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Spinal disease in practice, No obvious pain: Do not necessarily exclude…
Spinal disease in practice
How to recognise an animal with spinal disease
Spinal disease often characterised by
ataxia and paresis
spinal cord carries motor and sensory info - unlikely that only the ascending sensory tract (ataxia) or motor tract (paresis) affected alone
Gait abnormalities and neurological deficits
only occur when spinal cord affected
Disorders not involving spinal cord such as meningitis, will not result in ataxia or paresis
spinal cord itself has
no pain receptors
surrounding structures, such as meninges, intervertebral disc and periosteum have abundance of pain receptors
intrinsic spinal cord disorders e.g. degenerative myelopathy, will not be painful
clinical signs
ataxia
and
paresis
spinal hyperaesthesia
bladder dysfunction
neuro exam
Proprioceptive deficits
increased or decreased spinal reflexes
enables localisation to be narrowed down
Specific sequence of progressive neurological deficits (recovery occurs in opposite direction)
Proprioceptive deficits
Paresis and ataxia
Plegia
Bladder dysfunction
Tail dysfunction
Pain sensation/nociception
Obtain a reliable list of differentials
1)Onset
Per-acute (=seconds)
Spinal fracture or luxation
Ischaemic myelopathy (FCE)
Acute non compressive nucleus pulposus extrusion (ANNPE)
Acute
Intervertebral disc extrusion
herniation of the nucleus pulposus through the annular fibres and extrusion of mineralised nuclear material in the spinal canal
disc extrudes through the dorsal annulus causing ventral, ventrolateral or circumferential compression of the spinal cord
typically affects chondrodystrophic breeds (peak 4-6y/o) and is acute onset
often thoracolumbar region
The predominant sign of cervical disc herniation is neck pain, manifested as cervical rigidity and muscle spasms. There may be thoracic limb lameness or neurologic deficits, ranging from mild tetraparesis to tetraplegia.
In thoracolumbar disc herniation, there may be back pain, evident as kyphosis and reluctance to move. Neurologic deficits are usually more severe than those seen in cervical disc disease and range from pelvic limb ataxia to paraplegia and incontinence.
In paraplegic animals, the most important prognostic finding is whether there is deep pain perception caudal to the lesion. This is assessed by pinching the toe or tail and observing whether there is a behavioral response, such as a bark or turn of the head. It is important to pinch the bone to stimulate deep pain receptors, not just the skin, which tests only superficial pain. Reflex flexion of the limb must not be mistaken for a behavioral response.
differential diagnoses
trauma
FCE
discospondylitis
neoplasia
(meningo)myelitis
Definitive diagnosis
cross sectional imaging
radiography
Narrowing of intervertebral disc space
wedging of the disc space
narrowing of the intervertebral foramen
mineralised material in the spinal canal or superimposed over the intervertebral foramen
myelography
MRI
CT
surgery
Treatment
Medical
first time incident of spinal pain only
mild to moderate paraparesis
financial constraints of client (only indication for non-surgical treatment of a recumbent patient)
management
strict cage rest for 4-6 weeks
pain relief using anti-inflammatory drugs, opioids and muscle relaxants
1 more item...
gastrointestinal protectants may be necessary with use of anti-inflammatory drugs
Acupuncture is possible for pain management
monitor closely for deterioration of neurological status or persistence of pain, if worsens surgery is recommended
Methylprednisolone sodium succinate (MPSS) has been advocated as an adjunctive treatment for acute disc herniations causing paraplegia and loss of nociception
Recovery rates in non-ambulatory dogs are lower and recurrence rates higher following medical rather than surgical treatment
If ambulatory with pain only or mild paresis success 82-100%
Surgical
spinal pain or paresis unresponsive to medical therapy
recurrence or progression of clinical signs
non-ambulatory paraparesis or paraplegia with intact nocipeption
paraplegia without nociception (>48 hours)
prolonged loss of nociception over 48hr has a poor prognosis - owners should be aware of this.
