Cranial Nerve Examination and Differential Diagnosis Flashcards
What are the four stages evaluation of the cranial nerves can be divided into?
1 Assessment of symmetry of the face
2 Eyes (neurophthalmic examination)
3 Facial sensation
4 Gag reflex.
When a reflex is assessed, it will mostly evaluate the brainstem with…?
An afferent and efferent pathway
What change is seen in the following with forebrain lesion abnormalities:
A) Mental status?
B) Cranial nerves?
A) Altered mentation/change in behaviour
B) Contralateral lack of menace with normal PLR
What change is seen in the following with forebrain lesion abnormalities:
A) Posture/gait
B) Postural reaction?
A) Normal gait with poss abnormal posture
B) Contralateral deficits
What change is seen in the following with forebrain lesion abnormalities:
A) Spinal reflexes/muscle tone
B) Sensation
C) Other symptoms possibly seen? (2 - neuro)
A) Normal to increased contralaterally
B) Facial and body contralateral absent to decreased
C) Seizures/hemi-neglect syndrome
What change is seen in the following with brainstem lesion abnormalities:
A) Mental status?
B) Cranial nerves?
A) Altered
B) 3 - 12
What change is seen in the following with brainstem lesion abnormalities:
A) Posture/gait
B) Postural reaction?
A) Tetra/hemi paresis/plegia
B) Affected all 4 limbs/one side
What change is seen in the following with brainstem lesion abnormalities:
A) Spinal reflexes/muscle tone
B) Sensation
C) Other symptoms possibly seen? (not neuro!)
A) Normal to increased in all four limbs or ipsilaterally
B) Possible cervical hyperaesthesia
C) Poss cardiac/resp abnormailites
The two cranial nerves involved in the symmetry of the face are ?
trigeminal (CN V) and facial (CN VII) nerves.
The trigeminal nerve is sensory for the A) and motor for the B) through its mandibular branch.
A) entire face (cutaneous, cornea, nasal septum and oral cavity)
B) masticatory muscles
The facial nerve is innervating the A) of the face and sensory for the
A) muscles of the expression
B) rostral part of the palate and tongue.
Testing the palpebral reflex involves which nerves? (2)
facial (CN VII) and trigeminal (CN V) nerves.
Afferent nerve of the palpebral reflex?
Trigeminal (V)
Efferent nerve of the palpebral reflex?
Facial (VII)
The facial nerve has parasympathetic fibres supplying?
Lacrimal glands
Dysfunction of the facial nerve parasympathetic fibres can cause what? (2)
KCS (dry eye) and xeromycteria (dry nose)
PLR efferent pathway?
Oculomotor (III)
PLR afferent pathway?
Optic (II)
Aside from a lesion affecting the PLR pathways, the PLR can de decreased or absent in cases of? (3)
Iris atrophy
Drugs to dilate pupils
Light source of insufficient intensity.
Which nerves are involved in the menace response?
II and VII
How to perform a menace response?
The menace response is elicited by waving the hand toward one eye and blindfolding the other, creating a visual threat, the response is involving the awareness of the patient and should elicit the closure of the eyelid.
When is the menace response more reliable in cats?
When not blindfolded
Define nystagmus
Nystagmus is the involuntary rhythmic oscillation of the eyeball.
The extraocular muscles are controlled by which nerves? (3)
oculomotor nerve (CN III), trochlear nerve (CN IV), and abducens nerve (CN VI).
Physiological nystagmus can be elicited how?
moving the head from side to side and up and down.
When is pathological nystagmus seen?
At rest
However, in some cases no abnormal eye movement is seen at rest but can be observed if the vestibular system is challenged.
How could you then look for pathological positional nystagymus?
change the head position or have the patient on its back
How to assess facial sensation? (2)
Corneal reflex
Nasal stimulation
How to perfom the corneal reflex?
a damp cotton bud to touch the sclera of the eye and then evaluating closure of the eyelids and retraction of the globe.
Which nerves does the corneal reflex involve? (2)
ophthalmic branch of the trigeminal nerve (CN V)
facial nerve (CN VII)
In cases of involvement of the ophthalmic branch of the CN V when performing corneal reflex, what may occur? (2)
neuroparalytic keratitis and ulcerative keratitis
How to perform nasal stimulation; what are you looking for?
