Clinical Cases Flashcards

Question

Most common form of CNS blastomycosis? What are the most common systemic manifestations of blastomycosis?

Answer 1

Sinonasal and intracranial; ventriculitis w/ systemic disease NonCNS - Respiratory, lymphatic, ocular Vet Clin N. America

Answer 2

Aspergillus - Multifocal brain lesions +/- sinonasal lesions on MRI, also discospondylitis Histoplasmosis - Multisystemic disease + meningoencephalitis Vet Clin N. America

Answer 3

Cladophialophora bantiana and Coccidiomycosis Vet Clin N. America

Answer 4

1. fluconazole 2. voriconazole (neurotoxic in cats!) 3. posconazole 4. liposomal or lipid complex amphotericin B altered mental status - neg prognostic indicator Vet Clin N. America

Answer 5

CPP = MAP - ICP Cerebral blood flow = CPP / cerebral vascular resistance Cerebral vascular resistance: Ln/πr⁴ L = vessel length, n = viscosity, r = vessel radius * cerebral vascular resistance is controlled via pressure autoregulation (ability to maintain constant CBF and ICP from MAP 50 - 150mmHg) * influenced by PaCO2 * influences vessel diameter Vet Clin N. America

Answer 6

Mild head injury - 89% had skull fractures 11% had intracranial hemorrhage Severe head injury - 96% had hemorrhage Vet Clin N. America

Answer 7

1. Excitotoxicity 2. Depletion of ATP 3. Production of ROS 4. NO accumulation 5. Lactic acidosis Vet Clin N. America

Answer 8

Severely increased ICP --\> CBF decreases --\> CO2 accumulates locally Vasomotor center of the brain detects increase in CO2 --\> Increase sympathetic tone --\> peripheral vasoconstriction --\> increases MAP Baroreceptors sense hypertension --\> reflex bradycardia Vet Clin N. America

Answer 9

1. Motor activity 2. Brainstem reflexes 3. Level of consciousness Studies have shown that an MGCS of **8** within the first 48 hours of hospitalization approximates a 50% probability of survival Animal trauma triage: In dogs with head trauma, a score of **9** approximated 50% survival A recent retrospective study determined the strongest predictor for nonsurvival was a decreased MGCS Vet Clin N. America

Answer 10

75 minutes Colloids should not be used - leakage of albumin through a disrupted BBB may create oncotic shifts, promote edema formation leading to increased ICP and mortality * synthetic colloids have not been evaluated, only albumin Vet Clin N America

Answer 11

Immediately - osmotic effect expands the plasma volume, reduces viscosity, improves microcirculatory flow * Reduction in viscosity --\> reflex vasoconstriction of pial arterioles 15-30 minutes - osmotic gradient across BBB forms, persists for 2-5h, and shifts fluid from the brain into the intravascular space Also acts as a free radical scavenger \*\* in people, no difference in outcome has been found between patients with intracerebral hemorrhage that did or did not receive mannitol \*\* Concurrent use of furosemide is unproven Vet Clin N America

Answer 12

As concentrations increase \> 1 - 1.5x minimum effective alveolar concetration, ICP increases * At lower concentrations, vasodilatory effects of inhalants may improve CPP * If the ICP is increased, inhalants are contraindicated and total IV anesthesia is recommended * Propofol improves cerebral perfusion and maintains pressure autoregulation better than inhalant anesthetics * May be neuroprotective via modulation of GABA receptors, antioxidant effects * May cause hypotension and hypoventilation Vet Clin N America

Answer 13

Posttraumatic epilepsy: 3.5 - 6.8% Standard population epilepsy: 1.4% Vet Clin N America

Answer 14

PaCO2 Vet Clin N America

Answer 15

1. **Aplasia or hypoplasia of the cerebellar vermis** * Pyramis, uvula, and nodulus lobules involved in several dogs (hemispheres and flocculus also affected in some) * Retrograde degeneration of brainstem nuclei 2. **Cyst-like dilation of the 4th ventricle** * Fluid-filled cyst-like structure continuous with a dilated 4th ventricle that fills the posterior fossa 3. **Hydrocephalus** * Lat aperatures appear normal * Hydromyelia not usually a feature * believed to be a disorder of fusion of dorsal midline structures of the primitive neural tube * +/- syringomyelia and agenesis of the corpus callosum (Braund)

