Papilloedema

Question 1

What does optic disc swelling refer to?

Answer 1

Disc swelling secondary to any cause

Question 2

What does papilloedema refer to?

Answer 2

Bilateral optic disc swelling secondary to raised intracranial pressure

Question 3

What should all patients with bilateral optic disc swelling be suspected of having until proven otherwise?

Answer 3

Raised intracranial pressure due to a specific space occupying legion

Question 4

Is raised intracranial pressure serious?

Answer 4

Yes = medical emergency

Question 5

What is examined during ophthalmoscopy?

Answer 5

The optic disc = part of cranial nerve II examination

Question 6

What is included in an examination of cranial nerve II?

Answer 6

Visual acuity, pupil exam, ophthalmoscopy, visual field assessment, colour vision

Question 7

What is the different about the optic nerve?

Answer 7

It is actually an extension of the brain with meningeal sheaths

Question 8

What is the subarachnoid space around the optic disc continuous with?

Answer 8

The subarachnoid space that surrounds the brain

Question 9

What happens when there is raised intracranial pressure?

Answer 9

It is transmitted to the subarachnoid space to the optic nerve = interrupts axoplasmic flow and venous return causing the discs to swell

Question 10

What components are added together to give the intracranial pressure?

Answer 10

Brain (80%), blood (10%) and CSF (10%)

Question 11

What happens if one element of the components of the intracranial pressure rises?

Answer 11

There should be a compensatory decrease in the other elements to ensure the pressure remains constant

Question 12

Why is it important that the intracranial pressure remains constant?

Answer 12

The cranium is rigid and therefore cannot cope with changes in pressure and volume

Question 13

What structures may be damaged due to raised intracranial pressure?

Answer 13

Blood vessels are compressed leading to global ischaemia and swelling, brain herniates through foramen magnum, brainstem is compressed = death

Question 14

What does the brain need its blood supply to be?

Answer 14

Brain requires constant blood flow over a range of pressures = very intolerant of hypo/hyper-perfusion, process of auto-regulation

Question 15

What are some other causes, besides raised intracranial pressure, that may cause disc swelling?

Answer 15

Malignant hypertension and idiopathic intracranial hypertension

Question 16

What are the functions of the CSF?

Answer 16

Maintains stable extracellular environment for brain, buoyancy, mechanical protection, waste removal, nutrition

Question 17

Where is most CSF produced?

Answer 17

By the choroid plexus in the lateral ventricles

Question 18

Where does CSF travel through before it reaches the subarachnoid space?

Answer 18

The third then the fourth ventricles

Question 19

What is the choroid plexus?

Answer 19

Network of capillaries which filter blood to form CSF

Question 20

What can cause intracranial pressure to rise?

Answer 20

Obstructions to CSF production, overproduction of CSF or inadequate absorption of CSF

Question 21

What are some proposed mechanisms of idiopathic intracranial hypertension?

Answer 21

Stenosis of transverse cerebral sinuses (obstructs CSF)
Increased abdominal pressure (obesity)
Vitamin A (impairs CSF absorption)
Micro-emboli in sagittal sinus (blocks CSF absorption)

Question 22

What are some features of chronic disc swelling?

Answer 22

Swelling subsides = disc becomes atrophic and pale, loss of visual function and blindness may result