Exam 3 Spring (Neuro) Flashcards
Spinal Cord Segments in Dogs & Cats
o 7 cervical vertebrae BUT 8 spinal cord segments
o 13 thoracic
o 7 lumbar
o 3 sacral
o ~5 caudal
Patellar Reflex
o Monosynaptic
o L4-6 spinal cord segments & nerve roots
o Femoral nerve
o Innervates the quadriceps for extension of the stifle
Withdrawal Reflex
o Polysynaptic
o Pelvic limb -> L6-S1 -> Sciatic nerve
o Thoracic limb -> C6-T2 -> multiple nerves
o Innervates muscles for flexion of the limb
o Does not signify ability to feel
Cutaneous Trunci Reflex
o Start at hips
o Pinch dermatome
o Both lateral thoracic nerves
o C8-T1
o Bilateral cutaneous trunci contraction
o If there is cutoff: lesion is 1-2 spinal cord segments cranial
o If absent on one side: efferent problem on that side
CN II
o Optic Nerve
o Sensory for vision
CN III
o Oculomotor
o Motor to extraocular muscles, levator palpebrae
o Constricts pupil
CN IV
o Trochlear
o Motor to dorsal oblique
CN V
o Trigeminal
Opthalmic
Sensory to eye & medial canthus
Maxillary
Sensory to maxilla
Mandibular
Sensory to mandible
Motor to muscles of mastication
CN VI
o Abducent
o Motor to lateral rectus & retractor bulbi
CN VII
o Facial
Sensory
middle ear,
head blood vessels,
palate,
rostral 2/3 tongue
Motor
ears,
eyelid (orbicularis oculi),
cheeks,
lips,
rostral digastricus (skeletal)
mandibular / submandibular salivary glands
lacrimal glands
nasal glands (smooth - parasympathetic)
CN VIII, CN IX, CN XII
CN VIII
Vestibulocochlear
Hearing
CN IX
Glossopharyngeal
Sensory to carotid body, caudal tongue, rostral pharynx
Motor to pharyngeal muscles & parotid salivary gland
CN XII
Hypoglossal
Motor to tongue
CN X
Vagus
Sensory
* Aortic body
* Sinus
* Pharynx
* Larynx
* Thoracic & abdominal cavity
Motor
* Pharynx
* Larynx
* Esophagus
* Organs of the throax & abdomen
CN XI
Accessory
Internal Branch
* Motor to everything vagus is
External
* Motor to trapezius, sternocephalicus, brachicephalicus
Menace Response Pathway
o Optic nerve(CN2) ->
o optic chiasm ->
o cross over ->
o optic tract ->
o thalamus (lateral geniculate) ->
o visual / occipital cortex ->
o motor / frontal cortex ->
o cross back over ->
o descending tracts
o cerebellar influence ->
o Facial nerve (CN 7)
PLR Pathway
o Optic nerve ->
o Optic chiasm ->
o Cross over ->
o Optic tract ->
o Pretectal area ->
o Bilateral oculomotor nerve
o Direct constriction stronger than indirect
Which Nerves does the Oculovestibular Reflex Test
o CN 8
o MLF
o CN 3
o CN 4
o CN 6
Ocular Sensation Reflex Pathway
o Touch eye ->
o CN 5 (ophthalmic branch) ->
o CN 7 – blink
o CN 6 – eyeball retraction & elevation of 3rd eyelid
Palpepbral Reflex Pathway
o Touch canthus of eyes ->
o CN 5 (maxillary & ophthalmic) ->
o CN 7 blink
Facial Reflex Pathway
o Touch different spots on face ->
o CN 5 (ophthalmic, maxillary, mandibular) ->
o CN 7 ->
o Blink & twitch
Facial Response Pathway
o Cover eyes and put hemostats in nostril ->
o CN 5 (ophthalmic) ->
o Cross over ->
o Thalamus ->
o Somatosensory/parietal cortex ->
o Motor cortex ->
o Move head away from stimulus
Which Nerves do Jaw Tone, Facial Symmetry, Gag reflex, and the Tongue Test
Jaw Tone
o CN 5 (mandibular)
Facial Symmetry
o CN 5 & 7
Gag Reflex
o CN 9 & 10
Tounge
o CN 12
Perineal Reflex
constriction of the anus (anal tone)
o pudendal nerve -> S1-3
flexion of tail
o caudal spinal cord segments
Localizing UMN or LMN Lesions
Front Limb
UMN - Anything before C6
LMN - At C6-T2
Hind Limb
UMN – Anything before L4
LMN – At L4-S1
Decreased patellar reflex & normal withdrawal
L4-L6
Increased Patellar & decreased withdrawal
L6-S1
Nerves with Parasympathetic Function
o 3
o 7
o 10
o 11
UMN VS LMN Signs
UMN
Normal to increased spinal reflexes
Normal to increased muscle tone
increased step distance
Disuse muscle atrophy
LMN
Decreased to absent spinal reflexes
Decreased to absent muscle tone
decreased step distance
Neurogenic muscle atrophy
Types of Muscle Atrophy
Disuse
evolves more slowly,
less severe
Neurogenic
Fast (10-14 days)
severe
Primary Myopathic
variable
Stuporous Vs Comatose
Stuporous
Responds to deep pain only
Comatose
Non-responsive even to deep pain
Decerebrate Rigidity; Signs, Lesion
Signs
Opisthotonos
Extensor rigidity of all limbs
Stupor or coma
+/- respiratory problems
