1b Cerebral Inflammation Flashcards
What is meningitis?
Inflammation of the meninges caused by viral or bacterial infection
What is encephalitis?
inflammation of the brain caused by infection or autoimmune mechanisms
What is cerebral vasculitis?
inflammation of blood vessel walls (sometimes called angiitis)
What was the evidence which suggested the presence of the blood brain barrier?
In the late 19th and early 20th centuries, it was noted that dyes, and other tracers, injected intravenously, accumulated in most tissues, but were excluded from most areas of the CNS.
This suggested the existence of a Blood-Brain Barrier.
What term is used to describe the blood supply of the CNS?
Dense Vascularisation
No neurone is more than how far from a capillar?
100 micrometers
What cells form the blood brain barrier?
Endothelial cells and astrocytes
What do BB capillaries have at the endothelial cell-cell contacts?
Extensive tight junctions
What do the tight junctions of the BBB allow?
massively reduced solute and fluid leak across the capillary wall
What is the benefit of the BBB?
The BBB can then control the exchange of these substances using specific membrane transporters to transport into and out of the CNS (influx and efflux transporters).
Blood borne infections then have reduced entry into the CNS tissue
Describe the series of events which occurs when the BBB is disrupted?
- Endothelial layer disruption
- Fibringoen leakage
- Astrocytes retract their end feet in response
- Then inflammatory cells can more to the area
What are the initial symptoms of encephalitis?
flu-like with pyrexia (high body temperature) and headache
What are the symptoms of encephalitis which are experienced within a few days / weeks?
confusion or disorientation
seizures or fits
changes in personality and behaviour
difficulty speaking
weakness or loss of movement
loss of consciousness
What are the most common viral causes of encephalitis?
Herpes Simplex
Measles
Varicella (chickenpox)
Rubella (German measles)
What is encephalitis most commonly caused by?
Viral infections
What are the other non-viral causes of encephalitis?
Mosquito, tick and other insect bites
Bacterial and fungal infections
Trauma
Autoimmune
What treatments could be used for encephalitis?
Anti-virals eg acyclovir
Steroids - anti-inflammatory
Antibiotics / antifungals
Analgesics
Ventilation
What term is used to describe the classic presentation of MS?
Relapsing-remitting
What is MS?
Autoimmune attack on the oligodendrocytes causing demyelination (the myelinating cells of the CNS) which impairs normal transmission
What are the relapses of MS linked to?
Inflammatory activity
What happens to the axons over time in MS?
there is progressive, residual loss of axons
What is the progression of MS linked to?
Neurodegenration
What is the cellular pathology of MS?
Inflammation
Demyelination
Axonal Loss
Neurodegenration
What would be seen on a MRI scan of a patient with MS?
Whitening of the inner matter of the brain indicating a loss of myelination of the axons
Which cells are recruited to the area in MS?
Perivascular immune cell infiltration (CD3 T cells and CD20 B cells)
What is meningitis?
Irritation, inflammation and swelling of the meninges
What are the four bacterial causes of meningitis?
Meningococcal
Pneumococcal
Haemophilus Influenzae type b (Hib)
Streptococcal
Which is the most common bacteria to cause meningitis in the UK?
Meningococcal
Which is the most common bacteria to cause meningitis in new born babies?
Streptococcal
What is MS pathology characterised by?
MS pathology is characterised by perivascular and leptomeningeal inflammation
What are the other causes of meningitis?
Viral - rarely life threatening
Fungal
Why do the symptoms of MS vary between patient to patient?
Symptoms vary because the amount and location of damage to the nervous system is different in each person with MS
Which symptom is unique to meningitis and not encephalitis?
Photophobia
What are the other causes of meningitis?
Viral - rarely life threatening
Fungal
