Abnormal Neurologic Examination Flashcards
Demented
- Inappropriate response to a normal stimuli
Disoriented
- Lost in space
Depressed
- Behaviorally seems dull
Obtunded
- Severe depression and dullness
Stuporous
- Only responds to deep pain
Comatose
- Nonresponsive and does not respond to deep pain
Describe decerebrate rigidity
- Opisthotonos
- Extensor rigidity of all limbs
- Stupor or coma***
- +/- respiratory problems
- +/- heart rate and blood pressure problems
Where does decerebrate rigidity localize to?
- Midbrain** (thalamus and pons)
- Midbrain controls reticular activating system
- Alarm of wakeup for the cortex
- Cerebrum doesn’t get any input from the rest of the body
- Controls blood pressure, breathing, etc.
What can happen with breathing during decerebrate rigidity?
- Hyperventilation
Decerebellate rigidity appearance
- Opisthotonus
- Extensor rigidity of thoracic limbs +/- pelvic limbs
- Aware of the environment**
- Other cerebellar signs like intention tremors
Where does decerebellate rigidity localize?
- Cerebellum
What is the primary way to differentiate decerebrate and decerebellate?
- Decerebellate are aware of the environment, and decerebrate are not
Schiff Sherrington appearance
- Extensor rigidity of thoracic limbs
- NO opsithotonus
WHat causes Schiff Sherrington?
- Lack of inhibition to the extensors of thoracic limbs (border cells)
Where is the lesion usually with Schiff Sherrington?
- T3-L3 lesion
- UMN paraplegia
Can you use Schiff Sherrington as a prognostic indicator?
- NO
Head turn description
- Nose is deviated to one side or the other
Localization of lesion with head turn
- Supratentorial lesion
Where is the lesion most of the time with a head turn?
- Towards the side of the head turn
Head tilt description
- Head is tilted without deviation of the nose
Localization of head tilt
- Cerebellar or vestibular
- Usually towards the size of the lesion
- Paradoxical head tilt is away from the side of the lesion
Describe paradoxical head tilt
- Away from the side of the lesion
- Caudal cerebellar peduncle
- Flocculonodular lobe of the cerebellum
Cerebellar lesion features
- Head tilt (paradoxical)
- Nystagmus/ocular tremors
- Falling/wide-based stance
- Hypermetrix ataxia
- Circling
- Intention tremors
- Menace deficit (ipsilateral) but visual
- Rebound phenomenon
- Decerebellate rigidity
- Elevated 3rd eyelid, pupillary dilation, enlarged palpebral fissure
- Increased urination
- NO CP deficits or paresis
Should a dog with a cerebellar lesion have CP deficits?
- NO
Appearance of eyes with cerebellar lesions?
- Elevated 3rd eyelid
- Pupillary dilation
- Enlarged palpebral fissure
Menace with cerebellum
- present/absent?
- What side?
- Are they visual or not?
- Menace deficit (ipsilateral) but visual
Vestibular lesion features
- Head tilt
- Nystagmus
- Falling/wide-based stance/rolling
- Ataxia
- Circling
- Head tremors and eyelid contraction secondary to nystagmus
- Positional strabismus
- +/- CP deficits or paresis (>ipsilateral)
Where does a positional strabismus generally localize?
- vestibular lesion
Type of ataxia with cerebellar lesion?
- Hypermetric ataxia
What is rebound phenomenon?
- Elevate the head put out of orientation, they fall down
- Normally the dog should just put their head down normally
What are the two locations for vestibular lesions?
- Central (supratentorial or infratentorial)
- Peripheral (inner ear)
What are four ways to differentiate a central vestibular lesion from a peripheral lesion?
- Vertical nystagmus*
- Changing nystagmus*
- CN deficits other than 7 or 8**
- CP deficits
What CN deficits can you see with a peripheral vestibular lesion?
- CN 7 and 8
Case:
Right head tilt
Vertical nystagmus
Right hemiparesis
- Right sided central vestibular
Case:
Left head tilt
Vertical nystagmus
Right hemiparesis
- Right sided central vestibular/cerebellar with paradoxical head tilt
If you have contradicting left and right central vestibular signs what should you go with?
