Raised Intracranial Pressure

Question 1

Define raised ICP?

Answer 1

The volume inside the cranium is fixed so any increase in the contents can lead to raised ICP
This can be mass effect, oedema or obstruction to fluid outflow
Normal ICP in adults is < 15mm HG

Question 2

What are the causes of raised ICP?

Answer 2

Primary or metastatic tumours 
Head injury 
Haemorrhage 
Infection - meningitis, encephalitis, brain abscess 
Hydrocephalus 
Cerebral oedema 
Statuss epilepticus

Question 3

What are the presenting symptoms of raised ICP?

Answer 3

Headache: worse on coughing and leaning forwards, worse in morning
Vomiting
Altered GCS - drowsiness, irritability, coma
History of trauma
Poor vision

Question 4

What are the signs of raised ICP on physical examination?

Answer 4

Altered GCS
Falling pulse and rising BP (Cushing’s response_
Cheyne-Stokes respiration
Pupil changes - constriction first, later dilatation
Reduced visual acuity
Peripheral visual fluid loss
Papilloedema - unreliable sign but venous pulsation at the disc may be absent

Question 5

What is Cheyne-Stokes respiration?

Answer 5

Progressively deeper and sometimes faster breathing followed by a gradual decrease that results in a temporary stop in breathing - cycle repeats

Question 6

What investigations do we do for raised ICP?

Answer 6

U&E 
FBC 
LFT 
Glucose 
Serum osmolality 
Clotting 
Blood Culture 
CXR 
CT head

Question 7

Why do we do a CXR for raised ICP?

Answer 7

any source of infection may lead to abscess

Question 8

What other do investigations do we do for raised ICP?

Answer 8

Toxiciology screen

LP if it’s safe - measure opening pressure