Chronicity of disc extrusion at time of surgery may influence the ease with which the extruded disc material can be removed
myelitis
meningitis
discospondylitis
Chronic
Degenerative myelopathy
lumbosacral stenosis
intervertebral disc protrusion
type 2 herniation
any region of spinal cord caudal to C1-2
usually occurs at the mobile points of the spinal column
myelopathy usually seen in older animals of large non-chondrodystrophic breeds
cause: fibroid degeneration and weakening of the dorsal annulus
-> bulging of the nucleus pulpous within the weakened annulus fibrosus
-> protrusion of the disk into the vertebral canal to cause spinal cord compression
this chronic compression can lead to fiscal ischaemic and other microvascular derangements of the spinal cord
clinical signs
slowly progressive
pelvic limb general proprioceptive ataxia
weakness
reluctance to rise or jump onto furniture and difficulty climbing stairs
localisation is focal with asymmetrical or symmetrical weakness
paraspinal hyperaesthesia may be present
diagnosis
may be suspected on routine spinal radiographs that show degenerative changes to the spinal column e.g. spondylosis
myelography, CT myelography or MRI needed to locate the spinal cord compression
treatment and prognosis
medical
early-onset type II IVDD and mild deficits
also indicated in animals that are concurrently affected with suspected degenerative myelopathy
NSAIDs or corticosteroids
muscle relaxant e.g. diazepam, methocarbamol
consider in patients with spinal hyperaesthesia
not always responsive and surgical decompression may offer a better long term outcome
surigcal
type of surgical decompression depends on location of the lesion
hemilaminectomy
for lesions in the thoracic spine and lumbar spine cranial to L5
dorsal laminectomy if lesion located in lumbosacral area
prognosis
if surgery early then fair to good when patients are considered refractory to medical therapy
if disease has coursed for several months and associated with severe neurological signs e.g. paraplegia then prognosis is guarded
Neoplasia
Congenital
Intra-arachnoid cysts/arachnoid diverticulum
focal accumulations of CSF within the subarachnoid space. Accumulation over time causes progressive compression of the spinal cord and neurological deficits related to the site of compression
clinical signs
apparent predisposition of rottweilers and pugs
tetra paresis, paraparesis and ataxia
typically chronic
can present with faecal or urinary incontinence as an early sign
neck pain may be present
treatment
surgery is recommended
medical management may improve a small proportion of dogs but only recommended in animals mild neurological deficits
controlled exercise
anti-inflammatory doses of prednisolone
monitor regularly and surgery recommended if deterioration occurs
prognosis
good for young dogs with mild signs treated surgically
signs may recur in approx. 1/3 of dogs in the longer term
outcome is not as good in older dogs with a long history of clinical signs and surgery should be approached with caution in these animals
Acute or chronic
neoplasia
intervertebral disc protrusion
acute disc extrusion is characterised by the presence of soft disc material within the vertebral canal and extradural haemorrhage
chronic disc extrusion is characterised by extradural fibrous adhesions around herniated disc material, which becomes a hard mineralised mass.
2)Progression
Not progressive, spontaneous improving
Ischaemic myelopathy (FCE)
acute non compressive nucleus pulposus extrusion
Confirm with MRI
Sudden extrusion of non-degenerated (liquid) nucleus pulposus causes
contusion
, but no spinal cord compression
Typically during strenuous activity (60%) or during external trauma (40%)
Surgery not indicated
Intense physiotherapy and hydrotherapy
Good prognosis for functional recovery if deep pain sensation present
Not progressive, static
trauma
ischaemic myelopathy (fibrocartilaginous embolism)
Often during strenuous activity
intense physiotherapy and hydrotherapy
early intervention with rehabilitation aids recovery
can take up to 2 weeks until improvement is seen
can be dramatic over 1st 7 days and continues 1-3 months following injury (depends on extent of injury)
good prognosis for functional recovery if deep pain sensation present (nocioception preserved on affected side)
Clinical signs
