BLOCK 12

Question 1

what is epilepsy? and what is the diagnostic criteria?

Answer 1

A chronic disorder of the brain that predisposes you to recurrent, unprovoked seizures. Usually diagnosed when an individual has 2 or more unprovoked symptoms >48 hrs apart

Question 2

what the post-ictal phase?

Answer 2

Phase after the seizure where you typically have impaired conciousness

Question 3

how are clonic and myoclonic seizures different?

Answer 3

myoclonic seizures are SO much faster. like every 0.2 seconds compared with every 2 seconds

Question 4

what are the causes of seizures?

Answer 4

Vascular -s troke/haemorrhage
Infections e.g. meningitis, encephalitis
Trauma or toxins e.g. drug abuse or alcohol withdrawal
Autoimmune e.g. lupus
Metabolic e.g. electrolyte disturbances
Idiopathic/epilspy 
Neoplasm
Syncope or psychogenic seizures

Question 5

what are some medications that can trigger seizures?

Answer 5

antidepressants e.g. buproprion

isionizid

Question 6

whats the first line drug for generalise seizures?

Answer 6

sodium valproate

Question 7

whats the first line drug for focal seizures?

Answer 7

carbamazepine or lamotrigine

Question 8

whats the first line drug for absence seizures?

Answer 8

ethosuximide

Question 9

what drug is given to mothers with a diagnosis of eclampsia? why?

Answer 9

magnesium sulfate

it inhibits NMDA receptors, limiting the effect of glutamate

Question 10

whats the - first line drug to give in hospital to stop a seizure?

Answer 10

Lorazepam - benzodiazepam

Question 11

what age are febrile seizures most common?

Answer 11

6 months to 6 years

Question 12

what infection do febrile seizures usualyl follow?

Answer 12

roseola virus - human herpes virus 6+7

Question 13

what condition is closely related to epilepsy?

Answer 13

cerebral palsy

Question 14

why should phenytoin, carbazmazpine and sodium valproate be carefully considered when a patient is on other meds too?

Answer 14

phenytoin and carbamazepine induce P450s actions

sodium valproate inhibits P450s action

Question 15

what are some reversible causes of dementia?

Answer 15

alcohol dependance
hypothyroidism
vitamin B12 deficiency
neurosyphilis
depression

Question 16

wha are some irreversible causes of dementia?

Answer 16

alzheimers disease
vascular dementia
frontotemporal dementia
Lewy body dementia
parkinsons
huntington disease

Question 17

what is APP?

Answer 17

amyloid precursor protein

Question 18

how do beta amyloid plaques form?

Answer 18

amyloid precursor protein is broken up by beta secretes and gamma secretes (rather than alpha and gamma) which produces amyloid beta. this is not soluble and so bind together outside neurones, forming plaques.

Question 19

how does alzheimers impair brain function?

Answer 19

amyloid beta plaques get between neurones, impairing brain fucntion

Question 20

what happens if amyloid plaques deposit in blood vessels around the brain?

Answer 20

it causes amyloid angiopathy which weakens the vessels and increases risk of haemorrhage

Question 21

what are tau proteins?

Answer 21

proteins that holds microtubules in the cytoksleteon together

Question 22

how do beta amyloid plaques affect tau proteins?

Answer 22

the plaques (outside the cell) initiate kinase activity which adds phosphate groups to the tau protein. this makes the protein stop supporting the microtubule, gets tangles with other tau proteins = forms neurofibrillary tangles within the cell
neurones with tangles and non-functioning microtubules cant function and undergo apoptosis

Question 23

why is there low acetylcholine levels in the nucleus basalts and hippocampus in alzheimers disease?

Answer 23

due to impaired activity of choline acetyltransferase

Question 24

why are patients with the e4 allele for the APOE gene more likely to have alziemers than those who dont have this allele?

Answer 24

apolipoprotein e helps breakdown beta amyloid but the e4 allele is a lot less effective than other alleles so the patient is more likely to develop amyloid plaques

Question 25

which mutations are associated with... - sporadic alzheimers - familial alzheimers ?

Answer 25

sporadic - APOE- e4 | familial - PSEN-1 and PSEN-2 and trisomy 21

Question 26

what are PSEN-1 and PSEN-2?

Answer 26

presenelin-1 and presenilin 2 | protein subunits of gamma secretase

Question 27

what happens when you have mutations in PSEN-1 and PSEN-2?

Answer 27

we get a change in the location of where gamma secretase chops up APP, producing different length amyloid molecules. these seem to be more likely to clump up and form plaques

Question 28

on which chromosome is APP gene located?

Answer 28

21

Question 29

what are pick bodies?

Answer 29

tangles of tau proteins

Question 30

what are some examples of tauopathys?

Answer 30

pick disease and alzheimers disease

Question 31

whats the difference between pick disease and alzheimers disease (in relation to them both being tauopathys)

Answer 31

pick disease only has 3R isoforms | alzheimers has both 3R and 4R isoforms

Question 32

what forms Lewy bodies?

Answer 32

misfiled alpha synuclein

Question 33

which areas do lewy bodies mostly affect?

Answer 33

cortex and substantia nigra

Question 34

in what diseases are Lewy bodies seen in?

Answer 34

Lewy body dementia parkinson disease (may also see some Lewy bodies in the tangles seen in alzheimers)

Question 35

what is Parkinson disease?

Answer 35

a slowly progressive genetic disorder that is characterised by the loss of dopaminergic neurones in the substantial nigra (basal ganglia)

Question 36

why does the loss of dopaminergic neurones in the substantia nigra cause parkinsonian symptoms?

Answer 36

as usualy there is a balance of dopamine (promotes movement) and acetylcholine (inhibits movement) here loss of dopamine causes less moevement, difficulties in speech/swallowing as well as cognitive symptoms like dementia

Question 37

what is Huntington disease?

Answer 37

autosomal dominant neurodegenerative disorder

Question 38

what causes Huntington disease?

Answer 38

a mutation in the HD gene on chromosome 4. this gene encodes for a protein called Huntingtin. this gene contains CAG trinucleotide repeat which encodes for glutamine amino acid/huntington.

Question 39

where do we see neuronal cell death in Huntington disease?

Answer 39

in the caudate and putamen of the basal ganglia

Question 40

outline the neurotransmitter levels in Huntington disease?

Answer 40

basal ganglia has decreased GABA and ACh as well as increased dopamine also excessive activation of NMDA receptors which leads to glutamate excitotoxicity = damages neurones

Question 41

what are the main symptoms of alzheimers?

Answer 41

``` confusion disorientatin difficulty making decsions hallucinations probes with speech memory loss personality changes ```

Question 42

what are the main symptoms of vascular dementia?

Answer 42

``` memory issues balance problems slowness of thought difficulty understanding and concentrating changes to mood and behavuiur disorientation and confusion ```

Question 43

what are the main symptoms of Lewy body dementia?

Answer 43

``` mental ability issues hallucinations onfusion slow movement parkinsons symptoms fainting and unsteadiness disturbed sleep difficulty swallowing ```

Question 44

what are the main symptoms of frontotemporal dementia?

Answer 44

personality changes language and speech problems becoming distracted memory loss