Answer 16

1. Idiopathic polyradiculoneuritis/coonhound paralysis 2. Botulusm 3. Tick paralysis 4. Acute fulminating myasthenia gravis Weakness: all acute tetraparesis/tetraplegia with areflexia except TP - normoreflexia in mild cases; MG - normoreflexia CN: Dysphonia/aphonia for all Facial weakness - APN, MG Megaesophagus/dysphagia - botulism, MG Mydriasis/decreased PLR - botulism CSF - elevated protein in APN, rest normal Other - APN - hyperesthesia; Botulism - decreased mentation, urinary retention/incontinence; MG - urinary retention EMG - increased spontaneous activity in APN, rest normal CMAP - decreased amplitude in all except MG MNCV - normal in all excent APN - normal or mildly slow F-wave: normal ratio/latency in all except APN - slow F wave latency and prolonged ratio Supramax RNS - normal or incremental response for botulism; decremental response MG Less common: 1. Coral snake evenomation 2. Blue and green algae intoxication 3. Black widow spider evenomation (later stages) 4. Other rare toxicities (lasalocid in cattle feed) 5. Polymyositis (Vet Clin N America)

Answer 17

1. Contact with racoon saliva 2. Recent vaccination (especially Rabies) 3. Recent upper respiratory viral infection 4. Recent bacterial/viral GI infection 5. Toxoplasma gondii infection Biopsy: 1. Axonal degeneration 2. Paranodal/segmental demyelination 3. Infiltration of inflammatory cells (cells vary acute vs. chronic) * Lumbar/sacral ventral roots more severely affected * MILD involvement of the dorsal roots 4. Denervation in muscle (Vet Clin N America) (Vet Clin N America)

Answer 18

A recent study in dogs has demonstrated the presence of anti-GM2 ganglioside ABs in the sera from a high percentage of dogs with APN * In general IgG or IgM most common * Demonstration of anti-GM2 circulating ABs in serum has shown diagnostic sensitivity of 60% and specificity of 97% Strong evidence for a role of cell-mediated immunity * initial breakdown of blood-nerve-barrier is induced by the release of IFN-gamma from circulating activated T cells * Autoreactive CD4+ T cell interaction with APCs --\> clonal proliferation of B cells --\> production of antiganglioside, antiglycolipis, and antimyelin protein antibodies Fun fact - APN usually has INTACT pernieal reflex (Vet Clin N America)

Answer 19

* EMG - spontaneous activity (after day 4) * CMAP - decreased amplitude/increased temporal dispersion * MNCV - normal or mildly decreased * F wave latency, ratio - prolonged latency, decreased amplitude, increased ratio * Sensory nerve conduction - normal or mild decrease "All these findings indicate a _motor neuron axonopathy_ affecting the entire length of peripheral nerves, more severe in the _proximal portions_ of motor nerves, ventral nerve roots, or both. In addition, prolonged F-wave latencies and ratios indicate there is also _demyelination in the ventral nerve roots and proximal portions of motor nerves_." (Vet Clin N America)

Answer 20

Dogs and cats - type C Horses - B and C Cattle - C and D Clostridium botulinum = G+ spore forming, anaerobic (DeLahunta)

Answer 21

1. Ingestion of preformed toxin in a feed source (most common) 2. Ingestion of spores in the soil 3. Wound infection with organisms (Vet Clin N America)

Answer 22

* Ingestion of spores/bacteria --\> lysis of cells/spores --\> release of progenitor BoNT * BoNT stable at low pH, once reach small intestine the alkaline pH causes dissociation of progenitor toxin and release of BoNT * Small intestinal endocytosis of BoNT --\> lymphatic --\> blood * BoNT reaches cholinergic nerve junctions * Rapid and specific binding of BoNT to neuronal surface receptors (irreversible, susceptible to antitoxin, differences in affinity explain species susceptibility)n * Internalization of BoNT into endosome (no longer susceptible to inactivation) * Membrane translocation * Enzymatic cleavage of SNARE --\> inhibit docking and fusion of synaptic vesicles --\> LMN paralysis and autonomic dysfunction * Clinical signs develop in 6h - 6 days. More toxin --\> more rapid/severe clinical signs * Autonomic clinical signs: tachycardia/bradycardia, mydriasis, slow PLR, constipation, urinary retention, KCS (Vet Clin N America)

