Monoparesis

Question 1

Monoparesis

Answer 1

Disease that affects a single limb
Diffuse diseases - neuropathy, NMJ & muscular disease
Cranial neuropathy

Question 2

Neuropathy

Answer 2

Disorder of neurons - cell body, axon, Schwann cells

Question 3

Myopathy

Answer 3

Disorder of muscle fibers

Question 4

Junctionopathy

Answer 4

Dysfunction of the neuromuscular junction

Question 5

Motor unit definition

Answer 5

Lower motor neuron
- cell body in ventral horn of SC
- axon & supporting structures
Neuromuscular junction
Muscle fibers
- all the myofibers that the neuron innervates

Question 6

Mononeuropathy

Answer 6

Focal/single peripheral nerve dysfunction
- radial neuropathy, sciatic neuropathy

Question 7

Multiple mononeuropathy

Answer 7

Multiple nerves of one limb affected, but no other limbs affected
- brachial plexus avulsion

Question 8

Polyneuropathy

Answer 8

Diffuse peripheral nerve dysfunction
Secondary to diabetes mellitus

Question 9

Paresis

Answer 9

Decreased voluntary movement
(Mono paresis is decreased voluntary movement of a single limb)

Question 10

Plagiarism

Answer 10

Absent voluntary movement (paralyzed)
Monoplegia is complete paralysis of a single limb

Question 11

Weakness

Answer 11

Loss of strength

Question 12

What causes monoparesis

Answer 12

Motor unit dysfunction
- LMN cell body
- axons of LMN
- NMJ
- muscle
Sensory dysfunction
Autonomic nerves/ganglia

Question 13

Possible neurological exam findings

Answer 13

Decreased movement of affected limb
Weakness in limb
Decreased sensory function
Normal & decreased reflexes
Atrophy of affected limb
Pain
Nerve root signature - lameness due to nerve root injury
Horner’s syndrome
Abnormal cutaneous trunci reflex

Question 14

Neurological disease

Answer 14

Decreased voluntary movement
Reflexes often reduced
Atrophy generally severe, occurs rapidly
Horner’s syndrome

Question 15

Orthopedic disease

Answer 15

Generally consistent in each stride
Orthopedic exam reveals abnormalities
Normal neurologic exam

Question 16

Autonomous zones

Answer 16

Area that is innervated by only one nerve
Also for sensory testing of that nerve
Not all nerves have autonomous zones
Testing by 2 step pinch

Question 17

Important nerves of brachial plexus

Answer 17

Suprascapular
Musculocutaneous
Radial
Median & ulnar
Lateral thoracic
Sympathetic nerves to head & neck

Question 18

Suprascapular
Spinal cord segments
Muscles innervated
Reflex affected
Muscle function loss
Cutaneous sensation
Signs of dysfunction

Answer 18

Spinal cord segments - C6-7
Muscles innervated - supraspinatus/ infraspinatus
Reflex affected - NA
Muscle function loss - shoulder extension
Cutaneous sensation - shoulder
Signs of dysfunction - little/limited gait abnormality ± shoulder abduction

Question 19

Musculocutaneous

Answer 19

Spinal cord segments - C6-8
Muscles innervated - biceps brachii, brachialis
Reflex affected - biceps; withdrawal (flexor)
Muscle function loss - elbow flexion
Cutaneous sensation - medial antebrachium/first digit
Signs of dysfunction - limited gait abnormalities, weak elbow flexion

Question 20

Radial

Answer 20

Spinal cord segments - C7-T2
Muscles innervated - triceps, extensor carpi radialis, digit extensors
Reflex affected - triceps, extensor carpi radialis
Muscle function loss - elbow extension, carpus ext, digit ext
Cutaneous sensation - cranial antebrachium & foot
Signs of dysfunction - loss of weight bearing, knuckling

Question 21

Median & ulnar

Answer 21

Spinal cord segments - C8-T2
Muscles innervated - superficial & DDF, carpal flexor
Reflex affected - withdrawals
Muscle function loss - carpus flexion, digit flexion
Cutaneous sensation - caudal antebrachium, foot, 5th digit
Signs of dysfunction - little gait abnormalities, mild carpus hyperextension

Question 22

Lateral thoracic

Answer 22

Spinal cord segments - T1-3
Muscles innervated - dilator of pupil
Reflex affected - pupillary light
Muscle function loss - pupil dilation
Cutaneous sensation - NA
Signs of dysfunction - miosis,

