Neuro Flashcards
A “golf tee sign” observed on a myelogram is consistent with…
Intradural (subarachnoid) but extramedullary lesion
Best diagnostic to identify extradural lesions - CT, CT+ contrast or MRI?
MRI
Intramedullary spinal lesions - causes, differential diagnoses
An intramedullary pattern is typically associated with spinal cord edema, expansile parenchymal masses, or intraparenchymal hemorrhage. Differential diagnoses include fibrocartilaginous emboli, neoplasia (e.g., astrocytoma, lymphosarcoma), inflammatory disorders (e.g., granulomatous meningoencephalitis in dogs, feline infectious peritonitis [FIP] in cats), and trauma (e.g., hemorrhage, edema)
Intradural/extramedullary spinal lesions are often caused by…
Intradural/extramedullary patterns are most often associated with neoplasia, primarily meningiomas and nerve sheath tumors
Extradural-pattern spinal lesions are often caused by…
Intervertebral disk extrusion/protrusion is the most common cause of an extradural myelographic pattern. Other causes of extradural patterns include vertebral fracture/luxation, congenital vertebral anomalies, hypertrophied soft tissue structures (e.g., interarcuate ligament, synovial membranes), extradural hemorrhage, vertebral neoplasia, and soft tissue neoplasia (e.g., feline lymphosarcoma)
Most common site for CSF tap; advantage/disadvantage
cerebellomedullary cistern (cisternal tap).
Easy to obtain CSF
If needle penetrates the cord parenchyma and reached the ventral aspect it can lacerate the basilar artery (very serious)
Lumbar CSF tap location for large dogs vs small dogs/cats
Advantages
Large dogs: L4-5
Small dogs/cats: L5-6
Safer than cisternal tap; needle intentionally penetrates the spinal cord but usually does not cause adverse effects
CSF cellular abnormalities associated with Granulomatous Meningoencephalitis
Mononuclear cell pleocytosis refers to a predominance of lymphocytes or macrophages in the CSF.
7 components of the neurologic exam
1) Mentation
2) Gait
3) Posture
4) Cranial Nerves
5) Postural Reactions (proprioception)
6) Spinal Reflexes
7) Nociception
Define Obtunded Vs Stuporous Vs Comatose
Obtunded animals tend to appear depressed, listless, and disinterested in spontaneous activity. Although these patients often appear drowsy, they are easily aroused with a minor stimulus (vocal cues, other noises). Unlike other forms of depression (e.g., those due to metabolic disease), obtunded patients are often described as appearing “out of it.”
Stupor describes a dog or cat that is not conscious but can be aroused with a strong stimulus (e.g., toe pinch).
Coma refers to a state of unconsciousness that persists even after the application of a strong stimulus
Mental statuses most commonly associated with brain stem disease
Stupor or coma
Mental status most commonly associated with forebrain disease (cerebellum and diencephalon)
Obtunded
Trigeminal nerve functions
•Somatic motor to muscles of mastication
•Somatic motor to tensor tympani muscle
•Sensory to most of face
Trochlear nerve function (CN IV)
Somatic motor to dorsal oblique muscle of the eye
Functions of Oculomotor nerve (CN III)
•Somatic motor to most of the extraocular muscles (dorsal, medial, ventral rectus; ventral oblique; levator palpebrae superioris)
•Parasympathetic innervation to pupil (pupillary light response)
Functions of Abducent nerve (CN VI)
Somatic motor to lateral rectus and retractor bulbi muscles (extraocular)
Facial nerve functions (CN VII)
•Somatic motor to muscles of facial expression
•Somatic motor to stapedius muscle
•Parasympathetic innervation to salivary glands (mandibular, sublingual)a and lacrimal, palatine, and nasal glandsb
•Sensory to inner pinna
•Sensory (mechanoreception, thermal) and taste to rostral two-thirds of tongue (chorda tympani nerve)c
Functions of glossopharyngeal, Vagus and Accessory nerves (CN IX, X and XI)
•Somatic motor for laryngeal and pharyngeal function (nucleus ambiguus)
•Parasympathetic innervation to salivary glands (parotid and zygomatic—CN IX)d
•Parasympathetic innervation of viscera (CN X)
•Sensory innervation of pharynx (CN IX and X)
•Sensory and taste to caudal one-third of tongue (CN IX)
