Raised ICP

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 <15mmHg

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

Status epilepticus

Blood clot

Question 3

what are the presenting symptoms of raised ICP?

Answer 3

Headache: worse on coughing and leaning forwards, worse in morning – throbbing and constant

Vomiting without N

Altered GCS – drowsiness, irritability, coma

History of trauma

Poor vision

Question 4

What are signs of raised ICP on physical examination?

Answer 4

Altered GCS

wide pulse pressure, bradycardia, irregular breathing (Cushing’s response)

Cheyne-Stokes respiration –progressively deeper and sometimes faster breathing followed by a gradual decrease that results in a temporary stop in breathing - cycle repeats

Pupil changes – constriction first, later dilatation

Reduced visual acuity(as can cause hydrocephalus which may compress optic N)

Peripheral visual field loss

Papilloedema– unreliable sign but venous pulsation at the disc may be absent

Associated with cranial nerve 6 palsy due to long course so more areas it can be compressed

Question 5

what are the appopriate investigations for raised ICP?

Answer 5

• U&E, FBC, LFT, glucose, serum osmolality, clotting, blood culture
• Consider toxicology screen
• CXR – any source of infection may lead to abscess
• CT head
• Visual fields testing; optic disc photography
• Consider LP if safe (not due to a cerebral mass) – measure opening pressure