Question 23

Important nerves of lumbosacral plexus

Answer 23

Obturator
Femoral
Sciatic
Peroneal
Tibial

Question 24

Obturator

Answer 24

Spinal cord segments - L4-6
Muscles innervated - Pectineus, Gracilis
Reflex affected - NA
Muscle function loss - hip adduction
Cutaneous sensation - NA
Signs of dysfunction - limited gait abnormality

Question 25

Femoral

Answer 25

Spinal cord segments - L4-6 Muscles innervated - quadriceps group, psoas group Reflex affected - patellar Muscle function loss - stifle ext, hip flexion Cutaneous sensation - medial surface of limb & first digit Signs of dysfunction - loss of weight bearing

Question 26

Sciatic

Answer 26

Spinal cord segments - L6-S2 Muscles innervated - biceps femoris, semiM, semiT, cranial tibial, gastrocnemius Reflex affected - withdrawal, cranial tibial, gastrocnemius Muscle function loss - hip ext, stifle flex, hock flex & ext, digit flex & ext Cutaneous sensation - entire limb, except medial & 1st digit Signs of dysfunction - knuckling of paws & WB

Question 27

Peroneal

Answer 27

Spinal cord segments - L6-S2 Muscles innervated - cranial tibial Reflex affected - cranial tibial Muscle function loss - hock flex, digit ext Cutaneous sensation - craniolateral surface of limb, distal to stifle Signs of dysfunction - hyperextended hock, knuckled paw

Question 28

Tibial

Answer 28

Spinal cord segments - L6-S2 Muscles innervated - gastrocnemius Reflex affected - gastrocnemius Muscle function loss - hock ext, digit flexion Cutaneous sensation - caudal surface of limb, distal to stifle Signs of dysfunction - dropped hock

Question 29

Testing for neuromuscular disease

Answer 29

Signalment, history, exam/neuro exam CBC, chemistry (CK), urinalysis Thoracic radiographs, abdominal ultrasound

Question 30

Advanced testing for neuromuscular disease

Answer 30

Electrodiagnosis Muscle/nerve biopsy Advanced imaging - CT/MRI Cerebrospinal fluid sampling

Question 31

Nerve trauma

Answer 31

Focal - affecting single nerve - sciatic - radial Brachial plexus injury/avulsion

Question 32

Focal trauma

Answer 32

Sciatic - injection site, fractures to limbs, iatrogenic Radial - fractures

Question 33

Brachial plexus injury

Answer 33

Common in dogs & cats Usually secondary to motor vehicle accidents/falls Peracute onset - trauma Pathophys - traction injury - avulsion - ventral nerve root more susceptible than dorsal

Question 34

Pathophysiology of nerve injruy

Answer 34

Neuropraxia Axonotmesis Neurotmesis

Question 35

Neuropraxia

Answer 35

Transient interruption of nerve function, can last for days to months

Question 36

Axonotmesis

Answer 36

Separation of axon from cell body w degeneration of axon. Leads to Wallerian degeneration. Supporting structures remain intact (endoneurium, Schwann cells). Regeneration usually occurs but slowly

Question 37

Neurotmesis

Answer 37

Complete severing of axon, supporting structures. During regrowth, risk of a neuroma. Surgery rarely helpful. Recovery not likely.

Question 38

Localization and severity of localization

Answer 38

Exam, electro diagnostic like EMG Best clinical guideline is whether Nociception (pain sensation) is present Lack of pain sensation is poor prognostic indicator

Question 39

Nerve injury treatment & prognosis

Answer 39

Usually no specific treatment Occasionally with isolated nerve injury, surgery can be attempted, limb amputation may be recommended Intact nerves = better chance of functional recovery Severed nerves = grave prognosis

Question 40

Neoplasms

Answer 40

Nerve sheath tumors Lymphoma

Question 41

Peripheral nerve sheath tumors (PNST)

Answer 41

Signalment History - chronic, slowly progressive loss of limb function, muscle atrophy, pain, palpable mass Neoplasia - schwannoma, neurofibroma, malignant NST

Question 42

Diagnosing NST

Answer 42

Good exam palpation Systemic work up Radiographs Ultrasound CT/MRI Electro diagnostics

Question 43

NST treatment and prognosis

Answer 43

Pain management, surgery (location dependent) radiation, chemotherapy Guarded to poor Locally invasive rather than metastatic