Na+ channel inactivation
› Use dependent (binding is dependent on the opening of Na+ channels which then leads to inactivation)
› Results in a reduction of sustained high-frequency firing of action potentials - specifically act on rapidly firing neurons

Front 16

What is the mechanism of action of Ethosuximide (Zarontin) and Levetiracetam (Keppra)?

Back 16

Inhibit excitatory amino acid release – block Ca2+ channels

Front 17

What is the mechanism of action of barbituates?

Back 17

› May act alone or enhance actions of GABA
› Act on all GABAA receptors
- increase affinity for GABA
- increase Cl- conductance
- prolongs the open time of the channel

Front 18

Vigabatrin (γ-vinyl-GABA)

Back 18

› Synthetic structural analogue of GABA
› Specific inhibitor of GABA transaminase

Front 19

Tiagabine

Back 19

› GABA reuptake inhibitor
› GAT1 inhibitor
› Increase extracellular GABA levels

Front 20

Sodium valproate (Epilum)

Back 20

Mechanisms 1, 2 and 5
› Use-dependent Na+ channel blocker
- weaker than phenytoin and carbamazepine
› Ca2+ channel blocker
› Increases levels of GABA (unknown mechanism)

Front 21

Topiramate (Topomax)

Back 21

› Mechanism 1, 3, 4
› Inhibit voltage-dependent Na+ channels
› Antagonist at AMPA/Kainate receptors
› Augment GABA at some GABAA receptors

Front 22

Felbamate (Felbatol)

Back 22

› Mechanism 1, 3 and 4
› Inhibit voltage-dependent Na+ channels
› Antagonist at NMDA receptors (NR2B)
› Positively modulates GABAA receptors

Front 23

Back 23

Corpus callosum:
A. Splenium
B. Body
C. Genu

Front 24

Back 24

A. Optic chiasm
B. Thalamus
C. Hypothalamus

Front 25

Back 25

A. Pituitary
B. Superior Sagittal sinus
C. Superior cistern

Front 26

Back 26

A. Pontine cistern (with basilar artery)
B. Interpeduncular cistern
C. Cisterna magna (cerebromedullary cistern)

Front 27

Back 27

1. Middle meningeal arteries

Front 28

Name 6 things located in the epidural space of the vertebral canal?

Back 28

1. Loose areolar connective tissue
2. Semiliquid fat
3. Lymphatics
4. Arteries
5. An extensive plexus of veins
6. The spinal nerve roots as they exit the dural sac and pass through the intervertebral foramina

Front 29

Back 29