Cerebral Inflammation Flashcards
Meningitis
inflammation of the meninges caused by viral or bacterial infection
Encephalitis
inflammation of the brain caused by infection or autoimmune mechanisms
Cerebral vasculitis
inflammation of blood vessel walls (sometimes called angiitis)
The BBB
BBB capillaries have extensive tight junctions at the endothelial cell-cell contacts, massively reducing solute and fluid leak across the capillary wall
Pial vessels
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.
Blood Brain Barrier disruption
Blood component leak
Astrocyte withdraw end feet from vessel wall - compromise BBB even more
Overtime - buildup of collagen fibrin material - harden vessel wall
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 behaviour difficulty speaking weakness or loss of movement loss of consciousness
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
Treatments for encephalitis
Treatment depends onthe underlyingcause, but may include: Antivirals e.g. acyclovir Steroids Antibiotics/antifungals Analgesics Anti-convulsants Ventilation
Cellular pathology of Multiple Sclerosis
Inflammation
Demyelination
Axonal loss
Neurodegeneration
MS
Autoimmune demyelination of CNS
Producing antibodies against own myelin protein
Relapsing remitting - quick focal sign and recovery - lead to secondary progression
Relapse correlates with inflammation
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
Infection of spinal cord
Myelitis
When both the brain and spinal cord are involved, the condition is known as encephalomyelitis.
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.
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).
Diagnostics for 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.