Cover eyes, applying a forceps to the nasal mucosa; observing withdrawal of the head which is cortically mediated
Afferent pathway of the nasal stimulation?
Ophthalmic branch of V
Why might nasal stimulation be reduced?
Ipsilateral trigeminal lesion
contralateral forebrain/cortical lesion as it involves the contralateral cerebral hemisphere.
The swallowing or gag reflex can be elicited by
applying gentle pressure on the larynx after opening the mouth.
Which nerves are assessed with gag reflex? (3)
IX (glossopharyngeal),
X (vagus),
hypoglossal (CN XII)
Normal response to gag reflex?
The patient will normally close its mouth, swallow, and lick its nose.
Dysphagia due to reduced gag reflex can be seen in patient with what types of conditions (2)
neuromuscular conditions
brainstem lesions
Dysphagia due to lack of gag reflex; increases morbidity how?
Increased aspiration pneumonia
The aim of the neurological examination is to
achieve a neuro-anatomical localisation
localisations are generally divided into: (3)
Intracranial (prosencephalon, brainstem and cerebellar)
Spinal (C1-C5, C6-T2, T3-L3, L4-S2)
Neuromuscular system.
3 subdivisions of intracranial localisation?
prosencephalon,
brainstem
cerebellar)
The list of differential diagnoses is formulated based on: (4)
Signalment
Onset
Progression
Response to possible therapies tried.
what does VITAMIN D stand for for your D/Dx?
Vascular
Inflammatory
Trauma or Toxic
Anomalous
Metabolic
Idiopathic
Neoplastic
Degenerative.
C1 - C5 spinal cord segment lesions; escribe the abnormalities with:
A) Mental status?
B) Cranial nerves?
C) Posture/gait? (3)
A) Normal
B) Normal; possible ipsilateral horners
C) Tetraparesis
Hemiparesis/hemiplegia
Possible torticollis/scoliosis
C1 - C5 spinal cord segment lesions; describe the abnormalities with:
A) Proprioception?
B) Spinal reflex/muscle tone
C) Sensation?
A) All 4 limbs affected/ipsilateral side affected
B) Normal - increased in all 4 limbs
C) Poss cervical hyperaesthesia
C1 - C5 spinal cord segment lesions; wat “other” non defined signs may be seen? (4)
Persistent scratching on neck and shoulder
Respiratory difficulty
Nerve root signature
Urinary incontinence
What is nerve root signature
Neurogenic lame
C6- T2 spinal cord segment lesions; describe the abnormalities with:
A) Mental status?
B) Cranial nerves?
C) Posture/gait?
A) Normal
B) Normal; possible ipsilateral horners
C) Tetraparesis
Hemiparesis/hemiplegia
C6- T2 spinal cord segment lesions; describe the abnormalities with:
A) Proprioception?
B) Spinal reflex/muscle tone
C) Sensation? (3)
A) All 4 limbs affected/one side affected
B) Decreased in one or both thoracic limb and normal to increased in pelvic limbs
C) Possible hyperaesthesia at the level of the lesion
Possible reduced to absent sensation caudal to the lesion
Cutaneous trunci reflex depressed or absent (unilaterally or bilaterally)
C6- T2 spinal cord segment lesions; wat “other” non defined signs may be seen?
Urinary retention
T3 - L3 spinal cord segment lesions; describe the abnormalities with:
A) Mental status?
B) Cranial nerves?
C) Posture/gait? (3) Thoracic limbs?
A) Normal
B) Normal
C) Thoracic limbs unaffected
Paraparesis/plegia
Kyphosis
Schiff-Sherrington posture possible
T3- L3 spinal cord segment lesions; describe the abnormalities with:
A) Proprioception?
B) Spinal reflex/muscle tone
C) Sensation? (3)
A) One or both pelvic limbs affected
B) Normal in the thoracic limbs and normal to increased in the pelvic limbs
C) Possible hyperaesthesia at the level of the lesion
Possible reduced to absent sensation caudal to the lesion
Cutaneous trunci reflex depressed or absent (unilateral or bilateral)
T3- L3 spinal cord segment lesions; what “other” non defined signs may be seen?
Urinary incontinence
L4 -S2 spinal cord segment lesions; describe the abnormalities with:
A) Mental status?
B) Cranial nerves?
C) Posture/gait? (1) Thoracic limbs?