Explain Schiff-Sherington posture
This posture is characterized by rigid extension of the thoracic limbs (with preservation of thoracic limb function) accompanied by pelvic limb paresis or plegia. Increased extensor tone to the thoracic limbs is due to the interruption of a group of cells in the lumbar gray matter called border cells, or of those cells’ cranially directed axonal processes (Fig. 38.18). These cells project their axons cranially to tonically inhibit the lower motor neurons (LMNs) of thoracic limb extensor muscles. When the border cells or their axons are disrupted as the result of a spinal cord lesion caudal to the cervical intumescence region, the thoracic limb extensors are “released” from this tonic inhibition. The thoracic limbs have excessive extensor tone (especially when the patient is in lateral recumbency), but there are no associated thoracic limb neurologic deficits. Most patients with Schiff-Sherrington posture have T3-L3 myelopathies, probably because this is a very common neuroanatomic presentation, and most are nonambulatory in the pelvic limbs. This posture is an anatomic phenomenon without prognostic significance. Dogs and cats with lower lumbar spinal cord lesions can also display this posture as the result of interruption of the border cells directly (they are located in the dorsolateral ventral gray matter from L1–L7 spinal cord segments). As there is no brain involvement with this phenomenon, it should not be confused with other postures that display thoracic limb hyperextension (i.e., decerebrate and decerebellate rigidity).
3 types of ataxia
Sensory, vestibular and cerebellar
Wide, side-to-side head excursions during ambulation. Type of ataxia
Vestibular (peripheral or central), bilateral
•Due to interference with ascending spinal cord proprioceptive pathways
•Manifested as a swaying gait
•Toe dragging may be evident
•Clumsy gait
•May fall when turning
Type of ataxia ?
Sensory
Dorsal column (spinal cord) responsible for conscious proprioception. Name the three fascicles and where they are represented in the brain
Fasciculus gracilis, cuneatus and spinomedulary tract. Represented in the contra lateral cerebral cortex
Spinal fascicles conveying unconscious proprioception; where are they represented in the brain
Spinocerebellar tract; cerebellum (no cortex involvement, so no consciousness)
Clonus elicited during tendon reflex tenting is indicative of
Chronic UMN disease
The biceps tendon reflex assesses which nerve? From which cervical vertebral segments does this nerve originate?
Musculoutaneous N; C6-8
The triceps tendon reflex tests which nerves? On which spinal segments does this nerve originate?
Radial nerve, C7 - T1
The patellar tendon reflex assesses the integrity of which nerve? On which spinal segments does this nerve originate?
Femoral nerve, L4-L6
The gastrocnemius tendon reflex assesses the integrity which nerve? On which spinal segments does this nerve originate?
Sciatic nerve, L6-S2
The panniculus reflex assesses the integrity of which nerve? On which spinal segments does this nerve originate?
Lateral thoracic nerve, C8-T1
The perineal reflex assesses the integrity of which nerves? On which spinal segments do these nerves originate?
Sacral spinal cord S1-S3 and various branches of the pudendal nerve
Define spinal shock and it’s typical presentation in dogs
Spinal shock refers to a transient lack of reflex activity caudal to a severe spinal cord lesion; this phenomenon of hypotonia and hyporeflexia with lesions that should cause UMN signs is uncommon and short-lived in dogs and cats compared with humans. A form of this phenomenon may frequently be observed in dogs with spinal cord infarction (fibrocartilaginous embolic myelopathy) in the T3–L3 spinal cord region. These patients typically exhibit UMN signs with the exception of poor withdrawal reflexes; the withdrawal reflex returns to normal within 72 hours
Most important spinal pain pathway and dogs and cats
Spinothalamic tract
IV fluid of choice during cerebral surgery; why
Normal Saline. The blood-brain barrier prevents colloidosmotic pressure from working in the brain, so osmotic pressure becomes more important (sodium).