+/- HR & BP problems
Lesion
Midbrain
Decerebellate Rigidity; Signs, Lesion
Signs
Opisthotonos
Extensor rigidity of thoracic limbs +/- pelvic limbs
Awar of environment
Other cerebellar signs
Lesion
Cerebellar
Schiff Sherrington; Signs, Lesion
Signs
Extensor rigidity of thoracic limbs
Lesion
Acute, severe spinal cord injury of T3-L3
Head Turn Vs Tilt
Head Turn
o Supratentorial lesion
o Head toward side of lesion
Head tilt
o Cerebellar or vestibular
o USUALLY toward side of lesion (vestibular)
o Away from side of lesion can be w/ cerebellar lesion
Cerebellar Vs Vestibular Signs
Cerebellar
Intention Tremor
Menace deficit but visual
Decerebellate rigidity
Weird eye things
Increased urination
NO concious proprioception deficits
Vestibular
Head tremors & eyelid contraction secondary to nystagmus
Positional nystagmus
May have concious proprioception deficits
Vestibular; Central or Peripheral
Central
Vertical nystagmus
Changing nystagmus
CN deficits other than 7 & 8
conscious proprioception deficits
Localizing Lesion w/ Head tilt
If there is hemiparesis/paresis/weakness
o lesion is central & on side of paresis
If no paresis
o lesion on side of tilt
Circling
o Always circle to side of lesion
Tight circles
Cerebellar / vestibular (infratentorial)
Bigger circles
Supratentorial
Hugging wall
Usually blind in that side
Reasons for Ventral Neck Flexion
o Neck pain
o Myopathy / neuropathy
o Thiamine deficiency
o Myasthenia gravis
o Hyperthyroidism
o Organophosphate toxicity
o Ethylene glycol toxicity
o K, Na, Ca, phosphate abnormalities
Nerve Root Signature
o Dogs that are walking, stop, and hold one paw up
o Sign of a problem with the nerve root
o Can be infection but often tumor
o C6-T2 or L4-S3
Types of Ataxia
Vestibular
Falling & leaning
Cerebellar
Hypermetria (walking on hot rocks)
Cerebellum or spinocerebellar tracts of spinal cord
Proprioceptive/Sensory
Wide-based stance
Crossing over
Swaying
2 Engine Gait
o Decreased step distance in front
o Increased step distance in pelvic
o Lesion at C6-T2
Paresis; Definition, Types, Clinical Presentation
o Weakness at gait &/or supporting weight
Types
Para – pelvic limbs
Tetra – all 4 limbs
Hemi – front & hind limbs on one side
Mono – 1 limb
Classified as ambulatory or non
Clinical Presentation
Slow/shuffling gait
Dragging/knuckling paw
Collapse/falling
Exercise intolerance
Unable to support weight
Difficulty rising
Etc
Plegia
o No voluntary motor movement
Central Cord Syndrome
o CP deficits in front limbs only
o Due to lesion in central spinal cord
Signs of Problem w/ CN3
o Ptosis (droopy upper eyelid)
o Ventrolateral resting strabismus
o Mydriasis due to parasympathetic dysfunction
Horner’s Syndrome
o Miosis (anisocoria)
o Elevated 3rd eyelid
o Ptosis (droopy upper eyelid)
o Enopthalmos
Anisocoria; Causes of Miosis Vs Mydriasis
Miosis
Increased parasympathetic due to drugs or cerebrocortical dz
Decreased sympathetic due to horner’s
Corneal ulcer
Uveitis
Spastic pupil syndrome in FeLV/FIV cats
Mydirasis
Decreased parasympathetic due to atropine or CN3 dysfunction
Increased sympathetic due to phenylephrine
Blindness
Glaucoma
Iris atrophy
Cerebellar dz
Strabismus
CN 3, 4, 6 dysfunction
o resting strabismus
CN 8 dysfunction
o positional strabismus
Decreased Facial Sensation & reflex
o CN5 & CN 7 dysfunction
o Contralateral cortex dysfunction
CN 5 Mandibular Branch Dysfunction
o Atrophy of temporal muscle on affected side
o Drop jaw = bilateral dysfunction
o Neurotropic keratitis due to reduced blinking & lack of corneal nutrition
CN7 Dysfunction
o Paralysis = drooping of face on affected side
o Hemifacial spasm = contraction of face on affected side
Idiopathic Geriatric Vestibular Dz
o Older dogs
o Acute onset of peripheral vestibular signs
o Mild head tilt to severe imbalance / rolling (usually unilateral)
o Improve rapidly, although can take 2-3 wks for complete recovery
o Can have residual head tilt or relapse
o can happen in cats but at any age (rare)
Supratentorial; Location, Clinical Signs of Lesion
o Forebrain
o CN 1 & 2
Clinical Signs
Contralateral paresis
Contralateral CP deficits
Contralateral menace deficits
Contralateral facial response deficits
Contralateral hemi-neglect
Ipsilateral circling
Ipsilateral head turn
Seizures
Behavioral changes
