Thread by @EAFischer

1/ #tweetorial
⮞Optic disc edema vs. Papilledema
⮞Orbital anatomy
⮞Orbital #POCUS

2/ First what is 𝗽𝗮𝗽𝗶𝗹𝗹𝗲𝗱𝗲𝗺𝗮?

𝘐 𝘸𝘪𝘴𝘩 𝘐 𝘤𝘰𝘶𝘭𝘥 𝘨𝘦𝘵 𝘪𝘮𝘢𝘨𝘦𝘴 𝘭𝘪𝘬𝘦 𝘵𝘩𝘦𝘴𝘦...
[source bit.ly/3yceeCT]

3/ 𝗢𝗽𝘁𝗶𝗰 𝗱𝗶𝘀𝗰 𝗲𝗱𝗲𝗺𝗮 = optic nerve head edema + anterior bulging of physiologic cup

𝗣𝗮𝗽𝗶𝗹𝗹𝗲𝗱𝗲𝗺𝗮 is optic disc edema 𝙙𝙪𝙚 to 🡱intracranial pressure

**𝗡𝗼𝘁 𝗮𝗹𝗹 𝗼𝗽𝘁𝗶𝗰 𝗱𝗶𝘀𝗰 𝗲𝗱𝗲𝗺𝗮 𝗶𝘀 𝗽𝗮𝗽𝗶𝗹𝗹𝗲𝗱𝗲𝗺𝗮 [bit.ly/3wEIUwG]

4/ Non-arteritic anterior ischemic optic neuropathy is the most common cause of optic disc edema
bit.ly/3wF84JP

The presentation will clue you in to the ddx

5/ Specific causes of 𝗣𝗮𝗽𝗶𝗹𝗹𝗲𝗱𝗲𝗺𝗮 include
• Malignant hypertension
• Sinus venous thrombosis
• CNS space occupying lesion / mass effect
• Idiopathic Intracranial Hypertension (~pseudotumor)

6/ How do make this dx? With fundoscopy OR #POCUS

Fundoscopy:
Dilation is SAFE - <1% (some series 0%) acute glaucoma
bit.ly/3ihZATK

i.e. Tropicamide 1%, 1-2 drops (𝗮𝘃𝗼𝗶𝗱 𝗶𝗻 𝘀𝗲𝗿𝗶𝗼𝘂𝘀 𝗵𝗲𝗮𝗱 𝘁𝗿𝗮𝘂𝗺𝗮)

7/ @StanfordMed25 for fundoscopy primer
stanford.io/3xITLW2

8/ And #POCUS? 𝗢𝗽𝘁𝗶𝗰 𝗡𝗲𝗿𝘃𝗲 𝗦𝗵𝗲𝗮𝘁𝗵 𝗗𝗶𝗮𝗺𝗲𝘁𝗲𝗿 (ONSD) is a surrogate for disc edema

Here is orbital anatomy on ultrasound

9/ To measure ONSD:
⮞LOTS of gel
⮞Measure 3 mm behind globe, transverse & longitudinal
⮞𝘈𝘷𝘦𝘳𝘢𝘨𝘦 ~2+ 𝘮𝘦𝘢𝘴𝘶𝘳𝘦𝘮𝘦𝘯𝘵𝘴
@AnnaEMin5

10/ Is ONSD ready for primetime?

I think so, if...

https://twitter.com/PratsEM/status/1391731288600727559?s=20

11/ ...the 𝗢𝗡𝗦𝗗 measurement is interpreted in a spectrum of possibilities. An absolute cutoff is not practical, #POCUS likely not accurate enough

Per Wilson et al. in novices
⮞ONSD < 3.6 mm ~rules out
⮞ONSD > 5.3 mm ~rules in
⮞3.6-5.3 - ???
doi.org/10.1002/emp2.1…

The whole #POCUS anatomy rundown

This and other 3D models + GIFs
goodybedside.georgetown.domains/pocus/3Dpocus