Neuroscience Week 2: Myelin Disorders Flashcards

1
Q

MS pathophysiology

A

lymphocytes infiltrate and attack myelin and oligodendrocytes leading to demyelination and later axonal degeneration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

MS Etiology

A

unknown but is thought to be influences by genetic and environmental factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Histology Hallmarks of MS

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Potential pathophysiology of MS

5 listed

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Histology of MS

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

MS IHC staining

A
  • stain for active microglia
  • acute lesions have active microglia
  • chronic lesions don’t have active microglia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Diagnosis of MS

A

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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Confirmatory tests MS

4 listed

A
  • 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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Signs and Symptoms of MS

6 main systems

A
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

MS Babinski

A

positive Babinski and hyper reflexia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Types of MS and most common

4 listed

A
  • Relapsing Remitting MS (RRMS) (most common)
  • Secondary Progressive MS (SPMS)
  • Primary Relapsing MS (PRMS)
  • Primary Progressive MS (PPMS)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Medications to Treat MS

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Neuromyelitis Optica AKA

A

Devic’s Disease

or

NMO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Neuromyelitis Optica Description

A

Inflammatory CNS demyelinating disorder involving the bilateral optic neuritis and spinal cord demyelination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Neuromyelitis Optica Forms and commonality

A

2 forms

Relapsing (most common)

&

Monophasic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Neuromyelitis Optica Relapsing form epidemiology

A
  • effects mostly Asians, Africans and Native Americans
  • 8,000 NMO patients in the US
  • 80% are women
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Neuromyelitis Optica Pathogenesis

A

The disease is characterized by the presence of antibodies against aquaporin-4 the major water channel of astrocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Neuromyelitis Optica Signs and symptoms

A
  • loss of vision
  • weakness and numbness of arms and legs
  • paralysis
  • difficulty controlling the bladder and bowels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Neuromyelitis Optica Vs MS

A

aquaporin-4 antibodies which is the major water channel in astrocytes affecting mostly the optic nerve and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Neuromyelitis Optica Treatment

A

plasmapheresis and depletion of b cells with humanized anti-CD20 antibody (Rituximab)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Acute Disseminated Encephalomyelitis Description

A

Monophasic autoinflammatory CNS demyelinating disorder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Acute Disseminated Encephalomyelitis AKA

A

ADEM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

ADEM AKA

A

Acute Disseminated Encephalomyelitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Encephalomyelitis

A

inflammation of the brain and the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Proposed Acute Disseminated Encephalomyelitis Pathogenesis

A

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)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Acute Disseminated Encephalomyelitis Epidemiology

A

1/100,000 and affects mostly young and adolescent children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Acute Disseminated Encephalomyelitis Signs and Symptoms

A
  • loss of vision
  • ataxia
  • paralysis
  • some patients develop drowsiness and coma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Acute Disseminated Encephalomyelitis Treatment

A

anti-inflammatory and immunosuppressive agents

prognosis is generally favorable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Acute Disseminated Encephalomyelitis

AHLE

A
  • is less common
  • the hyperacute and frequently fatal form of ADEM with perivenular demyelination and diffuse hemorrhagic CNS necrosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Progressive Multifocal Leukoencephalopathy AKA

A

PML

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Progressive Multifocal Leukoencephalopathy Description

A

severe demyelinating disease of the CNS due to lytic infection of oligodendrocytes by the ubiquitous opportunistic polyoma (papova) virus JC (JCV)

32
Q

Progressive Multifocal Leukoencephalopathy Epidemiology

A

most cases occur in patients with AIDS, cancer and inflammatory disorders and organ transplant recipients

immunosuppressed patients

33
Q

Progressive Multifocal Leukoencephalopathy

A

PML begins with small demyelinating foci and the confluence of these foci results in large irregular white matter lesions that involve the cerebrum, cerebellum and brainstem

34
Q

Progressive Multifocal Leukoencephalopathy Signs and Symptoms

A

PML is characterized by a variety of neurological defects

  • Visual loss
  • paralysis
  • disorientation
  • dementia

Majority of patients die in a few months

35
Q

Progressive Multifocal Leukoencephalopathy Diagnosis

A

PML is diagnosed with

CSF test for JV virus DNA by PCR

or

brain biopsy to look for demyelination / enlarged oligodendrocyte nuclei

36
Q

Landry-Guillain-Barre Syndrome AKA

A

GBS

or

idiopathic polyneuritis

37
Q

Landry-Guillain-Barre Syndrome Epidemiology

A

the most common form of acute inflammatory peripheral neuropathy 8,000 cases/year in the US

The most common form of GBS in the US is the acute inflammatory demyelinating polyneuropathy (AIDP)

38
Q

Landry-Guillain-Barre Syndrome the most common form of GBS in the US?

A

The most common form of GBS in the US is the acute inflammatory demyelinating polyneuropathy (AIDP)

39
Q

Landry-Guillain-Barre Syndrome Description

A

polyneuritis - inflammation of the peripheral nerves both motor and sensory

Autoimmune-mediated demyelination of the peripheral nerves that appears 2-4 weeks after viral or allergic reaction

40
Q

Landry-Guillain-Barre Syndrome Histology

A

Nerves infiltrated by lymphoid cells with phagocytosis of myelin by macrophages (axons are not damaged)

41
Q

Landry-Guillain-Barre Syndrome Signs and Symptoms

A

Ascending muscle weakness

symmetric hyporeflexia and paralysis

in many cases there is respiratory paralysis but most patients recover

42
Q

Landry-Guillain-Barre Syndrome Treatment

A
  • plasmapheresis and IV-IgG
  • Remyelination occurs over 3-4 months because peripheral nervous system can remyelinate
43
Q

