Cerebral inflammation and disorders Flashcards
Define meningitis
inflammation of the meninges caused by viral or bacterial infection
define encephalitis
inflammation of the brain caused by infection or autoimmune mechanisms
what is Cerebral vasculitis?
inflammation of the blood vessel walls (sometimes called angitis)
What is myelitis?
infection of the spinal cord
what is encephalomelitis?
infection of the spinal cord and brain
What is the blood brain barrier (BBB)?
protective mechanism that helps maintain a stable environment for the brain creating an immune protected space
how vascularised is the CNS?
very densely vascularised, no neurone is more than 100micrometers from a capillary
How is the blood brain barrier formed?
formed from capillaries and extensive tight junctions at the endothelial cell-cell contacts, astrocytes help to maintain the structure
What are the advantages of the BBB?
blood borne infectious agents have reduced entry into the CNS tissue, specific transporters must be used to transport substances in and out of the brain
Outline what can happen if theres a disruption of the BBB?
Contents of blood can move into the parenchyma causing the glial cells to react, astrocytes retract which breaks down the barrier further resulting in a membrane basement change, this leads to disruption of collagen and sclerosis of vessels
Breakdown of the BBB evokes ____
a lot of cellular reaction
Outline the symptoms associated with encephalitis
initial flu-like symptoms (fever, pyrexia) and headache. subsequent: confusion/ disorientation, seizures, changes in behaviour, difficulty speaking, weakness or loss of movement and loss of consciousness
Most causes of Encephalitis are of what origin?
viral infection
List the most common viral infections which cause Encephalitis
Herpes simplex, measles, chickenpox, rubella,
other than those of viral infection origin, what are other causes of Encephalitis?
mosquito, tick, or other insect bites, bacterial and fungal infections, trauma, autoimmune mechanisms e.g MS
How is encephalitis treated?
depends on underlying cause but can include: antivirals, steroids, antbiotics/fungals, analgesics, anti-convulsants, ventilation
How is cerebral inflammation diagnosed?
neurological examination, scans (MRI, CT), lumbar puncture, EEG, blood tests
what would a lumbar puncture show in a patient with Meningitis?
low glucose and elevated WBC count
what diagnostic tests can be done to confirm Encephalitis?
MRI, EEG, spinal tap, blood tests
What is Multiple Sclerosis (MS)?
autoimmune demyelinating disease of the CNS, can cause encephalitis
Relapses of MS are related to____
inflammatory activity
progression of MS is related to ____
neurodegeneration (axonal loss)
what are the four aspects of the pathology of MS?
inflammation, demyelination, axonal loss, neurodegeneration
What would show on a positive MRI of MS?
pre-ventricular white matter changes, this will progress over time
describe the pattern of MS
a random disorder that affects the white matter anywhere in the CNS, symptoms vary between patients
What is perivascular cuffing?
inflammation around a blood vessel
outline the mechanism of inflammation seen in MS
perivascular cuffing causes infiltration of immune cells which cross BBB, this mainly includes CD3 Tcells and CD20 Bcells leading to leptomeningeal inflammation
what is the risk of permanent impairment associated with meningitis?
20%
The majority of causes of meningitis are of what origin?
bacterial
What are the bacterial causes of meningitis?
Meningococcal (neisseria meningitides), pneumococcal (strep. pneumoniae), haemophilus influenzae type B, streptococcal
What is the main cause of meningitis in newborns?
streptococcal infection
Other than those of bacterial origin, what are the causes of meningitis?
Viral (rare but life threatening), fungal
Outline the symptoms of meningitis
sudden fever, sudden headache, nausea and vomiting, double vision, drowsiness, photophobia, stiff neck, rashes
what are some of the long term effects of meningitis?
recurrent seizures, problems with memory and concentration, coordination problems, dizziness, speech problems, deafness, headaches, weakness, visual problems, movement and balance problems, learning difficulties
are seizures more commonly seen in meningitis or encephalitis?
often occur in encephalitis
Are focal neurological findings (weakness, visual disturbance, aphasia) a hallmark feature of meningitis or encephalitis?
encephalitis, however half of patients with meningitis develop focal findings
What is an infection of the spinal cord known as?
Myelitis
What diagnostic tests can be performed to investigate encephalitis and meningitis?
Neurological examination, CT, MRI, lumbar puncture (CSF is usually clear and colourless; low glucose in bacterial meningitis; raised white blood cell counts are a sign of inflammation), blood, urine analysis.
What are some of the long term effects of meningitis?
Long term learning disabilities, memory loss, poor concentration, clumsiness/co-ordination problems, headaches, deafness/hearing problems/tinnitus/dizziness/loss of balance, epilepsy, weakness/paralysis/spasms, speech problems, visual problems.
