Pathology Flashcards
What are the 3 ways in which microbes can get into the CNS
- direct spread
- blood-borne spread
- iatrogenic
What is meningitis
Inflammation of the leptomeninges
What are the leptomeninges
The pia and arachnoid
What is the causative organism of meningitis in neonates
E.coli
What is the causative organism of meningitis in 2-5 year olds
H. Influenzae
What is the causative organism of meningitis in 5-30 year olds
N. Meningitidis
What is the causative organism of meningitis in over 30 years
S. Pneumoniae
What are the complications of meningitis
Raised intracranial pressure leading to death
Cerebral abscess
Subdural empyema
Cerebral infarction
What is encephalitis
Inflammation of the brain parenchyma with the virus causing neuronal cell death
Which lobe does the herpes virus affect in encephalitis
Temporal lobe
Where does the poliovirus affect in encephalitis
Spinal cord motor neurones
Where does rabies affect in the CNS in encephalitis
The brainstem
What compensation mechanisms are there to help reduce intracranial pressure
Reduction in blood flow
Reduction in CSF volume
Brain atrophy
What a re the 3 types of brain herniation due to raised intracranial pressure
Subfalcine
Tentorial
Tonsilar
what is a subfalcine herniation
where the cingulate gyrus is pushed under the edge of the falx cerebri
what vessel is compressed in a subfalcine herniation
anterior cerebral artery
what is a tentorial herniation
where the uncus of the temporal lobe is pushed through the tentorial notch
what nerve is damaged in a tentorial herniation
oculomotor nerve
what vessels are occluded in a tentorial herniation
superior cerebellar and posterior cerebral arteries
what is a tonsilar herniation
where the cerebellar tonsils are pushed into foramen mags, compressing the brainstem
what is a stroke
a sudden event producing disturbances CNS function due to vascular disease
what are the risk factors for a stroke
high bp, diabetes, male, elderly
what causes intracerebral haemorrhage
hypertensive vessel disease
what causes subarachnoid haemorrhage
bursting of a berry aneurysm
what are prions
proteins needed for synaptic function
what is the pathology behind Alzheimers
tau proteins climb together forming plaques which have an amyloid centre. this causes neuronal damage and cell death