Answer 23

Loss of exernal anal sphincter tone and megaesophagus Botulism diagnosis * Mouse innoculation test - demonstrate BoNT in blood, feces, vomit, stomach contents or spoiled food * ELISA, mass spectrophotometry, PCR - measure activity of BoNT by cleavage of artificial substrates * Less sensitive than mouse inoculation test * Demonstration of 4x increase in BoNT-antibody titer All affected dogs recover spontaneously in 14-24 days unless secondary complications develop The Veterinary clinics of North America. Small animal practice

Answer 24

Dermacentor variabilis (American dog tick) Dermacentor andersoni (Rocky mountain wood tick) Female tick ! (those bitches) (Vet Clin N America)

Answer 25

Neurotoxin is created in the salivary glands of the female tick Tick bites --\> neurotoxin enters the bloodstream --\> interferes with the function of CALCIUM in the release of ACh from axon terminal Clinical signs: * Develop 5-9d after exposure, P is recumbent in 24 - 72 hrs * Spinal reflexes depressed/absent (stretch reflexes lost before withdrawal) * Urethral and sphinchter functions unaffected * Nociception normal, hyperesthesia absent * CN LMN signs uncommon (occasionally ME) (Vet Clin N America)

Answer 26

Antibodies bind NICOTINIC AChR --\> prevent attachment of ACh Once the antibody is bound, the entire unit is internalized into the muscle/no longer available Lg abundance of receptors provides a safety factor - many are spared from this antibody binding Fuminating form - antibodies are able to bind to nearly all of the receptors (Vet Clin N America)

Answer 27

Focal MG: esophagus, laryngeal muscles, facial muscles Acquired MG - bimodal distribution of age (3y ad 10y) in both dogs and cats Breeds: * Akitas * Scottish terriers (and other terriers) * German shorthair pointers * Chihuahua * German shepherd * Golden retrievers * Labs * Dachshunds * Observed in Newfoundlands and litter of great dane puppies * Cats - Abyssinian and Somali (Vet Clin N America)

Answer 28

Abnormal structure of AChR, insufficient # of AChR have developed, defect in ACh resynthesis/repackaging Treatment: some respond to acetylcholinesterase therapy, occasionally grow out of it (usually fatal) Diagnosis: biopsy external intercostal muscle --\> Localization of AChE, AChR, AChR subunits, EgG and complement components at the NMJ, Total volume of AChR determined (only helpful when deficiency of AChR is the cause) Positive tensilon test can be consistent with diagnosis of acquired MG but does not differentiate it from autoimmune acquired MG. Autosomal recessive gene in: Smooth fox terrier, Parson russel terrier, Honsehund (also Brahman calves - PCR DNA test is available) Reported in: Springer spaniel, miniature smooth dachshund, samoyed RARE IN CATS (Vet Clin N America)

Answer 29

\<5% of dogs, 25% of cats have a thymic mass Hypothyroidism in dogs with acquired myasthenia gravis has a significant incidence (causation unclear) Methimazole --\> acquired MG in cats Electrodiagnostics (not recommended) - RNS --\> immediate decrement in the response of the muscle (improves after tensilon) (Vet Clin N America)

Answer 30

Onset between 6 and 16 weeks of age, most within 2 mos of age * Generalized weakness and ataxia (worse in the PL) * Hypermetric gait * Abnormal proprioceptive placing * Normal reflexes (exception of 1 dog) * INSPIRATORY STRIDOR - consistent clinical feature due to laryngeal dysfunction * Other: positional strabismus, intention tremor, nystagmus * Some dogs with this disorder had concurrent ocular abnormalities Progression over several weeks. There is no treatment and the prognosis is grave Boxer dogs presented at 2 mos of age

Answer 31

* Forebrain and cerebellar dysfunction * Onset approximately 1 year of age * Progresses over several months * No treatment, prognosis grave (Dewey)