- Go with the side of the paresis
- Remember you can have a paradoxical head tilt
Type of circling with cerebellar and infratentorial vestibular lesion?
- Usually tight circles
Type of circling with supratentorial vestibular lesion?
- Usually bigger circles
Direction of circles in general?
- TOWARDS the side of the lesion
Kyphosis
- Dorsal curvature of the spine
Scoliosis
- Lateral curvature of the spine
Dfdx for scoliosis
- Painful or denervated on one side
Dfdx for ventral neck flexion
- neck pain
- Myopathy/neuropathy
- Myasthenia gravis
- Thiamine deficiency
- Hyperthyroidism
- Organophosphate toxicity
- Ethylene glycol toxicity
- Electrolyte abnormalities
Which electrolyte abnormalities associated with ventral neck flexion?
- K
- Na
- Ca
- Phosphate
Abnormal gaits associated with neurologic disease (also orthopedic disease!)
- Lameness
- Ataxia
- Dysmetria - hypermetria
- Increased step distance
- Decreased step distance
- Paresis
What is the nerve root signature?
Appearance and significance
- Intermittent packing of the limb and crying
- Should rule out a nerve root tumor
Ataxia definition
- Lack of an axis
- Failure of muscle coordination
Three types of ataxia
- Vestibular ataxia
- Cerebellar ataxia
- Proprioceptive/sensory ataxia
Vestibular ataxia appearance
- Falling/leaning
Cerebellar ataxia appearance
- Hypermetria
- Disease of cerebellum or spinocerebellar tracts of the spinal cord
Proprioceptive/sensory ataxia appearance
- Wide-based, crossing over, swaying; dz in CP pathway
Where is the lesion with cerebellar ataxia?
- CEREBELLUM or spinocerebellar pathways (spinal cord)
Definition of step distance
- Distance between the 2 thoracic limbs or 2 pelvic limbs when both are on the floor
What does increased step distance indicate?
- UMN lesion
What does decreased step distance indicate?
- LMN lesion or pain
Describe the two parts of the 2 engine gait
- Decreased step distance in the front (LMN)
- Increased step distance in the pelvic limb (UMN)
Where does a 2 engine gait localize?
- C6-T2
- LMN in the front and UMN in the hind
Paresis Description
- Weakness at gait
What causes paresis?
- partial loss of voluntary movement
- Deficiency in the generation of gait
- Deficiency in the ability to support weight
Clinical manifestations of paresis
- Slow or shuffling gait
- Dragging/ knuckling of the dorsum of the paw
- Collapse/falling
- Exercise intolerance/fatigability
- unable to support weight
- Other: difficulty rising
- inability to jump/climb stairs
- Unable to maintain squatting position to urinate or defecate
- Increased ROM - stiff/stilted gait
- Bunny hopping
What is this the definition for?
Weakness in both pelvic limbs
- Paraparesis
What is this the definition for?
Weakness in all four limbs
- Tetraparesis
What is this the definition for?
Weakness in the thoracic and pelvic limbs on one side
- Hemiparesis
What is this the definition for?
Weakness in one limb
- Monoparesis
How should you classify paresis further?
- Ambulatory or non-ambulatory
What is this the definition for?
No voluntary motor
- Plegia
Sitting position that suggests CP deficits in both pelvic limbs
- Sit on their caudal thigh muscles like people
What is central cord syndrome?
- CP deficits in the thoracic limbs more severely
What does central cord syndrome suggest?
- More disease in the central core of the spinal cord
Where are the thoracic tracts relative to the pelvic tracts in the spinal cord?
- The pelvic tracts are more lateral
What is happening with reflexes and muscle tone during a clonic event?
- Hypertonia and hyperreflexia
To review again with UMN lesions:
- Reflexes?
- Muscle tone?
- Atrophy type and progression?
- Reflexes are hyperreflexic or normoreflexic
- Hypertonia/stiff to normal tone
- Disuse atrophy - slow and less severe
To review again with LMN lesions:
- Reflexes?
- Muscle tone?
- Atrophy type and progression?
