what are normal ICP values
5-13mmHg
what is hydrocephalus
accumulation of excessive CSF within the ventricular system of the brain
what is the normal volume of CSF
120-150ml
where is csf produced
by the choroid plexus in the lateral and fourth ventricles
what reabsorbs CSF
arachnoid granulations
what is the typical daily csf turnover
500ml (3-5 times per day )
is blood usually present in CSF
NOOO
what are the normal findings in CSF
lymphocytes less than 4/mm3
protein less than 0.4g/l
glucose more than 2.2mmol/l
where is csf absorbed
superior sagittal sinus
what is the difference between non communicating and communicating hydrocephalus
non communicating - obstruction to flow of CSF is within ventricles
communticatin - obstruction is outside the ventricles eg arachnoid granulations
what happens if hydrocephalus develops before closure of cranial sutures
head enlarges
if after they have closed - raised ICP
what herniated in subfalcine herniation
cingulate gyrus under falx cerebri
what symptoms result in subfalcine herniation
compresses anterior cerebral artery - weakness/sensory loss in lower limbs
what is a tentoral hernia
hippocampal uncus and parahippocampal gyrun herniates over the tentorium cerebelli
what symptoms occur in tentoral hernia
third nerve palsy
what is a tonsilar herniation
dispplacemnt of cerebellar tonsils through foramen magnum
why is a tonsillar hernia particularly dangerous
braistem compression compromises respiratory centres in medulla oblongata
what is a trancalcarium hernia
swollen brain will herniate though defect in dura or skull
CARDINAL SIGNS OR RAISED ICP
papilledema
headache
vomiting
neck stiffness
what is the most common type of primary brain tumour
atrocytoma
what is the most common benign brain tumour in adults
menigioma
what is the most common brain tumour in children that is benigm
craniopharyngioma
what is the difference between primary and secondary glioblastoma (ie a grade four astrocytoma)
primary means that gliobastoma has arisen from normal brain tissue
secondary means it has progressed from lower grade astrocytomas ie anaplastic or diffuse astocytomas
secondary has slightly better prognosis but both prognosis are poor with mean survival les than 12 months
what age do people usually present with primary glioblastoma
mean is 62
what age do people usually present with secondary glioblastoma
mean is 45 yrs
how do brain tumours present
most with focal neurological deficit and headache
also vomiting
seizures and visual disturbance
what usually causes a single absess
otitis media sinusitis dental infections skull fracture neurosurgery
can arise without significant bacterial menigitis
what usually causes multiple absesses
usually from septicaemia eg
endocarditis
lung absess
intravenous drug use
what is cerebral oedema
increased water content of the brain
what type of cerebral oedema is seen in hypertensive encephalopathy
hydrostatic
what is the source of the bleed in extradural haemorrhages
meningeal arteries - usually middle menigeal
why are extra durals ‘walk and die’ injuries
results in uncal and cerebella herniation - death
what is the source of the blood in subdurals
bridging veins from surface of brain into subdural space
what type of brain bleed can be confused with dementia
chronic subdural
where do most berry aneurysms arise
in internal carotid
what haemorrhage do berry aneurysm causes
subarachnoid
are subarachnoid more common in women or men
women