Metachromatic Leukodystrophy AKA

A

MLD

44
Q

Metachromatic Leukodystrophy Description

A

Lysosomal storage disease caused by deficiency of sulfatide sulfohydrolase (sulfatidase, arylsulfatase A)

45
Q

Metachromatic Leukodystrophy Epidemiology

A

Inherited with Autosomal Recessive trait

Incidence 1:50,000

more prevalent in Habbanites Jews (1:75) and Navajos (1:2500)

46
Q

Metachromatic Leukodystrophy Forms

A

The disease presents in three forms of varying severity

Late infantile (60%) - most severe and die in a few years

Juvenile (20%)

Adult (20%)

47
Q

Metachromatic Leukodystrophy clinical Features

A
  • blindness
  • loss of speech
  • decreased intellectual functions
  • peripheral neuropathy
  • seizures
48
Q

Metachromatic Leukodystrophy Pathophysiology

A

Extensive demyelination of CNS and PNS axons

sulfatides accumulate inside OLs, Schwann Cells and Macrophages

they cause metachromasia

49
Q

Metachromatic Leukodystrophy Deficiency

A

Sulfatide Sulfohydrolase

causes accumulation of sulfatides

50
Q

Metachromatic Leukodystrophy Treatment

A
  • There is no effective treatment
  • HSCT has been shown to be beneficial
51
Q

Metachromatic Leukodystrophy Histology

A

MRI T2 areas of demyelination that are diffuse, also are symmtric

LFB staining of brain white matter has no myelin

Cresyl-Violet staining of white matter deep brown is sulfatides from acidic color change

TEM Schwann cells have a lot of lysosomes with high amounts of sulfatides

52
Q

Globoid-Cell Leukodystrophy AKA

A

GCL

or

Krabbe’s Disease

53
Q

Globoid-Cell Leukodystrophy Description

A

Lysosomal storage disease caused by a deficiency of ß-galactosidase or galactosylceramidase

54
Q

Globoid-Cell Leukodystrophy Epidemiology

A

Autosomal recessive disease

incidence in US 1:100,000

55
Q

Globoid-Cell Leukodystrophy Genetics

A

inherited with an autosomal recessive pattern

56
Q

Globoid-Cell Leukodystrophy Pathophysiology

A

Galactose-sphingosine or psychosine accumulates in the white matter of psychosine (galactosylsphingosine) which is toxic to oligodendrocytes

57
Q

Globoid-Cell Leukodystrophy Pathological Hallmark

A

presence of globoid cells, which are large, globe-shaped, PAS-positive, multinucleated macrophages

58
Q

Globoid-Cell Leukodystrophy Histology

A

PNS demyelination with the accumulation of galactocerebroside in Schwann Cells and macrophages

&

Hallmark

presence of globoid cells, which are large, globe-shaped, PAS-positive, multinucleated macrophages

59
Q

Globoid-Cell Leukodystrophy Treatment

A

There is no treatment and typically die

60
Q

Globoid-Cell Leukodystrophy Clinical features

A

the classic form of Krabbe’s Disease appear normal at birth but rapidly develop irritability, spasticity and progressive disease

61
Q

Adrenoleukodystrophy AKA

A

Classical ALD

or

X-linked ALD

62
Q

Adrenoleukodystrophy Description

A

severe demyelination and inflammation caused by mutations in ABCD1 gene located on the X-chromosome that codes for ALD protein which transports VLCFas into the peroxisome for ß-oxidation

63
Q

Adrenoleukodystrophy Etiology

A

caused by mutations in ABCD1 gene located on the X-chromosome that codes for ALD protein which transports VLCFas into the peroxisome for ß-oxidation

VLCFAs (cholesteryl esters) accumulate (toxic buildup) in many organs particularly the brain WM, testes and adrenal cortex

64
Q

Adrenoleukodystrophy Clinical Features

A

onset (6-10) with rapid deterioration

visual loss

ataxia

spasticity

adrenal insufficiency

65
Q

Adrenoleukodystrophy Treatment

A

There is no effective treatment to prevent demyelination but the administration of Lorenzo’s Oil and BMT have only minor effects

66
Q

Adrenoleukodystrophy AMN

A

Adrenomyeloneuropathy is a milder clinical variant of ALD characterized by adrenal insufficiency and progressive muscle weakness. also has later onset and better prognosis

67
Q

Charcot-Marie-Tooth Disease Description

A

Hereditary motor and sensory neuropathy Schwann cells cannot myelinate axons of peripheral nerves

68
Q

Charcot-Marie-Tooth Disease AKA

A

CMT

69
Q

Charcot-Marie-Tooth Disease Epidemiology

A

one ofthe most inhewrited neurological disorders affecting approximately 1:2,500 people in the US

70
Q

Charcot-Marie-Tooth Disease Variants

A

CMT-1A

CMT-1B

CMT-X

71
Q

CMT-1A

A

Autosomal dominant caused by duplication of PMP22 gene on chromosome 17

72
Q

CMT-1B

A

Autosomal dominant disorder caused by point mutation on P0 gene on chromosome 1

73
Q

CMT-X

A

caused by point mutations on Connexin 32 gene on X-chromosome

74
Q

Charcot-Marie-Tooth Disease Histological hallmark

A

CMT is characterized by segmental demyelination of peripheral nerves with incomplete remyelination and “onion bulb” formation

75
Q

Charcot-Marie-Tooth Disease Clinical Features

A

weakness of the foot and lower leg muscles as well as foot and hand deformities