Week 10 - Pathology Of The CNS Flashcards
(75 cards)
1
Q
Name the different lobes of the brain
A
Frontal, parietal, occipital, temporal
2
Q
What does the brain consist of?
A
- cerebral hemispheres (grey matter, white matter, basal ganglia, ventricular system)
- brain stem
- cerebellum
3
Q
What are the meninges?
A
- membranous coverings of the central NS
- protective function and important in production of cerebrospinal fluid
-dura mater –> arachnoid mater –> pia mater
4
Q
Explain the blood supply to the brain
A
- the cerebral arteries supply a defined territory within the cerebral cortex
- if blood supply to a particular part of the brain is interrupted - symptoms developed due to lack of blood supplied to that part of the brain by that vessel
-circle of Willis - arteries supplying brain
5
Q
Explain the venous drainage of the brain
A
Veins covering the brain to ensure venous drainage
6
Q
What is the skull and what can occur because of it?
A
- bony box which can’t expand
- if the volume of tissue fluid inside the skull increases, the intracranial pressure rises
- results in herniation where a part of the brain moves from one compartment of the skull to another
7
Q
What is herniation and what does it present with?
A
where a part of the brain moves from one compartment of the skull to another
- brain herniation frequently presents with abnormal posturing (characteristic positioning of the limbs indicative of severe brain damage)
- lowered level of consciousness - GCS score of 3-5
- one or both pupils dilated - fail to restrict in response to light
- vomiting can also occur due to compression of the vomiting centre in the medulla oblongata
8
Q
What is the function of the spinal cord?
A
-communication of motor and sensory functions between brain and peripheral nervous system
9
Q
Name the regions of the spine and how many nerve pairs it has
A
Cervical - 8 nerve pairs
Thoracic - 12 nerve pairs
Lumbar - 5 nerve pairs
Sacrum - 5 nerve pairs
1 coccygeal nerve
10
Q
What surrounds the spinal cord?
A
Meninges
11
Q
What is the basic neuroanatomy of the peripheral nervous system?
A
- spinal and cranial nerves
- branches of above linking CNS to peripheral sensory receptors and effector organs (muscles and glands)
- autonomic and somatic nervous systems
12
Q
What are the cells of the nervous systems?
A
Neurons - the processors
Glial cells - supporting functions
- Schwann cells, astrocytes and oligodendrocytes
13
Q
Where are the sensory and motor cortex located?
A
Sensory = post-central gyrus
Motor = pre-central gyrus
14
Q
Which areas are responsible for speech and language production?
A
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
15
Q
What is the frontal lobe responsible for?
A
- complex executive functions involved in decision making
- emotional reactions
- formation of some types of memory
- motor cortex
- olfactory function
- generation of fluent speech
16
Q
What is the parietal lobe responsible for?
A
- sensory cortex
- processing of sensory information
17
Q
What is the temporal lobe responsible for?
A
- language functions (auditory cortex and comprehension of written and spoken words)
- memory
18
Q
What is the occipital lobe responsible for?
A
-visual cortex
19
Q
What is the brain stem responsible for?
A
- conduction of major motor and sensory pathways
- control of cardiorespiratory function
- consciousness
- cranial nerve roots
20
Q
What is the cerebellum responsible for?
A
- precise motor control
- ? Others - language, attention (not yet well defined)
21
Q
What is the basic functional anatomy of spinal cord nerves/roots in the CNS?
A
Spinal cord nerve roots:
- 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
- sensory dermatomes
22
Q
What is a sensory dermatome?
A
A dermatome is an area of skin supplied by sensory neurons that arise from a spinal nerve ganglion
-symptoms that follow a dermatome (e.g. Like pain or a rash) may indicate a pathology that involves the related nerve root
23
Q
What are focal neurological signs?
A
Set of symptoms or signs in which causation can be localised to an automatic site in the CNS
24
Q
What is generalised neurological abnormality?
A
Essentially an alteration in level of consciousness
25
What focal neurological signs may arise from the frontal lobe?
- anosmia (lack of sense of smell)
- inappropriate emotions
- expressive dysphasia (language disorder marked by deficiency in the generation of speech)
- motor impairment
26
What focal neurological signs may arise from the parietal lobe?
- receptive dysphasia
| - sensory impairment
27
What focal neurological signs may arise from the temporal lobe?
- cortical deafness
| - receptive dysphasia
28
How are spinal cord lesions examined?
