ICP & Hydrocephalus Flashcards
What level is ICP at rest in adults?
7-15mmHg
What is the order in which fluid leaves the skull to compensate for raised ICP?
1) Venous blood
2) CSF
3) Arterial blood
Where is CSF made?
Choroid plexus of the Lat ventricles
What level of Cerebral Perfusion Pressure (CPP) is normal?
80-90
What level of CPP is life threating and not compatible with life?
Life threatening: 30
Not compatible with life >3min: 20
What is cerebral blood flow?
CPP/Cerebral vasc resistance
What does CO2 do to blood vessels?
CO2 is a potent dilator
What is communicating hydrocephalus?
Impaired CSF absorption
What are early signs of raised ICP?
Headache
Pupillary dysfunction +/- papilloedema
Changes in vision
Nausea and vomiting
↓ level of consciousness
What are late signs of raised ICP?
Coma
Fixed, dilated pupils
Hemiplegia
Bradycardia → Cushing’s triad
Hyperthermia
↑ urinary output
How is raised ICP managed non-medically?
Maintain head in midline to facilitate blood flow
Loosen tube ties, collars etc
HoB 30-45° elevation
Avoid gagging, coughing etc
Decrease environmental stimuli
Treat hyperthermia
Maintain fluid balance and normal electrolytes
Maintain normocarbia
How is raised ICP managed medically/surgically?
Diuretics (mannitol, hypertonic saline, furosemide)
Barbiturate coma (last choice before surgery)
Antiepileptics
Surgical decompression
What is chiari malformation?
When the cerebellar tonsils protrude below the area they are supposed to
What do patients with chiari malformation tend to present with?
Cough headache
Sleep apnoea
Syrinx (CSF flowing through central canal)
Can lumbar puncture be done in obstructive hydrocephalus?
No