- Hyporeflexia/areflexia
- Hypotonia/flaccid
- Neurogenic atrophy (acute and severe)
If you find a cut-off on a cutaneous reflex, where is the lesion?
- Lesion is 1-2 spinal cord segments cranial to the cutoff
What if cutaneous trunci reflex is absent on one side regardless of where you pinch?
- Efferent problem on that side (C8-T1 spinal cord segments and nerve roots, lateral thoracic nerve, or cutaneous trunci)
- More likely peripheral nerve or C8-T1 because there’s where cutaneous trunci afferent nerves go
Vertebral body associated with the last rib?
- T13
WHat spinous process is perpendicular to the last rib?
- L2
Brachial plexus avulsion appearance
- Efferent or lateral thoracic nerve on the left side
- Dog can’t extend the elbow
- Left thoracic limb can’t extend elbow or bear weight
Neuro exam findings associated with optic nerve deficit?
- Menace deficit (and avisual)
- Absent/decreased PLR
- Mydriasis
Neuro exam findings associated with oculomotor nerve deficit?
- Ptosis (droopy upper eyelid)
- Ventrolateral resting strabismus
- Mydriasis from parasympathetic CN3 dysfunction
Sympathetic dysfunction signs (i.e. Horner’s syndrome)
- elevated third eyelid
- Ptosis
- Miosis
- Enopthalmosis
What is the most common singular sign of Horner’s in SA?
- MIosis
In a large animal, what is the most common single sign of Horner’s?
- Ptosis
Describe the pathway for sympathetic innervation that is often disrupted with Horner’s syndrome? (1st, 2nd, and 3rd order cell body locations)
- 3rd order cell body: cranial cervical ganglion (goes through inner ear to brain and eye)
- 2nd order cell body (pre-ganglionic): T1-2 spinal cord segments (runs cranially as vagosympathetic trunk)
- 1st order cell body: hypothalamus (hypothalamus to brainstem to cervical spinal cord to T1-T2)
1st order neuron for sympathetic innervation to the eye route
- Hypothalamus –> down brain stem –> down spinal cord
2nd order neuron for sympathetic innervation to the eye route
- T1-T2 spinal cord segments - -> travels cranially with vagosympathetic trunk to the neck
3rd order neuron for sympathetic innervation to the eye route
- Cranial cervical ganglion –> through the tympano-occipital fissure into the inner ear –> travels into the ventral floor of the brain –> exit skull through orbital fissure
Five things that have sympathetic innervation within the eye and what happens when they lose innervation?
- Dilator muscles of the pupil (miosis)
- Periorbital smooth muscles (enophthalmos)
- Third eyelid (elevated)
- Eyelid/Muller’s muscle (ptosis)
- Blood vessels within and around the eyes
What is the word for this definition?
- Unequal pupil size
- Anisocoria
What are causes of miosis (constricted pupil)?
- Increased parasympathetic tone (pilocarpine or severe cerebrocortical disease)
- Decreased sympathetic (Horner’s syndrome)
- Primary ocular (corneal ulcer and uveitis)
- Spastic pupil syndrome - FeLV/FIV
What are causes of mydriasis (dilated pupil)?
- Decreased parasympathetic (atropine, CN3 dysfunction)
- Increased sympathetic (phenylephrine)
- Primary ocular (blindness, glaucoma, iris atrophy)
- Cerebellar disease (mydriasis)*
Trochlear nerve dysfunction examination findings
- which eye is impacted?
- CONTRALATERAL* ventromedial resting strabismus
- Superior oblique pulls eye medially normally, so without it, the eye rolls laterally
- Y of the retinal vessels is tilted in the fundus in dogs
- In cats, the pupils are tilted
Type of strabismus in a cat with CN IV dysfunction
- Ventromedial strabismus
- Vertical pupils
Type of strabismus in a horse with CN IV dysfunction
- Ventrolateral strabismus
- Horizontal pupils
If you have a cat with ventromedial strabismus in the left eye, where is the lesion?
- Right CN IV
Abducent nerve dysfunction examination findings
- Ventromedial or medial resting strabismus because you lose the lateral rectus
Which cranial nerves cause resting strabismus?