- 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 e.g. complete paralysis of the body and legs with maintained head and neck movement is caused by injuries to the cervical spine
29
What may a diffuse neurological injury present as?
- usually manifest as impairment of consciousness
- most often due to increased intracranial pressure (ICP)
- may occur as a primary process or as a secondary to response of to a focal injury
30
What may be the causes of reduced consciousness?
- may be obvious on external examination (e.g. trauma) or easily identified on basic observations (e.g. hypoxia, hypothermia)
- may require additional bedside tests or more clinical history (e.g. hypo/hyperglycaemia, post-ictal state in an epileptic patient)
31
How is consciousness assessed?
Basic - assess responsiveness
- A = alert
- V = voice
- P = pain
- U = unresponsive
More complex - Glasgow coma scale (GCS)
- best response = 15
- comatose client = 8 or less
- totally unresponsive = 3
32
What are the functions of the nervous system?
Basic: sensory --> motor
(mediated by central and peripheral NS, autonomic and somatic)
Higher:
(consciousness, complex and learned motor skills, memory and planning, communication and language)
33
What does cerebrovascular disease incorporate?
- strokes
- TIAs
- intracerebral haemorrhage
34
What are the 2 main pathological processes in cerebrovascular disease?
- hypoxia, ischaemia and infarction due to impaired blood supply/oxygenation
- haemorrhage from CNS vessels
35
What does the brain require a constant supply of?
Glucose and oxygen
36
Why is cerebral blood flow autoregulated?
-maintain adequate perfusion over a wide range of blood pressure and intra-cranial pressure (ICP)
37
What affects the severity of cerebral vascular disease?
Blood flow reduced to a portion of the brain, tissue survival depends on:
- collateral circulation
- duration of ischaemia
- magnitude and rapidity of flow reduction
-blood flow reduced to the whole brain e.g. global hypoperfusion (e.g. hypotension, cardiac arrest) can result in generalised neuronal dysfunction
38
What is a TIA and what is its symptoms?
- transient ischaemic attack
- characterised by temporary loss of function that resolves itself within 24 hours
- 'mini-stroke'
- symptoms similar to that of a full stroke but recovery is rapid
39
How is a TIA treated?
- 10% chance of having a full stroke within 4 weeks if left untreated
- anti-platelet therapy: aspirin or clopidogrel
- control BP
- lower cholesterol
40
What is a stroke?
Loss of function lasting greater than 24hrs
2 main types
- ischaemic
- haemorrhagic
41
What are the risk factors of a stroke?
- hypertension
- diabetes mellitus
- heart disease - ischaemic, AF
- previous TIAs
- hyperlipidaemia
42
What are the causes of a stroke?
Hypoxia of brain
- blockage of blood vessel by atheroma
- blockage of blood vessel by embolus
Bleed into the brain
- hypertension related
- berry aneurysm
43
How are strokes managed?
Depending on type
- thrombolysis
- aspirin/clopidogrel
- physio
- occupational health
- SALT
- supportive treatment
44
What can cause haemorrhagic events?
- hypertension
- vascular malformation
- berry aneurysm
- neoplasia
- trauma
- drug abuse
- iatrogenic (relating to illness caused by medical examination or treatment - e.g. side effects of drugs)
45
What are the different types of haemorrhage in the brain?
- intracerebral
- subarachnoid
- subdural
- extradural
46
What is an intracerebral haemorrhage?
- 'haemorrhagic stroke'
- presents as headache with rapid or gradual decrease in conscious level - localises depending on site of bleed
- usually arterial in origin
- show mass effect
- in 80% cases with hypertension the bleed is 'capsular haemorrhage'
- few survive
47
What is a subarachnoid haemorrhage?
- spontaneous
- often catastrophic
- 80% rupture of saccular aneurysms
- thunderclap headache
- 'meningitis like' signs
- requires neurosurgical input
48
What is a subdural haemorrhage?
- 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
49
What is an extradural haemorrhage?
- post head injury, slowly falling conscious level, possibility with lucid period
- often with fractured temporal of parietal bone
- typically the middle meningeal artery
50
What is dementia?
- progressive and largely irreversible clinical syndrome with widespread impairment of mental function
- complex needs and high levels of dependency and morbidity
51
What are the risks/signs of dementia?
- >65 years old increased risk
- memory loss
- speed of thought
- language
- understanding/judgement
- disinterest in usual activities
- difficulties in controlling emotions
52
What types of dementia are there and how prevalent is each type?
