Central Nervous System

Question 1

Functions of CNS

Answer 1

basic = sensory + motor (mediated by CNS and PNS, autonomic and somatic)
higher = > consciousness, complex and learned motor skills, memory and planning, communication/language

Question 2

Brain structure

Answer 2

cerebral hemispheres:
- grey matter
- white matter
- basal ganglia
- ventricular system
brain stem
cerebellum

Question 3

Meninges

Answer 3

membranous coverings of the CNS
protective function - important in CSF production
> dura mater
> arachnoid mater
> pia mater

Question 4

Blood vessels in CNS

Answer 4

cerebral arteries -
- if blood supply to a particular part if the brain is interrupted, the patient will develop symptoms due to the lack of function of the part of the brain supplied by the vessel
cerebral veins -
- venous blood drains eventually to the internal jugular vein

Question 5

The skull

Answer 5

cannot expand
if the volume of tissue/fluid inside the skull increases the intracranial pressure rises = herniation
herniation is where a part of the brain moves from one part of the skull to the other

Question 6

Spinal chord

Answer 6

8 cervical nerve pairs
12 thoracic nerve pairs
5 lumbar nerve pairs
5 sacral nerve pairs
1 coccygeal nerve pair

Question 7

Peripheral NS

Answer 7

spinal and cranial nerves
branches off linking CNS to peripheral sensory receptors and effector organs (muscles and glands)
autonomic and somatic

Question 8

Name the cells in PNS and CNS

Answer 8

1. neurones - the processors
2. glial cells - supporting functions
   > Schwann cells
   > astrocytes
   > oligodendrocytes

Question 9

What area of the brain is the motor cortex?

Answer 9

pre-central gyrus

Question 10

What area of the brain is the sensory cortex?

Answer 10

post-central gyrus

Question 11

What and where is Broca’s area in the brain?

Answer 11

frontal lobe, anterior to the pre-motor cortex

predominantly responsible for speech production

Question 12

What and where is Wernicke’s area in the brain?

Answer 12

temporal lobe, posterior to auditory cortex

responsible for processing speech and comprehension of written and spoken language

Question 13

Frontal lobe

Answer 13

decision making, emotional reactions, formation of some types of memory, motor cortex, olfactory function, fluent speech

Question 14

Parietal lobe

Answer 14

sensory cortex, processing of sensory info

Question 15

Temporal lobe

Answer 15

language functions and auditory cortex, comprehension of written and spoken words, memory

Question 16

Occipital lobe

Answer 16

visual cortex

Question 17

Brain stem

Answer 17

conduction of major motor and sensory pathways, cardio-respiratory functions and consciousness, cranial nerve roots

Question 18

Cerebellum

Answer 18

precise motor control, language attention ??

Question 19

Spinal chord nerve roots

Answer 19

specific spinal nerves innervate defined motor functions and sensory territories
damage to spinal chord at specific level = loss of function of spinal nerves below that level

Question 20

What are focal neurological signs?

Answer 20

a set of symptoms or signs in which causation can be localized to an anatomic site in the central nervous system

Question 21

What is generalised neurological abnormality?

Answer 21

Essentially an alteration in level of consciousness

Question 22

Frontal lobe focal neurological signs
Parietal lobe focal neurological signs
Temporal lobe focal neurological signs

Answer 22

anosmia (loss of smell), inappropriate emotions, expressive dysphasia, motor impairment

receptive dysphagia, sensory impairment

cortical deafness, receptive dysphagia

Question 23

Spinal chord lesions

Answer 23

Physical examination helps to identify the level of injury in spinal cord lesions
Signs limited to a single dermatome or nerve root suggest either a focal nerve root injury or injury to a peripheral nerve
Signs affecting several nerve roots below a certain level eg. Complete paralysis of body and legs with maintained head and neck movement is caused by injuries to the cervical spine (usually traumatic)

Question 24

Diffuse neurological injury

Answer 24

Usually manifest as impairment of consciousness
Most often due to increased intracranial pressure
May occur as a primary process or as a secondary to response to a focal injury

Question 25

How do we assess consciousness?

