Raised ICP

Question 1

What is the normal range for ICP?

Answer 1

5-15 mmHg

Question 2

What is CPP?

Answer 2

Cerebral perfucsion pressure

The net pressure gradient causing cerebral blood flow to the brain

Question 3

How is CPP calculated?

Answer 3

CPP = MAP - ICP

Question 4

What is the Monro-Kellie doctrine?

Answer 4

Relationship between contents of the cranium and ICP

Question 5

What are the major components found in the cranium?

Answer 5

Brain tissue
CSF
Blood

Question 6

What happens if the volume of one of these components rises?

Answer 6

Causes a rise in ICP

So one of the other components needs to decrease in volume

Question 7

What are the main compensatory mechanisms for raised ICP?

Answer 7

Increased blood drainage

Increased CSF drainage

Brain herniation

Question 8

What can cause raised ICP?

Answer 8

Idiopathic intracranial hypertension 
Traumatic head injuries 
Infection 
Tumours
Hydrocephalus

Question 9

What are features of raised ICP?

Answer 9

Headache - worse in morning
Vomiting
Reduced consciousness
Papilloedema

Cushing’s triad

Question 10

What is Cushing’s triad?

Answer 10

Widened pulse pressure
Bradycardia
Irregular breathing

Question 11

How is raised ICP investigated?

Answer 11

Neuro imaging

Invasive ICP monitoring

Question 12

How is ICP monitored?

Answer 12

Subarachnoid bolt

Epidural bolt

External ventricular drain

Question 13

How is raised ICP managed?

Answer 13

Find underlying cause

Head elevation to 30 degrees

IV mannitol

Controlled hyperventilation

CSF drainage

Question 14

How does controlled hyperventilation work?

Answer 14

Reduce pCO2 -> vasoconstriction of cerebral arteries -> reduced ICP

Question 15

How is CSF drained?

Answer 15

Catheter placed into lateral ventricles

Repeated LP

Ventriculoperitoneal shunt

Question 16

What is idiopathic intracranial hypertension?

Answer 16

Condition where there is raised ICP without a cause

Question 17

What are risk factors for idiopathic intracranial hypertension?

Answer 17

Obesity
Female sex
Pregnancy

Drugs

• COCP
• steroids
• lithium

Question 18

What are features of idiopathic intracranial hypertension?

Answer 18

Headache
Blurred vision
Papilloedema
Enlarged blindspot

Question 19

How is idiopathic intracranial hypertension managed?

Answer 19

Weight loss
Diuretics
Topiramate
Repeated LP

Question 20

What is hydrocephalus?

Answer 20

Accumulation of CSF in the cerebral ventricles

Question 21

How can hydrocephalus be classified?

Answer 21

Obstructive

Communicating

Question 22

What is obstructive hydrocephalus?

Answer 22

Blockage to natural ventricular drainage system

Question 23

What can cause obstructive hydrocephalus?

Answer 23

Tumour
Cysts
Congenital

Question 24

What is communicating hydrocephalus?

Answer 24

Reduced absorbance of CSF by arachnoid villi

Question 25

What can cause communicating hydrocephalus?

Answer 25

Infective meningitis SAH Congenital Normal pressure hydrocephalus

Question 26

What is normal pressure hydrocephalus?

Answer 26

Ventricular dilatation in the absence of raised CSF pressure

Question 27

What are teh features of normal pressure hydrocephalus?

Answer 27

Parkinsonin gait Urinary incontinence Dementia

Question 28

How is normal pressure hydrocephalus managed?

Answer 28

CSF shunt

Question 29

What are features of hydrocephalus?

Answer 29

N+V Morning headache Altered GCS Blurred vision

Question 30

How is suspected hydrocephalus investigated?

Answer 30

CT brain LP

Question 31

What is seen on a CT head in hydrocephalus?

Answer 31

Enlarged ventricles Loss of sulcal gyral pattern CSF exudation from ventricles = hypodensity around ventricular margins

Question 32

How is hydrocephalus managed?

Answer 32

Insertion of external ventricular drain Treat underlying cause