neuropathology Flashcards
What are primary and secondary events that can occur with head injury?
Primary changes are neural and vascular
Secondary changes are ischaemia, oedema and infection
What is the mechanism by which diffuse axonal injury occurs in acceleration/decclleration injuries?
This is mechanoporation in which stretched axon membranes are no longer able to conduct properly
How soon will axonal bulbs be visible after brain injury?
After 24 hours
What type of bleeding will cause an extradural haemorrhage?
Usually middle meningeal artery?
What type of bleeding will cause a subdural haemorrhage?
Usually a venous bleed from the bridging veins
What type of bleeding will cause a subarachnoid haemorrhage?
usually from damage to the vertebral or intracerebral arteries
What are the two factors that raised ICP is due to in head injury?
Can be due to cerebral oedema as a reaction to injury
Can be due to the mass effect of a haematoma
What are the two most common forms of infection in the brain?
Meningitis
Cerebral abscess
What typically happens to proteins in neurodegenerative disease?
They become misfolded and this leads to accumulation. Protein disulphide isomerase helps protein maturation, this can be damaged by free radicals and then it cannot rearrange these misfolded proteins
What are the four most common types of dementia in order?
Alzheimer’s
Vascular
Lewy Body
Frontotemporal
What is the pathogenesis in alzheimers disease?
There is amyloid plaque formation. This causes frontal and temporal lobe atrophy due to reduced dendritic branching and basal nuclear damage resulting in reduced cholinergic input
What is a genetic risk factor for alzheimer’s?
The beta amyloid precursor protein (BAPP)
What is the pathogenesis for lewy body disorders such as lewy body dementia and parkinsons?
There is loss of pigmented cells in the substantia nigra, this reduces dopaminergic input to the basal ganglia
What is the pathogenesis behind vascular dementia?
This is grey matter lesions due to bilateral infarcts. This is due to small vessel disease.
What is the mechanism behind motor neurone disease?
Primary lateral sclerosis of the upper motor neurones. It also causes progressive uscluar atrophy due to lower motor neurone disease. This is due to uiquitination of motor neurones resulting in axonal loss.
What are prions and how do they lead to neurodegenerative disease?
They are infective protein particles that may form amyloid and prevent proper protein folding. This results in synaptic failure and cell death.
What is the pathogenesis behind multiple sclerosis?
It is inflammatory demyelination of the myelin sheaths surrounding the neurones
What is the definition of a stroke?
A rapid onset signs of focal disturbance of cerebral function, lasting more than 24 hours, of vascular origin
What are the three main types of strokes?
Ischaemia from thrombus or emboli
Haemorrhagic
Inflammatory - due to vasculitis
What are the degenerative changes that can follow a cerebral infarct?
There will be clear demarkation of the affected area at 3 weeks. Cysts can form from 3 - 8 weeks
What are the three main types of aneurysms?
congenital (berry), infectious (mycotic) or atherosclerosis (fusiform)
How does infection tend to get to the CNS?
Through the nasopharynx then spreads through the blood to the sinuses or middle ear to CNS.
What pathological changes occur in bacterial meningitis?
there will be purulent exudate over the brain surface, cerebral abcesses can also form
how can chronic meningitis present?
Isidious onset where pus can collect at the base of the brain and cause cranial nerve defects