often in the lumbosacral or brachial intumescence
usually large, young, non chondrodystrophic breeds
Shetland sheepdogs, miniature schnauzers and yorkshire terriers often have signs localised to C6-T2 spinal cord segment
often dramatically lateralised, resulting in hemiparesis
involvement of the sympathetic tracts in the cervical spinal cord
Horner's syndrome
vasodilation on the affected side
differential hyperthermia (detect by comparing temperature of front feet or external pinnae)
Pathogenesis
Fibrocartilage embolisms in spinal cord vasculature, causing an area of ischaemic necrosis entered on the spinal cord grey matter (lateralised signs as embolus usually lodges in distal arterial branch)
Diagnosis
Absence of spinal pain
Differentiate from
Cervical disc herniations
These animals often have neck pain
Survey radiographs unremarkable and no evidence of spinal cord compression
On T2-weighted MRI the infarcted area is visible as an intraparenchymal hyperintensity
CSF: disproportionately elevated protein and neutrophilic pleocytosis
acute non compressive nucleus pulposus extrusion
Progressive
Myelitis
Meningitis
Discospondylitis
Intervertebral disc disease
Degenerative myelopathy
neoplasia
congenital
Intermittent
cervical problems can cause episodic clinical signs
3) Symmetry
Clear
(only when obvious for owner)
asymmetry
/lateralisation of clinical signs
Ischaemic myelopathy (FCE)
acute non compressive nucleus pulpous extrusion
caudal lumbar IVDE
Degenerative myelopathy (early stage)
4) Pain
Non-painful
Vascular
fibrocartilaginous embolism
Acute non-compressive nucleus pulposus extrusion
Intramedullary neoplasia
Degenerative myelopathy
Myelitis
Often painful
intervertebral disc (related) disease
Extra medullary neoplasia
Always painful
meningitis
Discospondylitis
Spinal pain is most common initial sign
signalment
intact male, large, young- middled-age dogs
rare in toy and chrondrodystrophic breeds of dogs
rare in cats
pure bred dogs more commonly affected than mixed breeds
Proliferation of inflammatory tissue, compression of neural tissue can lead to ataxia, paresis and occasionally paralysis depending on where lesion located
approx. 30% od dogs have signs of systemic illness such as fever and weight loss
Pathogenesis
infection of the intervertebral disc and adjacent vertebral endplates
if confined to the ventral body = osteomyelitis/spondylitis
Coagulase +ve Staphylococcus spp most common
haematogenous spread from distant foci of infection (urogenital tract, skin, oral cavity)
in all cases diagnostic investigation of potential systemic infectious foci should be considered
abdominal USS: prostatic or renal disease
thoracic USS: pulmonary disease
cardiac USS: endocarditis
penetrating wounds/surgery/plant material migration
immunosuppression e.g. hyperadrenocorticism
Diagnosis
Haematology
changes not usually present unless concurrent conditions e.g. endocarditis
urine cytology
may reveal bacterial or fungal agents
blood and urine cultures should be performed in all suspected cases
positive in up to 75-50% of cases
test before initiating antibiotic therapy
serology for brucellosis (zoonotic potential) reported positive in up to 10% of cases
Diagnosis
Spinal radiographs usually lead to definitive diagnosis
radiographic changes may not be present for first 2-4 weeks of infection
can be a multifocal disease, so entire spine should be imaged
radiographic evidence
narrowing of disc space
subtle irregularity of both endplates through to gross lysis and osseous proliferation of the adjacent vertebral bone and even fractures
can also be used fro monitoring response to treatment/progression of disease
If radiographic evidence treatment for the common pathogen Staphylococcus intermedius should be initiated
potentiated amoxicillin
cefalexin
CT + MRI
Percutaneous needle aspiration of the disc space be performed to obtain tissue for bacterial/fungal culture and cytology
if urine and blood culture and brucellosis serology have not identified an etiological agent
Requires GA, sterile surgical prep and fluoroscopic/CT guidance of needle
usually only performed in patients who are unresponsive to initial broad spectrum antibiotics
complete neurological resolution may take 2-3 months after treatment
Osteolytic lesions
Trauma
fracture
Luxation
5) Signalment
Species
Breed
Age
young
congenital
