ND - CNS Disorders and Cranial Tumours - Week 9

Question 1

What is the general prevalence of dementia, and its prevalence >80yoa?

Answer 1

5% increasing to 20-40%

Question 2

What are the two kinds of dementia causes and percentage of cases.

Answer 2

Degeneration 55%

Infarct 45% of the limbic system

Question 3

What is the most common form of degeneration type dementia?

Answer 3

Alzhiemers disease

Question 4

List three causes of dementia in young people. Is it common?

Answer 4

Creutzfeldt-jakob disease (prion)
Picks disease (hereditary)
Alcoholic toxicity

Question 5

What is the average prognosis for dementia?

Answer 5

From diagnosis to death is ~8 years

Question 6

What is the limbic system and what does it mediate (3)?

Answer 6

A group of interconnected nuclei that mediates emotions, learning, and memory

Question 7

What forms neurofibrillary tangles in alzhiemers disease? What do these proteins normally do?

Answer 7

Microtubule protein tau binds tubules in the normal brain

In AD, phosphorylation produces free tau, resulting in tubule breakdown resulting in tangles

Question 8

Describe how amyloid plaques form in AD. What is it a byproduct of? Where does it accumulate and hat does it result in?

Answer 8

B-amyloid is a byproduct of neural tube breakdown
Accumulates in the ECM, forming plaques
It is neurotoxic, resulting in CNS apoptosis

Question 9

What ultimately happens with AD?

Answer 9

The brain atrophies

Question 10

List three CNS effects of limbic system degeneration in AD.

Answer 10

Cortical atrophy
Shrinkage of brain mass
Enlarged ventricles (in the brain)

Question 11

List a PNS effect of limbal system degeneration in AD and why.

Answer 11

Apoptosis/glaucoma due to decreased bDNF

Question 12

What is the outcome of limbal system loss in AD (2)?

Answer 12

Dementia (memory/speech)

Visual processing loss ± glaucoma

Question 13

Are there any ocular signs of AD? Explain (4).

Answer 13

Some research indicates there is
Retinal nerve fibre layer thinning
Resence of B-amyloid plaques in the retina
Retinal vessel calibre changes
Retinal blood flow changes

Question 14

Where does myelination first begin in the visual system and where does it proceed to and stop?

Answer 14

Starts 5th month gestation in the LGN, proceeds to the eye

Stops at the lamina 6th month

Question 15

How does a myelinated retina appear (2)? What happens if an individual with a myelinated retina has MS?

Answer 15

Feathery white appearance
Distinct fibres visible
May disappear with MS

Question 16

What is the primary function of myelin?

Answer 16

To facilitate inter-nodal axonal conduction

Question 17

List three causes of demyelination and the most common.

Answer 17

Multiple sclerosis (most common)
Toxicity (CO problems)
Inflammation

Question 18

In what percentage of MS cases is optic neuritis a presenting sign? What percentage of MS cases have optic neuritis?

Answer 18

~20% optic neuritis as the presenting sign

~85% of MS cases have optic neuritis

Question 19

What are two presentations of optic neuritis?

Answer 19

Visible at the lamina called papillitis

Retrobulbar to orbit called retro-bulbar neuritis

Question 20

What is an ocular sign of retrobulbar neuritis?

Answer 20

No obvious ophthalmic signs

Question 21

What can be seen with OCT analysis of retrobulbar neuritis (2)?

Answer 21

Loss of RNFL and optic atrophy

Question 22

What can form in regions of dense inflammation in retrobulbar neuritis (2)?

Answer 22

Scarring and plaque formations

Question 23

List 4 eye involvements (symptoms) of retrobulbar neuritis.

Answer 23

Distorted/loss of vision, colour vision
Abnormal visual evoked response
Eye movement anomaly or diplopia

Question 24

List 5 systemic problems of MS.

Answer 24

Muscle symptoms
Bowel/bladder symptoms
Numbness/tingling/pain
Decreased attention span/poor memory
Fatigue

Question 25

What is required to identify multiple sclerosis?

Answer 25

Multiple lesions over multiple episodes (MRI)

Question 26

What is a consequence of expansive disorders?

Answer 26

Raised intracranial pressure

Question 27

List 5 common diseases associated with raised intracranial pressure.

