neuropathology 1

Question 1

important considerations for sampling neuro tissue

Answer 1

◼ Take precautions to avoid zoonotic disease
◼ When to take brain and spinal cord!

Question 2

neurological disease lesion localization / categories

Answer 2

peripheral nerve disease
- neuritis (inflammation of peripheral nerve)
- neuronopathy, axonopathy, or myelinopathy
> degenerative, non-infectious, non-inflammatory
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spinal disease
- myelitis
- myelopathy
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brain disease
- encephalitis
- encephalopathy

Question 3

terminology
- -itis vs -opathy

Answer 3

◼-itis inflammation
◼-opathy degenerative process.

Question 4

what produces myelin?

Answer 4

substance produced by neurolemmocyte (Schwann
cell) or oligodendrocyte

Question 5

terminology
◼ Myelin-
◼ Myel-
◼ Neur-
◼ Neuron

Answer 5

◼ Myelin- substance produced by neurolemmocyte (Schwann
cell) or oligodendrocyte
◼ Myel- medulla/spinal cord (same prefix that is used for bones)
◼ Neur- nerve or nervous system
◼ Neuron- cell of nervous system

Question 6

Disease of the Nervous System - nature of patterns we see

Answer 6

◼ Follows general pathogenetic mechanisms of disease
◼ Has many exceptions.
◼ Exceptions can seem confusing

Question 7

Peripheral nerve ismade up of:

Answer 7

• Axons,
• Myelin sheaths
• Fibrous tissue > Endoneurium, Perineurium, Epineurium

Question 8

Peripheral Nervous System is comprised of:

Answer 8

Ganglia and nerves
except Cranial Nerves I and II

Question 9

what allows nerves to stretch?

Answer 9

they have ‘waves’

Question 10

how to take nerve sample

Answer 10

• take distal nerve
• take a little bit of cardboard (manilla folder, or paper plate)
  > make little cuts on the end, fold nerve into those cuts > it will hold and fix (see next page)
  > you can then write the name of the nerve on the cardboard, and that goes in the formalin jar

Question 11

peripheral nervous system - what part are permenant? what can regrow?

Answer 11

Neurons are permanent, axons regrow

Question 12

Trauma to peripheral Nerves - common examples

Answer 12

◼ Radial nerve paralysis
◼ Injections into sciatic nerve
◼ Calving paralysis (obturator nerve)
◼ Downer (or anesthetized) cow and horse
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Same kind of injury:
◼ Cervical spinal stenosis (cervical stenotic myelopathy, Wobbler)

Question 13

Trauma to nerve
- difference between mild, intermediate, severe injury

Answer 13

◼ Mild injury blocks conduction
◼ Intermediate injury leaves connective tissue intact
> damages axon, but it will eventually regrow
◼ Severe injury transects nerve

Question 14

Neuronal alterations in trauma, for body and axon

Answer 14

◼ Neuron cell body - central chromatolysis
◼ Axon - axonopathy (primary and secondary)

Question 15

Neuron Response to axonal injury - 3 things happen

Answer 15

• Central chromatolysis
• Swollen axon and myelin sheaths
• digestions chambers
  <><><><><><><>
  ◼ Axonal swelling and fragmentation
  ◼ Myelin sheath > Swelling
  ◼ Digestion chamber > monocytes - myelin macrophages

Question 16

drugs that are toxic to neurons

Answer 16

◼ Cisplatin
◼ Doxrubricin
◼ Organic mercury

Question 17

what vitamin deficiency is toxic to nerves

Answer 17

◼ Pyridoxine (Vit B6) deficiency or toxicosis

Question 18

Neuropathy;
Neuronopathy
> causes, target

Answer 18

◼ Drug toxicosis
> Cisplatin
> Doxrubricin
> Organic mercury
◼ Pyridoxine (Vit B6) deficiency or toxicosis
◼ Neuron cell body is target

Question 19

Neuropathy;
Primary Axonopathy
- what is this? causes?

Answer 19

◼ Also called ‘die back’ (where do you sample for this?)
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◼ organophosphate toxicosis
◼ laryngeal hemiplegia in horses
◼ diabetes mellitus

Question 20

Neuropathy
Primary demyelination
- causes

Answer 20

◼ Chronic lead toxicosis
◼ Acute polyradiculoneuritis (Coonhound
paralysis)
◼ Hypothyroidism
◼ Copper deficiency
◼ Immune mediated (MS)

Question 21

neoplasia of the peripheral nervous system

Answer 21

Nerve sheath tumor (NST)
◼ Neurolemmocyte (Schwann cell) tumor
◼ Neurofibroma
◼ Perineuroma
◼ Neurofibromatosis > multiple nerves affected, usually seen in cattle
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◼ Malignant NST
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◼ Ganglioneuroma
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Examples
◼ brachial plexus tumor of dogs
◼ neurofibromatosis of cattle