Cerebral Inflammation

Question 1

meningitis

Answer 1

inflammation of the meninges caused by viral or bacterial infection

Question 2

encephalitis

Answer 2

inflammation of the brain tissue itself caused by infection or autoimmune mechanisms

Question 3

cerebral vasculitis

Answer 3

inflammation of the blood vessel walls

Question 4

blood brain barrier structure

Answer 4

formed by capillaries that have extensive tight junctions at the endothelial cell-cell contacts

very dense vascularisation of the CNS - no neuron is more than 100 micrometres from a capillary

astrocytes also help maintain the structure of the BBB

Question 5

blood brain barrier function

Answer 5

protects brain tissue from the contents of the bloodstream as tight junctions massively reduces passive movement of solutes and fluids across the capillary wall

allows BBB to control the exchange of these substances using specific membrane transporters

blood borne infectious agents have reduced entry into CNS tissue

Question 6

blood brain barrier disruption

Answer 6

endothelial layer disruption can cause collagenous disruption (which can cause sclerosis)

this causes fibrinogen leakage (commonly seen after internal brain trauma) which results in astrogliosis (astrocytes retract) and astrocyte end feet change

Question 7

symptoms of encephalitis

Answer 7

initially:
- flu-like symptoms
- pyrexia
- headache

within hours, days or weeks:

• confusion/disorientation
• seizures or fits
• changes in personality and behaviour
• difficulty speaking (dysphasia)
• weakness or loss of movement
• loss of consciousness

symptoms caused by brain swelling due to to encephalitis

Question 8

causes of encephalitis

Answer 8

usually viral infection, commonly:

• herpes simplex
• measles
• varicella (chickenpox)
• rubella (german measles)

other causes include:

• mosquito, tick and other insect bites
• bacterial and fungal infections
• trauma (disruption of BBB)
• autoimmune

Question 9

treatment of encephalitis

Answer 9

treatment and outcome depends on the cause:

• antivirals e.g acyclovir
• steroids (to reduce inflammation)
• antibiotics/ antifungals
• analgesics
• anti-convulsants
• ventilation

Question 10

multiple sclerosis

Answer 10

autoimmune demyelinating disease of the CNS

Question 11

presentation of MS

Answer 11

intermittent symptoms (relapsing/remitting phases)

relapses linked to inflammatory activity caused by the demyelination

random disorder - symptoms vary because amount and location of damage to white matter is different in every person

Question 12

progression of MS

Answer 12

after a point, neurological deficit increases permanently and progressively (linked to axonal loss) and inflammation decreases

Question 13

cellular pathology of MS

Answer 13

inflammation
demyelination
axonal loss
neurodegeneration

Question 14

inflammation in MS

Answer 14

characteristically perivascular and leptomeningeal inflammation

influx of immune cells into brain (mainly T and B cells)

Question 15

impact of meningitis

Answer 15

• 6th most common infectious disease killer
• affects more than 5 million people per annum worldwide
• leaves 1 in 5 of the infected people with an impairment

Question 16

symptoms of meningitis

Answer 16

• rash (not always)
• sudden pyrexia
• severe headache
• nausea and vomiting
• double vision
• drowsiness
• photophobia
• stiff neck

Question 17

causes of meningitis

Answer 17

bacterial:
more common, initially cause upper respiratory tract infection and then travel through blood to brain
- meningococcal (most common cause in the UK)
- pneumococcal (most serious)
- haemophilus influenza type b (Hib)
- streptococcal (main cause in babies)

other causes:

• viral (very rarely life threatening)
• fungal

Question 18

infection of spinal cord

Answer 18

myelitis

Question 19

infection of both brain and spinal cord

Answer 19

encephalomyelitis

Question 20

diagnostic tests and results for infection

Answer 20

neurological examination
CT
MRI
lumbar puncture
bloods
urinalysis

CSF usually clear and colourless
low glucose in bacterial meningitis
raised WBC is sign of inflammation