Intracranial Pressure Flashcards
1
Q
Monro-Kellie Doctrine
A
- Skull has 3 main components: Brain tissue, blood and CSF
- If volume of one components increases, then ICP will increase unelss the volume of another component is reduced
2
Q
Cerebral Blood Flow
A
- Is under auto regulation
- Rises in BP causes cerebral blood vessels to constrict to limit blood flow
- can accommodate a wide range from 50mmHg to 150 mmHg
3
Q
Communicating Hydrocephalus
A
- decreased CSF absorption by arachnoid granulations –> can lead to increased ICP, papilledema and herniation
4
Q
Normal Pressure Hydrocephalus
A
- There is an increase in subarachnoid space volume due to expansion of the ventricles
- There is NO INCREASE in CSF pressure b/c of the expansion of the ventricles
Clinical triad:
- Urinary incontinence
- Ataxia
- Cognitive dysfunction
5
Q
Hydrocephalus Ex Vacuo
A
- Dilation of ventricles during brain atrophy (ICP is normal)
- e.g., Alzheimer’s Disease
6
Q
Non-Communicating Obstructive Hydrocephalus
A
- Caused by structural blockage of CSF circulation within the ventricular system (e.g., stenosis of the aqueduct of Sylvius)
7
Q
Psuedotumor cerebri
A
- increase in intracranial pressure, but without a mass lesion causing it
8
Q
Papilledema
A
- optic disc swelling that is caused by increased intracranial pressure.
9
Q
- Signs of High ICP
- Contraindications for Lumbar Puncture
A
High ICP
- altered mental status
- Morning Headache / Morning Lethargy
- Papilledema
- Projectile Vomiting (without nausea)
- Cushing’s triad: HTN, bradycardia, respiratory irregularities
- Falsely localizing sig of CN VI Palsy: CNVI originates at the Pontomedullary junction; however, increase in ICP can also damage CN VI, causing internal strabismus and diplopia
10
Q
Interventions for Elevated ICP
A
- Hyperventilate the patient
- Osmotic diuresis: Draw out excess CSF fluid
- Hemicraniectomy: temporarily remove portion of skull to allow brain expansion
