Neuropathology Flashcards
What are the main types of neuropathology
Infection Prion disease Raised intracranial pressure Tumour Dementia Stroke
What are the modes of spread of CNS infections
Direct
Blood-borne
Iatrogenic
Give examples of direct spread in CNS infections
Middle ear infection
Basilar skull fracture
Give examples of blood-borne CNS infections
Sepsis Infective endocarditis (septic emboli)
What are the main sites of infection in CNS
Meningitis: infection of leptomeninges (pia + subarachnoid mater)
Encephalitis: infection of neural parenchyma
What are the causative organisms of meningitis (by age group)
Neonates: E. Coli
2-5: H. Influenzae
5-30: Neisseria meningitides
>30: Strep. pneumoniae
What are the pathological features of meningitis
Meninges red + swollen
Pus around vessels
What is chronic meningitis
Slowly developing meningitis that lasts > 4 weeks
What organism causes chronic meningitis
M tuberculosis
What are pathological features of chronic meningitis
Granulomatous inflammation
Fibrosis of meninges
Nerve entrapment (involves brainstem)
What are clinical features of chronic meningitis
Insidious onset of: headache, neck stiffness, fever
Focal cranial nerve palsies - nerve entrapment in brainstem due to meningeal fibrosis
What are the complications of meningitis
Death - raised ICP Cerebral abscess Cerebral infarction Subdural empyema Epilepsy (neural damage and scarring) Sepsis
What are pathological features of encephalitis
Brain haemorrhagic and swollen
What are causative organisms of encephalitis
Virus: Herpes simplex (temporal lobe) Cytomegalovirus Polio (spinal cord motor neurones) Rabies (brainstem)
What are prion proteins
Proteins normally present in pre and post synaptic compartments of nervous system
What is prion disease
Group of progressive encephalopathies caused by accumulation of mutated prion proteins
NOT an infection
What is the pathophysiology of prion disease
- Presence of mutated prion protein: sporadic, familial, ingested
- Accumulation of mutated PrP: abnormal PrP bind to normal PrP to cause post-translational conformational change
- Neural cell death: aggregated PrP v stable, accumulate and cause local cell damage
- Spongiform encephalopathy: holes in grey matter
What are the types of prion disease
Variant Creutzfeld-Jacob disease: in humans
Bovine spongiform encephalopathy: in cattle
What is normal intracranial pressure
0-10mmHg
What are the compensatory mechanisms to maintain normal ICP
When are these mechanisms effective
Reduced CSF production
Reduced cerebral blood volume
Brain atrophy
In gradual rise in ICP
Up to 60mmHg, otherwise blood flow compromised
What are the causes of raised intracranial pressure
Haemorrhage Tumour Infarction (inflammation + swelling) Abscess Generalised inflammation (meningitis, encephalitis)
Raised ICP is a cause of neuropathology. What types of neuropathology does it cause?
Atrophy around lesion
Displacement of midline
Herniation
What are the types of brain herniation
Subfalcine
Tentorial
Tonsillar
What is subfalcine herniation
What are the consequences
Protrusion of cingulate gyrus under free edge of falx cerebri
Compression of ACA - infarction of medial parts of frontal + parietal lobes