Answer 25

A: alert V: voice P: pain U: unresponsive

Question 26

Cerebrovascular diseases

Answer 26

strokes, TIA, intracerebral haemorrhages 2 main pathological processes: > hypoxia, ischaemia, infarction due to impaired o2/blood supply > haemorrhage from CNS vessels if blood flow is decreased to a portion of the brain, survival of tissue depends on: - collateral circulation - duration of ischaemia - magnitude and rapidity of decrease blood flow reduced blood flow to the whole brain = global hypofusion = generalised neuronal dysfunction

Question 27

Stroke

Answer 27

``` Face (drooping) Arms (may not be able to raise them) Speech (slurred) Time loss of function lasting greater than 24 hours 2 types; - ischaemic - haemorrhagic risk factors: hypertension, DM, heart disease, hyperlipidaemia ```

Question 28

Causes of a stroke

Answer 28

hypoxia of the brain due to blockage of blood vessels by an atheroma or embolus bleed into the brain caused by hypertension or aneurysm Left MCA territory infarct - - damage to speech area in L hemisphere = loss of speech (aphasia) - damage to L visual pathway = loss of vision to R (hemianopia) - damage to left motor cortex and internal capsule = weakness of R face, arm and leg

Question 29

Management of strokes

Answer 29

``` thrombolysis Aspirin, Clopidogrel physiotherapy occupational therapy SALT ```

Question 30

Transient ischaemic attack (TIA)

Answer 30

temporary loss of function that resolves itself within 24 hours "mini strokes" symptoms similar to stroke but rapid recovery treatment = anti-platelet therapy eg. Aspirin, Clopidogrel, control BP, lower cholesterol

Question 31

Causes of haemorrhagic events

Answer 31

hypertension, aneurysm, neoplasia, trauma, drug abuse, iatrogenic

Question 32

Intracerebral haemorrhage

Answer 32

"haemorrhagic stroke" headache, with rapid or gradual decrease in consciousness, localises depending on site of bleed usually arterial few survive

Question 33

Subarachnoid haemorrhage

Answer 33

spontaneous, usually catastrophic 'thunderous' headache meningitis like signs requires neurosurgical input

Question 34

Subdural haemorrhage

Answer 34

fluctuant conscious levels often on anti-coagulants blood between dura and arachnoid often minor trauma in the elderly

Question 35

Extradural haemorrhage

Answer 35

post head injury, slowly falling consciousness levels often with fractured temporal or parietal lobe typically middle meningeal artery

Question 36

Dementia

Answer 36

65+ increased risk memory loss, decreased speed of thought, language, understanding and judgement affected, have difficulty controlling emotions 70% is Alzheimer's, 15% is vascular dementia (recurrent small strokes), 15 % dementia with Lewy Bodies assessment: - TSH (ensure thyroid function is normal) - CT scan - vitamin B12, thiamine = alcoholism

Question 37

Alzheimer's disease

Answer 37

due to loss of neurones and synapses, and accumulation of AB amyloid leads to defects of visual-spatial skill, memory loss, decreased cognition and lack of awareness treatment = multi-disciplinary approach, cholinesterase inhibitors eg Rivastigmine

Question 38

Epilepsy

Answer 38

a recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain manifest as seizures which can take many forms: - focal twitching, trance-like, convulsions usually no identifiable cause management = - lifestyle changes eg. driving - drug compliance (can have side effects = teterogenic0 eg. Sodium Valproate, Carbamazepine, Phenytoin, Lamotrigine

Question 39

Meningitis

Answer 39

diffuse infection Bacterial: Neisseria meningitidis, Pneumococcus, Meningococcus Viral Fungal presentation: EARLY - headache, cold hands and feet, pyrexial, LATE - neck stiffness, photophobia, non-blanching rash, seizures

Question 40

Brain abscess

Answer 40

focal infection leads to focal brain damage presents with headache, temp seizures can spread via blood eg. embolus from bacterial endocarditis, IV drug user at risk can spread directly eg. from an inner ear infection

Question 41

Parkinson's disease

Answer 41

movement disorder sporadic, familial can be drug induced clinically: rigidity, bradykinesia (slowness of movement), resting tremor, postural instability treatment = MDT approach, L-dopa eg. Madopar, anticholinergic drugs eg Orphenadrine, SURGERY

Question 42

Tumours

Answer 42

benign lesions can cause problems depending on location/mass effects can effects skull/meninges/brain itself presentations: headaches, seizures, cognitive/behavioural change, vomiting, altered consciousness

Question 43

Tumour metastasis

Answer 43

cancer elsewhere in the body can metastasize the brain eg. breast and small cell lung cancer eg. meningioma's, astrocytoma's, pituitary tumours, glioblastoma

Question 44

Meningioma's

Answer 44

benign tumour slow growing derived from meningothelial cells

Question 45

Astrocytoma's

Answer 45

range from grade 1-4, grade 4 being fatal

Question 46

Pituitary tumours

Answer 46

``` cause compression symptoms eg. optic nerve can be hormonally active > classified based on hormone production eg. Prolactinoma surgically removed transphenoidally ```