Intracranial Pressure

Question 1

What are the clinical symptoms of increased ICP?

Answer 1

• Headache
• Nausea/Vomiting
• Drowsiness
• Papilloedema

Question 2

What are the unique characteristics of headache related to increased ICP?

Answer 2

• Worse in the AM

- ICP increases during sleep 2/2 to CO2 retention.

Question 3

When is nausea/vomiting worse re: ICP?

Answer 3

• Morning

Question 4

What does drowsiness indicate in person w/ suspected ICP?

Answer 4

• Neurological deterioration

Question 5

What does papilloedema indicate in a person w/ suspected ICP?

Answer 5

• Raised intracranial pressure transmitted along subarachnoid sheath of optic nerve.
• Filling of optic cup and dilation of retinal vessels.

Question 6

What is the Cushings Reflex?

Answer 6

• Hypertensive response elicited with bradycardia.

Question 7

What is normal ICP?

Answer 7

• 20 mmHG

Question 8

What is normal supine ICP?

Answer 8

10-15 mmHG

Question 9

What are the intracranial contents?

Answer 9

• Brain
• CSF
• Blood

Question 10

Causes of ICP include?

Answer 10

• Increased volume of normal constituents

- (cerebral edema, benign IC HTN, hydrocephalus, vasodilation due to hypercapnia).

Question 11

What is autoregulation re: ICP?

Answer 11

Ability of brain to maintain constant cerebral blood flow by altering vessel diameter and tone (20% of cardiac output) – following cerebral insult becomes dependent on MAP

Question 12

Equation for CBF?

Answer 12

CBF = CPP/CVR; CPP = MAP - ICP, CBF = MAP-ICP/CVR

Question 13

What are the presenting features of benign intracranial pressure?

Answer 13

Obese females with headache + visual disturbance on OCPs with endocrine or menstrual disturbances

Question 14

How do you diagnose BIP?

Answer 14

Imaging: CT/MRI will show NO CAUSE of papilledema and ventricles will be small.

Question 15

What are the visual disturbances associated with BIP?

Answer 15

• Papilloedema 2/2 to optic atrophy

- Diplopia 2/2 to 6th cranial nerve palsy

Question 16

How do you treat BIP?

Answer 16

• Weight loss
• Stop meds (OCP, tricyclics)
• Diuretic
• Acetazolamide

Question 17

What is hydrocephalus?

Answer 17

• Abnormal enlargement of ventricles 2/2 to excessive accumulation of CSF resulting in 1) disturbance of flow 2) absorption 3) secretion

Question 18

What is the difference between communicating and non-communicating hydrocephalus?

Answer 18

communicating = No obstruction to flow of CSF within the ventricular system (2/2 to failure of absorption or obstruction outside ventricular system)
non-communicating = obstruction to flow of CSF via ventricular system

Question 19

What are presenting features of hydrocephalus?

Answer 19

• Failure to thrive
• Failure to achieve milestones
• Increased skull circumference
• Tense anterior fontanelle
• Impaired coo/vomiting
• Thin scalp with dilated veins
• Setting sun appearance due to lid retraction
• Impaired upward gaze from ventricular pressure on 3rd nerve/tectum
  (adult can present with ICP plus upward gaze palsy)

Question 20

How do you diagnose hydrocephalus?

Answer 20

• CT/MRI (communicating = all ventricles very dilated)

Question 21

How do you treat hydrocephalus?

Answer 21

• Ventriculoperitoneal shunt or removal of mass