Myelin disorders Flashcards
Oligodendrocytes are found in…and myelinate
CNS
several internodes
Schwann cells are found in …and myelinate
PNS
a single internode
What type of conduction occurs with myelination?
Saltatory conduction
- continuous conduction from one node of Ranvier to the next
What causes stress to demyelinated neurons
The use of large calibre Na channels to mediate conduction
Re-myelination will not occur if
the damage is due to intrinsic myelin defect
A cause of secondary myelin loss is
axonal loss
Function of astrocytes
Control permeability of BBB
Function of microglia
Macrophages of CNS
Destruction of myelin sheathes with preservation of the axons =
Demyelination
in demyelination there is the axon is
initially preserved
Dysmelination is
a genetic disorder of the formation or maintenance of myelin
MS transverse myelitis Neuromyelitis optics PML are all examples of
Dysmyelinating disorders
dysemelinaÒon in the pons causes
Locked in syndrome
MS is an inherited or acquired autoimmune disorder
acquired
MS is attributable to white or grey matter lesions
white
Radiology
fluffy spots
MS
Gross appearance of MS
acute
chronic
sharply circumscribed plaques in white matter
acute - pink or tan ( pink Is cute)
chronic - grey or glassy
- old ppl have grey hair + glasses
Acute microscopic features of MS
The things driving the myelin loss
- lymphocytes + macrophages
- loss of myelin + debris
Chronic microscopic features of MS
- less oligodendrocytes
- gliosis - astrocyte scar tissue
- macrophages filled w debris
- secondary axonal loss
might see remyelination
Does MS affect the CNS or PNS
CNS
What stain is used for myelin
Lugol fast blue
is MS more prevalent at poles or equator?
poles
Is MS more common in men or women?
women 2:1
TH ? are involved in MS
TH1 and 17
TH17 active …via…to become …
th17 activate microglia via IFNy to become macrophages
What is the best predictor of long term outcome of MS
Axonal loss detected in optic disc
swing flashlight to bad eye - pupil dilates
colour desaturation - pale optic disc
NO RED EYE
RED EYE =
Uveitis
Uhthoff’s phenomenon
Vision problems with MS
symptoms worsen with heat
What indicates active MS on MRI?
Gadolium enhancement
What can be detected in the CSF of a patient with MS?
Are these found anywhere else
Oligobands in CSF and plasma
should not be in both
What can be used to suppress trafficking and Th17 activity in MS?
IFN B1
Natalizumab targets… to frustrate….
targets vessels to frustrate lymphocyte trafficking
What is the function of mitoxantrone
Suppress lymphocyte proliferation
Once off inflammation of the spinal cord, bilateral / symmetrical
Transverse myelitis
Devic’s neuromyelitis Optics is caused by
Anti-aquaporin antibodies
AQP4 in brain
risk of recurrence with Acute disseminated encephalomyelitis?
0 -once off
20% risk of mortality though
Is actute necrotising haemorrhagic encephalomyelitis due to an autoimmune conditon?
No
due to immune complexes + complement activation
PML ?
JC virus latent infection in B cells, kidney and CNS
reactivation occurs in immnocompromised
Possible consequence of a vigorous correction of low serum sodium?
Central pontine myelinolysis aka osmotic demyelination syndrome
- locked in syndrome
Galactocerebroside B galactosidase deficiency
manifestation?
prognosis?
treat?
Krabbe disease
- auto recessive
- Rapid motor difficulties from 3-6 months
- die before age 2
- bone marrow transplant to replace microglia
Build up of sulfatides
deficient lysosomal arylsulfatase A - > metachromatic leukodystrophy
Galactosyl sphingosine and globoid cells
4 months old baby with motor difficulties
Krabbe’s disease
adrenoleukodystrophy is associated with an accumulation of ….
Very Long Chain Fatty Acids
What is the target of the MS antigen?
Mylein basic protein