Infratentorial; Location, Clinical Signs of Lesion
o Hind brain
o CN 3-12
Clinical Signs
Ipsilateral paresis
Ipsilateral CP deficits
Ipsilateral CN deficits (contralateral CN 4)
Cerebellar / vestibular signs
Decerebrate & decerebellate rigidity
Abnormal respiration
Severe altered mental status
Intracranial Degenerative Dz
o Slowly progressive signs
o Non-painful
o Multifocal or widespread signs
o May have organomegaly if storage dz
Congenital Hydrocephalus; Clinical Signs, Diagnosis, Treatment
o Often due to stenosis of mesencephalic aqueduct
o Often toy breeds
Clinical Signs
Dome shaoed head
Persistent fontanels
Ventral/lateral strabismus
Poor learners
Visual deficits
Circling
Seizures
Diagnosis
Ultrasound, CT, MRI
CSF analysis to rule out inflammatory dz
Treatment
Pred to decrease CSF production
Acetazolamide or mannitol
Omeprazole to decrease CSF production (lifelong)
Ventricular CSF shunting
Hydrancephaly
o Cerebral hemisphere reduced to fluid filled sac
o Meninges & ependyma intact
o Associated w/ panleukopenia in kittens
Lissencephaly; Basics, Clinical Signs
o Smooth brain = minimal sulci/gyri
o Abnormal cerebral cortical neuronal migration during fetal development
Clinical Signs
Seizures
Poor learning
Blindness
Typically non-progressive or lethal
Cerebellar Hypoplasia;
o Congenital & rare abnormal development of cerebellum
o Cats: panleukopenia virus exposure in utero
o Dogs: Maybe herpes or parvo exposure in utero
o Incoordination & CP deficits
o Non-progressive & may learn to compensate over time
Caudal Occipital Malformation Syndrome; Signalment, Pathophysiology
Signalment
Small breed dogs
Cavalier King Charles especially prone
Pathophysiology
Malformation of caudal occipital area overcrowds caudal fossa ->
Cerebellar compression & herniation ->
Focal meningeal hypertrophy at foramen magnum ->
Increase CSF pressure ->
Hydrocephalus ->
Concurrent syringohydromyelia
Caudal Occipital Malformation Syndrome; Clinical Signs, Diagnosis, Treatment
Clinical Signs
Scratching at head
Spinal pain
Paresis/paralysis
CP deficits
Diminished menace
Seizures
scoliosis
Diagnosis
MRI w/ occipital defect & fluid around spinal cord
Treatment
Prednisone
+/- omeprazole
+/- gaba for pain
Surgical foramen magnum decompression if does not improve w/ meds
Hepatic Encephalopathy; Pathophysiology, Clinical Signs, Diagnosis
Pathophysiology
Liver failure or shunt ->
GABA, aromatic acid, mercaptans, skatoles, ammonia not filtered out of blood ->
Demyelination of white matter
Ischemic necrosis of grey matter ->
Clinical Signs
Obtundation
Abnormal behavior
Head pressing
Visual deficits
Ptyalism in cats
Signs can worsen after meals
Diagnosis
Widened sulci on MRI
Lentiform nuclei light up on MRI
Hypoglycemia; Mechanism, Neuro Signs
Mechanims
Neuroglycopenia ->
Sympathetic nervous system stimulation
Clinical Signs
Coma
Irritability
Pupillary dilation
Seizures
Tremors
Weakness
Visual defects
Na Abnormalities; Consequences of Correcting too Fast; Safe Correction
Too rapid correction of hypernatremia
Cerebral edema
Too rapid correction on hyponatremia
Thalamic myelinolysis
Brain cell dehydration
Hemorrhage
Safe correction
< 0.5meq/L/hr
Hypothyroidism; Neuro Signs,
CN 5, 7, 8 deficits
Decreased facial sensation
Facial paralysis
Vestibular dysfunction
Lar par and/or megaesophagus due to CN 10 dysfunction
Appendicular neuropathy
Myasthenia gravis
Hypertension -> atherosclerosis -> stroke
Myopathy
Myxedematous stupor/coma (rare)
Hyperthyroidism; Neuro Signs
o Restlessness, irritability, aggressiveness
o Wandering, pacing, circling
o Stroke due to hypertension
o Tremors
o ventral neck flexion
Hyperadrenocorticism; Neuro Signs
Myopathy type II – muscle atrophy & myotonia
Neuropathy
Systemic hypertension & stroke
hydrocephalus
Seizures 7/or blindness due to space occupying tumor
Thiamine Deficiency; Basics, Brain Areas Affected, Clinical Signs, Treatment
o All fish diet in cats (thiaminase)
Areas Affected
Polioencephalomalacia
Bilateral oculomotor
Vestibular
Lateral geniculate nuclei
Caudal colliculus
Clinical Signs
Acute & rapidly progressive
Lethargy, anorexia
Dilated pupils
Vestibular signs
Visual deficits
Ventral neck flexion
Coma
Opisthotonos
Death
Treatment
Thiamine hydrochloride