- Alzheimer's disease (70%)
- vascular dementia - recurrent small strokes (15%)
- Lewy body dementia (15%)
- along with some rare causes - e.g. Syphilis
53
If the frontal lobe is affected by dementia, what dysfunction may occur?
- behaviour disorders
- mood
- motivation
- judgement
- planning
- reasoning
- appetite and continence
- disinhibition
54
If the temporal lobe is affected by dementia, what dysfunction may occur?
Memory dysfunction
55
If the parietal lobe is affected by dementia, what dysfunction may occur?
Dysphasia - language disorder marked by deficiency in the generation of speech
Dyspraxia - difficulties in activities requiring coordination and movement
56
If the subcortical area of the brain is affected by dementia, what dysfunction may occur?
-slowness of thought processes
57
What assessments can be done for people with dementia?
- TSH - ensure thyroid function is normal
- CT scan (not all cases) - to check for intracranial pathology
- vitamin B12, thiamine - alcoholism
58
What is the cause of Alzheimer's disease and what does it lead to?
- due to and accumulation of AB 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)
59
How is dementia treated?
- multidisciplinary team
| - new treatments include cholinesterase inhibitors e.g. rivastigmine (use closely controlled - NICE)
60
What is epilepsy?
A recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the 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
61
How is epilepsy diagnosed?
- good history taking
- exclude structural abnormality
- EEG - electroencephalogram - test that measures and records the electrical activity of your brain
- any triggers e.g. TV?
62
How is epilepsy managed?
- compliance very important
- depending on seizure type
- have serious side effects (teratogenic)
- examples = sodium valproate (epilim), carbamazepine, phenytoin, lamotragine
63
What types of infections can occur in the brain?
Diffuse infection
-e.g. Meningitis
Focal infection
-e.g. Abscess
64
What types of meningitis can you get?
Bacterial
- neisseria meningitidis
- pneumococcus
- meningococcus
Viral
Fungal (rare - HIV etc.)
65
What is the presentation of meningitis?
Early
- headache
- cold hands and feet
- pyrexial
Late
- neck stiffness
- photophobia
- Kernig's sign (pain and resistance on passive knee extension with hip fully flexed)
- non-blanching rash
- seizures
66
What is a brain abscess, how does it spread and what are the effects?
- focal infection
- can lead to focal brain damage or mass effect
- can present with headache, seizures, temperature
- radiologically a 'ring enhancing lesion' - differential diagnosis is a glioblastoma
- can spread via blood e.g. Embolus from bacterial endocarditis, IV drug users at risk
- can spread directly e.g. from an infected inner ear
67
What is Parkinson's disease?
- movement disorder
- sporadic or familial
- can be drug induced
-associated with the degeneration of the basal ganglia of the brain and a deficiency of the neurotransmitter dopamine
68
What are the clinical signs of Parkinson's disease?
- rigidity
- bradykinesis (slowness of movement)
- resting tumour
- postural instability
69
How is Parkinson's disease treated?
- multidisciplinary team approach
- L-DOPA e.g. madopar
- anticholinergic drugs e.g. orphenadrine
- drug induce Parkinson's (e.g. Haloperidol) can be helped by procyclidine
- surgery?
70
What types of tumours can affect the brain and why?
- benign and malignant
- benign tumours can cause problems depending on location and mass effects
- can affect the skull, the meninges or the brain itself
71
What are the symptoms/presentation of a brain tumour?
- headaches
- seizures
- cognitive or behavioural change
- vomiting
- altered consciousness
72
Can metastasis occur in the brain?
Yes
- cancers elsewhere in the body can metastasise in the brain
- must be included when tumours are found on CT and MRI scans - e.g. Breast and small cell lung cancer
73
What is the most common benign tumour to arise in the brain?
Meningiomas
- benign
- generally well circumscribed, slow growing
- derived from meningothelial cells
- enlarge slowly, don't often infiltrate the brain and can be often removed surgically
- can be found incidentally on brain imaging scans
74
What malignant tumours are commonly known to arise in the brain?
Astrocytomas
- range from WHO grade I-IV
- grade I generally good outcome but grade 4 usually fatal
Glioblastoma
75
Explain about pituitary tumours
- cause compression symptoms (e.g. of the optic nerve)
- can be hormonally active (classified based on hormone produced, e.g. Prolactinoma)
- surgically removed transphenoidally (brain surgery where an endoscope and/or surgical instruments are inserted in to part of the brain by going through the nose and the sphenoid bone)
