Neurology 2 Flashcards
What is degenerative myelopathy?
Degeneration of axons + myelin in the thoracolumbar spinal cord
Genetic–mostly in German Shepherds
What are the signs of degenerative myelopathy?
- Over months (6-36) progressive paresis and ataxia
- Palpation very important–must differentiate from hip dysplasia (in which steroids would improve condition)
- > 8 yrs–German Shepherds and others–Chesapeake, Boxer, Corgi, Ridgeback, Standard poodle, Kerry blue
- Pelvic limb
- Knuckling, dragging, crossing (walk in tight circle–back legs swing out/cross), dysmetria, ataxia
- Often see scuff marks on dorsal aspects of digits
- Often asymmetrical
- Continence + pain spared (still feel pain on hind legs)
- Later get LMN signs
- Knuckling, dragging, crossing (walk in tight circle–back legs swing out/cross), dysmetria, ataxia
- Progressive = eventually will affect front limbs
In a dog with degenerative myelopathy, what will you find during a clinical exam?
- Conscious proprioeptive deficits (possibly)
- Scruffy motions, will leave paw upside-down when you displace it, etc.
- UMN signs:
- Hyperreflexia
- Normal pain sensation
- No spinal hypesthesia (not painful when palpaiting down spine)
How do you diagnose degenerative myelopathy? How do you treat it?
- Diagnosis
- Histopath–not practical
- Exclusion–no changes on x-rays; normal CSF
- Myelin basic protein elevated?
- Could be, but it increases when anything goes wrong with the spinal cord–isn’t specific to DM
- DNA test–superoxide dismutase 1 protein
- Not all animals with the gene are affected, but 100% of the animals affected have the gene
- Treatment
- NONE–cortico’s, NSAIDs, B + E vit do nothing
- Good nursing/physiotherapy - months - euthanasia
- Aminocaproic acid/aminocysteine
- Supposedly worked in trial, but no paper ever published (= sketchy)
Lumbosacral malarticulation-malformation (instability)
Particularly in working dogs–transfer of forces (back legs to front)
Type II disc degeneration–general
See pain + LMN signs
Annulus fibrosis, interarcuate ligament
Doesn’t act as a shock absorber anymore
What instability is seen with type II disc degeneration?
- Stenosis
- Sacral facet osteophytes
- L7 and S1 can move from side to side (normally fixed in place)–> continues to damage cauda equina by trapping it between the two vertebrae
- Yellow ligament can thicken–> pressure on cauda equina from above
What is the signalment and history of type II disc degeneration?
- Signalment
- Older, large breed, working dogs
- History
- Hunched
- Takes away pain or could be from losing function of sciatic nerve
- Rising/stairs, flacid tail,
- Incontinent (far down the line)
- Hunched
What is seen during the physical exam of a dog with type II disc degeneration?
- Pain
- Palpation L7S1
- Lordosis test (won’t differentiate from hip problem)
- Tail jack test
- Better test–localizes pain to L7S1 joint
- Paresis
- Sunken hock
- Sciatic and flexor
- Pudendal (hyporeflexia)
- Hyperreflexia in patella
- Sciatic n. not functional to act against the knee jerk reflex
- Tail
- Only hip flexes–controlled by femoral n.
What is the diagnosis?
Type II disc degeneration (lumbosacral instability)
What is this? In which breed is it most common? What does it predispose the dog to developing?
Transitional vertebrae–most common in GSD
The vertebra is joining the pelvis on one side and making a transverse process on the other
Dogs with this instability are predisposed to developing lumbosacral instability
What is the treatment for lumbosacral instability (type II disc degeneration)?
- Cage rest + NSAIDs don’t do much–working dogs don’t rest well
- Dorsal laminectomy +/- stabilization (80%)
- Incontinence +/- response
- Drill away ‘roof’ of bone so cauda equina is no longer compressed
- Various materials used–problematic
Thoracolumbar intervertebral disc disease–general
- 70% of neuro cases
- Discs (not C1/C2)–shock absorbers, movement
- 2 types of degeneration
- Aging
- Fibrocartilage vs. hyaline cartilage
- Aging
What are the 2 types of disc disease/prolapse?
- Hansen type I
- Chondrodystrophic breeds >3 yr
- Explosive extrusion (like a bullet–painful)
- Acute progression, hyaline degeneration
- Can feel within spinal cord–gritty, very painful
- Dorsal longitudinal ligaments
- Spinal cord compression
- Cuts off blood supply–> all kinds of problems, including neuro dysfunction
- Hansen type II
- Large breed dogs >5 yr
- Slow protrusion
- Dorsal ligaments
- Fibrocartilage degeneration (heals, then ruptures more, heals some, ruptures more, etc.)
- Worse prognosis
What are the signalments for thoracolumbar intervertebral disc disease?
- Adults 3-5 yr
- Dachs > Poodles > Peeks > Beagles
- Cats–50-100%
- Calcifications common, problems rare
- Occasional pain/paresis
Diskospondylitis
- Bacterial infection of end plate and disc
- S. intermedius, B. canis + Strep
- Hematogenesis–skin, urinary, heart, testes
What are the signs associated with diskospondylitis?
- Large, middle-aged male dogs
- Hansen type II
- Hyperesthesia (severe back pain), fever, depression, weight loss
- Untreated:
- Proliferation
- Spinal cord compression + neuro signs
- Creates space between vertebrae–> body tries to seal off infection with bone–> protrudes–> pressure put on sc
- Any dog that comes in with fever + back pain–> THINK DISKOSPONDYLITIS–don’t want to wait until neuro signs appear
How do you diagnose diskospondylitis?
- Spinal cord signs + systemic signs
- Radiographs–lysis, sclerosis, spondylosis (C6/7, T4-6, L7S1)
- Will see ‘hot spots’ in bone–where inflammation is occurring (more RBCs)
- CSF normal–infection is in bone, not spinal cord
- Serology–Brucella **zoonosis**
What are the generaly types of vertebral and spinal neoplasias? Which are more common in dogs and cats?
- Intramedullary (tumor within spinal cord)–primary and mets
- Intradural-extramedullary
- Extradural
- Dog
- 50% ost/fibro/chon
- 30% - meningiomas
- 20% - hemangiomas
- Cat
- lympho - FeLV 80-90%
- Meningiomas
- Any cat with progressive spinal cord dysfunction
What is this an example of?
Intramedullary spinal neoplasia
Vertebral columns get wider and wider because the tumor is creating pressure–> causes them to expand
What causes most vertebral fractures/luxations? What are the signs? Diagnosis?
- Trauma–sacroiliac/thoracolumbar
- Lumbosacral most common
- Tail tugs in cats
- Signs
- History, wounds, fracture, nails, shock
- Can see LMN signs for up to 24 hrs
- Spinal hyperesthesia/anesthesia paresis/paralysis, crepitus, alignment, Shiff-Sherrington
- Diagnosis
- Radiographs/myelograms
What miscellaneous vertebral fracture occurs in Bostons and Bulldogs?
Hemivertebrae–L/R fusion
Laminectomy if signs severe (rare)
What is this an example of?
Blocked or fused vertebrae
