Central Nervous System

Question 1

Functions of the nervous system

Answer 1

Basic : Sensory → Motor
(mediated by central and peripheral nervous system, autonomic and somatic)

Higher : 
Consciousness
Complex and learned motor skills
Memory and planning
Communication/language

Question 2

Brain

Answer 2

Cerebral hemispheres
Grey matter
White matter
Basal ganglia
Ventricular system
Brain stem
Cerebellum

Question 3

Meninges

Answer 3

Membranous coverings of the central nervous system
Protective function and important in production of cerebrospinal fluid
Dura reflected from underlying surface of arachnoid, including tumour (meningioma).

Question 4

Blood vessels - arteries

Answer 4

The cerebral arteries supply a defined territory within the cerebral cortex

If blood supply to a particular part of the brain is interrupted, the patient will develop symptoms due to lack of function of the part of the brain supplied by that vessel

Question 5

The skull

Answer 5

The skull is a bony box which cannot expand
If the volume of tissue or fluid inside the skull increases the intracranial pressure rises
This results in herniation where a part of the brain moves from one compartment of the skull to another

Question 6

Basic Neuroanatomy

Answer 6

Spinal and cranial nerves
Branches of above linking CNS to peripheral sensory receptors and effector organs (muscles & glands)
Autonomic and somatic nervous systems

Question 7

Neuro Cells

Answer 7

Neurons - the processors
Glial cells - supporting functions
- Schwann cells astrocytes & oligodendrocytes

Question 8

Speech and Language

Answer 8

Broca’s area

• Frontal lobe, anterior to pre-motor cortex
• Predominantly responsible for speech production

Wernicke’s area

• Temporal lobe, posterior to auditory cortex
  
  • Speech processing and comprehension of written and spoken language

Question 9

Frontal lobe

Answer 9

Complex executive functions involved in decision making; Emotional reactions: Formation of some types of memory; Motor cortex; Olfactory function; Generation of fluent speech

Question 10

Parietal lobe

Answer 10

Sensory cortex and processing of sensory information

Question 11

Temporal lobe

Answer 11

Language functions including auditory cortex and comprehension of written and spoken words; Memory

Question 12

Occipital lobe

Answer 12

Visual cortex

Question 13

Brain stem

Answer 13

Conduction of major motor and sensory pathways; Control of cardiorespiratory function and consciousness; Cranial nerve roots

Question 14

Cerebellum

Answer 14

Precise motor control; ?Others – language, attention (not yet well defined)

Question 15

Spinal cord nerve roots

Answer 15

Specific spinal nerves innervate defined motor functions and sensory territories
Damage to spinal cord at a specific level will cause loss of function of spinal nerves below that level

Question 16

Focal neurological signs

Answer 16

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

Question 17

Generalised neurological abnormality

Answer 17

Essentially an alteration in level of consciousness

Question 18

Clinical application

Answer 18

People who have regular contact with patients are often more likely to notice subtle changes in neurological parameters allowing prompt investigation and treatment
Basic neurological examination often allows localisation of lesion/injury in a patient with focal neurology
Imaging is usually required to confirm and better characterise the nature of the pathological process
Identification of the likely site by examination can assist in the precise radiological identification of a lesion
Assessment of consciousness allows identification of progression of a neurological insult

Question 19

focal neurological signs - frontal lobe

Answer 19

Anosmia
Inappropriate emotions
Expressive dysphasia
Motor impairment

Question 20

focal neurological signs - parietal lobe

Answer 20

Receptive dysphasia

Sensory impairment

Question 21

focal neurological signs - temporal lobe

Answer 21

Cortical deafness

Receptive dysphasia

Question 22

Spinal cord leisons

Answer 22

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 23

diffuse neurological injury

Answer 23

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

Question 24

Causes of reduced consciousness

Answer 24

May be obvious on external examination (eg. Trauma) or easily identified on basic observations (eg. Hypoxia, hypothermia)
May require additional bedside tests or more clinical history (eg. Hypo/ hyperglycaemia, post-ictal state in an epileptic patient)

