Flashcards in 2.6: Papilloedema Deck (23)
Describe swollen discs?
This is swelling of the optic disc
This is swelling of the optic disc caused SPECIFICALLY by raised intracranial pressure
What does ICP mean? What does IOP mean?
ICP = Intracranial pressure. The pressure within the skull , where the brain is
IOP = Intraocular pressure. The pressure within the eye
All patients with bilateral disc swelling should be suspected of having what?
Raised intracranial pressure caused by a space occupying lesion
Raised ICP caused by a SOL
Raised ICP is a medical emergency
True or False?
Raised intracranial pressure is a medical emergency
69 Year old male presents with headaches and blurred vision
Visual Acuity: 6/6 On both left and right
Fundoscopy: Bilateral disc swelling
What is causing the disc swelling?
Diagnosis: Space Occupying Lesion (Brain Tumour)
Disc swelling is caused by raised ICP
This is a TRUE PAPILLOEDEMA
Describe how raised ICP leads to a swollen disc?
The subarachnoid space surrounds the brain and is continuous with the subarachnoid space surrounding the optic nerve.
When intracranial pressure is raised, this pressure is transferred first to the subarachnoid space and then onto the optic nerve
Compression of the optic nerve leads to disruption of the 'axoplasmic flow' (nerve impulse conduction) and venous congestion
Results in disc swelling
1. Raised ICP
2. Transferred to subarachnoid space
3. Transferred to Optic Nerve
4. Disruption of axoplasmic flow (nerve conduction)
5. Disc Swelling
Describe the components of intracranial pressure?
The sum of:
Describe the Monro-Kelli hypothesis?
If one component is increased, the other components will decrease to maintain the intracranial pressure at a constant level
Describe how the intracranial pressure is kept equal?
If one component is increased, the other components will decrease to maintain to in cranial pressure at a constant level and vice versa
Describe the effect increasing intracranial mass has on intracranial pressure?
At first, compensatory mechanisms prevent the pressure from rising
However, these can only work for so long
After the compensatory mechanisms fail, a small change in intracranial mass causes a large change in intracranial pressure (exponential)
Describe the link between the blood and the brain?
The brain requires a constant supply of blood
It is very intolerant to hypo/hyperperfusion
Blood undergoes auto-regulation to prevent this
Describe malignant hypertension?
Relevance to ophthalamology?
High blood pressure that develops rapidly and causes some type of organ damage
Can cause bilateral disc swelling
This is a differential for bilateral disc swelling (Not all patients with raised ICP have an SOL)
In patients with bilateral disc swelling and very high blood pressure:
- What are you less concerned about?
- What are you more concerned about?
Less likely to be a space occupying lesion and more likely to be malignant hypertension
More concerned about malignant hypertension as this can cause damage and is a serious problem
What simple, easy, clinical test should always be done in bilateral disc swelling?
Hint: Learned this in 1st year
Done all the time
What are the functions of the CSF?
Protection for the brain
Removes waste products
Stable extracellular environment for the brain
Where is CSF produced?
Produced in the choroid plexus of the lateral ventricles
What is the choroid plexus?
Network of blood capillaries
These filter produce to produce CSF
Briefly describe CSF circulation?
How can the CSF cause raised ICP?
Lack of CSF Absorption
25 year old female
Presents with headaches
BMI of 40
Visual Acuity: 6/6 on both left and right
Fundoscopy: Bilateral Disc Swelling
Lumbar Puncture: Raised CSF opening pressure
Idiopathic Intracranial Hypertension
Describe idiopathic intracranial hypertension briefly?
Not fully understood
Could be caused by obstructing CSF or impairing CSF absorption
Leads to swollen discs