Meningioma; Basics, Clinical Signs, Diagnosis, Treatment
o Most common brain tumor in cats / dogs
o Arise from the arachnoid layer
o Usually histopathologically benign
o Extraneural metastasis rare
o Cats - well-encapsulated, firm, easily removable, can have multiple masses
o Dogs – usually solitary, meshwork of vessels internally, intimately attached to underlying tissue – more difficult to remove
Clinical Signs
Supratentorial signs
Diagnosis
MRI w/ contrast
Treatment
Corticosteroids to decrease edema & inflammation
Chemo
Radiation
Sx + radiation or chemo
Meningioma; Prognosis
Cats
* w/ sx – 22-27mo
* may be curative
Dogs
* w/ sx 7mo
* w/ radiation 1-2yrs
* w/ sx + radiation 16mo – 3yrs
Unilateral Muscle Atrophy
o tumor tumor tumor
o maybe infectious or trauma
Nerve Sheath Tumor Treatment
Sx but difficult to get clean margins
Fractionated radiation therpay
Radiosurgery if <2cm
Pituitary Macroadenoma; Basics, Treatment
o Sella or suprasellar location
o >1 cm, expands into diencephalon
o Contrast enhancing
Treatment
Fractionated radiation therapy
Radiosurgery if <2cm
Transsphenoidal hypophysectomy through hard palate (75% success)
Canine Distemper Clinical Signs
Hyperkeratotic foot pads
Polioencephalomyelopathy & seizures in younger dogs
Leukoencephalomyelopathy w/ cerebellar/vestibular signs in older dogs
Myoclonus (repetitive muscle contraction)
Rabies Clinical Signs
o Seizures
o Hypersensitivity to light & sound
Furious
Aggression
Forebrain signs
More common in cats
Paralytic
LMN to CNs signs
Dropped jaw
Swallowing deficit
Hypersalivation
More common in dogs
Cryptococcus; Clinical Signs, Diagnosis, Treatment
o Multifocal symptoms
Diagnosis
Round organisms w/ halo on CSF cytology
Treatment
Fluconazole
Cage rest
Physical therapy
Granulomatous Meningoencephalitis (GME); Basics, Clinical Signs, Signalment, Treatment, prognosis
o Granulomatous infiltration of lymphocytes, plasma cells & macrophages
o Primarily effects white matter
o Causes mass effect
Clinical Signs
Optic neuritis
Focal Brainstem signs
Disseminated cerebrum, cerebellum, brainstem, & cervical spine
Signalment
Young - middle age
Small breeds
Treatment
Corticosteroids
Azathioprine
Cyclosporin
Cytosine arabinoside
Procarbazine
Survival
Weeks to years
Can’t be cured & relapse will occur
Encephalitis Protocol
o TMS
o Clindamycin
o Doxycycline
o Pred
Once infectious agents ruled out
Discontinue antibiotics
Increase pred to 2-4mg/kg/day
+/- another immunosuppressive drug
Necrotizing Leukoencephalitis (NLE); Signalment, Clinical Signs, Prognosis
Signalment
Yorkies
Juvenile – young adult
Clinical Signs
Forebrain & brainstem signs
White matter necrosis & cavitation
Prognosis
Fatal w/in wks to months
Necrotizing Meningoencephalitis (NME); Signalment, Clinical Signs, Prognosis
Signalment
Pugs
Maltese
Juvenile to young adult
Clinical Signs
Forebrain signs
Seizures
Grey & white matter necrosis & cavitation
Prognosis
Fatal w/in wks to months
Generalized Tremor Disorder; Clinical Signs, Signalment, Diagnosis, Treatment
Clinical Signs
Diffuse, fine, whole body tremor
Signalment
Small breeds
Usually young
Diagnosis
CSF w/ mild lymphocytic pleocytosis
Treatment
Responds really well to pred but relapse possible
Idiopathic Trigeminal Neuritis; Clinical Signs, Treatment, Prognosis
Clinical Signs
Dropped jaw
Masseter/temporalis atrophy
Bilateral mandibular branch problem
+/- sensory branch problem
+/- Horner’s
Treatment
Nutritional support
PT
Prognosis
Jaw function recovers in 4-6wks
Persistent muscle atrophy
Idiopathic Facial Paralysis; Clinical Signs, Treatment, Prognosis
Clinical Signs
Unilateral/bilateral CN 7 palsy
+/- CN 8 problem
Exposure keratitis of eye
Treatment
No specific
Lubricate eyes
Prognosis
Some never recover
Can recover after 3-6 wks
Pupil Abnormalities
Bilateral miotic (constricted) pupils
Diffuse cerebrocortical dz
Unilateral mydriasis
Unilateral caudal transtentorial herniation
Bilateral Mydriasis
Bilateral caudal transtentorial herniation or foramen magnum herniation
Caudal transtentorial herniation or foramen magnum herniation; Clinical Signs
Non-responsive mydriasis
Seizures
Respiratory changes
Cushing’s reflex (hypertension + bradycardia)
Brain heart syndrome (VPCs)
Monroe-Kelli Doctrine
o 3 compartments w/in rigid skull
