CNS Flashcards
What are the order of layers of the brain from outside in?
dura mater
arachnoid
pia mater
What regulates the blood supply to the brain?
circle of willis
- often a site for aneurysms and bleeds
What does the brain not have that the rest of the body does?
lymphatic system - tumours can not metastasize to the brain this way
The skull is a bony box that can not expand. Therefore if the volume of tissue of fluid inside the skull increases what happens?
- intracranial pressure rises
- results in herniation(abnormal protrusion) where part of the brain moves from one compartment of the skull to another
What do the neurons do compared to the glial cells?
- Neurons - the processors
- Glial cells - supporting functions (includes schwann cells, astrocytes & oligodendrocytes)
Frontal lobe is responsible for …
planning
parental lobe which is responsible for …
movement
occipital lobe responsible for …
vision
cerebellum which is responsible for..
co-ordinating movement and balance
Brain stem is responsible for…
vital functions like regulation BP, resp rate ect.
pre central and post central gyrus are responsible for …
pre - motor cortex
post - sensory cortex
Frontal and temporal lobe are responsible for …
speech and language
includes brocas area in frontal lobe
includes wernickes area in temporal lobe
What is the brain stem composed of (3 areas)?
midbrain
pons
medulla
What is focal neurological signs?
a set of symptoms or signs in which causation can be localized to an anatomic site in the central nervous system
What is generalised neurological abnormalities?
Essentially an alteration in level of consciousness
If you have damage to the frontal lobe what are the likely signs?
Anosmia (inability to smell)
Inappropriate emotions
Expressive dysphasia (cant get words out )
Motor impairment
If you have damage to the parietal lobe what are the likely signs?
Receptive dysphasia ( not understanding language) Sensory impairment
If you have damage to the temporal lobe what is the likely signs ?
- cortical deafness
- Receptive dysphasia
Diffuse neurological injury is usually manifest as impairment of consciousness. Most often due to what?
- increased intracranial pressure
- may occur as a primary response
- or as a secondary to response to a focal injury (injury to specific area)
What are the 2 main pathologies types of strokes?
- ischaemic (as result of blockage, atheroma or thrombosis or emboli)
- haemorrhagic (as a result of berry aneurysm or hypertension related)
What is the only difference between a stoke and a TIA
- the duration in which the symptoms last (TIA resolves within 24 hours)
In cerebrovascular disease survival depends on what 3 things ?
- duration of ischaemia
- what collateral circulation available
- how much reduction of flow and quickly it happens
What are the treatments for TIA’s?
- antiplatelet therapy (aspirin or clopidogrel)
- control BP
- lower cholesterol
What are the risk factors for strokes?
- hypertension
- diabetes
- heart disease
- Previous transient ischaemic attacks
- hyperlipidaemia
What are causes of haemorrhagic events (strokes ect.)?
- hypertension
- vascular malformation (berry aneurysm )
- neoplasia
- trauma
- drug abuse
- iatrogenic
What are the management of strokes?
- thrombolysis (break up blood clot)
- aspirin/ clopidogrel
- physiotherapy
- occupational therapy
- SALT
- supportive treatment
intracerebral haemorrhage (haemorrhagic stroke) presents as what symptoms?
- headache
- rapid or gradual decrease in conscious level
- localises depending on site of bleed
Subarachnoid haemorrhage normally occur ?
- spontaneous
- when berry aneurysm ruptures
What are the symptoms of a subarachnoid haemorrhage?
- thunderclap headache (bad!)
- meningitis like signs (photophobia ect.)
- requires neurosurgical input
where does a subdural haemorrhage occur?
- bleeding from bridging veins between cortex and venous sinuses
- blood between dura and arachnoid
What may cause a subdural haemorrhage?
- often on anticoagulants
- often minor trauma in the elderly
- common in alcoholics
Symptoms of subdural haemorrhage normally take days, weeks or months to present as it involves veins. What are the symptoms?
- fluctuant conscience level
What is an extradural haemorrhage ?
haemorrhage outside the dura
typically affecting the middle meningeal artery
What may cause an extradural haemorrhage?
post head injury
often with fractured temporal or parietal bone
What are the symptoms of extradural haemorrhage?
- slowly falling conscious level
possibly with lucid periods
What should a dementia assessment include?
TSH – ensure thyroid function is normal CT scan (Not all cases) to check for intracranial pathology Vitamin B12, thiamine – alcoholism
What is Alzheimer’s disease due to?
- accumulation of AB amyloid, tau-neurofibrillary tangles and plaques
- loss of neurones and synapses
What does the accumulation in amyloid, tau-neurofibrillary tangles and plaques in Alzheimer’s disease lead to ?
- defects of visual-spatial skills (gets lost)
- memory loss
- decreasing cognotion
- ansognosia (lack of awareness)
What is the treatment for Alzheimer’s disease?
- MDT
- cholinesterase inhibitors (rivastigmine)
What is epilepsy ?
A recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain, manifest as seizures
What can epilepsy be due to?
- space occupying lesions
- stroke
- alcohol withdrawal
What is treatment of epilepsy?
- avoid triggers
- drugs such as sodium valproate, carmazepine, phenytoin, lamotrigine
There are two types of infection in the brain these are diffuse or focal infection. Give an example of each.
diffuse infection - meningitis
focal infection - abscess
What are the early symptoms of meningitis?
- headache
- cold hands and feet
- pyrexial (fever)
What are the late stages of meningitis?
- neck stiffness
- photophobia
- kernigs sign (extension of knee causes pain in the neck)
- non-blanching rash
- seizures
What are the 3 main examples of bacteria causing meningitis?
Neisseria meningitidis
Pneumococcus
Meningococcus
What can a brain abscess symptoms present as?
- headaches
- seizures
- temperature
What does ring enhancing lesion in radiology suggest ?
- brain abscess
How can brain abscess occur?
via blood - embolus from bacterial endocarditis - IV drug users at risk direct - from inner ear infection
What is parkinsons disease?
- movement disorder
- sporadic or familial
- can be drug induced
What are the symptoms of parkinsons?
- rigidity
- bradykinesis (slowness of movement)
- resting tremor
- postural instability (prone to falls, start with difficulty)
What is parkinsons a results of ?
- decreased dopamine with the brain (in substantia nigra, which is decreased also )
What are the presentations of a tumour in the brain?
- headaches
- seizures
- cognitive or behavioural change
- vomiting
- altered consciousness
Most tumours in the brain are secondary deposits from somewhere else. Where might these include?
breast
small cell lung carcinoma
What are the two most common primary benign brain tumours?
meningiomas
astrocytomas
A meningioma is a slow growing tumour where do they arise from?
derived from menigothelial cells
Pituitary tumours can cause..
compression
hormonally active
