Flashcards in Raise ICP, SOLs and trauma Deck (77)
What is the normal volume of CSF?
500ml a day
What produces CSF?
Choroid plexus in the lateral and 4th ventricles of the brain
What absorbs CSF?
What do lymphocyres in the CSF suggest?
Infection; viral or fungal
What do neutrophils in the CSF suggest?
What is the definition of hydrocephalus?
Accumulation of excessive CSF within the ventricular system of the brain
What can cause hydrocephalus?
Obstruction to flow: inflammation, pus, tumours
Decreased reabsorption; post SAH, meningitis
Overproduction; very rare cause due to choroid plexus tumour
What is non-communicating hydrocephalus?
Obstruction to flow of CSF occuring within the ventricular system
What is communicating hydrocephalus?
Obstruction to flow of CSF outside of the ventricular system e.g. in subarachnoid space or at the arachnoid granulations
What occurs if hydrocephalus occurs before the closure of the cranial sutures?
Cranial enlargement occurs
What occurs if hydrocephalus occurs after the closure of the cranial sutures?
Expansion of the ventricles with an increase in intracranial pressure
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
What are the causes of increased ICP?
Diffuse lesion in brain e.g. oedema
Increased venous volume
Physiological; hypoxia, hypercapnia, pain
What are the consequences of raised ICP?
Intracranial shifts and herniations
Distortion and pressure on CNs and vital neurological centres
Impaired blood flow
Reduced level of consciousness
How is cerebral perfusion pressure calculated?
MAP - ICP; therefore ICP is too high, it will reduce blood flow
What are the 4 types of shifts and herniations within the brain?
What is a subfalcine herniation?
Unilateral or asymmetrical expansion of the cerebral hemisphere which displace the cingulate gyrus underneath the falx cerebri
What does a subfalcine herniation result in?
Compression of the anterior cerebral artery resulting in weakness and/or sensory loss on the contralateral side
What is a tentorial herniation?
Medial aspect of the temporal lobe (uncus) herniates over the tentorium cerebellar
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
What is a tonsillar herniation?
Displacement of the tonsillar cerebellum through the foramen magnum
What will a tonsillar herniation result in?
Compression of the respiratory centers of the medulla oblongata
What is a transcalvarial herniation?
Brain herniating through any defect in the skull e.g. fracture
What are the clinical signs of an increased ICP?
What are the different types of SOLs?
Tumours; primary brain tumours, mets
Localised brain swelling; swelling and oedema around cerebral infarct
What are the Si/Sy of brain tumours?
Sy: focal, headache, vomiting, seizures, visual disturbances
Signs; focal deficit, papilloedema
What is the difference in location of brain tumours between children and adults?
Children; 70% below tentorium cerebelli
Adults; 70% above tentorium cerebelli
What common cancers will metastasize to the brain?
Breast, bronchus, kidney, thyroid, colon and melanomas
What is used to grade primary brain tumours?