e.g. congenital hydrocephalus
infectious
E.g. neosporosis
old
degenerative
e.g. degenerative myelopathy
Neoplastic
e.g. meningioma
(Sex)
6) Localisation
Forebrain
Brainstem
Cerebellum
Neuromuscular
Spinal cord
C1-C5
C6-T2
T3-L3
L4-S3
Appropriate care for non-ambulatory patients
prevention of 2ry complications
Urinary tract infections
Bladder rupture
Permanent bladder wall atonia
urine scalding
decubital ulcers
joint and muscle contractions
enhance mental well-being
Soft and washable bedding
Regular turning if necessary (every 4 hr)
Physio and hydrotherapy
promotes blood flow through affected limbs
decrease risk joint and muscle contractures
limits effects of muscle disuse or denervation
limits effects of spasticity and muscle rigidity
improves muscular strength
stimulates proprioceptive input and facilitates re-education pathways for balance and gait
improves control of pain
minimises period of recumbency
motivating and improving mental wellbeing - patient and owner
Mental well-being influences neurological recovery e.g. sit dog outside, toys
Bladder management
paraplegic animals considered unable to urinate until proven otherwise
urinary incontinence = loss of ability to fill and empty bladder involuntarily
Upper Motor neuron bladder
typically seen in disorders affecting the T3-L3 spinal cord segments
Large and full bladder
Feels firm and turgid
Resistance to manual expression
important
development of UTI
damage bladder wall by overstretching
overstretching can result in persistent bladder atony
urine leaking resulting in skin irritation (urine scalding)
methods
manual bladder expression
repeated aseptic catheterisation
indwelling catheter with closed collection system
Lower motor neuron bladder
typically seen in disorders affecting the L4-S3 spinal cord segments
decreased and flaccid bladder tone
constant leaking of urine
can be easily expressed
90% of dogs with spinal disease are represented by these 10 conditions
1) Hansen type I intervertebral disc disease
2) Hansen type II intervertebral disc disease
3) Ischaemic myelopathy
4) spinal neoplasia
5) Syringomyelia
6) Meningoencephalitis
7) Acute non-compressive nucleus pulposus extrusion
8) Lumbosacral disease
9) Cervical spondylomyelopathy
10) Steroid responsive meningitis arteritis
11) subarachnoid diverticulum
4 most common causes of acute paralysis in dogs
acute hansen type I intervertebral disc extrusion
The nucleus pulposus undergoes dehydration and becomes calcified, losing its gelatinous consistency.
The annulus fibrosis can now rupture and this can be accompanied by sudden extrusion of fragmented, calcified and hard nucleus pulposus into the vertebral canal.
results in acute spinal cord contusion and sustained spinal cord compression
common in chondrodystrophic dogs between 3-7 y/o
at risk breeds: Dachshund, French Bulldog, Cocker spaniel, shih-tzu + beagle
acute onset and often progressive clinical signs
Severity often graded
· Grade 0: Paraplegia with absent deep pain perception
· Grade 1: Paraplegia with absent superficial pain perception
· Grade 2: Paraplegia with intact pain perception
· Grade 3: Non-ambulatory paraparesis
· Grade 4: Ambulatory paraparesis
· Grade 5: Spinal pain without neurological deficits
Diagnosis
Myelography
CT scan
MRI
survey radiographs can be supportive/suggestive, but
cannot
be used to make final diagnosis
most specific radiographic abnormality is
narrowing of the intervertebral disc space
note: intervertebral disc space between T10 and T11 is always physiologically narrowed
note: intervertebral disc spaces at the periphery of the radiograph will appear narrowed due to radiographic distortion. Only intervertebral disc spaces in the centre of the radiograph should therefore be evaluated
may see radiopaque material in the vertebral canal and narrowing of the intervertebral foramen
Radiographic calcification of the intervertebral disc should not be considered a reliable indicator of intervertebral disc disease, as it is seen in many neurologically normal chondrodystrophic dogs
Spondylosis deformans ventral of the intervertebral disc also seen in neurologically normal dogs
Around 85% of thoracolumbar intervertebral disc extrusions occur between T11 and L2
Management
Ambulatory dogs (grades 5 + 4) are typically managed
MEDICALLY
Strict rest, anti-inflammatory and analgesic drugs.
