Demyelinating Disorders Flashcards
What are components of myelin in the CNS that can be targeted by the immune system?
- Myelin Basic Protein - cytoplasmic side
- Proteolipid Protein - intramembranous
What is key in determining a diagnosis of Multiple Sclerosis?
Lesions in Time and Space
- different areas
- different ages
What are the demographics of patients who are diagnosed with MS?
- Temperate Climates
- Female
- 1st degree relatives who were diagnosed
What does the gross pathology look like in MS and where?
- Periventricular White Matter degradation - loss of white
- Optic Nerve and Chiasm
- Cerebellum
What is the difference between an active plaque and and inactive plaque?
Active - macrophages with myelin debris and immune cells
Inactive - minimal macrophages and other immune cells
— Both have Axon preservations —
Where are MS lesions almost always found?
– Periventricular
Who does Acute Disseminated Encephalomyelitis generally affect the most?
- Children
What might be the most likely diagnosis if perivenous demylination is found?
- Acute Disseminated Encephalomyelitis
What is a characteristic finding of ADEM on MRI?
- Generalized lesions throughout the white matter wide-spread “dissemination” - perivenular regions
What disorder is found to have antibodies to Aquaporin (AQP4)?
Neuromyelitis Optica
- attack the foot process of the astrocytes
When might you most common find ADEM manifest in a child?
Following a viral infection or vaccination
– due to cross reactive antibodies –
What are findings consistent with Neuromyelitis Optica?
- Neuritis of the optic nerve/chiasm (necrosis/inflammation)
- Longitudinal Spinal Cord Demyelinating Lesions
If a chronic alcoholic presents to the ED with severe hyponatremia and is rapidly infused with saline, what is he at risk for?
Central Pontine Myelinolysis
What are the clinical manifestations of central pontine myelinolysis?
Damage to the pons
- weakness in all extremities
- dysfunctional cranial nerves
- “locked in syndrome”
What cells are thought to be most responsible for Multiple sclerosis?
- CD4 T-cells autoreactive to self oligodendrocytes
- Myelin Basic Protein (MBP)
- Myelin Oligo Glycoprotein (MOG)
- Proteolipid Protein (PLP)
What are general characteristics that occur during the etiology of MS?
- Activation of CD4 cells
- Breakdown of BBB, allowing more immune infiltrates
- Demyelination at areas of infiltrate
What are common symptoms that occur at onset of MS, compared to symptoms during disease course?
- Sensory Distruptions
- Weakness
- Visual Loss
- -Weakness
- -Sensory
- -Ataxia
- -Bladder Dysfunction
What are the different modalities the disease course can present?
- Relapsing-Remitting – acute episodes, returns to baseline or gets worse after each attack (Most patients)
- Secondary Progressive – acute attacks with worsening baseline between and after each attack (From Relap-Remit)
- Primary Progressive – constant progressive without attacks
- Progressive-relapsing – constant progressing with attacks
Can you diagnose a patient with MS if they have focal clinical finding with single lesion identified on MRI?
– NO. Must be “dissemination in time and space”
They have to have another episode
What are clinical criteria used for diagnosing MS?
- Need >1 lesion on MRI and more than one attack, or suspicious history of previous attack
“Time and Space Disseminated”
How is Clinically Isolated Syndrome different from MS?
This is considered the FIRST clinical demyelinating event, predictive of development of MS
- if there is already one lesion = 88% chance of MS development
- if there are no lesions = 19% chance
What are the current treatments to treat MS?
For reducing symptoms and disability
- Interferon B – delays progression
If a patient develops acute vision loss and pain with movement of the eyes, what is the most concerning diagnosis?
– Demyelinating Optic Neuritis
What are the classic signs of Demyelinating Optic Neuritis?
- -Female 30s
- -Decreases acuity, color, and contrast vision
- -Pain with eye movements
For Demyelinating Optic Neuritis, do steriod change the long term prognosis?
Oral Prednisone – INCREASES RISK of Recurrance
- -IV Steroids – increase rate of recovery from the episode without increased rate of recurrance
- Most people fully recover without lasting deficits
What are benefits of giving IV Steroids to Demyelinating Optic Neuritis during an acute episode?
- -Decreases amount of time to recover
- -Short-term protective effect against MS
What are the risks associated with DON and MS?
- if DON does not have any MRI lesions = 25% Risk of MS
- if DON has at least 1 lesion = 72% Risk of MS
What is a common presentation for Acute Disseminated Encephalomyelitis?
– Multiple Neurologic deficits
– Children who are very ill, possibly coma
However, Prognosis is very good with steroid treatment
What is a unique characteristic of ADEM on imaging?
- -Multiple/extensive lesions in both hemispheres including grey matter involvement
- Histo –> Perivenous Demyelination/Inflammation
If a patient is experiencing electrical sensations in the arms due to neck movement and/or intermittent brief attacks of painful limb movement triggered by limb movement, what might be the cause?
Transverse Myelitis
- -Lhermitte Sign – electric sensations
- -Paroxysmal Tonic Spasms – extremities pain
What is the difference between complete and incomplete transverse myelitis?
- complete – most severe, more suggestive of infectious disorder
- incomplete – most suggestive of progressing to MS
- *Treat with high dose IV steroids if not infectious**
If a patient develops marked vision loss and an MRI finds scattered areas of demyelination in the optic nerves and longitudinal spinal lesion (3+ segments). What might be most likely diagnosis?
Neuromyelitis Optica
What might be a characteristic finding in Neuromyelitis Optica?
–Optic disc may appear swollen
– severe loss of vision, sometimes bilateral
++Aquaporin-4 IgG Antibody to Astrocyte foot processes
What is the difference between Neuromyelitis Optica and Demyelinating Opticneuritis?
Differences –
DON – Pain with eye movement, inflammation of optic nerve – not necessarily lesion there, IV steroids help, associated w/ MS
NMO – swollen optic disc, scattered dymyelination of optic nerves/SPINAL CORD involvement + Aquaporin Antibodies
