Neuropathology Flashcards
What are the layers of the meninges
- Dura mater
- Arachnoid
- Pia mater
What are the arachnoid trabeculae
- are delicate strands of connective tissue that loosely connect the two innermost layers of the meninges – the arachnoid mater and the pia mater
- They are found within the subarachnoid space where cerebrospinal fluid is also found
What is the normal volume of CSF
- 150ml
What is hydrocephalus
- Obstruction CSF flow
- Impaired reabsorption at arachnoid granulations
- Shrinking of brain tissue(eg dementias) = ex vacuo
- Very rarely overproduction
What does hydrocephalus before fusion of the cranial sutures cause
- It causes enlargement of the head circumference
What is the classification for raised intracranial pressure
- Mean CSF pressure above 200mm H2O
What can caused raised intracranial pressure
- Increased CSF volume(hydrocephalus)
- Intracranial space occupying lesion(neoplasm, haemorrhage, abscess)
- Cerebral oedema
Give examples of types of herniation
- Subfalcial(cingulate)
- Central/transtentorial
- Tonsillar/cerebellar
What is the clinical significance of a tonsillar/cerebellar herniation
- May cause compression of the medulla oblongata with impairment of vital respiratory and cardiac functions
What are duret haemorrhages
- are small lineal areas of bleeding in the midbrain and upper pons of the brainstem
- They are caused by a traumatic downward displacement of the brainstem
Give examples of types of haemorrhages
- Extradural/epidural haemorrhage
- Subdural haemorrhage
- Subarachnoid haemorrhage
- Intracerebral haemorrhage
- Ischaemic infarct with subsequent oedema or haemorrhage
What is coup and contrecoup in head trauma
Coup - brain moves forward due to collision
Contrecoup - heads hits the back as well due to intertia
- If hit by a mobile object, there will only be one area of impact as the object moves away
What is an extadural haematoma usually caused by
- Severe trauma with arterial laceration(m.meningeal artery)
What is a subdural haematoma usually caused by
- Trauma may be minor in atrophy(bridging veins)
What is a subarachnoid haematoma usually caused by
- Rupture of saccular(berry) aneurysm (circle of willis)