Localization And Differentiation Of Neurologic Dz p107-130

Question 1

When assessing muscle tone in a recumbent animal, what does flexing of the limbs reveal?

Answer 1

In normal animals, repeated flexion is accompanied by an increase in tone in the flexed limb. The limbs of animals with a LMN lesion remain flaccid.

Question 2

List the components of the afferent and efferent reflex arc of myotatic reflexes.

Answer 2

Afferent: muscle spindles (stretch detectors), sensory fibers in the peripheral nerve, dorsal nerve root and ganglion, connection from sensory nerve fiber to LMN in ventral horn of same spinal cord segment

Efferent: LMN, ventral nerve root, motor fibers in peripheral nerve, NMJ and muscle being tested

Question 3

Is this describing an upper motor neuron or a lower motor neuron?

Body in brain and axons that terminate at synapses within the brain or spinal cord; lesions have normal to increased reflexes, variable severity of weakness, variable increased muscle tone (spasticity)

Answer 3

Upper motor neuron

Question 4

Is this describing an upper motor neuron or a lower motor neuron?

Body in nuclei of CN in the brain stem or ventral horn grey matter of the spinal cord and axons exiting CNS coursing with the peripheral or cranial nerves and terminate at NMJs; lesions cause decreased spinal reflexes, ataxia, moderate to severe weakness, decreased muscle tone and rapid, pronounced atrophy of the denervated muscles

Answer 4

Lower motor neuron

Question 5

What is posture and what are some abnormalities that can be seen?

Answer 5

Posture refers to the position of the body and head in space. Head tilt, circling and head turn are some abnormalities seen. These most often occur toward the direction of the lesion.

Question 6

If hopping and hemiwalking are seen to be abnormal on the ipsilateral side of the lesion, where could the lesion be localized to?

Answer 6

Skeletal muscle, peripheral nerves, spinal cord, medulla oblongata

Question 7

If hopping and hemiwalking are abnormal contralateral to the lesion, where might the lesion be located?

Answer 7

Midbrain or forebrain

Question 8

Where are lesions located that produce mild to moderate proprioceptive and postural deficits in the contralateral limbs?

Answer 8

Rostral to the medulla oblongata

Question 9

Where are lesions located that produce severe proprioceptive and postural deficits in the ipsilateral limbs?

Answer 9

In the medulla oblongata or the spinal cord

Question 10

What are examples of dementia?

Answer 10

Head pressing, compulsive walking, frequent yawning, loss or absence of innate behaviors

Question 11

What clinical signs are suggestive of lesions in the limbic system of the forebrain? The limbic system is an assembly of interconnected neurons in the brain involved in emotional response and patterns of behavior.

Answer 11

Hyperexcitability, rage, mania, exaggerated fear, frantic motor activities

Question 12

What is the ascending reticular activating system responsible for? What is it’s relationship with the cerebral cortex?

Answer 12

The ARAS of the brain stem is the source of mental alertness. Important in maintaining the animals level of consciousness and arousal. Cerebral cortex determines the content of consciousness and the ARAS determines the level of consciousness.

Question 13

If there is a lesion unilateral retina/optic nerve, what would the menace response be ipsilateral and contralateral?

A) Absent, Absent
B) Absent, Present
C) Present, Absent
D) Present, Present

Answer 13

B) Absent (ipsilateral), Present (Contralateral)

Question 14

If there is a lesion bilateral retina, optic nerve, optic chiasm, what would the menace response be ipsilateral and contralateral?

A) Absent, Absent
B) Absent, Present
C) Present, Absent
D) Present, Present

Answer 14

A) Absent (ipsilateral), Absent (contralateral)

Question 15

If there is a lesion unilateral occulomotor nerve, what would the menace response be ipsilateral and contralateral?

A) Absent, Absent
B) Absent, Present
C) Present, Absent
D) Present, Present

Answer 15

B) Absent (ipsilateral), Present (contralateral)

Question 16

If there is a lesion unilateral occipital cortex, what is the menace response ipsilateral and contralateral?

A) Absent, Absent
B) Absent, Present
C) Present, Absent
D) Present, Present

Answer 16

C) Present (ipsilateral), Absent (contralateral)

Question 17

If there is a lesion bilateral occipital cortex, what would the menace response be ipsilateral and contralateral?

A) Absent, Absent
B) Absent, Present
C) Present, Absent
D) Present, Present

Answer 17

A) Absent (ipsilateral), Absent (contralateral)

Question 18

If there was a lesion bilateral vagosympathetic trunk, what would the menace response be ipsilateral and contralateral?