Answer 27

``` Uncontrolled systemic hypertension Cranial mass Pseudotumour cerebri Subarachnoid haemorrhage Intracerebral haemorrhage ```

Question 28

Describe the mass effect.

Answer 28

When a space occupying lesion expands in the confines of a fixed volume

Question 29

What does raised intracranial pressure result in (3)?

Answer 29

Pain (headache) Axoplasmic stasis Vascular compromise

Question 30

List 7 neurologic signs of raised intracranial pressure.

Answer 30

Severe/different CONSTANT headaches Rigidity about the neck with loss of forward flexion Gait problems (unsteady) Projectile vomit with no nausea Hemi-paresis Reduced state of alertness Worstening symptoms ith straining, valsalva, posture change

Question 31

List 5 ocular signs of raised intracranial pressure.

Answer 31

``` Photophobia Short-lived visual disturbance, blur, or loss (5-30 secs) Diplopia Pupil abnormality Papilloedema ```

Question 32

What is the cause of ocular signs manifesting with raised intracranial pressure?

Answer 32

Due to transmission of intracranial pressure down the ONH sheath to the lamina cribrosa

Question 33

What two things would make one highly suspicious of raised intracranial pressure?

Answer 33

Papilloedema ith at least one other neurological sign

Question 34

How are intracranial pressure abnormalities diagnosed?

Answer 34

Lumbar puncture

Question 35

Within what timespan of raised intracranial pressure can papilloedema occur? hat is it typically?

Answer 35

Can occur within 24h | Typically 3-7 days

Question 36

Is spontaneous venous pulsation a reliable rign of raised intracranial pressure?

Answer 36

No

Question 37

Is papilloedema always bilateral? Explain.

Answer 37

Yes, but often asymmetrical

Question 38

Describe foster-kennedy syndrome and what it is due to.

Answer 38

Optic atrophy in one eye due to crunch and papilloedema in the other eye due to mass effect

Question 39

How is papilloedema caused by raised intracranial pressure?

Answer 39

Transmission of intracranial pressure along the sub-arachnoid space

Question 40

With papilloedema, describe the following: Pole where it is most marked Blood vessels at the disc (2) Vessels in general Papilla In addition to this, list three three features you would see.

Answer 40

``` Most marked at the inferior pole Disc hyperaemia and buried blood vessels Venous engorgement Papilla swelling Peripapillary haemorrhage Cotton wool pathes Retinal or choroidal folds ```

Question 41

What are cotton wool spots?

Answer 41

NFL infarcts

Question 42

How many types of papilloedema can be seen and when do they manifest? What does the type depend on (2)?

Answer 42

``` Long term (>3 months), 2 types can be seen Type depends on the level of vascular compromise and shunt development ```

Question 43

Describe compensated papilloedema (shunt, venous flow, axoplasmic stasis).

Answer 43

Shunt established, venous flow compromised but axoplasmic stasis still present

Question 44

What appearance does compensated papilloedema have (2)?

Answer 44

Clean appearance with gross intravitreal swelling of the ON

Question 45

Describe non-compensated papilloedema (shunt)?

Answer 45

Shunts not established

Question 46

What appearance does non-compensated papilloedema have (3)?

Answer 46

Very dirty appearance with haemorrhages and cotton wool spots

Question 47

What is pseudotumour cerebri and who does it typically affect?

Answer 47

False brain tumour, typically affecting premenopausal obese women

Question 48

What are the signs of pseudotumour cerebri (2)?

Answer 48

Signs as per papilloedema, but all investigations fail to find a cause

Question 49

What kind of diagnosis is pseudotumour cerebri?

Answer 49

Diagnosis by exclusion

Question 50

Does pseudotumour cerebri present with many neurological signs?

Answer 50

Few neurological signs

Question 51

What are the symptoms of pseudotumour cerebri?

Answer 51

As per papillodema

Question 52

What percentage of patients with pseudotumour cerebri have severe vision loss?

Answer 52

2%%

Question 53

What cranial nerve involvement and hat ocular problems are common with pseudotumour cerebri?

Answer 53

CN6 involvement and BV problems

Question 54

Why do aneuryms and subarachnoid haemorrhages often involve vision or visual pathways?

Answer 54

Due to the location of major cerebral blood vessels

Question 55

What is an aneurysmal rupture considered?

Answer 55

Neurological emergency

Question 56

When do symptoms of rupture occur before and after rupture (in terms of percentages for each)?

Answer 56

After rupture - 90% | Before rupture due to growth/compression - 10%

Question 57

What can symptoms of an aneurysm give prodrome for?

Answer 57

Impending aneurysmal rupture

Question 58

List three typical symptoms of aneurysms.

Answer 58

Severe headaches Visual disturbances ± neurological symptoms

Question 59

List 7 symptoms of a subarachnoid haemorrhage.

Answer 59

Recent onset of constant or severe headache that do not comply with recognised patterns (thunderclap/migraine) Short-lived losses of visiond, blur or visual field Photophobia Rigidity about the neck with loss of forward flexion Papilloedema Intraorbital haemorrhage Gradual ON atrophy with/without cupping Changes in consciousness/alertness