Three most common types of craniotomy
Transfrontal, rostrotentorial and suboccipital
Important vascular structures to avoid during brain surgery
Dorsal sagittal sinus and transverse sinuses
Most common reason to perform a transfrontal craniotomy in the dog
To remove meningiomas in the olfactory bulb
Surgical approach to relieve Chiari-like malformation
Suboccipital craniotomy
Most common immediate postoperative complications after a craniotomy
Swelling, hemorrhage and cardiovascular dysfunction (brainstem surgery)
Most common and second most common brain tumor in dogs
Meningiomas, followed by gliomas
Most common and severe complication of brain tumor removal in dogs / percentage; mortality rate
Pneumonia, 20%; 50% mortality
Is the reparation of a feline intracranial meningioma advisable?
Yes, the success rate is high and the same as for the initial surgery
Prognosis for secondary brain tumors in dogs and cats
Poor
A “two engine” gait is typically associated with …
Caudal cervical myelopathy. Ambulatory patients with caudal cervical myelopathy tend to have obvious pelvic limb weakness and ataxia, with less severe, sometimes even subtle, thoracic limb dysfunction. In many such cases, the thoracic limbs move with short, stilted steps, whereas the pelvic limbs display obvious ataxia
Serious thoracic limb neurological deficits are more typically associated with Cranial or caudal myelopathy?
Cranial
Define central cord syndrome - affected region, expected neuro deficits, most common causes
A phenomenon called central cord syndrome is sometimes appreciated in dogs and cats with caudal cervical spinal cord lesions that are confined to the central region of the cord. In this syndrome, the thoracic limbs display severe lower motor neuron (LMN) weakness, but the pelvic limbs are minimally affected or neurologically normal. This occurs because the centrally located lesion interferes with LMNs innervating the thoracic limbs, but it spares the more peripherally located white matter upper motor tracts that innervate the pelvic limb LMNs. Central cord syndrome is most commonly associated with intraaxial lesions like syringomyelia and neoplasia
Phrenic nerve - UMN or LMN? Originates on what spinal segments?
LMN, C5-7
Explain the phenomenon or abdominal breathing in the context of cervical spinal lesion
Descending tracts from the medullary respiratory centers traverse the cervical spinal cord to innervate the phrenic nerve LMNs (C5–C7) and the LMNs of intercostal muscles in the thoracic spinal cord. Damage to these tracts can lead to respiratory compromise. Caudal cervical spinal cord lesions that spare innervation to the phrenic nerve LMNs (e.g., lesions caudal to the C5–C7 segments) but disrupt normal activation of intercostal LMNs can lead to the phenomenon of abdominal breathing. In this scenario, the diaphragm bears the sole burden of moving air through the lungs because of the denervated chest wall, and this motion causes the abdomen to visibly move back and forth during respiration.
Explain severe hypotension in the context of cervical myelopathies
Tonic input to the sympathetic LMNs in the thoracolumbar spinal cord that maintain normal blood pressure is provided by neurons in the medulla (rostroventrolateral medulla). Because these medullary neurons send their processes through the cervical spinal cord, cervical myelopathies may be associated with severe hypotension.
Advantages and disadvantages of a dorsal versus ventral approach the cervical spinal cord
Ventral approach - technically less demanding, more bone available for implant placement, limited exposure of the spinal cord, higher likelihood of severe venous sinus hemorrhage.
Dorsal approach - allows wide decompression / access to the dorsal and lateral aspect of the spinal cord, technically more difficult, slower patient recovery, minimal stock for implant placement (articular facets)
What joint in the vertebral column lacks an intravertebral disc?
C1-C2
Name the three ligaments connecting the dens of the Axis to the Atlas
Apical ligament, Alar ligaments and transverse ligament
muscles that must be divided during a ventral approach to the cervical vertebral column
Sternocephalicus and sternohyoideus and longus colli muscles
Two paired muscles to be split and one to elevate during the dorsal approach to the cranial cervical vertebral column
rectus capitis dorsalis muscle cranially and the spinalis cervicis muscle caudally ; elevate the multifidus muscle (C4-C7)
What are the typical differences in the clinical presentation of Type 1 IVDD and HNPE ?