A) Absent, Absent
B) Absent, Present
C) Present, Absent
D) Present, Present

Answer 18

D) Present (ipsilateral), Present (contralateral)

Question 19

If there was a lesion bilateral cerebellar cortex, what would the menace response be ipsilateral and contralateral?

A) Absent, Absent
B) Absent, Present
C) Present, Absent
D) Present, Present

Answer 19

A) Absent (ipsilateral), Absent (contralateral)

Question 20

If there was a lesion unilateral retina/optic nerve, what would the PLR be ipsilateral and contralateral?

A) Absent, Normal
B) Fixed, Normal
C) Mydratic, Normal
D) Miotic, Normal

Answer 20

A) Absent (+/- slightly dilated, ipsilateral), Normal (contralateral)

Question 21

If there was a lesion bilateral retina/optic nerve/optic chiasm, what would the PLR be ipsilateral and contralateral?

A) Absent, Absent
B) Fixed, Fixed
C) Mydratic, Normal
D) Miotic, Normal

Answer 21

B) Fixed (ipsilateral), Fixed (Contralateral)

Question 22

If there was a lesion unilateral occulomotor nerve, what would the PLR be ipsilateral and contralateral?

A) Absent, Absent
B) Fixed, Fixed
C) Mydratic, Normal
D) Miotic, Normal

Answer 22

C) Mydratic (nonresponsive, ipsilateral), Normal (contralateral)

Question 23

If there was a lesion unilateral occipital cortex, what would the PLR be ipsilateral and contralateral?

A) Absent, Absent
B) Normal, Normal
C) Mydratic, Normal
D) Miotic, Normal

Answer 23

B) Normal (ipsilateral), Normal (contralateral)

Since this is a reflex, no processing is needed or response. The light reaches the chiasm, and does not need input from the cortex.

Question 24

If there was a lesion bilateral occipital cortex, what would the PLR be ipsilateral and contralateral?

A) Absent, Absent
B) Normal, Normal
C) Mydratic, Normal
D) Miotic, Normal

Answer 24

B) Normal (ipsilateral), Normal (contralateral)

Question 25

If there was a lesion bilateral vagosympathetic trunk, what would the PLR be ipsilateral and contralateral?

A) Absent, Absent
B) Fixed, Fixed
C) Mydratic, Normal
D) Miotic, Normal

Answer 25

D) Miotic (ipsilateral), Normal (contralateral)

Question 26

If there was a lesion bilateral cerebellar cortex, what would the PLR be ipsilateral and contralateral?

A) Absent, Absent
B) Normal, Normal
C) Mydratic, Normal
D) Miotic, Normal

Answer 26

B) Normal (ipsilateral), Normal (contralateral)

Question 27

If an animal has a unilateral vestibular disorder, how does strabismu present in the ipsilateral and contralateral eye?

A) Ventral, Lateral
B) Lateral, Ventral
C) Dorsal, Ventral
D) Ventral, Dorsal

Answer 27

D) Ventral (ipsilateral), Dorsal (contralateral)

Question 28

What is the vestibular system composed of?

Answer 28

Sensory structures in the inner ear, vestibular portion of CN VIII, central components in the medulla oblongata and cerebellum.

Question 29

If there are lesions in the vestibular portion of the medulla oblongata, how do these differ from lesions in the vestibular portion of the cerebellum?

Answer 29

Lesions in the medulla oblongata would result in central vestibular signs, where lesions in the cerebellum would result in paradoxical vestibular signs.

Question 30

Where does the sympathetic innervation from the head come from? Lesions along these fibers can cause Horner syndrome, which manifests as what?

Answer 30

Nerve fibers that innervate the head come from the first three thoracic spinal cord segments. Horner syndrome manifests as miosis, ptosis, and increased heat on the ipsilateral side of the face.

Question 31

Match the following manifestations of nerve function with their corresponding nerve.

CN III, CN IV, VI

A) Ventrolateral strabismus
B) Medial strabismus
C) Dorsomedial strabismus

Answer 31

A) Ventrolateral strabismus seen with CN III dysfunction
B) Medial strabismus seen with CN VI dysfunction
C) Dorsomedial strabismus seen with CN IV dysfunction

Question 32

Distinguish the difference between lesions distal to the optic chiasm (optic nerve, retina, globe) to lesions proximal/central to optic chiasm.

Answer 32

Lesions distal to the optic chiasm produce ipsilateral visual deficits.
Lesions proximal/central to the optic chiasm produce contralateral visual deficits.

