Cerebral inflammation Flashcards
What is Meningitis?
Meningitis – inflammation of the meninges caused by viral or bacterial infection
What is Encephalitis?
Encephalitis – inflammation of the brain caused by infection or autoimmune mechanisms
What is cerebral vasculitis?
inflammation of blood vessel walls (sometimes called angiitis)
What is the Blood Brain Barrier?
“Highly selective semipermeable border of endothelial cells” (physical cellular entity)
-BBB capillaries have extensive tight junctions at the endothelial cell-cell contacts, massively reducing solute and fluid leak across the capillary wall
How does the Blood Brain Barrier work?
- Because of the “tightness” of the BBB capillaries, solutes that can exchange across peripheral capillaries cannot cross the BBB.
- This allows the BBB to control the exchange of these substances using specific membrane transporters to transport into and out of the CNS (influx and efflux transporters).
- Blood-borne infectious agents have reduced entry into CNS tissue
What is the role of the astrocytes in the BBB?
“Produce the BBB”
- Provide secreted factors
- The secreted factors to lead to association b/t the cells of the BBB
- and the formation of strong tight junctions
What happens when the BBB is disturbed?
- Damage to the BBB- endothelial cells rupture
- Fibrinogen leaks out of the blood
- Astrogliosis: Abnormal increase in the no. astrocytes to minimize + repair the damage to the BBB
- Astrocytes end- feet change (the astrocytes retract their end feet- exposing the tissue and opening the BBB)
- Immune cells & inflammatory cytokines can now enter the brain tissue (can lead to encephalitis)
What are the symptoms of encephalitis?
Initially symptoms are flu-like with pyrexia (high body temperature) and headache
Subsequently, within hours, days or weeks:
confusion or disorientation
seizures or fits
changes in personality and behavior
difficulty speaking
weakness or loss of movement
loss of consciousness
What are the causes of encephalitis?
In most cases, encephalitis is caused by viral infection, the commonest of which are:
Herpes Simplex
Measles
Varicella (chickenpox)
Rubella (German measles)
Other causes include:
Mosquito, tick and other insect bites
Bacterial and fungal infections
Trauma
Autoimmune (mainly attacks channel receptors like Ca+)
How is encephalitis treated?
Treatment depends onthe underlyingcause, but may include:
Antivirals e.g. acyclovir
Steroids (anti-inflammatory)
Antibiotics/antifungals
Analgesics
Anti-convulsants (treat seizures)
Ventilation
What is Multiple Sclerosis?
-Autoimmune demyelinating disease of the CNS (demyelination around the axons- reduced transmission (slowed down or stopped completely)
- Relapses linked to inflammatory activity (patients recover then deplete again)
- Progression linked to neurodegeneration (even though patients “recover” this is just improvement is state- they never regain their original neurological state/ never completely recover)
- Deficits usually very specific
- Symptoms vary because the amount and location of damage to the nervous system is different in each person with MS
-common symptom= visual disturbance
What is the cellular pathology of multiple sclerosis?
Inflammation
Demyelination
Axonal loss
Neurodegeneration
What is seen on an MRI of multiple sclerosis?
“White patches”- indicate lesions
What are the causes of meningitis?
Bacterial
Meningococcal – the most common cause of bacterial meningitis in UK
Pneumococcal
Haemophilus Influenzae type b (Hib)
Streptococcal – the main cause in new-born babies
Other causes
Viral - very rarely life-threatening
Fungal
What are the symptoms of meningitis?
a high temperature (fever)
being sick
a headache
a rash that does not fade when a glass is rolled over it (but a rash will not always develop)
a stiff neck
a dislike of bright lights
drowsiness or unresponsiveness
seizures (fits)