NSAIDs +/- opioids common
strict rest avoids further extrusion of the calcified nucleus pulposus
gives opportunity for the ruptured annulus fibrosis to heal
corticosteroids contraindicated
Surgery recommended in non-ambulatory dogs or dogs not responding to appropriate medical management
associated with very good prognosis, as long as deep pain perception present (if not 50% of dogs have a good outcome)
often not recommended when pain perception lost for a period greater than 24h
dogs should not be discharged from hospital if unable to urinate voluntarily
medical management is possible if owner does not want to refer
first signs of improvement typically only seen after several days
most dogs will be able to walk again, although ataxic and paretic, 4 weeks after surgery
acute non-compressive nucleus pulposus extrusion
Pressure in the intervertebral disc becomes excessively high and the healthy intervertebral disc can suddenly rupture and the nucleus pulposus extrudes with forces into the vertebral canal.
can cause substantial spinal cord contusion
paracute onset of severe clinical signs
the liquid nucleus pulposus dissipates quickly and so spinal cord compression will not be present.
surgery never indicated for this condition
can occur after external trauma
differentiate from vertebral fracture and luxation
usually only mildly painful in first 24h
differentiate from ischaemic myelopathy
some persistent ataxia can be seen, as can partial or complete urinary and faecal incontinence
ischaemic myelopathy/fibrocartilaginous embolism (FCE)
vascular disorder characterised by paracute spinal cord infarction caused by embolism of fibrocartilage tissue
due to segmented nature of spinal cord vasculature, ischaemia and near deficits can be asymmetrical (lateralised)
vertebral fracture and luxation
Less common causes of acute paralysis
hydrated nucleus pulposus extrusion (HNPE)
Myelitis
Acute cervical hyperaesthesia without neurological deficits
acute type I intervertebral disc extrusion
French bulldogs can present atypically to other breeds
intermittent episodes of violent vocalising
muscle fasciculations in the caudal cervical/shoulder area
Steroid responsive meningitis arteritis
breed predisposition: beagles, boxers, nova scotia duck tolling retrievers and bernese mountain dogs
clinical presentation typically consists of
pyrexia
stiff gait
severe cervical hyperaesthesia
lethargy
blood results often show leucocytosis
diagnosis by CSF
often respond to prolonged period of corticosteroids
An initial immunosuppressive dose is started, consisting of 2mg/kg BID until the dog demonstrates obvious improvement. This is usually seen in the first 24 to 48 hours. The dose is then changed to 1mg/kg BID and continued for 2-4 weeks. The dose is slowly tapered over the following 4-6 months.
syringomyelia
formation of fluid filled cavities in spinal cord caused by alterations in cerebrospinal fluid flow
most prevalent in the cavalier king charles spaniel
associated with chiari-like malformation or overcrowding of the skull
clinical signs variable
cervical hyperaesthesia
spontaneous episodes of vocalisation
reluctance to exercise
rubbing the face
phantom scratching towards the neck and shoulder region
caused by abnormal sensory processing
can be induced sometimes by touching the shoulder region
majority of patients is treated medically with a combination of anti-inflammatory drugs (NSAIDs) and gabapentin (10mg/kg BID or TID).
may use drugs that slow CSF production (omeprazole, cimetidine)
type II intervertebral disc protrusion
neoplasia
cervical spondylomyelopathy (wobblers syndrome)
Meningomyelitis of unknown aetiology
immune mediated polyarthritis
Most common feline spinal disorders (bold = acute onset)
1) Neoplasia (non-lymphoid) - 19.9%
spinal lymphoma
compared to other feline spinal neoplasia has a more acute onset and more rapid progression of clinical signs
2) Degenerative intervertebral disc disease - 19.0%
3) Spinal fracture and luxation - 15.4%
4) Ischaemic myelopathy - 10.0%
5) FIP virus myelitis - 8.1%
6) Spinal lymphoma - 7.2%
7) Thoracic vertebral canal stenosis - 5%
8) Acute non-compressive nucleus pulposus extrusion (ANNPE) - 5%
9) Traumatic spinal cord contusion - 3.6%
10) Spinal arachnoid diverticulum - 3.2%
No obvious pain
: Do not necessarily exclude painful conditions
Pain
: exclude non-painful conditions