L17 - Neuropathology Flashcards
describe the histology of the brain
- Neurons
- Glia
- Meninges
- Blood vessels
look at slide 4 to label the histology of a sample of brain tissue
how was it
describe the structure of the stuff surrounding the brain from hair
- SKIN
- Aponeurosis
- periosteum
- Bone
- Meninges- Dura mater, Arachnoid, Pia mater
describe how cerebrospinal fluid is absorbed and produced
Production by choroid plexus in the lateral ventricles (450ml per 24h)
Resorption by arachnoid granulations in the subarachnoid space
describe the normal volume of cerebrospinal fluid
Normal volume 150ml
give 4 importances of cerebrospinal fluid
Metabolic importance
Cushioning of the CNS
Role in immune regulation and defense
Cerebral autoregulation of blood flow
describe hydrocephalus
Obstruction to CSF flow
Impaired resorption at arachnoid granulations
Shrinking of brain tissue (e.g. dementias) = ex vacuo
Very rarely overproduction
what are the 2 types of hydrocephalus
- communicating
- non-communicating
describe what happens if hydrocephalus occurs before fusion of the cranial sutures
causes enlargement
of the head circumference.
describe what is classified as raised intracranial pressure
-Mean CSF pressure above 200mm H2O
what can cause raised intracranial pressure
Increased CSF volume (hydrocephalus)
Intracranial space occupying lesion (neoplasm, haemorrhage, abscess)
Cerebral oedema
what are the different types of herniations in the brain
Subfalcial (cingulate)
Central/transtentorial
Tonsillar/cerebellar
where do the different types of herniations occur in the brain
slide 13
what can a tonsillar/cerebellar herniation cause
Tonsillar/cerebellar herniation may cause compression of the medulla with impairment of vital respiratory and cardiac functions.
what can be observed on autopsy of a brain that has had tonsillar herniation occur
Coning herniation
&
compression of the medulla oblongata
&
Duret haemorrhages
describe the different classifications of a space occupying lesions
Extradural/epidural haemorrhage
Subdural haemorrhage
Subarachnoid haemorrhage
Intracerebral haemorrhage
Ischaemic infarct with subsequent oedema or haemorrhage
Neoplasm
Abscess
what are the different types of head trauma
- skull fracture
- parenchymal injury
- Coup and Countercoup
- Vascular injury
describe different types of parenchymal Injury
- Contusion (bruising) Concussion is a clinical term/syndrome
- Laceration (penetration or tearing)
- Diffuse axonal injury
describe coup and countercoup
CSF plays a major role in coup and countercoup injuries to the brain.
When a moving object impacts the stationary head, coup injuries are typical, while contrecoup injuries are produced when the moving head strikes a stationary object
describe vascular injury types
Extradural: Severe trauma with arterial laceration (m. mening. a.)
Subdural: Trauma may be minor in atrophy (bridging veins)
Subarachnoid: Rupture of saccular (berry) aneurysm (circle of Willis)
Intraparenchymal:
(hypertension)
look at slide 19-21 for pictures of different types of haemorrhages
how was it?
describe the different causes of cerebral oedema
Vasogenic:
-Increased vascular permeability
Cytotoxic:
-Neuronal, glial or endothelial cell damage
describe cerebral infarction
15% of cardiac output
20% of O2 demand
Stroke = sudden onset of neurological symptoms
Hypoxia vs ischaemia (global vs focal)
Neurons are the most O2 sensitive cells
Haemorrhagic infarction in emboli (petechial lesions e.g. BM)
Ischaemic infarction in thrombosis
describe the histology of ischaemic infarction
- Acute neuronal injury
- ‘Red neurons’
- Pyknosis of nucleus
- Shrinkage of the cell body
-Loss of nucleoli
Intense eosinophilia of
cytoplasm
-Owing to irreversible
hypoxic/ischaemic insult
(look at slide 26)
describe where neoplasms occur
Gliomas (astrocytoma, oligodendroglioma, glioblastoma)
Neural tumours (ganglion cell tumours)
Meningiomas
Poorly differentiated neoplasms (medulloblastoma)
Primary CNS lymphoma
Metastasis (lung, breast, skin/melanoma, kidney, GI tract)
Peripheral nerve tumours (schwanoma, neurofibroma, MPNST
describe the type of infections that can occur in the brain and which pathogen causes them
- Meningitis ,bacterial (acute or chronic), viral , fungal ,RMSV, neurosyphilis, lyme disease, malaria
- Abscess- Usually bacterial
- Encephalitis-Viral (HSV, CMV, HIV, JC polyoma virus)
Localised-Toxoplasmosis, cysticercosis
name some progressive degenerative diseases
Neurodegenerative diseases (Alzheimer d., Parkinson d.,)
Spinocerebellar degenerative diseases:
-Accumulation of protein aggregates leading to loss of cellular and subsequent loss of CNS functions: Dementia, behavioural and personality changes, language disturbance, movement and coordination disturbance, paralysis.
Demyelinating diseases (Multiple sclerosis)
Prion diseases (Creutzfeldt-Jakob disease)
Genetic metabolic diseases (Neuronal storage diseases)
Toxic & aquired metabolic diseases (Vit B1 & B12 def., CO toxicity, alcohol toxicity, radiation toxicity)
