ONH - NERVE EDEMA Flashcards
what is papilledema?
- bilateral swollen optic nerves 2/2 increased intracranial pressure (ICP)
what are causes of ICP?
- intracranial mass
- IIH
- inhibition of the arachnoid villi from absorbing cerebral spinal fluid
- malignant HTN
- venous sinus thrombosis
what happens to axon flow if the ICP increases too much?
axoplasmic flow from optic nerve is halted or reversed. This backflow causes bilateral swollen optic nerves
why is papilledema bilateral?
b/c ICP occurs posterior to the optic chiasm
what are symptoms of papilledema?
- Blurry vision
- Headache
- Nausea
- Color vision abnormalities
- Transient vision disturbance
- Dimming of vision
- APD
signs of papilledema?
- bilateral swollen ONH
- abnormal red saturation test
- VF defect – enlarged blind spot
- Patron’s lines – retinal folds due to stretching over the edema
tx for papilledema?
- Measure BP – r/o malignant HTN
- Order FAF – r/o pseudopapilledema (ONH drusen)
- Order MRI/CT scan to r/o mass – always suspect intracranial mass
- Order lumbar puncture if MRI/CT scans are clean – checks CSF prssure
- Order CBC, fasting blood sugar, ESR, CRP, ANA, ACE – find out etiology
- Refer to neurology to tx underlying etiology
what is IIH?
it is papilledema with no apperant cause
who is most likely to get IIH?
FAT, FERTILE, FEMALE
what are some drugs associated with IIH?
pneumonic: VaN CATS
1. Vitamin A
2. Nalidixic acid
3. Contraceptives
4. Accutane
5. Tetracyclines
6. Synthroid
symptoms of IIH?
same as papilledma:
1. Blurry vision
2. Headache
3. Nausea
4. Color vision abnormalities
5. Transient vision disturbance
6. Dimming of vision
7. APD
In order to be classified as IIH, what 3 criteria must be met?
- papilledema (due to increased ICP)
- normal brain MRI/CT
- high cerebral spinal fluid pressure on lumbar puncture (>200 mmH2O in non-obese & >250 mmH2O in obese patients)
tx for IIH?
tx is aimed to eliminate possible cause factors:
* d/c known associated medication
* obese patients should lose weight
* oral acetazolamide should be used to reduce the production of cerebral spinal fluid at the choroid plexus
* f/u every 3 weeks to 3 months depending on severity & respond to tx.
what is nonarteritic ischemic optic neuropathy (NAION) & arteritic ischemic optic neuropathy (AION)?
Both unilateral disc edema due to ischemia from blockage of the posterior ciliary artery.
Which dz NAION or AION is an emergency? what is the pneumonic to remember it by?
Arteric is Alarming
NonArteritic is Not Alarming
what is NAION caused by?
Caused by cardiovascular disorders:
* HTN
* DM
* hypercholesterolemia
* smoking
Caused by drugs (VISA):
* Amiodarone
* Imitrex
* Vardenafil
* sildenafil
what is AION caused by?
AION is caused by GCA which is characterized by inflammation of both medium and large size arteries.
why is it important to tx AION quickly?
patient may lose vision in the fellow eye within 24 hours
what are symptoms of both NAION & AION?
- sudden, unilateral, painless vision loss
what specific symptoms of AION?
- amaurosis fugax
- HA
- Malaise
- fever
- scalp tenderness over ipsilateral temporal artery
- jaw claudication
- weight 2/2 jaw claudication
what are signs of both NAION & AION ?
- unilateral swollen ONH
- APD
- VF defects
- small optic cup (disc at risk)
what is the most common VF defect for AION?
Inferior altitudinal
what is the a specific finding for NAION?
long term optic nerve pallor
tx/managment for AION/NAION?
- immediately start IV steroids for inflammation
- STAT CRP & ESR should be ordered
- temporal biopsy should also be ordered – may be false negative due to skip lesions
- If testing r/o AION – then pts should d/c steroids & start taking aspirin as prophylaxis.
what indicates abnormal ESR?
- men = age/2
- femal = age + 10/2
what is optic neuritis?
inflammation of the optic nerve
what systemic dz is optic neuritis associated with?
Multiple sclerosis (MS)
symptoms of optic neuritis?
- unilateral sudden loss of vision – due to swelling of the ONH
- pain on eye movment – swelling compresses EOMs
signs of optic neuritis?
- unilateral swollen ONH w/ APD
- unilateral color vision defects
- variable VF defects
- May need an MRI of the brain and orbit to r/o retrobulbar optic neuritis (inflammation behind the globe)
tx for optic neuritis?
- refer to neurology for MRI to investigate for MS
- IV steroids then transition to oral steroids
- f/u every 1-6 months depending on the severity and response of tx