Plasticity and Pathology Flashcards
What is neuroplasticity?
The adaptive capacity of the CNS and its ability to modify its own structural organisation and functioning
Why is neuroplasticity in the CNS important?
The CNS cannot undergo Wallerian regneneration like the PNS can
Only the hippocampus and the olfactory bulb can undergo neurogenesis
How is neuroplasticity done?
There are many pathways which lie dormant, having minimal effect
After removal of a primary pathway, dormant pathways become more effective and become stronger with increased use
Collateral sprouting occuts, the main axon is lost so an outgrowth develops from the shaft of another axon
How is neuroplasticity and therefore neuro-rehabillitation encouraged?
Practice and repetition Active participation Meaningful activity Feedback Attention Instructions Motivation Perception of ability Sleep
What is meningitis?
Inflammation of the leptomeninges (pia and arachnoid mater)
Can be acute or chronic
Why is prompt diagnosis and treatment of meningitis vital?
The meninges become completely destroyed by the pathogen and resultant acute inflammatory response
Presentation of acute meningitis?
Headache Neck stiffness Fever Photophobia Vomiting Rigors
What are the main causative organisms of meningitis in -neonates -2-5 years 5-30 years 30+ years
Neonates: E. coli, Listeria monocytogenes, Streptococcus agalactiae
2-5: H influenzae type B
5-30: Neisseria meningitidis
Over 30: Strep pneumoniae
What can cause chronic meningitis?
Post-primary non-pulmonary M tuberculosis
Cryptococcus
How does chronic meningitis present?
Chronic headache
What is seen in chronic meningitis?
Granulomatous formations
Fibrosis of meninges
Nerve entrapment, can cause CN palsies
Main complications of meningitis?
RICP due to inflammation and swelling Cerebral infarctions Cerebral abscesses Subdural empyema Epilepsy All can result in death
What is encephalitits?
An infection of the neural parenchyma, mainly grey matter, which normally has a viral cause
Presentation of a patient with encephalitis?
Headache Fever Confusion Drowsiness Fatigue Seizures or tremors
Causative organisms of encephalitis?
Herpes simplex virus Cytomegalovirus HIV Toxplasmosis Polio
What are prions?
Constituents of the neuronal synapse, function there
How can you get mutated prion proteins (PrP)?
Familial or sporadic mutation
Ingesting mutated PrPs which interact with normal PrPs, allowing them to undergo post-translational conformational changes
What happens with mutated PrPs?
They aggregate causing neuronal death and holes in grey matter
Produce spongiform encephalopathies
What is prion disease seen in?
Creutzfeldt–Jakob disease
Kuru
When is ICP increased physiologically?
Coughing or sneezing
What are the adaptive mechanims to maintain are normal ICP?
Reduced bloodflow
Reduced CSF volume
Spatial - brain atrophy/shrinkage
What are the most common benign and malignant tumours of the CNS?
Benign: Meningeal origin - meningioma
Malignant: Astrocytoma
What is the difference between primary and secondary damage in a head injury?
Primary - the damage caused by the force of the injury, normally caused by movement of the brain as it hits the front and back of the skull
Secondary - reaction to the primary damage, which worsens the injury
What are the types of primary damage?
Focal damage: where there is bruising and laceration of the brain (cerebral contusion). Can be coup or contrecoup
Diffuse damage: tearing of axons from cell bodies as a result of the injury - known as diffuse axonal injury