Question 25

CEREBROVASCULAR DISEASE

Answer 25

Leading cause of mortality and morbidity Incorporates strokes, TIAs, intracerebral haemorrhage 2 main pathological processes Hypoxia, ischaemia and infarction due to impaired blood supply/oxygenation Haemorrhage from CNS vessels Brain requires constant supply of glucose and oxygen Brain accounts for 1-2% body weight but receives 15% resting cardiac output and accounts for 20% blood oxygen consumption Cerebral blood flow is autoregulated to maintain adequate perfusion over a wide range of blood pressure and ICP

Question 26

Blood flow reduced to a portion of the brain, tissue survival depends on :

Answer 26

Collateral circulation Duration of ischaemia Magnitude and rapidity of flow reduction Blood flow reduced to the whole brain ie. Global hypoperfusion (eg hypotension, cardiac arrest) can result in generalised neuronal dysfunction

Question 27

F A S T

Answer 27

Face- facial drooping Arms- person may not be able to raise both arms and keep them raised due to weakness or numbness Speech- slurred speech Time- is of the essence ring for ambulance urgently

Question 28

Stroke or Transient Ischaemic Attack

Answer 28

TIAs are characterised by temporary loss of function that resolves itself within 24 hours Sometimes called “mini-strokes” Symptoms are similar to that of a full stroke but recovery is rapid

Question 29

Treatment of TIA's

Answer 29

1 in 10 chance of having a full stroke within 4 weeks if left untreated Anti-platelet therapy: aspirin or clopidogrel Control blood pressure Lower cholesterol

Question 30

Stroke

Answer 30

Loss of function lasting greater than 24 hours 2 main pathological types: Ischaemic Haemorrhagic

Question 31

Stroke risk factors

Answer 31

``` Hypertension Diabetes mellitus Heart disease – ischaemic, atrial fibrillation Previous transient ischaemic attacks Hyperlipidaemia ```

Question 32

Stroke causes

Answer 32

Hypoxia of brain Blockage of blood vessel by atheroma Blockage of blood vessel by embolus Bleed into the brain Hypertension related Berry aneurysm

Question 33

Left MCA territory infarct

Answer 33

Damage to speech area in Left hemisphere -> loss of speech (aphasia) Damage to L visual pathway-> Loss of vision to Right (Hemianopia) Damage to left motor cortex and internal capsule -> Weakness of Right face, arm and leg

Question 34

Management of Stroke patients

Answer 34

``` NICE guidance Thrombolysis Aspirin/Clopidogrel Physiotherapy Occupational therapy SALT Supportive treatment ```

Question 35

causes of haemorrhagic events

Answer 35

``` Hypertension Vascular malformation Berry aneurysm Neoplasia Trauma Drug abuse Iatrogenic ```

Question 36

intracerebral haemorrhage

Answer 36

‘Haemorrhagic stroke’ Presents as headache, with rapid or gradual decrease in conscious level – localizes depending on site of bleed Usually arterial in origin Show mass effect In 80% of cases with hypertension bleed is ‘capsular haemorrhage’ Few survive

Question 37

subarachnoid haemorrhage

Answer 37

``` Spontaneous Often catastrophic 80% rupture of saccular aneurysms ‘Thunderclap headache’ ‘Meningitis like’ signs Requires neurosurgical input ```

Question 38

subdural haemorrhage

Answer 38

``` Fluctuant conscious level Often on anticoagulants Bleeding from bridging veins between cortex and venous sinuses Blood between dura and arachnoid Often minor trauma in the elderly ```

Question 39

extradural haemorrhage

Answer 39

Post head injury, slowly falling conscious level, possibly with lucid period Often with fractured temporal or parietal bone Typically the middle meningeal artery

Question 40

Dementia

Answer 40

Progressive and largely irreversible clinical syndrome with widespread impairment of mental function. Complex needs and high levels of dependency and morbidity People should have chance to make decisions about their care in conjunction with the medical teams

Question 41

Dementia presentation

Answer 41

``` 80,000 people in the UK > 65 years old increased risk Memory loss Speed of thought Language Understanding/Judgement People can become disinterested in usual activities Have difficulties in controlling emotions ```

