Flashcards in Raise ICP, SOLs and trauma Deck (77)
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1
What is the normal volume of CSF?
120-150ml
500ml a day
2
What produces CSF?
Choroid plexus in the lateral and 4th ventricles of the brain
3
What absorbs CSF?
Arachnoid granulations
4
What do lymphocyres in the CSF suggest?
Infection; viral or fungal
Autoimmune infection
Inflammation
5
What do neutrophils in the CSF suggest?
Bacterial meningitis
6
What is the definition of hydrocephalus?
Accumulation of excessive CSF within the ventricular system of the brain
7
What can cause hydrocephalus?
Obstruction to flow: inflammation, pus, tumours
Decreased reabsorption; post SAH, meningitis
Overproduction; very rare cause due to choroid plexus tumour
8
What is non-communicating hydrocephalus?
Obstruction to flow of CSF occuring within the ventricular system
9
What is communicating hydrocephalus?
Obstruction to flow of CSF outside of the ventricular system e.g. in subarachnoid space or at the arachnoid granulations
10
What occurs if hydrocephalus occurs before the closure of the cranial sutures?
Cranial enlargement occurs
11
What occurs if hydrocephalus occurs after the closure of the cranial sutures?
Expansion of the ventricles with an increase in intracranial pressure
12
What is hydrocephalus ex vacuo?
Dilation of the ventricular system and an increase in compensatory CSF volume secondary to the loss of brain parenchyma for example in alzheimer's disease
13
What are the causes of increased ICP?
Hydrocephalus
SOL
Diffuse lesion in brain e.g. oedema
Increased venous volume
Physiological; hypoxia, hypercapnia, pain
14
What are the consequences of raised ICP?
Intracranial shifts and herniations
Midline shift
Distortion and pressure on CNs and vital neurological centres
Impaired blood flow
Reduced level of consciousness
15
How is cerebral perfusion pressure calculated?
MAP - ICP; therefore ICP is too high, it will reduce blood flow
16
What are the 4 types of shifts and herniations within the brain?
Subfalcine
Tentorial
Cerebellar
Transcalvarial
17
What is a subfalcine herniation?
Unilateral or asymmetrical expansion of the cerebral hemisphere which displace the cingulate gyrus underneath the falx cerebri
18
What does a subfalcine herniation result in?
Compression of the anterior cerebral artery resulting in weakness and/or sensory loss on the contralateral side
19
What is a tentorial herniation?
Medial aspect of the temporal lobe (uncus) herniates over the tentorium cerebellar
20
What will a tentorial herniation result in?
Compression of the ipsilateral CN3; resulting in a blown pupil with impairment of ocular movement on the side of the lesion
21
What is a tonsillar herniation?
Displacement of the tonsillar cerebellum through the foramen magnum
22
What will a tonsillar herniation result in?
Compression of the respiratory centers of the medulla oblongata
23
What is a transcalvarial herniation?
Brain herniating through any defect in the skull e.g. fracture
24
What are the clinical signs of an increased ICP?
Papilloedema
Headache
N+V
Neck stiffness
25
What are the different types of SOLs?
Tumours; primary brain tumours, mets
Abscess; single/multiple
Haematomas
Localised brain swelling; swelling and oedema around cerebral infarct
26
What are the Si/Sy of brain tumours?
Sy: focal, headache, vomiting, seizures, visual disturbances
Signs; focal deficit, papilloedema
27
What is the difference in location of brain tumours between children and adults?
Children; 70% below tentorium cerebelli
Adults; 70% above tentorium cerebelli
28
What common cancers will metastasize to the brain?
Breast, bronchus, kidney, thyroid, colon and melanomas
29
What is used to grade primary brain tumours?
Mitoses
Neovascularization
Necrosis
Atypia, cellularity
30
