Some optics neuritis pearls in a short #Medtweetorial 🧵…. We all know that optic neuritis is frequently associated with multiple sclerosis (MS). But optic nerve inflammation can exist from autoimmunity, infection, granulomatous disease, paraneoplastic disorders, & demyelination Image
Classical ON from MS is unilateral, moderate, painful color vision loss with an afferent pupillary defect & normal fundus examination.
In those with ON, 95% of patients showed unilateral vision loss & 92% had associated retroorbital pain that frequently worsened w/ eye movement.
If there bilateral vision loss, lack of pain, & severe loss of vision, it should raise concern for an alternative inflammatory optic neuropathy
Pay attention to the Vision loss.. Neuromyelitis optica spectrum disorder (NMOSD) & myelin oligodendrocyte glycoprotein (MOG)-IgG optic neuritis cause severe vision loss & are more frequently bilateral.
The absence of an afferent pupillary defect should raise diagnostic concern unless the patient has bilateral involvement or a history of optic neuropathy in the fellow eye. Image
In idiopathic ON & ON assoc w/ MS, high-contrast visual acuity loss is moderate, with the majority of patients having acuity better than 20/200. Those w/ neuromyelitis optica spectrum disorder (NMOSD) or MOG-IgG often presents w/ severe vision loss worse than 20/400.
Fundscopic exam for ON is typically normal, with less than 25% of patients presenting w/ disc edema. Significant disc inflammation, disc hemorrhages, or ocular inflammation should raise concern for infection, granulomatous inflammation, or MOG-IgG.
MRI of the orbits is the most sensitive diagnostic test (90%) for optic neuritis; however, a normal orbital MRI scan DOES NOT exclude optic neuritis. Image negative ON. Hmmmmm
What about an ANA? Its not specific for any cause of ON, A pos ANA is more common in patients w/ NMOSD or MOG-IgG ON than in those with MS.
What about the appearance of the On on MRI? Can it clue us in? Yes it can…As Perineural optic nerve enhancement (optic perineuritis) is frequent with MOG-IgG-assoc ON, syphilis, tuberculosis, sarcoidosis, and granulomatosis with polyangiitis (GPA)
And a @k_vaishnani favorite. Check for Bartonella henselae in cases of neuroretinitis in which optic disc edema is accompanied by a macular star of exudates located in a radial pattern around the fovea Image
What about the CSF? A mild CSF pleocytosis is frequently observed w/ acute ON; with extensive pleocytosis (>100 cells/mm3) more often in pt w/ MOG-IgG. Pleocytosis of < 50 cells/mm3 is noted in cases of MS-associated ON.
Oligoclonal bands & intrathecal IgG synthesis, hallmarks of optic neuritis associated w/ MS, are uncommon in NMOSD & MOG-IgG-related ON. ncbi.nlm.nih.gov/pmc/articles/P…

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More from @RosenelliEM

30 May
Some cool #Syphilis Pearls from an article that @k_vaishnani shared ncbi.nlm.nih.gov/pmc/articles/P… Primary syphilis first manifests into a painless chancre at the site of inoculation 1 to 6 weeks later…
Hematogenous dissemination then can occur typically 4 to 10 weeks later, giving rise to secondary syphilis. <40% of pts w/ syphilis have primary syphilis diagnosed. These “Secondary” lesions last for several weeks before spontaneously resolving. Coined “early, latent infection”
What does late infection mean? When syphilitic lesions recur after 1 year from the initial eruption, or seropositivity is detected more than 1 year after the initial eruption, it is termed late latent syphilis.
Read 5 tweets
1 Oct 20
If you have not listened to the @CuriousClinPod most recent podcast (Episode 10: Why does metronidazole treat both bacterial and parasitic infections?) then I suggest you tune in.

curiousclinicians.com/2020/09/30/why…

I'll summarize their show notes here in short #medtweetorial
First a question:

Was metronidazole first used as an antibiotic or as an antiparasitic?
If you guessed antiparasitic, then you would be correct!

It was developed in the 1950s to treat the parasite trichomonas & then was used in the 1960s to treat other parasitic infections, like giardia and amoebiasis.
Read 14 tweets
1 Oct 20
When you order a serum alcohol level, what does the lab measure? An answer and a quick #Medtweetorial on false elevations in #ETOH
If you guessed NADH, you would be correct.
Most lab assays for serum alcohol utilize a reagent containing alcohol dehydrogenase & NAD+

This is used to convert all present ethanol to acetaldehyde

Thereby reducing present NAD+ to NADH.
Read 11 tweets
26 Sep 20
A Teal pain in the neck:

Follow along for a short #medtweetorial on #CervicalArteryDissection

or see the full handout here emboardbombs.com/s/Cervical-Art…

from @EMBoardBombs @blakebriggsMD @IltifatMD
This review will focus on spontaneous dissections, not traumatic, as well as the pathophys, risk factors, presentation, diagnosis, and management.

Cervical artery dissections are a common cause of stroke in young(<50 years )w/ some reports of up to 20% being from dissections
Much like aortic dissections, there is some loss of structure along the wall of either the internal carotid artery or vertebral artery

This allows blood to collect within the intima.

In patients <50 years old, cervical artery dissections account for 20% of ischemic strokes.
Read 24 tweets
26 Sep 20
Time for some #SpacedRepetition from @CPSolvers @DxRxEdu @rabihmgeha

Some chat recap #ClinicalPearls and bonus pearls from #VirtualMorningReport on Friday Sept 25th clinicalproblemsolving.com/morning-report…

Case by the brilliant @Rafameed Image
A 31-year-old M born and raised in Brazil w/ no PMH presented with a 3 mon history of worsening DOE, orthopnea, 7kg weight loss, abdominal distention, dry cough, and syncope

Base rate of disease for an ID case with @k_vaishnani and @Rafameed is very high
An interesting fact from @3owllearning : Depending on the clinical problems, the studies of disease probability for differential diagnosis often show 10 - 25% of cases are unexplained, even after careful examination and testing.
Read 17 tweets
22 Sep 20
We didn't have a #Neuro case today on @CPSolvers #VMR with @AaronLBerkowitz but don't worry! Let's recap a prior episode for some #SpacedLearning @DxRxEdu @rabihmgeha

With @ddeng_22 @KannuBansalMD

clinicalproblemsolving.com/morning-report…
A 26 yo M w/ a PMH of nodular sclerosing hodgkins lymphoma p/w left-sided facial droop, L arm weakness, and dysarthria.

He presented 12 hours after onset and his symptoms had resolved.

3 months prior he had an autologous stem cell transplant and is currently on Brentuximab.
First of remembering that E=MC2

Time of onset and localization

Sudden Onset: Think stroke, seizure, Todd's paralysis, toxic metabolic, migraine with aura

Localization: Brainstem ipsilateral face and contralateral body
Read 24 tweets

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