1b// Cerebral inflammation & disorders 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
aka angiitis
What led to the suggestion fothe blood brain barrier?
How would you desribe the vascularisation of the CNS?
dense, no neurton is more than 100 micro m from a capillary
What do BBB capillaries have?
BBB capillaries have extensive tight junctions at the endothelial cell-cell contacts, massively reducing solute and fluid leak across the capillary wall
what does the histology of meningitis look like?
infiltration of subarachnoid space by WBCs, pussy exudate
what does the histology of viral encephalitis look like?
perivascular cuffing
how vascularised is the brain?
no neuron is more than 100micrometers from a capillary
how does the BBB form?
BBB capillaries have extensive tight junctions at endothelial cell-cell contacts, nothing can freely diffuse
what happens if the BBB is broken?
blood leaks into brain, astrocytes attempt to clear blood borne products by retracting end feet (leaving BBB undefended)
what may happen long term if the BBB is chronically disrupted?
fibrosis in brain vessels, small vessel disease
what are the initial symptoms of encephalitis?
flu like with pyrexia and headache
what are the overall symptoms of encephalitis? (7)
confusion/disorientation seizures or fits depending on lobe affected: changes in personality/behaviour difficulty speaking weakness or loss of movement loss of consciousness catatonicity
within hours, days or weeks
what are the viral causes of encephalitis? (4)
herpex simplex
measles
varicella
rubella
what are the non-viral causes of encephalitis?
mosquito/insect bites
bacterial or fungal infections - untreated meningitis
trauma
autoimmune
how is encephalitis treated?
depends on underlying cause: antivirals/antibiotics/antifungals steroids analgesics anti-convulsants (often prophylactically) ventilation
what is multiple sclerosis?
demyelinating autoimmune disease of the CNS
relapsing and remitting - 1st resolves spontaneously
What is relapse and progression of multiple sclerosis linked to?
relapse= inflammatory activity
progression= neurodegeneration
what is the cellular pathology of multiple sclerosis?
inflammation
demyelination & axonal loss (larger grey areas)
neurodegeneration
Why do symptoms vary in multiple sclerosis?
Symptoms vary because the amount and location of damage to the nervous system is different in each person with MS
What happens during inflammation in multiple slcerosis?
perivascular immune cell infiltration (CD3 T cell and CD20 B cells)
What is meningitis?
Irritation, inflammation and swelling of the meninges
6th most common infectious disease killer
Leaves 1 in 5 of the infected people with an
impairment
what are the bacterial causes of meningitis?
meningococcal (most common)
pneumococcal
haemophilus influenzae type B
streptococcal (main cause in newborns)
what are the causes of meningitis?
bacteria
viruses (rarely life threatening)
fungi
how is meningitis diagnosed?
lumbar puncture for CSF sample
what are the hallmarks of meningitis?
sudden onset of fever, headache, nausea, double vision, photophobia, stiff neck, rash
what are some long term effects of meningitis? (7)
disabilities memory loss coordination loss behaviour changes paralysis/weakness speech coord issues visual defects
what diagnostic tests are useful for suspected encephalitis or meningitis?
lumbar puncture - raised WCC, pink colour
low csf glucose in bacterial men
CT/MRI
neurological assessment
What is an infection of the spinal cord known as?
myelitis
What types of infections can cause encephalitis and meningitis?
Encephalitis: more commonly viruses (e.g. Herpes Simplex, measles, varicella (chickenpox), rubella (German measles).
Meningitis: more commonly bacteria which initially cause an upper respiratory tract infection and then travel through the blood to the brain. Types of meningitis include (most serious is pneumococcal - streptococcus pneumoniae; meningococcal - Neisseria meningitides; Haemophilus influenzae meningitis caused by Haemophilus influenzae b– reduced by Hib vaccination, previously a leading cause in children under 5).
What are some hallmarks of encephalitis and meningitis?
Encephalitis: fever, seizures, change in behaviour, and confusion and disorientation.
Meningitis: sudden fever, severe headache, nausea or vomiting, double vision, drowsiness, sensitivity to bright light, and a stiff neck, rash (not always).
What diagnostic tests can be performed for encephaltiis, meningits and multiple sclerosis?
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.
**
