Neuroscience Week 2: Myelin Disorders Flashcards
MS pathophysiology
lymphocytes infiltrate and attack myelin and oligodendrocytes leading to demyelination and later axonal degeneration
MS Etiology
unknown but is thought to be influences by genetic and environmental factors
Histology Hallmarks of MS
the presence of demyelinated plaques in the brain WM (most localized around the ventricle), spinal cord and optic nerves that can either be active or inactive
Potential pathophysiology of MS
5 listed
Histology of MS
2 types of lesions
Acute inflammatory lesions
lymphocytes and macrophages have crossed blood brain barrier and demyelination around it
myelin staining LFB, myelin is reduced around the vein but intact further away
Chronic lesions are hypocellular with no evidence of active demyelination
MS IHC staining
- stain for active microglia
- acute lesions have active microglia
- chronic lesions don’t have active microglia
Diagnosis of MS
mostly clinically
- presence of signs/symptoms referable to CNS separated in time (more than one event) and space (more than one CNS area involved)
Confirmatory tests
- MRI (Gd-enhanced T1 MRI (acute lesions) and T2 MRI (chronic lesions))
- CSF Analysis (High IgG content and oligoclonal bands are present)
- Evoked potential studies (Abnormal VER and SSER)
Confirmatory tests MS
4 listed
- MRI Gd-enhanced T1 for Acute lesions (Gadolinium enhanced)
- MRI T2 for chronic lesions
- CSF analysis (high IgG content and oligoclonal bands present) typically the IgG is not in the serum but is in the brain
- Evoked potential studies (Abnormal VER and SSER) visual evoked potentials takes longer for signal (light shined in the eye) to transduce
these tests are sensitive but not specific
Signs and Symptoms of MS
6 main systems
- unilateral optic neuritis, changes in vision, double vision, nystagmus
- cognitive impairment (deficits in attention, reasoning and executive function)
- Muscle weakness, stiffness and painful spasms, bladder dysfunction, erectile impotence, constipation
- uncoordinated limb movement and gait ataxia
- Pain and Fatigue
- Temperature sensitivity and exercise intolerance
MS Babinski
positive Babinski and hyper reflexia
Types of MS and most common
4 listed
- Relapsing Remitting MS (RRMS) (most common)
- Secondary Progressive MS (SPMS)
- Primary Relapsing MS (PRMS)
- Primary Progressive MS (PPMS)
Medications to Treat MS
Neuromyelitis Optica AKA
Devic’s Disease
or
NMO
Neuromyelitis Optica Description
Inflammatory CNS demyelinating disorder involving the bilateral optic neuritis and spinal cord demyelination
Neuromyelitis Optica Forms and commonality
2 forms
Relapsing (most common)
&
Monophasic
Neuromyelitis Optica Relapsing form epidemiology
- effects mostly Asians, Africans and Native Americans
- 8,000 NMO patients in the US
- 80% are women
Neuromyelitis Optica Pathogenesis
The disease is characterized by the presence of antibodies against aquaporin-4 the major water channel of astrocytes
Neuromyelitis Optica Signs and symptoms
- loss of vision
- weakness and numbness of arms and legs
- paralysis
- difficulty controlling the bladder and bowels
Neuromyelitis Optica Vs MS
aquaporin-4 antibodies which is the major water channel in astrocytes affecting mostly the optic nerve and spinal cord
Neuromyelitis Optica Treatment
plasmapheresis and depletion of b cells with humanized anti-CD20 antibody (Rituximab)
Acute Disseminated Encephalomyelitis Description
Monophasic autoinflammatory CNS demyelinating disorder
Acute Disseminated Encephalomyelitis AKA
ADEM
ADEM AKA
Acute Disseminated Encephalomyelitis
Encephalomyelitis
inflammation of the brain and the spinal cord
Proposed Acute Disseminated Encephalomyelitis Pathogenesis
appears to be caused by molecular mimicry of
viral infections (mumps, measels, varicella, rubella)
or
Bacterial infection (chlamydia, rickettsia)
or
vaccinations (mumps, rabies, pertussis, rubella)
Acute Disseminated Encephalomyelitis Epidemiology
1/100,000 and affects mostly young and adolescent children
Acute Disseminated Encephalomyelitis Signs and Symptoms
- loss of vision
- ataxia
- paralysis
- some patients develop drowsiness and coma
Acute Disseminated Encephalomyelitis Treatment
anti-inflammatory and immunosuppressive agents
prognosis is generally favorable
Acute Disseminated Encephalomyelitis
AHLE
- is less common
- the hyperacute and frequently fatal form of ADEM with perivenular demyelination and diffuse hemorrhagic CNS necrosis
Progressive Multifocal Leukoencephalopathy AKA
PML