o If one increases, others have to decrease
o Cerebral perfusion pressure = mean arterial BP – Intracranial pressure
o Constricting vessels -> decrease ICP
o Lowering CO2 - > decrease ICP
Traumatic Brain Injury; Stabilization, Surgery
Stabilization
Treat hypovolemic shock
Treat hypoxemia
Mannitol (once hydrated) to decrease intracranial fluid
Hypertonic saline to increase perfusion to brain
Elevate head
Monitor CO2
Keep calm & quiet
NO steroids
Craniotomy/ectomy
If medical management is not working
Open skull fractures
Depressed skull fractures
Foreign bodies
Hematomas
Must take images prior
Physiology of a Seizure
o Glutamate causes excessive excitation
o GABA does not adequately inhibit
Cluster Seizures Vs Status Epilepticus
Cluster Seizures
o 2 - more seizures w/in 24hrs
o Poor prognosis
Status Epilepticus
o 5 – more mins of continuous seizure
o Incomplete return to consciousness between seizures
o Guarded prognosis
Focal Vs Generalized Seizures
Focal
o One hemisphere involved
o May or may not lose consciousness
o Lateralized or regional signs
o Can progress to generalized
Generalized
o Both hemispheres involved
o Typically lose consciousness
o Motor +/- autonomic
o Tonic/Clonic/Atonic/Myoclonic
Reactive Seizures Vs Epilepsy
Reactive
Response to transient disturbance
Reversible when underlying disturbance is treated
Metabolic/Toxic
Epilepsy
Dz of brain predisposing to seizures
2 – more seizures >24hrs apart
Can be idiopathic or structural
EEG; Basics, Methods to Perform
o Electroencephalography
o Distinguishes between seizures and other events
o Also useful for sleep disorders
o ]Ideally catch patient during an episode
o Can have false negatives
Sedated
Looks for interictal activity
Short
Ambulatory
Longer, unsedated
More likely to catch an episode
When to treat Seizures
o ≥2 seizures in 6m
o Cluster seizures
o Status epilepticus
o Known structural brain disease
o Prolonged severe post-ictal periods
Step 1 Emergency Seizure Control
o Benzo bolus to bind GABA
o Diazepam (IV, IN, PR)
o Midazolam (IV, IM, IN)
Step 2 Emergency Seizure Control
o If benzo bolus unsuccessful
Benzo CRI
Diazepam may bind to tubing
Midazolam not useful after 6-12hr
Phenobarb or Keppra bolus
Useful for clusters
Ketamine bolus
Useful for status epilepticus
Not useful for cluster
Step 3 Emergency Seizure Control
o Propofol or inhalant anesthesia
o Works on GABA R
o Safe for refractory status epilepticus
o Must intubate
o Refer or call for consult
Seizure Maintenance
o Balance between seizure control & side effects
o Pick one drug and use until maxed out dose
o Treat patient not levels
Goals
>50% reduction in seizures
1 seizure every 3m or less
Phenobarbitol
o Binds to GABA R
o Increases Cl influx -> hyperpolarization
o Longest history & best efficacy seizure drug
o 1st line treatment in most species
o Inexpensive
o Highly bioavailable
o Hepatic metabolism
o Q12
o Reach stead state in 2wks
Potassium Bromide
o Mimics Cl -> hyperpolarization
o Good efficacy
o 1st or 2nd line treatment
o NO cats
o Inexpensive
o Renal secretion
o SID
o Steady state at 3mo
Levetiracetam (Keppra)
o Prevents neurotransmitter release
o Efficacy variable
o Rapid oral absorption
o Little hepatic metabolism
o Mostly excreted unchanged in urine
o “Honeymoon” period
o Often used as adjunct treatment
o Q8hr
o Steady state at <48hr
Zonisamide
o Blocks Na channels -> hyperpolarization
o Carbonic anhydrase inhibitor
o Moderate efficacy
o Hepatic metabolism
o Q 12
o Narrow dose range
o “honeymoon” effect
Misc Adjunct Seizure Therapies
o Oral benzos (stop working over time & contraindicated in cats)
o Ketogenic diet (sometimes works)
o CBD oil (no regulations, meh)
o Vagal nerve stimulation (questionable)
o Transcranial magnetic stimulation (questionable)
Spinal Shock
o Sudden severe UMN injury
o Transient period of reduced excitability of spinal neurons distal to site of injury
o Initial Loss of Perineal (15mins), patellar (30min-2hr), & withdrawal (12+hr) reflexes
o Bladder reflexes may be affected longer
o NOT neurogenic shock
White Matter of Spinal Cord
Ascending
Sensory
Dorsolateral
Peripheral (less protected)
Descending
Motor
Ventrolateral
Central (more protected)
Order of Loss of Function w/ Spinal Cord Injury
o Ataxia + CP deficits +/- pain
