PNS, neuropath, neurocytology Flashcards
1
Q
segmental demyelination
A
- happens in schwann cells
- could be dysfunction (m. or sensory neuropathy) or acquired damage (Guillain-Barre)
- axon intact; purely problem w/ myelination
- peripheral n. will try to remyelinate; onion bulbs in CS
2
Q
grouped atrophy
A
- happens when m. fibers lose their innervation
- atrophic fibers look small and angular
- seen in ALS, traumatic injury
3
Q
Wallerian degeneration
A
- happens to the distal portion of a transected n.
- axon begins to break down; schwann cells start to destroy myelin and engulf the axon fragments
- macrophages to the area
4
Q
what happens to the proximal portion of a transected n.?
A
- degeneration for 2-3 distal internodes
- undergoes regenerative activity
5
Q
Guillain-Barre syndrome
A
- active inflammatory demyelinating polyradiculoneuropathy
- ascending paralysis; areflexia
- can be caused by vaccinations
6
Q
Charcot-Marie-Tooth
A
- autosomal dominant demyelinating disease
- kids or young adults
- ascending demyelination but generally only below the knee
- pes cavus = key finding; atrophy will set in; progressive paralysis
7
Q
Lambert-Eaton syndrome
A
- ds of NMJ; can be presentation of small cell lung carcinoma
- proximal m. weakness
- inc. NCS w/ repetitive stimulation
8
Q
mature neurons do not …?
A
- DIVIDE!
- loss of neurons w/ age
- CNS neurons don’t regenerate over long distances
- infarcts that transect internal capsule = permanent motor deficits
9
Q
neuromelanin
A
- located in substantia nigra
- locus coeruleus
- CNVI
- median raphe
- highly eosionophilic granular appearance
10
Q
chromatolysis
A
- damage to neuron
- injured neuron swells = nissl substances to periphery = nucleus becomes eccentric
11
Q
histo characteristics of prion disease
A
- seen in creutzfeld-jacob disease
- spongiform encephalitis = holes make it look like a sponge
- neurons very atrophied; become hyperchromatic
12
Q
histo changes in CMV
A
- would see clear ‘halos “ around nuclei
13
Q
histo changes in rabies
A
- cytoplasmic “Negri body”
- looks like RBC
14
Q
astrocytes
A
- star shaped glial cells
- stain w/ GFAP or silver = will look eosinophilic
- found in gray and white matter; act as BBB
15
Q
most important histo indicator of CNS injury?
A
- astrocytosis aka reactive gliosis
- 12h - 2d after injury; result in glial scar
