Neurology | Musculoskeletal Flashcards
Opening Na channels causes depolarization/hyperpolarization of the neuronal cell, while opening K channels causes depolarization/hyperpolarization of the neuronal cell.
Depolarization/hyperpolarization
What are three neurolocalizations for a completely recumbent animal?
Brainstem lesion, cervical lesion, neuromuscular
Opisthotonus with extensor rigidity of the limbs, but with the hips flexed localizes to where?
Severe cerebellar lesion
opisthotonus with rigid extension of the neck and all four limbs localizes to where?
Rostral cerebellar and/or midbrain
Contralateral CP deficits would be present in neuroanatomic localization where?
cerebrum and/or thalamus
What can cause delayed paw placement test?
Diminished CP, weakness, defect in other accessory sensory pathways (spinocerebellar tract), rarely normal pets
Patellar reflex is mediated by what nerve from which spinal cord segment?
femoral nerve through spinal
cord segments L4-L7
Nerve and spinal cord segments for bicep reflex? Tricep reflex?
The musculocutaneous
nerve mediates the biceps reflex through spinal cord segments C6-C8. The radial nerve mediates the triceps reflex through spinal cord segments C7-T2.
What nerve and segments mediate the pelvic limb withdrawal/flexor reflex?
sciatic nerve through spinal cord
segments L6-S1
Manifestation of CN IV abnormality in dog?
lateral deviation of retinal vein (in cats they have dorsomedial strabismus)
Which cranial nerve can manifest as megaesophagus with abnormalities (either as primary cause or in association with CN abnormality)?
CN 10 (vagus nerve)
Medial strabismus associated with abnormalities of which CN?
CN6
Localize the lesion:
Left pupil normal size, Light in left eye, only left pupil constricts, positive menace response
Right pupil complete dilation, Light in right eye, no pupil constricts, negative response
Right retrobulbar
Localize the lesion:
Left pupil dilated, light in left eye = only right pupil constricts, positive menace response
Right pupil normal, light in right eye = only right pupil constricts, positive menace response
Left oculomotor nerve
Gait is normal in forebrain lesions. T/F?
True - critical UMNs responsible for gait generation in domestic species (rubrospinal and reticulospinal tracts) are spared, being located more caudally in the midbrain, pons,
and medulla
With peripheral vestibular lesions, the fast phase of the nystagmus is away from
the lesion; the opposite is true for central lesions. T/F?
False -central lesions can be away or towards
Hypermetric gait is associated with a lesion where?
Cerebellar
What would be pelvic limb gait of a dog/cat with polyneuropathy and sciatic dysfunction?
Because sciatic dysfunction does not affect weight bearing, the pelvic limb gait is not short-strided. Despite being a LMN problem, an exaggerated pelvic limb gait is present in which the pet repeatedly initiates the gait from a plantigrade position and “flings” its pelvic limbs forward
Localization for fine, whole body tremor?
Diffuse CNS disease [dysmyelinogenesis, diffusemeningitis (idiopathic tremor syndrome, disseminated granulomatous meningoencephalomyelitis, infectious
meningitis) and various toxicoses (e.g., molds, algae, ethylene glycol).]
Cranial nerves associated with brainstem lesions?
CV5-12
Most metabolically demanding area of brain (thus metabolic differentials and toxicities usually result in these signs)
Forebrain
What type of central edema is generally treatable with steroids and osmotic therapies?
Vasogenic (not interstitial - from obstructive hydrocephalus or cytotoxic - from ischemia)
General treatments for hydrocephalus?
Steroids +/- seizure meds; or carbonic anhydrase inhibitors or proton pump inhibiitors; diuretics [mannitol for acute signs]
Excessive scratching of the neck
vocalization and facial rubbing with CP deficits in a Brussels Griffon should raise concern for what disease?
Chiari-like malformations (CM) and syringohydromyelias (other breed is CKCS)
First signs of lysosomal storage diseases?
Cerebellar signs of dysmetria, truncal ataxia, and nystagmus
In terms of intracranial neoplasias, dolichocephalic breeds are more likely to have ____, while brachycephalic breeds are more likely to have _____
Meningioma, glioma
Secondary neoplasia accounts for how much of all canine intracranial tumors?
50%
When does consensus recommend epileptic treatment for dogs?
(1) identifiable structural lesion or prior history of brain disease or injury; (2) acute repetitive seizures (status epilepticus) has occurred; (3) interictal period is < 6 months (i.e., 2 or more seizures within 6 month period); (4) prolonged, severe or unusual post-ictal periods; and (5) epileptic seizure frequency and/or duration is increasing and/or seizure severity is worse over three interictal periods
Dog breeds least likely to go into remission or have > 50% decrease in seizure activity?
Border Collie, German Shepherd Dog and Staffordshire Terrier
Dog breed over-represented for ischemic stroke?
Greyhound
Diseases that predispose to nonhemorrhagic ischemic stroke?
metabolic disorders (hypothyroidism,
pheochromocytoma, hypertension), sepsis, parasitism, cancer, or hypercoagulopathy (diabetes mellitus, hyperadrenocorticism, renal disease, protein-losing nephropathy)
Causes for hemorrhagic stroke?
coagulopathy (including Angiostrongylus vasorum), hypertension (can cause microbleeds), toxins, trauma, sepsis, inflammation, and metastasis (hemangiosarcoma)
NOTE - hemorrhagic strokes can be hemorrhagic ischemic or hemorrhagic stroke
Canine degenerative myelopathy (DM) - pathogenesis & disease stages?
Late-onset progressive neurodegenerative disease affecting many pure and mixed-breed dogs. Homogenous clinical spectrum within and across breeds. 4 stages of disease progression (see table).
CSx - multisystem neurodegeneration, resulting from progressive axonal
degeneration of the central and peripheral NS. Superoxide dismutase 1 gene (SOD1) mutations (SOD1:c.118A, SOD1: c.52T) are risk factors for DM, mostly autosomal recessive inheritance. Note SOD1 mutations are incompletely penetrant, so genetic screening is insufficient for diagnosis - ideally need spinal cord histopath.