o Ambulatory para/tetraparesis
o Nonambulatory para/tetraparesis
o para/tetraplegia w/ nociception (deep pain)
o para/tetraplegia No nociception (deep pain)
Myelomalacia; Basics, Clinical Signs
o Spinal cord necrosis secondary to ischemia from injury
o Can occur up to 10 days after injury
Clinical Signs
+-fever
Hyperesthesia
Decreased abdominal tone
Reflex deficits
Decreased anal tone
Ascending cutaneous trunci reflex
Decreased thoracic wall movement & dyspnea
Eventual thoracic reflex deficits +/- horner’s
Fatal
IVDE: Intervertebral Disc Extrusion; Signalment, Pathophysiology, Clinical Signs, Diagnosis
Signalment
Chondrodystrophic breeds (short legs/long back)
Young
Genetic defect in chromosome 12 and/or 18
Pathophysiology
Degeneration of nucleus pulposus ->
Compression & contusion of spinal cord
Clinical Signs
Acute onset
Progressive
Painful
Most commonly UMN T3-L3 signs
Possibly cervical UMN signs
Diagnosis
MRI w/ dark disks & spinal cord deviation
IVDE: Intervertebral Disc Extrusion; Treatment
Medical
* If good motor function
* CRATE REST 4-6wks
* +/- analgesia & NSAIDs
* Avoid jumping
* Carry up stairs
Surgery
* Failed medical management or no motor function
* Still need 4-6wks crate rest post-op
* Deep pain (-) has poor prognosis
IVDP: Intervertebral Disc Protrusion; Signalment, Pathophysiology, Clinical Signs, Diagnosis
Signalment
Older
Med-large breed dogs
Pathophysiology
Chronic fibrosis & degeneration of entire disc ->
Protrusion of entire disc
Clinical Signs
Chronic
Progressive
Often non-painful
T3-L3 UMN signs
Diagnosis
MRI
IVDP: Intervertebral Disc Protrusion; Treatment
Medical
* Preferred
* NSAIDs
* Rest
* PT
* Steroids if edema in cord
Surgery
* Rare
* May slow progression but not return fxn
ANNPE: Acute Non-compressive Nucleus Pulposus Extrusion; Pathophysiology, Clinical Signs, Treatment
Pathophysiology
Acute extrusion of disc fluid ->
Spinal cord contusion but no compression
Clinical Signs
T3-L3 UMN signs acutely after high activity
+/- pain
Treatment
Crate rest 4-6wks
Physical therapy
HNPE: Hydrated Nucleus Pulposus Extrusion; Basics, Diagnosis, Treatment
o Similar to ANNPE
o May not have inciting event
o Contusion & compression of spinal cord
o Most common in cervical region
Diagnosis
MRI
Treatment
Crate rest 4-6 wks
Physical therapy
Lumbosacral Stenosis (Cauda Equina Syndrome); Signalment, Pathophysiology
Signalment
Older, Large breed
Maybe young active dogs
Maybe cats
Pathophysiology
L7-S1 IVDP +
DJD & proliferation of articular facets +
Hypertrophic ligaments ->
Narrowing of lumbosacral canal & foramen
Lumbosacral Stenosis (Cauda Equina Syndrome); Clinical Signs, Diagnosis, Treatment, Prognosis
Clinical Signs
Painful
Marked nerve pain
bunny hopping, tucked tail, short stride
Pelvic Limb lameness
pain on palpation
+/- incontinence
+/- pelvic limb reflex deficits
NO ataxia
Diagnosis
MRI (gold)
CT
Rads
Treatment
Crate rest + steroids for 4-6wks
Physical therapy
Lean BCS
Dorsal laminectomy if medical fails
Prognosis
Poor if incontinent
Degenerative Myelopathy; Basics, Diagnosis, Treatment
o Chronic, progressive
o T3-L3
o Middle aged – older
o German shepherds, corgis, etc
o SOD1 mutation
Diagnosis
Genetic testing (shows risk not diagnosis)
Degeneration of white matter on necropsy
Diagnosis of exclusion
Treatment
No real treatment
May slow neuro decline w/ physical therapy
Degenerative Myelopathy; Clinical Signs
Initial
* T3-L3
* Ataxia
* CP deficits
* Paraparesis
* Non-painful
Late
* Progression to paraplegia & LMN signs
* Progression to thoracic limbs
* Ascend to brainstem if ignored
Osseus Associated Wobbler’s (Cervical Spondylomyelopathy); Basics, Clinical Signs, Diagnosis
Young giant breeds
Some large breeds
Bony proliferation of vertebrae -> dorsolateral compression of spinal cord
Clinical Signs
* Chronic progressive
* Cervical pain
* Ataxia
* Tetraparesis
* +/- hypermetria
* Proprioceptive deficits
* +/-reflex deficits
* Pelvic often worse than thoracic
Diagnosis
* MRI (gold)
Disc Associated Wobbler’s (Cervical Spondylomyelopathy); Basics, Clinical Signs, Diagnosis
Middle aged large breed dogs
Commonly dobies
Clinical Signs
* 2-engine gait
Diagnosis
* MRI
Wobbler’s (Cervical Spondylomyelopathy); Treatment
Medical
* Crate rest 4-6 wks
