Neurocognitive Disorders & White Matter Disease Flashcards

1
Q

Are neurocognitive disorders (NCDs) developmental or acquired?

A

Acquired

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2
Q
  • Significant cognitive decline
  • Interfere with independence
  • Not due to delirium
  • Not due to other mental disorder
A

Major NCD

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3
Q
  • Moderate cognitive decline
  • Does not interfere with the independence
  • Not due to deliurium
  • Not due to other mental disorders
A

Minor NCD

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4
Q

What cognitive domains are specified by DSM-5 to be affected in NCD. (6)

A
  1. Complex attenuation
  2. Executive function
  3. Learning and memory
  4. Language
  5. Perceptual-motor
  6. Social cognition
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5
Q

How does delirium differ from other NCDs?

A
  1. Rapid onset (hours to days)
  2. Linked to medical condition, substance use, withdrawal, medications, etc
  3. May be acute (hours to days) or persistent (weeks to months)
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6
Q

What are the criteria for a diagnosis of delirium? (6)

A
  1. Rapid onset of impaired attention
  2. Rapid onset of lack of awareness of environment
  3. Change in at least one cognitive domain (memory, orientation, language, perception)
  4. Changes in sleep/wake cycle
  5. Changes in emotional state
  6. Worsening of behavioral problems in the evening
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7
Q

What are the symptoms of NCD due to Lewy Body Disease (LBD).

A
  1. Fluctuating cognition/attention/alertness
  2. Visual hallucinations (well-formed and detailed)
  3. Parkinsonian movement ~1 year after cognitive impairment
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8
Q

Is onset of NCD due to LBD prolonged or rapid?

A

Prolonged

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9
Q

Is onset of NCD due to AD prolonged or rapid?

A

Prolonged onset and gradual progression

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10
Q

What are the criteria for probable AD?

A
  • Evidence of AD genetic mutation, or…
  • All of the following:
    • Impairment in memory +1 other domain
    • Progressive gradual decline
    • No other possible etiology
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11
Q

What is dysmyelination?

A
  • Inability to complete the myelination or formation of abnormal dysfunctional white matter
  • Early manifestation in developmental window
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12
Q

What is demyelination?

A
  • Destruction of an already formed myelin sheath
  • Caused by complex etiological agents that are toxic to microenvironment
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13
Q

Is myelination a prenatal or postnatal process?

A

Postnatal

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14
Q

Over what time period is the most intensive myelination in humans?

A

0-2 years

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15
Q

What are leukodystrophies?

A
  • Group of genetic disorders affecting enzymes of lipid metabolism, which leads to white matter diseases
  • Typically affect peroxisomes, lysosomes, and mitochondria
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16
Q

Metachromatic Leukodystrophy (MLD) is caused by a loss of function mutation in what lysosomal enzyme? What is its normal function?

A
  • Arasulfatase A (ARSA)
  • Catalyzes the hydrolysis of sulfatides as part of the cerebroside biosynthetic pathway
17
Q

Which lipid type is significantly enriched in myelin?

A

Cerebroside

18
Q

What are the signs and symptoms of MLD?

A
  • Progressive motor and cognitive decline
  • Diffuse symmetric myelin abnormalities on MRI
  • Accumulation of intracellular sulfatide granules
19
Q

What two proteins account for ~80% of all proteins found in myelin?

A
  1. Myelin basic protein (MBP) (30%)
  2. Proteolipid proteins (PLPs) (50%)
20
Q

Where are the two PLP isoforms (PLP and DM20) encoded on the genome?

A
  • Single locus on X chromosome
  • Alternative splicing
21
Q

What is Pelizaeus-Merzbacher disease (PMD)?

A
  • All types of mutations at the PLP locus; gain of function duplications most common
  • White matter abnormalities (type of leukodystrophy)
  • Result in hypomyelination
22
Q

What are the symptoms of PMD?

A
  1. Muscle weakness
  2. Nystagmus
  3. Ataxia
  4. Seizures
23
Q

What is the most common demyelinating disease in the US?

A

Multiple sclerosis

24
Q

What are the symptoms of MS?

A
  1. Optic neuritis
  2. Muscle weakness
  3. Sensory loss
  4. Ataxia
25
Q

Explain relapse-remitting MS (RRMS)

A
  • Most common form of MS (>80% of cases)
  • Discrete episodes of exacerbation of symptoms followed by remission
  • Patients experience full or partial recovery in remissions
26
Q

Explain primary-progressive MS (PPMS)

A
  • 10-20% of cases
  • Gradual progression of MS over time
  • No relapses
27
Q

Explain progressive-relapsing MS (PRMS)

A
  • Rare
  • Presents initially as primary-progressive
  • Individuals suffer from exacerbated episodes followed by partial relapse
28
Q

Explain secondary-progressive MS (SPMS)

A
  • Late-onset development of primary-progressive after an extended period (2-40 years) of relapse-remitting
29
Q

How is MS diagnosed?

A
  • Mainly clinical
  • MRI for demyelinated foci in the brain
  • CSF fluid contains high IgG (still specific to MS though)
  • No single definitive genetic or pathological markers in LIVING patients
30
Q

What is Interferonβ (INFβ)?

A
  • Most commonly prescribed therapeutic for RRMS
  • Modulates the immune response to inflammation
31
Q

True or false. White matter is incapable of regeneration after it is destroyed

A

False. White matter can regenerate (aside from MS)

32
Q

What disease is classified as a deficiency in the aspartoacylase (ASPA) enzyme? What is the normal function of this enzyme?

A
  • Canavan disease
  • Hydrolysis of N-Acetyl Aspartate (NAA)
33
Q

At what locus is the ASPA gene located?

A

17p13

34
Q

What are some of the clinical features of Canavan disease? (8)

A
  1. Hypotonia in infancy
  2. Lack of head control
  3. Macrocephaly
  4. Seizures/epilepsy
  5. Visual abnormalities/blindness
  6. Failure to thrive
  7. Severe motor impairment
  8. Mental retardation
35
Q

Describe the neuropathology of Canavan disease

A
  1. Spongy change of lower parts of cortex, subcortical white matter, and cerebellar cortex
  2. Accumulation of fluid within myelin lamellae
  3. Disintegration of myelin sheaths
  4. Swollen astrocytes
  5. Severe vacuolation
36
Q

Why is Canavan disease a good candidate for gene therapy?

A
  • It’s a single gene disorder
  • Non-invasive markers of efficacy (NAA, myelin, diffusion tensor imaging)