Exam 2 - Generalized Neuromuscular Disease

Question 1

what are the 4 classifications used for neuromuscular disease?

Answer 1

1. neuropathies
2. junctionopathies
3. myopathies
4. neuromyopathies

Question 2

in an animal with neuromuscular disease, will they be ataxic? paretic?

Answer 2

animal will have paresis/paralysis

NO ATAXIA

Question 3

T/F: motor neuron/neuromuscular disease should not affect proprioception

Answer 3

true

Question 4

to adequately see appropriate postural reactions in a patient with neuromuscular disease, you must what?

Answer 4

support the patient

Question 5

what clinical signs may be seen with muscular weakness of the pharynx, larynx, & esophagus in animals with neuromuscular disease?

Answer 5

dysphagia, dysphonia, megaesophagus, regurgitation, & weak gag reflex

Question 6

how do neurons die?

Answer 6

compression, ischemia, systemic metabolic disease, neuron-specific metabolic disease, infection, & toxicity

Question 7

what is neurapraxia? what are some examples?

Answer 7

reversible damage to the nerve & sheath

compression, stretch, & mild ischemia

Question 8

what is axonotomesis? what is the period of regrowth?

Answer 8

axonal degeneration with preserved sheath - regrowth at 1-2mm/day

Question 9

what is neurotomesis?

Answer 9

irreversible damage to the nerve & sheath

Question 10

what are the components of wallerian degeneration?

Answer 10

axonal degeneration, myelinolysis, phagocytosis, schwann cell proliferation, & axonal sprouting

Question 11

what process is represented on this histopathology sample?

Answer 11

demyelination

Question 12

how does neurotransmission fail at the presynaptic neuron?

Answer 12

disruption of vesicle docking or insufficient Ca

Question 13

how does neurotransmission fail at the synaptic cleft?

Answer 13

altered ACh degeneration

Question 14

how does neurotransmission fail at the postsynaptic neuron?

Answer 14

receptor damage, channel inactivation, & excitation-contraction decoupling

Question 15

what is an example of a neuromuscular disease that causes failure at the presynaptic neuron?

Answer 15

botulism

Question 16

what are examples of categories of how muscles get injured under inflammatory causes?

Answer 16

infectious or immune-mediated

Question 17

what are examples of categories of how muscles get injured under non-inflammatory causes?

Answer 17

systemic metabolic disease, myofiber-specific metabolic disease, toxins, & ischemia

Question 18

T/F: diffuse neuromuscular diseases can all look alike

Answer 18

true

Question 19

how are neuromuscular diseases diagnosed?

Answer 19

diagnosis of exclusion

Question 20

T/F: animals with diffuse LMN disease are weak & have decreased reflexes

Answer 20

true

Question 21

what is a type I myofiber type?

Answer 21

oxidative & slow

Question 22

what is a type II myofiber? type IIM?

Answer 22

type II - glycolytic & fast

type IIM - only in the first brachial arch going to the muscles of mastication (which certain diseases will take out)

Question 23

what is mentation like in animals with neuromuscular disease?

Answer 23

usually unaffected, but systemic or multifocal disease may alter consciousness

Question 24

what are the big differentials in a dog that is ‘bunny-hopping’?

Answer 24

hip dysplasia/orthopedic disease vs. neuromuscular disease

Question 25

what common clinical signs associated with gait are seen in animals with neuromuscular disease?

Answer 25

short-strided in all limbs (bunny hop), lameness, reluctance to walk & frequent sitting (more pronounced with exercise), & may collapse on one or more limbs when walking

Question 26

what common clinical signs associated with posture are seen in animals with neuromuscular disease?

Answer 26

limbs kept under trunk, distal joints may show excessive flexion/extension, trembling, & cervical ventroflexion in cats

Question 27

when localizing a lesion in neuromuscular disease, what is interpreted as far as clinical signs?

Answer 27

absence of signs of intracranial disease

absence of or minimal ataxia or postural reaction deficits

presence of - hyporeflexia, hypotonia, atrophy, & functional deficits attributable to weakness

Question 28

what makes up a LMN?

Answer 28

cell body within the CNS

axon within the PNS

Question 29

what is the structure of a spinal nerve?

Answer 29

dorsal & ventral branches with dorsal & ventral roots

Question 30

what is the order of events at the neuromuscular junction?

Answer 30

nerve impulse travels down the presynaptic neuron & enters through voltage gated calcium channels which trigger the release of neurotransmitters into the synaptic cleft

neurotransmitters bind to ligand gated channels on the post-synaptic neuron which create a post-synaptic potential and a nerve impulse

Question 31

if there is a lesion at C1-C5, what can you expect to see?

Answer 31

thoracic & pelvic limb hyperextension

Question 32

if there is a lesion at C6-T2, what can you expect to see?

Answer 32

thoracic limb hypoextension & pelvic limb hyperextension

Question 33

if there is suspected neuromuscular disease affecting all limbs, what can you expect to see?

Answer 33

hypoextension in both thoracic & pelvic limbs