* Gaba or pregabalin
* NSAIDs or steroids
* Physical rehab
Surgical
* Decompression
* Stabilization
Atlantoaxial Instability; Basics, Pathophysiology, Clinical Signs, Diagnosis, Treatment
o Young Toy breed dogs
o Any breed w/ trauma
Pathophysiology
Lack of ligaments + incomplete C1 ->
Neck flexion ->
Spinal cord compression
Clinical Signs
Acute onset
Cervical pain
Ataxia
Dullnes
Tetraparesis
+/- vestibular signs
Diagnosis
Rads showing increased C1-C2 space or malalignment of C1-C2
VERY careful w/ neck flexion for rads
Treatment
Crate rest 6-8wks + neck brace
Surgery (difficult)
Vertebral Anomalies; Basics, Types
o Common in frenchies & pugs
o Usually incidental
o Block vertebrae (fused vertebrae)
o Hemivertebrae (major bend to spine)
o Butterfly vertebrae (type of hemi)
o Transitional vertebrae (vertabrea that developed partly into different type)
Spina Bifida
o Bull dogs & manx cats
o Failure of closure of dorsal vertebral arch
o Lumbar/lumbosacral region
o Progressive T3-Cd signs
o Maybe incontinent
o May need sx
Spinal Neoplasia; Extradural Vs Intradural Extramedullary Vs Intramedullary
Extradural
Common
Lymphoma, Chondrosarcom, osteosarcoma, hemangioma
Maaaaybe nerve sheath tumors or meningiomas
Intradural Extramedullary
Common
Meningioma, nerve sheath tumors, nephroblastoma
Intramedullary
Uncommon
Hemangiosarcoma, glioma, ependymoma
Maaaaybe nephroblastoma
Spinal Neoplasia; Types In Dogs
Meningioma
* Common in older dogs
* C1-C5
* Often surgical
Nephroblastoma
* Young dogs
* T3-L3
* Often surgical
Peripheral Nerve Sheath Tumors
* Large breeds
* C6-T2
* Pain & lameness (nerve root signature)
Spinal Neoplasia; Types In Cats
Lymphoma
* Young or old
* Extradural masses w/ infiltrate
* Thoracic spinal cord
Glioma
Spinal Neoplasia; Clinical Signs, Diagnosis, Treatment
Clinical Signs
Pain
lameness
Diagnosis
thoracic & abdominal rads for mets
spinal rads for vertebral lysis
MRI for surgical planning
Treatment
Pred to reduce spinal cord edema
Sx
Radiation (often w/ sx)
Discospondylitis; Basics, Etiology, Agents
o Infection of disc & endplate
o Young -> middle aged large breed dogs
o Rare in cats
o Male > female
Etiology
Migrating foreign body
Penetrating wound
Hematogenous
Iatrogenic
Agents
Most commonly
E. coli
Aspergillus (Germans)
Discospondylitis; Clinical Signs, Diagnosis, Treatment
Clinical Signs
Pain
+/- fever, anorexia, weightloss
Myelopathy
Diagnosis
Irregular/lytic endpaltes on rads
Blood/urine culture
Urine Asper testing
RSAT fro Brucells
+/- echo
Maybe CT in early dz
Treatment
Activity restriction
Antibiotics based on C/S
Empirically w/ Cephalexin or TMS
+/- NSAIDs
Treat for 6mo-1yr although pt will feel better in 1-2wks
Recheck reds q2-3mo or at 6mo
Granulomatous Meningoencephalitis/myelitis; Basics, Clinical Signs, Diagnosis, Treatment, Prognosis
o Usually small dogs
o Any age
Clinical Signs
Acute, progressive
May wax & wane
Pain
Lameness
Hunched posture
Diagnosis
CSF pleocytosis
CSF culture
PCR of CSF for infectious dz
Histopathology post mortem (definitive)
Treatment
Immune suppression w/ pred, cyclosporine etc
Prognosis
Lifelong treatment
Steroid Responsive Meningitis Arteritis; Basics, Clinical Signs, Diagnosis, Treatment
o Young large breed dogs
o Looks very similar to discopondylitis
Clinical Signs
Acute, progressive
May wax & wane
Mostly cervical pain
Dullness/lethargy
Stiff gait
Often febrile
NO neuro deficits
Diagnosis
Rule out other dz
Neutrophilic pleocytosis & elevated protein on CSF
Treatment
steroids
Priorities During Spinal Trauma Emergencies
o ABCs
Brain
Mentation
pupil size
PLR
physiologic nystagmus
Spinal Cord
Look for voluntary motor fxn
Check reflexes
Check deep pain
DO NOT MOVE pt
3 Compartment Model
o When looking at spinal trauma on CT
o Large dorsal – small middle – large ventral
o Trauma to >1 compartment = instabile
Stable Vs Unstable Spinal Trauma
Stable
No fractures or non-displace fractures
Only 1 compartment effected
More spinal cord contusion than bony compression
+/- disc herniation
Unstable
Visible vertebral fractures
Subluxation or luxation
Spinal cord compression
+/- disc herniation
May worsen w/ movement
Spinal Trauma Treatment
o Strict crate rest 6-8wks
o External coaptation for cervical region
o Analgesia w/ fentanyl & NSAIDs