HNPE cases are characteristically peracute to acute and tend to cause fairly severe neurologic dysfunction (nonambulatory tetraparesis or tetraplegia), often without obvious evidence of cervical hyperesthesia; this contrasts with typical calcified type I extrusions, which commonly lead to substantial cervical hyperesthesia that is less frequently associated with severe neurologic dysfunction
Normal and abnormal appearance of the nucleus pulposus on T2-weighed MRI
Normal - hyperintense (The annulus is hypointense)
Degenerative – hypointense
What is the expected clinical presentation in a dog with a cervical type I disk extrusion with a predominant lateral displacement of disk material?
Unilateral cervical pain with or without lameness (Root signature) without proprioceptive or motor deficits
What is the preferred diagnostic modality for the diagnosis of syringomyelia?
MRI
A hyperintense “seagull” appearance of extruded disk material on T2-weighed MRI is consistent with…
HNPE
Inflammatory/infectious conditions that mimic cervical disc extrusion/protrusion
Other diseases that can cause similar or identical signs of cervical disc extrusion/protrusion include inflammatory/infectious conditions (e.g., corticosteroid-responsive meningitis, discospondylitis, granulomatous meningoencephalomyelitis), syringomyelia, traumatic fracture/luxation, neoplasia, and congenital abnormalities (e.g., Chiari-like malformation [CLM], AA instability, atlanto-occipital overlapping [AOO]).
Percentage of dogs likely to experience a positive response to conservative management of type I IVDD characterized by cervical pain with mild to no neuro deficits. Percentage of recurrences
50 to 70% Strict cage restriction, NSAIDs (no steroids) and possibly adjunct analgesics such as tramadol or pregabalin; 30% recurrence
Can HNPE be managed medically?
Yes (Limited number of reported cases). The biochemical nature of the extruded material allows for a more rapid resorption compared with calcified disk material.
Clinical criteria for surgical treatment of type 1IVDD
Repeated episodes of pain, pain that is not responding to medical therapy or severe neurologic deficits (tetraparesis, tetraplegia)
Surgical procedure of choice for a cervical disc extrusion
Ventral slot
Most common complications associated with surgery for cervical disc extrusion/protrusions
Transient neurologic worsening and venous sinus hemorrhage
Overall success rate of surgically managed type 1 cervical disc extrusions in small and large breed Nonambulatory tetra paretic or tetraplegic dogs. Time until return to ambulation
99%; 1 week
What are the two distinct clinical entities associated with the term cervical spondylomyelopathy (CSM), also known as “wobbler syndrome”
Disc associated CSM (DA-CSM) and Osseous-associated CSM (OA-CSM)
Typical signalment of dogs affected by DA-CSM; most commonly affected intervertebral segments
Middle-age to older, large and giant breed dogs (Doberman pinchers). Typically affecting the caudal cervical vertebrae, particularly C5-C6, C6-C7
Pathoanatomy of DA-CSM
Combination of vertebral malformation and malarticulation typically affecting the caudal cervical vertebrae and associated soft tissue structures (disc, articular process joint capsules, dorsal longitudinal ligament and ligamentum flavum). Soft tissue structures become hypertrophied, leading to impingement of the spinal cord
Pathoanatomy of OA – CSM
Congenital bony stenosis of cervical vertebrae most commonly occurring in young large or giant breed dogs (usually 1–3 years, great Dane, mastiff, Bernese mountain dog, Doberman pincher, basset hound). Typically called “ wobbler syndrome” ; has several distinguishing characteristics from DA-CSM. Primarily bony proliferation associated with the articular processes and associated joint capsule, as well as the dorsal lamina and pedicles, usually without substantial disc protrusion. Cystic enlargement of the articular process joint capsule (extradural synovial cyst) may also be observed.
Vertebral segments most commonly associated with OA-CSM
C2-C3 through T1-T2
Breeds commonly affected by DA – CSM
Doberman pincher, Rottweiler
Typical signalment of patients affected by OA-CSM
Young adult giant breeds (great Dane, mastiff) with progressive signs of cervical myelopathy
Typical clinical signs associated with cases of DA-CSM and OA-CSM
Signs of caudal cervical myelopathy with pelvic limbs usually more obviously affected than thoracic limbs. If ambulatory, the patient typically exhibits a stiff, choppy, shuffling thoracic limb gait and an ataxic, wide-based pelvic limb gate (two engine gait). Thoracic limb posture characterized by elbow abduction and internal rotation of the digits. Signs of proprioceptive deficits maybe exacerbated by making the patient walk with a slightly extended head/neck. Patient may be reluctant to walk in this position.
