Intracranial Pressure Pathology Flashcards
What is the formula for raised intracranialr pressure
Increase in volume / mass of intracranial contents within fixed capacity of skull
If superior to 30cubic cm
IC compartment % of brain
85%
IC compartment % of blood
10%
IC compartment % of CSf
5%
First substance affected by raised intracranial pressure which is displaced
CSF
In raised intracranial pressure what event leads to increase in cranial cavity
Intravascular pressure increase because of compression
Normal pressure in cranium
10-15 mmHg
Upper limit of normal intracranial pressure
20 mmHg
Moderate increase of intracranial pressure which is not too dangerous
20-40mmHg
Severe increase of intracranial pressure which is very dangerous
More than 40 mmHg
Causes of raised intracranial pressure
Any intracranial expanding lesions ( tumors , hematoma, abscess, granulomatous , swollen infarct )
Infections ( meningitis , encephalitis)
Hydrocephalus
Cerebral edema
Hydrocephalus
Accumulation of excessive CSF within the ventricular system
Reasons of accumulation of CSF
Blockage of fluids which is congenital or acquired
Decreased absorption by arachnoid villous fibrosis or destruction , or sinus thrombosis
Increased production of CSF by choroid plexus papilloma or hyperplasia
Types of hydrocephalus
Communication or non communicating
Hydrocephalus ex vacuo
What is Hydro ex vac
When can Hydrocephalus occur in children
Before or after closure of sutures
Causes of cerebral edema
Cytotoxicity ( intracellular )due to hypoxia leading to cell swelling because can’t eliminate sodium
Vasogenic ( extracellular) bbb disrupted , leakage of fluid from capillaries -> mainly in white matter
Interstitial ( hydrocephalic) increased brain fluid due to CSF blockage
Cerebral edema appearance
Broad gyri, flattening of gyri
What a spatial compensation in increased intracranial pressure
Expansion of a lesion can lead to compression which can reduce CSF volume and reduce blood flow in vasculature
What are the alterations in the brain due to the raised intracranial pressure
focal or localized destruction of neurons due to direct pressure effects
General neuronal degeneration due to the diffuse compression of blood vessels leading to ischemia
Causes of of displacement of brain tissue in IC effect
Herniation
What effect can lead to cranial nerve palsies
Intravascular pressure
What is cranial herniation
Displacement of brain tissue past rigid folds (falx and tentorium ) or through openings in the skull like forâmes magnum
Types of cranial herniation
Internal
External
What is internal herniation
What is external herniation
Types of herniation
Sulbfalcine
Transtentorial
Tonsillar
Arteries at risk of compression in subfalcine herniation
Compression of anterior cerebral artery
Transtentorial herniation conséquence
Oculomotor nerve compression -> ocular changes
Ischemia in area supplied by posterior cerebral artery
Compression of kernohans notch leading to Hemiparesis
Hemorrhage in brainstem - duret
Tonsillar herniation consequence
Respiratory and cardiac centers compromised
Raised Intracranial pressure systemic effects
arterial hypertension
Myocardial dysfunction
Respiratory dysfunction
Mucosal ulcérations
