Neuropathology Flashcards
How do infections enter the CNS? (3 Ways)
direct spread e.g. middle ear, ethmoid bone
Blood-borne, sepsis or infective endocarditis
Iatrogenic -
what are the leptomeninges ?
Arachnoid
pia mater
what 2 features may be present in meningitis ?
Inflammation of leptomeninges
+/- septicaemia
what is a sign of meningococcal septicaemia?
what is its histological appearance ?
non-blanching rash
Neutrophils
what are caustive oragnisms in meningitis by age range :
Neonates
2-5
5-30
Neonates – E. coli, L. monocytogenes
• 2-5 years old – H. influenza
• 5-30 years – N. meningitidis
what is are features of Chronic Meningitis ?
Photosensitivity
Granulomas
Meningeal fibrosis
Cranial nerve entrapment
what are complications of meningitis ?
Death due raised intracranial pressure Cerebral infarction (stroke) Cerebral abscess Subdural empyema Epilepsy sepsis Bilateral adrenal haemorrhage
what is the causative organism of Chronic Meningitis ?
M. tuberculosis
what is encephalitis ?
what is it classically caused by ?
Inflammation of brain parenchyma not meninges -can occur as a
complication of meningitis
viral
what is seen histologically in encephalitis ? why?
intracellular viral
inclusion bodies
neuronal death
what affects temporal lobe in encephalitis ?
Herpesviruses
what affects spinal lobe in encephalitis ?
Polio
what affects Brainstem in encephalitis ?
rabies
where are prions found ?
synapses
how can PrP turn to PrPsc ?
sporadic mutation,
familial inheritance of mutated gene or following ingestion of PrPsc
How would ingested a PrPsc propagate itself ? why is there no immune response ?
PrPsc induced post translational conformational change in normal PrPs
Stable and it is recognised as self protein
how do prions (PrPsc) cause damage ?
PrPsc- aggregates which destroy neruones and
cause the grey matter to take on a sponge-like (spongiform) appearance
Name 2 Spongiform Encephalopathies
Scrapie in sheep BSE in cows (‘mad cow’ disease) Kuru in New Guinean tribes (due to cannibalism and ingestion of PrPsc) Creutzfeld Jacob disease (CJD)
What is vCJD ? what is it linked with ? difference between vCJD and CJD?
Strongly linked to BSE through ingestion of
prions] higher
prion load associated with earlier age (28) at
death and more prominent psychiatric
symptoms
look at table in lecture
what are Koch’s Postulates ?
the Microorganism must be found in abundance in the suffered
Must be isolated and grown in culture
cultured organism must cause disease in healthy individuals
Reisolated from inoculated and identified as same as original host
define dementia
Acquired global impairment of intellect, reason and personality without
impairment of consciousness
what is the main cause of dementia ?
what are other causes ?
Alzheimer’s
vascular, lewy body and Picks
define Alzheimer’s
what is its appearance
loss of cortical neurones
decrease in brain weight
cortical atrophy
narrow gyri and wide sulci
what causes Alzheimier’s ?
neurofibrillary tangles and amyloid
plaques
what are Neurofibrally tangles ?
Intracellular twisted filaments of Tau that has been hyperphosphorylated
- normally bind to stabilise microtubules
what are senile plaques ?
Foci of enlarged axons, synaptic terminals
and dendrites
Amyloid deposition in centre of plaque
associated with vessels- central to pathogenesis
what syndrome is associated with early onset AD?
what mutations specifically ?
Trisomy 21 Down's APP Presenilin -secretase gene leads to incomplete breakdown of APP = amyloid disposition
what is normal range of ICP ?
0-10mmHg
• Coughing/straining can increase it to 20mmHg
What are compensatory mechanisms for ICP?
what is the limit for vascular mechanism ?
Reduce blood volume
reduced CSF
brain atrophy = chronic
<60mmHg
what do SoLs do to the brain?
Deforms or destroys surrounding brain
Displaces midline structures – loss of symmetry, midline shift
Herniation
what is a subfalcine herination?
Cingulate gyrus is pushed under the free edge of the
falx cerebri
what can subfalcine herination lead to ?
ischaemic due to
compression of anterior cerebral artery leading to infarction
what is a tenotrial herination?
Medial temporal lobe (classically the uncus) pushed
down through the tentorial notch
why are tentorial herinations often fatal ?
sedondary heamorrhage into brianstem (Duret) leads to resp and CVS control problems
common mode of death in those with large tumours and IC heamorrhage
what are the symptoms of tentorial herination ? why?
ipsilateral third
nerve palsy contralateral UMN signs in limbs-
compress ipisilateral oculomotor nerve and
ipsilateral cerebral peduncle
name 1 benign and 1 malignant Brain tumour
Meningioma
Astrocytoma
where do astrocytomas usually mets to ?
spread along nerve through sub arch space to spine - hard to remove
what is the most common cause of brain tumours ?
metastasis
Name 2 ways tumours can spread in the brain ?
white matter pathways
CSF
what is Neurofibroma
tumour of Schwann cells of
peripheral or cranial nerve
what are tumours of ependymal cells lining
ventricular system?
Ependymoma
what tumours can arise from Non-CNS tissues?
mets
Lymphomas
what is a stroke ?
A sudden event producing a disturbance of CNS function due to vascular
disease
name 2 sources an embolism may come from
Heart (due to AF, mural thrombus)
Atheromatous debris (carotids)
Thrombus over ruptured plaque
Aneurysm
where would a thrombus form in a stroke if it did not embolise from somewhere ?
cerebral arteries
what s a lacuna stroke ?
Small (less than 1cm area affected)
Associated with hypertension
Commonly affect basal ganglia and internal capsule
what is seen and associated with intracerebral haemorrhage leading to stroke ?
ncreased age, hypertensive vessel
damage and amyloid deposition in vessels
Charcot-Bouchard aneurysms are seen May be inherited
Produces a space occupying lesion
what causes subarachnoid haemorrhage ?
Rupture of berry aneurysms, usually found at
branch points in circle of Willis
Blood in subarachnoid space can cause secondary
spasm of cerebral arteries
what are some risk factors for subarachnoid haemorrhage?
Male
• Hypertension
• Atherosclerosis
what are some symptoms of Subarachnoid haemorrhage?
Thunderclap headache
• May be preceded by a ‘sentinel’ headache
• Loss of consciousness
• Often instantly fatal