Preferred diagnostic modality and positioning for the diagnosis of CSM
MRI with linear traction views
Possible sources of compression in a patient with DA-CSM (disk associated cervical spondylomyelopathy)
Ventral compression from a malaligned vertebral body, Protruded dorsal annulus, hypertrophied dorsal longitudinal ligament, dorsal compression from hypertrophied ligamentum flavum, lateral compression from hypertrophied articular facets and associated joint capsule tissue.
Can medical therapy be attempted for the treatment of a CSM? If so, what are the recommendations, success rate and the chance of recurrence?
Yes, medical treatment consisting of cage confinement for 3 to 4 weeks, anti-inflammatory medication (prednisone) and potentially the use of a neck brace Is effective in approximately 53% of the cases. Median survival for medical management 3.6 years compared with 5 years for surgical management. Patient treated medically and more likely to be euthanized due to worsening neurologic condition than those surgically treated.
What is the currently favored surgical procedure for the treatment of DA-CSM?
Distraction-stabilization procedures (Not ventral slot) using pin or screw placement into vertebral bodies with a PMMA bridge, and PMMA “plug” insertion into the distracted ventral slot.
What is the surgical procedure of choice for the treatment of OA – CSM?
Dorsal laminectomy
Success rate of the distraction-stabilization techniques for the treatment of DA-CSM
70 to 90%
Four more common Craniocervical junction anomalies (CJA’s)
Chiari-like malformation (CLM)
AA instability
Atlanto-occipital overlapping (AOO)
Dorsal compression at C1–C2
Most common cause of atlantoaxial instability
Hypoplasia or aplasia of the dens
Typical signalment of a dog affected by AA instability
Miniature toy breed dog, younger than two years of age. Yorkshire terrier, Pomeranian, toy poodle, Chihuahua, Pekinese. May occur in cats.
Typical clinical presentation for a dog affected by AA instability, AOO or C-1-C2 dorsal compression
neck pain and varying degrees of ataxia of all four limbs. Nonambulatory tetraparesis and tetraplegia occur in severe cases.
Recommended diagnostic approach to craniocervical junction anomalies CJA’s; Advantages/disadvantages of diagnostics
Radiographs typically diagnose AA instability but require stress views which can be dangerous. MRI is much safer but does not offer a good bone detail. CT offers good detail saw MRI followed by CT is a current recommendation.
Potential complications of AA instability surgery; rationale
Respiratory and cardiac arrest due to damage to brainstem centers
Upper respiratory function disorder such as gagging, coughing and laryngeal paralysis
Aspiration pneumonia, likely due to pharyngeal disorder
Success rate of AA instability surgical treatment; poor prognostic indicators
Above 80%
Length of clinical disease prior to surgery and severity of clinical dysfunction
Most common sites for spinal Arachnoid diverticula
Craniocervical (most commonly over C2 C3) and caudal thoracic regions. Typically located on the dorsal or dorsal lateral aspect of the spinal cord
Breed commonly affected by spinal arachnoid diverticula
Rottweiler, typically in the cranial cervical region. Also pugs and French bulldogs
Typical clinical presentation for dogs with spinal arachnoid diverticulum
Slowly Progressive ataxia and tetraparesis
Typical cerebrospinal fluid analysis results for a patient with spinal subarachnoid diverticula
Mild mononuclear pleocytosis with elevated protein concentration
Most common extradural tumors in dogs
Osteosarcoma, chondrosarcoma, myeloma, fibrosarcoma and hemangiosarcoma
Most common spinal tumor of cats
Lymphosarcoma (primary or metastatic)
Most common intradural/extra medullary neoplasm in dogs
Meningiomas and MNST‘s
Most common site for spinal meningiomas and MNST
Cervical intumescence
Most common clinical feature of extradural and intradural/extra medullary spinal neoplasia
Spinal hyperesthesia
Most common cervical spinal disorders associated with a progressive neurologic decline
Type II disc protrusion, Syringomyelia, CCSM, CJA’s, infectious/inflammatory disorders and neoplasia
Spinal tumors amenable to chemotherapy
Liposarcoma, myeloma, meningioma & glioma
Prognosis for dogs with Spinal MNST’s
Poor, with median postoperative survival of approximately 5 to 6 months. Disease-free interval of approximately one month.