o Antibiotics if open wounds
o Surgery – faster recovery
Fibrocartilagenous Embolism; Pathophysiology, Clinical Signs, Diagnosis, Treatment, Prognosis, Recovery Rules
Pathophysiology
Piece of dic embolizes in spinal cord vascular supply ->
Ischemic injury
Clinical Signs
Looks a lot like ANNPE
Peracute onset
Non painful
Lateralized
Non-progressive
Diagnosis
Intrinsic lesion on MRI
Pleocytosis +/- neutrophils on CSF
Histo at necropsy
Treatment
Support
PT
Prognosis
UMN good
LMN guarded & may persist
Loss of nociception (pain) grave
Recovery Rules of Thumb
Want to see SOME improvement by 2wks
Spinal cord should be mostly healed by 6wks
Upper Motor Neuron Bladder; Injury, Pathophysiology, Clinical Signs, Treatment
o Spinal injury above S1-S3
o Usually T3-L3
Pathophysiology
No detrusor contraction
Increased filling
Increased urethral tone
Disruption of sensory input from bladder
Clinical Signs
Large, distended turgid bladder
Unable to urinate voluntarily
Hard to express
Bladder may overflow & result in dribbling
Risk of atony
Treatment
Prazosin for internal sphincter
Diazepam for external sphincter
Bethanechol for detrusor
Lower Motor Neuron Bladder; Injury, Pathophysiology, Clinical Signs, Treatment
o Injury at S1-S3
o L4-S1
o Cauda equina
Pathophysiology
No detrusor contraction
Decreased urethral tone
Disruption of sensory input from bladder
Clinical Signs
Small or large flaccid bladder
Poor urethral tone
Dribbling urine
May or may not express easily
Treatment
Very difficult
Poor prognosis
Detrusor Atony; Stretch Vs Neurogenic
Stretch
UMN
Severe bladder distension
Damage of tight junctions
Obstruction of outflow
DON’T express
catheterize
Neurogenic
LMN
Bladder anatomy normal
May recover if neuro issue treated
Express or catheter
Primary Detrusor Sphincter Dyssynergia
o Middle aged large breed male dogs
o Normal neuro
o Easy to catheterize
Detrusor Overactivity; Basics, Treatment
o Usually underlying cystitis
o Occasionally idiopathic
Treatment
Propantheline
Urethral Sphincter Mechanism Incompetence; Basics, Treatment
o Female spayed dogs
o Most common cause of leaking urine
o Normal neuro
Treatment
PPA
Estrogens
Testosterone in males
Top 3 differentials for LMN dz
o Tick paralysis
o Botulism
o Polyradiculoneuritis (Coonhound paralysis)
Tick Paralysis; Clinical Signs, Diagnosis
Clinical Signs
Ascending paresis -> flaccid paralysis of all limbs in 12-72hrs
Diagnosis
Find tick
Response to tick med
Should resolve in 12-48hrs
Botulism; Clinical Signs, Treatment
Clinical Signs
Pelvic paresis -> flaccid paralysis of all limbs
Treatment
Support
Polyradiculoneuritis; Clinical Signs, Treatment
o Auto-immune
Clinical Signs
Pain
Pelvic paresis -> flaccid paralysis of all limbs
Treatment
Support
If in need of ventilator -> poor prognosis
Myasthenia Gravis; Types, Clinical Signs, Treatment
Types
o Congenital – lack of Ach receptor
o Acquired – Ach receptor antibody
Clinical Signs
Short choppy gait worsens w/ activity
Decreased palpebral reflex
Megaesophagus
Lar par or stridor
Dysphagia
Ventral neck flexion (cats)
Treatment
Oral pyridostigme
Feed elevated if have megaesophagus
Myasthenia Gravis; Diagnosis
Tensilon test (not definitive)
* Edrophonium IV –> increase Ach at the NMJ
* Exercise patient to point of collapse
* See clinical improvement in gait and palpebral reflex within 30-60 seconds
* Effect lasts 5-10minutes
* Intubation & ventilation in case cholinergic crisis
Muscle biopsy for congenital
Ach receptor Ab titer for acquired
Brachial Plexus Avulsion; Pathophysiology, Clinical Signs
o Traumatic abduction of limb -> C6-T2 stretched
Clinical Signs
LMN
Non painful
Metronidazole Toxicity
vestibular signs in dogs
blindness & seizures in cats
Masticatory Myositis; Clinical Signs, Diagnosis, Treatment
Clinical Signs
Trismus (Lock jaw)
Swollen, painful masseter & temporalis muscles
Exophthalmos
Highly elevated CK
Diagnosis
2M antibody titer
Muscle biopsy for prognosis
Treatment
Must treat VERY quickly
Immunosuppressive pred
PT
Tetanus; Clinical Signs, Treatment
Clinical Signs
Sardonic grin & lock jaw
Blepharospasm
Extensor rigidity of limbs
Exacerbated by excitement
Treatment
Quiet environment
Sedation
Muscle relaxants
Wound treatment
Metronidazole & penicillin
Maybe antitoxin (controversial)