A) Normal
B) Norm
C) Thoracic limbs unaffected, paraparesis/plegia
L4 - S2 spinal cord segment lesions; describe the abnormalities with:
A) Proprioception?
B) Spinal reflex/muscle tone
C) Sensation? (3)
A) One or both pelvic limbs affected
Decreased muscle tone
B) Unaffected in thoracic limbs
Decreased in the pelvic limbs
C) Possible hyperaesthesia at the level of the lesion
Possible reduced to absent sensation caudal to the lesion
L4 - S2 spinal cord segment lesions; what “other” non defined signs may be seen? (5)
Urinary and faecal incontinence
Nerve root signature
Lameness
No perineal tone and sensation
Tail paresis-paralysis Decreased sensation of tail
A lesion in which spinal cord segments may cause ipsilateral Horner’s syndrome?
C1- C5
C6-T2
If spinal reflexes are decreased in the thoracic limbs and increased in the pelvic limbs, which spinal cord segment is affected?
C6 - T2
Which spinal cord segment is affected in an animal with pareparesis and decreased spinal reflexes in the pelvis limbs?
L4 - S2
In an animal presenting in Schiff-Sherrington posture, which spinal cord segment is affected?
T3 - L3
Neuromuscular lesions; what abnormalities are seen with:
A) Mental status
B) Cranial nerves
C) Posture/gait
A) Normal
B) Poss deficits of 7, 9, 10
C) Flaccid tetraparesis/plegia
Neuromuscular lesions; what abnormalities are seen with:
A) Proprioception
B) Spinal reflexes/muscle tone
C) Sensation
A) Deficits on affected limbs
B) Decreased to absent in affect limbs
C) Decreased to absent nociception and sensation
What non neuro signs might be seen with neuro muscular lesions?
Self mutilation
D/Dx that are neuroVascular (3)
Hemorrhagic myelopathy
Ischemic myelopathy / fibrocartilaginous embolism
Acute non compressive nucleus pulposus extrusion
D/Dx that are Inflammatory and Infectious (6)
Discospondylitis
Spinal empyema
Bacterial meningo-myelitis
Neospora / Toxoplasma / Crytococcus myelitis
Feline coronavirus meningo-myelitis (FIP)
distemper meningomyelitis
D/Dx that are Inflammatory and non-Infectious (3)
Meningomyelitis
Meningoencephalitis of unknown origin
Steroid-responsive meningitis-arteritis
D/Dx that is due to Trauma (4)
Spinal trauma (vertebral fracture -luxation)
Traumatic disc extrusion
Spinal cord contusion
Brachial and lumbar plexus avulsions
D/Dx that are neuro Toxic (2)
Tetanus
Botulism
D/Dx that are anomalous? (9)
Atlantoaxial instability and subluxation
Arachnoid cysts/pseudo-cysts
Constrictive myelopathy and associated articular facet dysplasia
Chiari-like malformations and syringomyelia / hydromyelia
Dermoid sinus
Spina bifida/meningomyelocoele
Vertebral malformation and associated kyphosis / scoliosis / lordosis
Globoid leukodystrophy
Mucopolysaccharidosis type 1/ VI
D/Dx that are Metabolic (nutritional) (2)
Hypervitaminosis A
Nutritional secondary hyperparathyroidism
D/Dx that are Idiopathic (4)
Idiopathic facial neuropathy
Idiopathic trigeminal neuropathy
Idiopathic vestibular syndrome
Idiopathic epilepsy
D/Dx that are Neoplastic (7)
Spinal meningiomas
Peripheral nerve sheath tumours
Spinal lymphoma
Vertebral body tumour
Vertebral plasma cell tumour
Spinal ependymomas
Neuroepithelioma
D/Dx that are Degenerative (5)
Degenerative myelopathy
Afghan Hound myelopathy
Motor neuron disease in German Shepherds
Hereditary ataxia
Rottweiler leukoencephalomyelopathy
D/Dx that are Structural / Compressive Degenerative Disorders (9)
Calcinosis circumscripta
Cervical spondylomyelopathy (disc associated wobbler syndrome or osseous associated wobbler syndrome)
Constrictive myelopathy
Foraminal Stenosis
Intervertebral disc degeneration and extrusion (Hansen type I) or protrusion (Hansen type II)
Degenerative lumbosacral stenosis
Osteochondromatosis
Spondylosis deformans
Spinal synovial cysts