Most common site for cervical fracture’s
C1-C2
Most likely diagnosis for sudden onset of neurological deficits without history of trauma and without spinal hyperesthesia
Fibrocartilagenous embolism
Current thoughts regarding the use of corticosteroids and polyethylene glycol in patients with spinal cord trauma
Corticosteroids have not been shown to be beneficial and significantly increase the risk of gastrointestinal ulcers. PEG has not been shown to be a benefit either.
What are the two primary objectives in the surgical treatment of spinal fractures? Which one should have priority?
Stabilization and decompression. The most pressing goal is stabilization
Bone reduction forcep helpful during stabilization of spinal fractures
ASIF small fragment reduction forcep
Define hemilaminectomy and dorsal laminectomy
Hemi laminectomy is the unilateral removal of the lamina, articular processes and part of the pedicle. Dorsal laminectomy is removal of the dorsal lamina bilaterally, including removal of the dorsal spinous process
Thoracolumbar myelopathies are more commonly associated with upper or lower motor neuron bladder?
UMN
UMN Bladder dysfunction is more common with cervical or thoracolumbar myelopathy?
Thoracolumbar
Thoracic segments in which the articular processes are oriented dorso-eventually
T1-T10
From which intravertebral joint segment caudally are the articular processes located in a sagittal plane, with the cranial articular process joint surface facing medially in the caudal articular process joint surface facing laterally
T10-T11
Anticlinal vertebra
T11
Important surgical landmark for implant placement on the lumbar vertebrae
The “elbow” of the transverse process, oriented cranially and slightly ventral lateral
The order muscles are encountered on a dorsal approach to the thoracic vertebral column
Trapezius, rhomboideus, serratus dorsalis, spinallis and semispinalis
What structures must a surgeon be careful to preserve while performing the tenotomy of the longissimus lumborum muscles during a thoracolumbar approach to the vertebral column
Spinal nerves
The low incidence of intravertebral disc disease cranial to T10 – 11 maybe attributed to which anatomical structure?
Intercapital ligament
Most common site for type one disc extrusion in small breed dogs
T12-T13; T13-L1
Most common site for type I intravertebral disc extrusion in large dogs
L1-L2; L2-L3
Does the degree of spinal cord compression or the presence of multiple disc extrusion‘s affect prognosis For return to normal function in dogs with type one IVDD?
No
Typical indication for a lateral corpectomy
Tape 2 IVDD
Define the Cobb angle it how it applies to clinical practice
The Cobb angle is derived from the intersection of two lines: one of the cranial aspect of the kyphotic vertebral segment and the other on the caudal aspect of the segment. Angles above 35° are associated with a higher chance of neurologic dysfunction in dogs with vertebral Kyphoscoliosis formation
Most common methods employed in the stabilization of kyphoscoliotic vertebral segments
Modified segmental spinal fixation (spinal stapling) and vertebral body pins with PMMA
Spinal Nephroblastoma - Typical location, predisposed breed and age range
Thoracolumbar region, typically between 10th thoracic and third lumbar vertebrae, typically extra medullary intradural, six months to three years of age, German shepherds
Extradural spinal mass in a young cat. Most likely diagnosis
Lymphoma
Define “pseudohypereflexia”
The patellar reflex may appear hyperreflexive when the inhibitory action of the stifle flexion muscle group is removed by disruption of the nerve supply to these muscles. This is frequently the case with cauda equina syndrome, when contributing roots to the sciatic nerves are affected.
Nerve injury classification - explain
Class I: neurapraxia
Class II: axonotmesis
Class III: neurotmesis
Are dogs with transitional lumbosacral vertebrae more predisposed to DLSS?