Question 33

Localize the lesion with the following manifestations: flaccidity and muscular atrophy of the tail and anus, paraphimosis, urethral sphincter is dilated, causing continuous dripping of urine.

A) T2 - L2
B) L3 - L6
C) S1 - S2
D) S3 - Cd5

Answer 33

D) S3 - Cd5

Animal is unable to defecate and unable to evacuate the bladder

Question 34

Localize the lesion with the following manifestations: bladder dissension and flaccidity, urine may drip continuously

A) T3 - L2
B) L3 - L6
C) S1 - S2
D) S3 - Cd5

Answer 34

C) S1 - S2

Animals can also have LMN efferent and proprioceptive afferent lesions to the hind legs, resulting in paraparesis or paraplegia.

Question 35

Localize the lesion with the following manifestations: urinary bladder distention, large residual volume, urethral sphincter is intact, urine is only voided when the intravesicular pressure exceeds the sphincter.

A) T3 - L2
B) L3 - L6
C) S1 - S2
D) S3 - Cd5

Answer 35

B) L3 - L6

Animals with this lesion can also have deficits in the LMN efferent and general proprioceptive afferent to the hind limbs. These animals may also have paraparesis or paraplegia.

Question 36

Localize the lesion with the following manifestations: paraparesis and ataxia in the pelvic limbs, intermittently assuming a dog-sitting position, urinary plodder distended, residual volume large, urethral sphincter normal, rarely seen Schiff-Sherrington syndrome with front legs in extension (hypertonic of thoracic limbs)

A) C1 - C5
B) C6 - T2
C) T3 - L2
D) L3 - S2

Answer 36

C) T3 - L2

Question 37

Localize the lesion with the following manifestations: flaccidity and hyporeflexia of the thoracic limbs, hypertonic and hyperreflexia of the pelvic limbs, voluntary control of urination is poor or absent, posturing for urination is difficult, urinary bladder is large and has large residual volume

A) C1 - C5
B) C6 - T2
C) T3 - L2
D) L3 - S2

Answer 37

B) C6 - T2

These animals may have a reduction in perception of painful stimuli in all four limbs. If the lesion involves white, not grey matter, there is no thoracic limb hypotonia. If the lesion is in T1 - T3 grey matter, may see Horner syndrome (miosis, ptosis, and ipsilateral heating of the head/neck)

Question 38

Which of the following localizations CANNOT cause the following clinical signs: quadriparesis and hemiparesis

A) Midbrain
B) C1 - T2 spinal cord segments
C) Forebrain
D) Medulla oblongata

Answer 38

C) Forebrain
Lesions of the forebrain do not produce appreciable paresis and ataxia when the animal is walking in a straight line on level surface; but contralateral subtle proprioceptive and postural reaction deficits are present.

Question 39

Which of the following lesion localizations CANNOT cause the following clinical signs: dysphonia, inspiratory dyspnea, dysphagia, neurologic atrophy of the trapezius, sternocephalicus and brachiocephalicus muscles.

A) CN VIII
B) CN IX
C) CN X
D) CN XI

Answer 39

A) CN VIII does not contribute to dysphagia, dysphonia or stridor.

Roaring and stridor are common chief complaints by o. Roaring is most commonly seen on peak inspiration, due to idiopathic left recurrent laryngeal neuropathy.

Question 40

Which lesion localization is responsible for these clinical signs in ruminants: ruminal distention with fluid, ruminal tympani, abomasal stasis, +/- hypochloremic, hypokalemic metabolic alkalosis

A) CN VIII
B) CN IX
C) CN X
D) CN XI

Answer 40

C) CN X - lesions of the visceral efferent component of the vagus nerve causes vagal indigestion in ruminants

Question 41

Loss of or reduced sensory perception on the face, unilateral, can be caused by damage to all of following EXCEPT:

A) Contralateral forebrain disease
B) Peripheral portion of the trigeminal nerve
C) Vestibulocochlear nerve
D) Trigeminal ganglion isn’t he personal bone or its connections to the pons

Answer 41

C) CN VIII lesions do not contribute to loss of sensory perception in the face

Question 42

When distinguishing cerebellar disorders, which of the following is NOT a common finding:

A) Hypermetria or hypometria
B) A lateralized lesion causing signs on the contralateral side of the body
C) Postural placements within normal limits
D) Intention tremors

Answer 42

B) A lateralized lesion causing signs on the IPSILATERAL side of the body can be a manifestation of cerebellar disease, however, this disease is more commonly bilaterally symmetric.