ICP and Head Injuries Flashcards
What is the normal range of intracranial pressure?
5-15mmHg
Which brain herniation is most common?
Subfalcine herniation (beneath falx cerebri)
What is the uncus?
The medial part of the temporal lobe, at the base of the cerebrum
What part of the brain does an uncal herniation compress?
The midbrain: ipsilateral oculomotor nerve, cerebral peduncle
What are the symptoms of subfalcine herniation?
Headache, contralateral leg weakness (if anterior cerebral artery affected)
On a CT, the midline shifts
What are the symptoms of uncal herniation?
Ipsilateral dilated pupil, contralateral leg weakness, decreased consciousness level.
(May be false localising if midbrain pushed against opposite side of tentorium)
Where do the cerebellar tonsils herniate through?
The foramen magnum
What structures does a tonsillar herniation compress?
Medulla and upper spinal cord
What effect does tonsillar herniation compression of the spinal cord have?
Cardiac and respiratory dysfunction
What is Cushing reflex?
A physiological nervous system response to continual raised ICP, resulting in Cushing’s triad of raised BP, irregular breathing, and bradycardia
What are the four causes of raised ICP?
Increased cerebral blood volume, increased CSF volume, expanding mass (eg: abscess, tumour), cerebral oedema (eg: meningitis, encephalitis, infarction)
What is the most common cause of raised ICP?
Traumatic brain injury (often due to hemorrhage)
Where are the two age peaks for brain tumours?
Childhood and late middle age
What are the most common types of childhood brain tumour?
Astrocytomas (astrocytes), medulloblastomas (neuroectodermal cells)
What are the most common types of adult brain tumour?
Gliomas and meningiomas, metastases from lung/breast/kidney