Dogs with transitional lumbosacral vertebrae are eight times as likely to develop DLSS
Breed most commonly affected by degenerative lumbosacral stenosis (DLSS); typical clinical presentation
German Shepherd, presumably due to the high incidence of transitional lumbosacral vertebrae and articular facet joint tropism (asymmetry between left and right processes)
Chronic history of pain and unilateral or bilateral lameness with or without pelvic limb weakness. Difficulty rising, inability or unwillingness to climb stairs, scuffing of the toenails in the back limbs, muscle atrophy of the caudal thighs, urinary or fecal incontinence, abnormal tail carriage, biting/chewing at the base of the tail or paws
Typical physical examination findings in patients with DLSS
Lumbosacral pain on palpation (Most common finding), progressive loss of pelvic limb proprioception, followed by loss of motor function (weakness) typically associated with the area of the sciatic nerve. Deficient pelvic limb withdrawal reflex at the level of the hock[(Flexion of the hip and stifle remain normal)
Preferred diagnostic procedures for the diagnosis of DLSS
MRI, followed by Discography and epidurography
Typical age of dogs affected by solitary or multiple cartilaginous exostosis or spinal lymphosarcoma
Less than 1 year
Most likely cause for lysis of an intervertebral foramen
Nerve root tumor (neurofibroma, meningioma)
Are steroids indicated prior to spinal surgery?
No, steroids have not been shown to protect spinal tissue/nerve roots.
MRI features associated with canine cognitive dysfunction syndrome
Decreased interthalamic adhesion thickness; enlarged ventricles, brain atrophy
Protein that accumulates in the brains humans and dogs with cognitive dysfunction syndrome
Neurotoxic Beta amyloid (neurotoxic A-beta)
The main proposed biochemical imbalance observed in the brains of dogs and humans with cognitive dysfunction syndrome
Catecholamine disfunction
drug to improve cognitive function and decrease hyperexcitability in animal models of cognitive disfunction.
Levetiracetam; potential mechanisms of action include improved central nervous system mitochondrial function and associated improved synaptic transmission come out inhibition of beta amyloid-induced astrocyte glutamate release.
Area of the spinal cord typically affected by degenerative myelopathy
T3-L3
Only definitive diagnostic test for degenerative myelopathy
Necropsy
Major differential diagnosis for degenerative myelopathy
Type II IVDD
Most common causes of strokes in dogs
Hypothyroidism, followed by chronic renal disease and hyperadrenocorticism
Breed most commonly affected by cerebellar ischemic/vascular events. Why…
Cavalier King Charles spaniel
Presumably due to this breeds propensity to develop heart disease, inherited platelet abnormalities, or to local aberrations in regional arterial blood flow resulting in Chiari like malformations (CLMs)
Most common cause of myelopathy in schnauzer
FCE
Typical clinical presentation of FCE
Set an onset of acute discomfort during exercise, followed by non-progressive paraparesis or paralysis without discomfort. Focal discomfort can typically be elicited at the site of infarct in the first 12 hours.
Most common Nuro anatomic localization of FCE
T3-L3, followed by L4-S1
Typical T2-weighed appearance of FCE on MRI
Hyperintense
Contrast enhancement varies depending on timing Since onset
Acute onset of T3-L3 Myelopathy with spinal hyperesthesia. Most likely diagnosis in Staffordshire terrier versus border collie
Staffordshire terrier – FCE
Border collie - HNPE
C1-C5 spinal compressive lesion - FCE or HNPE more likely?
HNPE
Histological character of GME
Perivascular infiltrates of primarily mononuclear cells (lymphocytes, macrophages and plasma cells)
Presumed etiology of GME
Autoimmune, specifically delayed type hypersensitivity reaction ( T cell mediated)
Brain tissue most commonly affected by GME, three clinical forms
White matter. Focal, multifocal and ocular
Necrotizing encephalitis (NE) – two distinct disorders, hystopathological features
Necrotizing Meningoencephalitis (NME) and necrotizing Leukoencephalitis (NLE). Both similar and characterized by multiple cavitary necrotic nonsuppurative inflammatory brain lesions that involve both gray and white matter.
