[22] Raised ICP Flashcards
What is raised ICP?
When the pressure inside the skull (and thus the brain and CSF) is increased
What is a normal ICP at rest in a supine adult?
7-15mmHg
Is raised ICP acute or chronic?
Can be either
What are the ways in which the body can regulate the ICP?
- Changes in CSF production and absorption
- Autoregulation
- Chemoregulation
What happens in autoregulation (re: ICP)?
Vasoconstriction and vasodilation can occur in response to changes in blood pressure
What happens in chemoregulation (re: ICP)?
There is vasodilation in response to low cerebral pH
What are changes in ICP attributed to?
Changes in the volume of one or more of the constituents within the cranium
What can change in volume within the cranium to lead to raised ICP?
- Blood
- CSF
- Brain (and other tissue)
What are the common causes of raised ICP?
- Localised mass lesions
- Neoplasms
- Abscess
- Focal oedema
- Disturbance of CSF circulation
- Obstruction to major venous sinuses
- Diffuse brain oedema and swelling
- Idiopathic intracranial hypertension
What is an example of a localised mass lesion that can lead to raised ICP?
Traumatic haematoma
Give examples of neoplasms that can cause raised ICP?
- Glioma
- Meningioma
- Metastases
What can lead to focal oedema causing raised ICP?
- Trauma
- Infarction
- Tumour
What are the types of CSF disturbance?
- Obstructive hydrocephalus
- Communicating hydrocephalus
What happens in obstructive hydrocephalus?
There is blockage to the circulation of the CSF causing back pressure to build up
What happens in communicating hydrocephalus?
There is impaired absorption of the CSF but no obstruction to flow
What can cause obstruction to major venous sinuses?
- Depressed fractures overlying the venous sinuses
- Cerebral venous thrombosis