Raised ICP Pathology Flashcards
What is normal ICP?
5-13mmHg
What is normal number of lymphocytes in CSF?
<4 cells/ml
What is the normal protein in CSF?
<0.4g/l
What is normal glucose in the CSF
> 2.2mmol/l
What are hte causes of hydrocephalus?
obstruction of CSF eg inflammation, pus and tumours; decreased resoption of CSF- post SAH or meningitis; overproduction of CSF- rare- tumours of choroid plexus
How is hydrocephalus classified?
non-communicating adn communicating hydrocephalus
What is non-communicating hydrocephalus?
obstruction to flow of CSF occurs within ventricular system
What is communicating hydrocephalus?
obstruction to flow of CSF outside of ventricular system eg in subarachnoid space or arachnoid granulations
What happens to the brain with hydrocephalus?
expansion of hte ventricles; flattening of the dyrae; fullness of the sulci and riased ICP
What is hydrocephalus ex vacuo?
dilation of the ventricular system and a compensatory increase in CSF volume secondary to loss of brain parenchyma
What is a subfalcine hernation?
unilateral or asymmetric expansion of cerebral hemisphere displaces the cingulate gyrus under the falx cerebri
What happens in a tentorial hernation?
medial aspect of temporal lobe (hippocampus) herniates over the tentorium cerebelli
What is tonsillar herniation?
displacement of cerebellar tonsila through the foramen magnum
What is the consequences of tonsillar hernation?
brainstem compression and vital respiratory centresi nthe medulla
What is a consequence of tentorial herniation?
compression ipsilateral CNIII and its parasympathetic fibres
What is a consequence of subfalcine hernation?
compression of the anterior cerebral artery and weakness and /or sensory loss in leg
What are the features of an ICP induced headache?
worse on lying down; coughing; sneezing and straining
Where do tumours o the brain in children arise?
mostly below the tentorium cerebelli
Where do CNS tumours in adults tend to arise?
above the tentorium cerebelli
What are hte most common origins of brain metastates?
breast; bronchus; kidney; thryoid; colon and melanoma