Cranial Neuropathy

Question 1

Trigeminal nerve disorders

Answer 1

Could be idiopathic trigeminal neuropathy
Or caused by neoplasia
Intracranial portion of CN V is susceptible to diseases that affect the brain

Question 2

Sensory signs for trigemnial neuropathy

Answer 2

Reduced / abnormal facial sensation
Reduced palpebral, corneal, lip pinch, nasal sensation

Question 3

Motor signs for trigeminal neuropathy

Answer 3

Atrophy of muscles of mastication
Masticatory muscles paresis/paralysis
Dropped jaw - with bilateral lesions*

Question 4

Idiopathic trigeminal neuropathy

Answer 4

Aka trigeminal neuritis
More common in dogs than cats
Acute onset of dropped jaw, drooling, abnormal facial sensation, mast muscle atrophy

Question 5

Other differentials for trigeminal neuritis I

Answer 5

Neoplasia - lymphoma
Infectious - rabies

Question 6

Diagnosing CN V neuritis

Answer 6

History, signs, work up
Negative for 2M antibody
MRI & CSF - trigeminal nerves may appear abnormal

Question 7

Treatment for CN V neuritis

Answer 7

Supportive therapy
Usually resolves without specific treatment

Question 8

Trigeminal neoplasia

Answer 8

Primary or secondary neoplasia
Lymphoma or nerve sheath tumor
Diagnosis in 50% of dogs w unilateral trigeminal neuropathy

Question 9

Facial nerve disorder causes

Answer 9

Metabolic
Neoplasia
Idiopathic facial nerve paralysis
Infectious
Trauma
(Facial nerve is closely associated with CN VII)

Question 10

Facial neuropathy clinical signs

Answer 10

Facial paresis or paralysis - lips, eyes, lack of ear movement
Parasympathetic - dry eye/nose
Sensory - medial surface of pinna, abnormal test

Question 11

Chronic facial neuropathy

Answer 11

Can see contraction of muscles, deviation TO the abnormal side

Question 12

Idiopathic facial nerve paralysis

Answer 12

Occurs in dogs & cats
Acute, unilateral, facial nerve paresis
Exam results would be consistent w unilateral facial nerve paresis

Question 13

Diagnosing idiopathic facial nerve paralysis

Answer 13

Rule out other causes
Otoscopic exam
MRI/CSF
Treat with artificial tears to prevent development of keratitis
Prognosis is usually good

Question 14

Otitis media/interna

Answer 14

Facial neuropathy can occur with otitis
Except vestibular signs
Can except horner’s syndrome esp in cats

Question 15

Hypothyroidism

Answer 15

Has been linked to facial, trigeminal and vestibular signs
May also cause a polyneuropathy
Common in older large breed dogs

Question 16

Clinical signs for hypothyroidism

Answer 16

May or may not have hypo clinical signs
Neuropathy of any of the nerves mentioned
Diagnosis should be compatible clin signs
Treat the hypo & prognosis should be fair to good

Question 17

Vestibular nerve disorders

Answer 17

Hypothyroidism
Neoplasia
Otitis media interna
Polyp
Idiopathic
Toxin
Often see vestibular dysfunction w intracranial disease

Question 18

Clinical signs of vestibular disease

Answer 18

Head tilt, leaning, rolling
Nystagmus
Circling - tight
Strabismus
Ataxia
Nausea

Question 19

Cochlear nerve disorders

Answer 19

Degenerative
Congenital hearing loss
Inflammatory - otitis
Toxins
- furosemide
- aminoglycosides
- chlorhexidine

Question 20

Cochlear clinical signs

Answer 20

Hearing loss
Conductive - failure of sound transmission through the inner ear - otitis media interna
Sensorineural - failure of sound transduction by organ of corti of failure of cochlear nerve - congenital deafness

Question 21

BAER

Answer 21

Brainstem auditory evoked response
Test of hearing/brainstem function
Performed awake or sedated
Can be sued to differentiate types of hearing loss

Question 22

Hypoglossal nerve disorders

Answer 22

Caused by neoplasia or inflammation

Question 23

Hypoglossal clinical signs

Answer 23

Paresis & paralysis of tongue - unilateral or bilateral
Difficulty prehanding food
Generally tongue deviates towards affected side