- 3, 4, and 6
Which CN causes positional strabismus?
- CN VIII
Where are the issues potentially with decreased facial sensation (reflex and response)?
- CN V
- CN VII
- Contralateral cortex
What should you think of with a severe atrophy of the temporalis muscle?
- mandibular branch of CN V dysfunction
- Mostly due to a nerve sheath tumor
Where is the dysfunction with a dropped jaw?
- BILATERAL*** Mandibular branch dysfunction (CN5)
Which CN is associated with neurotropic keratitis?
- CN5
Why does CN5 dysfunction lead to neurotropic keratitis (2 primary reasons)?
- Lack of eyeball and eyelid sensation due to ophthalmic and maxillary dysfunction –> reduce blinking –> corneal drying
- Lack of proper corneal nutrition due to ophthalmic branch dysfunction –> corneal necrosis
CN 7 clinical signs
- Facial nerve paralysis (acute
- Also hemifacial spasm (peracute or chronic)
Causes of facial paralysis (and two most common)?
- Idiopathic*** (must rule out other causes)
- Inner/middle ear disease*
- Hypothyroidism (always recommend a T4)
- Trauma
- Neoplasia - brainstem level of in the nerve peripherally
- Polyneuropathy
What are two causes of hemifacial spasm?
- Irritated CN7 (initially)
2. result of chronic CN7 paralysis (fibrosis of muscles)
In a horizontal nystagmus, where is the slow phase of the nystagmus away from/towards the lesion/
- TOWARDS the lesion
- Fast phase is FLEEING the lesion
Again, where does a positional strabismus with no resting strabismus localize?
- CN 8 vestibular dysfunction** (central or peripheral)
- MLF (medial longitudinal fasciculus)
- CN 3 (oculomotor)
- CN 4 (trochlear)
- CN 6 (abducent nerve)
peripheral causes of vestibular disease
- Ear infection
- Foreign body
- Polyp
- Trauma/hemorrhage
- Tumor
- Hypothyroidism
- Drugs - aminoglycosides, furosemide, ear cleaning agents (make sure inner ear is intact)
- Congenital
- Idiopathic (geriatric vestibular disease)
Central causes of vestibular disease
- Tumor
- Encephalitis or meningitis (either infectious from CDV, RMSF, FIP or auto-immune/non-infectious)
- Hydrocephalus
- Trauma or hemorrhage
- Cerebral vascular accidents
- Drugs (metronidazole)
- Thiamine deficiency
What is the dose of metronidazole that can cause a central vestibular lesion?
- more than 50 mg/kg/day
Who gets idiopathic geriatric vestibular disease?
- Older dogs lol
Clinical signs of idiopathic geriatric vestibular disease
- Acute onset of PERIPHERAL vestibular signs
- Mild head tilt to severe imbalance/rolling
- Usually unilateral signs
Treatment of idiopathic geriatric vestibular disease
- No treatments
- Supportive care
- May decide to keep them in a comfortable environment
- Can put them on valium or trazodone
- Antihistamines like benadryl or meclizine
How long can it take for dogs to recover with idiopathic geriatric vestibular disease?
- Improve rapidly, but can take 2-3 weeks for complete recovery
- Usually ambulatory within 1 week
Residual signs of idiopathic geriatric vestibular disease?
- Can have a residual head tilt
- Can be relapsing
Diagnosis of idiopathic geriatric vestibular disease
- Diagnosis of ruling out other causes of peripheral vestibular disease
- Doing good blood work (hypothyroid)
- otoscopic exam
- Drug history
Idiopathic vestibular disease in cats - how common? what age?
- Happen in cats but at any age and is more rare
Which CNs could be affected with poor gag or swallow?
- CN 9
- CN 10
CN dysfunction associated with megaesophagus potentially -
- CN 10
- May see dilation of the throat area
- Pretty uncommon to see
Hypoglossal nerve dysfunction signs
- Ipsilateral or contralateral to lesions?
- See a shriveling of the tongue
- Often falls towards the weaker side but as you get more chronic it goes toe the stronger side
- Ipsilateral