Question 42

Patterns of dysfunction frontal

Answer 42

``` Disorders of behavior Mood Motivation Judgment Planning Reasoning Appetite and continence Disinhibition ```

Question 43

Patterns of dysfunction temporal

Answer 43

Memory dysfunction

Question 44

Patterns of dysfunction Parietal

Answer 44

Dysphasia and dyspraxia

Question 45

Patterns of dysfunction subcortical

Answer 45

Slowness of thought processes

Question 46

Dementia assessment

Answer 46

Can include TSH – ensure thyroid function is normal CT scan (Not all cases) to check for intracranial pathology Vitamin B12, thiamine – alcoholism

Question 47

Alzheimer's Disease

Answer 47

Due to an accumulation of Aβ amyloid, Tau – neurofibrillary tangles and plaques, and loss of neurones and synapses Leads to defects of visual-spatial skill (gets lost), memory loss, decreasing cognition, ansognosia (lack of awareness)

Question 48

Alzheimer's Disease Treatment

Answer 48

Needs multidisciplinary team approach New treatments include cholinesterase inhibitors eg rivastigmine Their use is closely controlled by NICE

Question 49

Epilepsy

Answer 49

``` A recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain, manifest as seizures’ Seizures can take many forms Focal twitching, trance-like, convulsions Usually no identified cause For example, can be due to Space occupying lesions Stroke Alcohol withdrawal ```

Question 50

Epilepsy diagnosis

Answer 50

Good history taking Exclude structural abnormality EEG Any triggers?

Question 51

Epilepsy management

Answer 51

``` Compliance is very important Depending on seizure type Have serious side effects, eg teratogenic Examples Sodium valproate – epilim Carbamazepine Phenytoin Lamotragine ```

Question 52

Meningitis

Answer 52

``` Bacterial Neisseria meningitidis Pneumococcus Meningococcus Viral Fungal ```

Question 53

Meningitis presentation

Answer 53

``` Early Headache Cold hands and feet Pyrexial Late Neck stiffness Photophobia Kernig’s sign Non-blanching rash Seizures ```

Question 54

Brain Abscess

Answer 54

Focal infection Can lead to focal brain damage or mass effect Can present with headaches, seizures, temperature Radiologically a ‘ring enhancing lesion’ – differential diagnosis is a glioblastoma Can spread via blood, eg. Embolus from bacterial endocarditis IV drug users at risk Or direct, eg. From an infected inner ear

Question 55

Parkinson's disease

Answer 55

Movement disorder Sporadic or familial Occurs 1 in 1000, usually over 50 years Can be drug induced

Question 56

Parkinson's disease presentation

Answer 56

``` rigidity bradykinesis resting tremor postural instability Postural instability due to the progressive degeneration of the dopaminergic nigrostriatal system and other neuronal networks. ```

Question 57

Parkinson's disease treatment

Answer 57

MDT approach L-dopa eg Madopar Anticholinergic drugs eg orphenadrine Drug induced Parkinson’s (eg Haloperidol) can be helped by procyclidine

Question 58

TUMOURS/SPACE OCCUYPING LESIONS

Answer 58

Benign tumours can cause problems depending on location and mass effects Can affect the skull, the meninges or the brain itself

Question 59

TUMOURS/SPACE OCCUYPING LESIONS presentation

Answer 59

``` Headaches Seizures Cognitive or behavioral change Vomiting Altered conciousness ```

Question 60

Meningiomas

Answer 60

Benign tumours Generally well circumscribed, slow growing Derived from meningothelial cells Enlarge slowly, don’t often infiltrate the brain, and can be often be removed surgically Can be found incidentally on brain imaging scans

Question 61

Astrocytomas

Answer 61

Range from WHO Grade I-IV Grade I generally good outcome, grade 4 usually fatal

Question 62

Pituitary tumours

Answer 62

``` Cause compression symptoms For example of the optic nerve These can be hormonally active Classified based on the hormone produced For example a prolactinoma Surgically removed transphenoidally ```