Multiple Sclerosis Flashcards
What is MS?
Presumed autoimmune demyelinating disorder of the central nervous system
What is the prevalence of MS?
Affects >400k people in the US, but is thought to be underestimated
Lifetime risk is 0.1- 0.2%
What is Charcot’s Triad of MS?
Nystagmus, intention tremor and scanning speech
Who is the stereotypical patient that gets MS?
younger females, 20-50 yrs old of northern european descent that live farther from the equator (lower vitamin D levels)
Females: Males is 2:1 or 3:1
What is the genetic contribution to MS?
There is a genetic component -certain HLAs and SNPs increase risk- but it is not a genetic disease
What three factors influence the onset of MS?
Genetics, germs, and geography
What is the pattern of symptoms seen in MS?
The disease is characterized by clinical relapses (new neurological signs/symptoms lasting more than 24 hours) due to CNS demyelination followed by remission (complete or partial improvement of symptoms
Over time, patients develop progressive symptoms without clear clinical relapses or new lesions
What are some optic syndromes highly suggestive of MS?
Optic neuritis (Decreased monocular vision, Often involving central vision,,Pain with eye movement Decreased red/green color, Clinically associated with an afferent pupillary defect (APD or Marcus-Gunn pupil),Uhthoff phenomeon (heat intolerance) “Hot bath test”)
What is a Marcus Gunn Pupil?
Afferent pupillary defect- Marcus Gunn pupil is a medical sign observed during the swinging-flashlight test whereupon the patient’s pupils constrict less (therefore appearing to dilate) when a bright light is swung from the unaffected eye to the affected eye. The affected eye still senses the light and produces pupillary sphincter constriction to some degree, albeit reduced.
What are some brainstem syndromes highly associated with MS?
Internuclear ophthalmoplegia (MLF lesion) Oculomotor dysfunction Ataxia Trigeminal Neuralgia Facial nerve palsy CST/upper motor neuron involvement
What are some spinal cord syndromes associated with MS
Partial myelopathy
Lhermitte’s “sign” (electric shock sensation with the neck flexed)
Numbness/sensory level
Deafferented hand
Urinary urgency, incontinence, erectile dysfunction (do not occur with GBS—commonly misdiagnosed)
Progressive asymmetric spastic paraplegia
How is MS diagnosed?
Diagnosis rests on the objective demonstration of CNS white matter lesions—based on clinical and radiographic grounds—that are disseminated in time & space for which there is no better alternative diagnosis
What test confirms MS?
There is no single test that “confirms” MS—it is ultimately a clinical diagnosis with radiographic corroboration
What are the four typical MS lesions seen on MRI?
Juxtacortical, periventricular, GdE, and infratentorial
How large is a typical MS lesions?
< 3mm
What characteristic lesions seen on MRI are pathognomonic for MS?
Dawson’s fingers
Where do MS spinal cord lesions tend to appear?
Spinal cord lesions are usually small (< 1/2 vertebra), and located in the cord periphery, especially the dorsal columns.
What is the white cell count in someone with MS?
Usually low- some patients experience a white count of up to 50 mm3
How are CSF protein levels affected by MS?
rarely > 100/dL
High levels are associated with cord inflammation
How is glucose affected by MS?
Glucose levels are normal
What’s the role of oligoclonal bands in teh diagnosis of MS?
Not mandatory for diagnosis but highly tested…
increased oligoclonal bands. Lots of disease processes lead to an increase in oligoclonal bands though..
how is IgG affected by MS/
IgG levels are elevated
What are some ddx’s for MS?
Neuromyelitis Optica, Acute disseminated Encephalomyelopathy (ADEM), Progressive multifocal Leukoencephalopathy (PML)
What clinical features help differentiate MS from neuromyelitis optica?
MS has unilateral optic neuritis
NMO has bilateral optic neurities
What lesions are seen on imaging for NMO (neuromyelitis optica)
Longitudinally extensive spinal cord lesions. with normal or minimal brain lesions
WHat is acute disseminated encephalitis (ADEM)?
Think of it as a bad, one time experience of MS.
Often a post-infectious process that commonly presents with HA, vomiting, dizziness, and meningism. Affects kids more than adults.
How do ADEM lesions appear on MRI?
Large, “fluffy” multifocal lesions
What is the cause of progressive multifocal leukoencephalopathy?
PMl is caused by opportunistic infections such as the JC virus. It is commonly seen in patients with HIV (often a presenting symptom)
Can lead to death or severe neurologic injury
PML can be a rare side effect of what?
Taking the drug natalizumab (for MS) in people who are also JC virus positive
What is the primary goal in treatment of MS?
Reduce the rate of relapse –> make life as “normal” as possible
What are very important considerations when choosing treatment for someone with MS?
-Side effect profile
Long term safety profile
Will the patient take the medicine?
What is the preferred tx for a relapse in MS?
IV steroids, (also oral prednisone, but IV steroids on exam)
ACTH
Plasmapharesis
IVIG
What is the most important tool for diagnosing MS?
Clinical suspicion. MRI corroborates, but clinical suspicion is the most important.