Answer 32

1. Cerebral vascular changes (blood vessel wall fibrosis), microhemorrhages 2. Meningeal thickening 3. Gliosis 4. Cerebral atrophy/ventricular dilation 5. Progressive accumulation of beta-amyloid in and around neurons * Form neuritic plaques most prominent in the frontal cerebral cortex and hippocampus * The degree of beta-amyloid accumulation correlates with degree of cognitive impairment 6. Intraneuronal accumulation of tau protein * The tau protein does not form neurofibrillary tanlges 7. Amyloid deposition (meningeal and parenchymal 8. Axonal degeneration with myelin loss 9. Astroglial hypertrophy and hyperplasia 10. Intraneuronal accumulation of lipofuscin, polyglucosan bodies, ubiquitin) (Dewey)

Answer 33

DISHAAL * Disorientation/confusion * Interactions/social relationships abnormal * Sleep-wake cycles abnormal * House soiling * Activity (increased/repetitive or apathetic/depressed) * Anxiety * Learning and memory abnormal (Dewey)

Answer 34

* irreversible inhibitor of monoamine oxidase B * Reported to restore dopaminergic balance * Enhance catecholamine levels * Decrease free radicals * Questionable if it works (Dewey)

Answer 35

RI and VB ratio were both significantly higher in clinically hydrocephalic dogs compared with dogs having ventriculomegaly with no signs of dysfunction * RI changed with changes in neurologic status EEG - slow-frequency, high voltage activity (Dewey)

Answer 36

Bind to alpha-2-delta-1 subunit of GABA receptor --\> inhibit calcium influx Pregablin has higher affinity for the alpha2-delta-1 subunit Gabapentin half life 3-4 hrs Pregablin half life 7 hrs (Dewey)

Answer 37

Forebrain signs/seizure Cerebellovestibular dysfunction Neck pain Lissencephaly/pachygyria and polymicrogyria * Lissencephaly/pachygyria - reduced numbers, or the absence of gyri on the surface of the cerebral hemispheres and an abnormally thickened, histologically disorganized cerebral cortex * Clinical signs - prosencephalic dysfunction, seizures @ 10-12mos * Most common in the lhasa apso * Also described in the wirehaired fox terrier, Irish setter, Korat cat * Polymicrogyria - excessive small gyri on the cerebral cortex * Described in 4 related standard poodles that also displayed asymmetric dilation of the lateral ventricles * Disorganization of the cerebral cortex was also evident histologically in these standard poodles

Answer 38

1. Increased circulating levels of aromatic amino acids 2. Increased circulating benzodiazepine-like substances 3. Increased glutamine, decreased glutamate --\> oxidative damage and astrocyte mitochondria dysfunction 4. Increased GABAergic tone 5. Changes in serotonin metabolism 6. Astrocyte accumulation of manganese --\> oxidative damage Acute HE - major pathologic consequence is cerebral edema and raised intracranial pressure Chronic HE - major consequence is neurotransmitter dysregulation

Answer 39

Hyperosmolality/hypernatremia --\> shrinkage of brain parenchymal cells --\> stretching and tearing of small intracranial blood vessels - hemorrhage * Intracellular dehydration and hemorrhage may contribute to encephalopathy * Chronic hypernatremia: brain produces idiogenic osmoles to compensate for increased extracellular osmolality. Correction of hypernatremic state --\> cerebral edema * Chronic uremia also causes hyperosmolality and rapid dialysis can cause dialysis disequilibrium syndrome via same mechanism * Ketotic and nonketotic diabetes mellitus can both contribute to hyperosmolality (Dewey)

Answer 40

Hyponatremia can result in swelling of brain parenchymal cells with subsequent brain edema - compensates by EXTRUDING cosmetically active particles (potassium, amino acids) * Hyponatremia is corrected --\> axonal shrinkage due to relative lack of intracellular osmolality and subsequent demyelination in the brainstem (particularly thalamus) similar to central pontine myelinolysis in people

Answer 41

Decreased excitability of neuronal cell membranes (Dewey)

Answer 42

All dogs with a poor outcome (3/18) had an elevated CRP, there was a trend for the median CRP to be higher in the dogs with a poor outcome ROC analysis - CRP concentration of \> 8.6 was 100% specific for predicting a poor outcome Retrospectice study (ACVIM 2017)

Answer 43

Galactosylceramidase (GALC) Similar MST * Survival time for stereotactic radiation therapy was approximately 371 in one study, (240 days progression-free interval) (ACVIM 2017)

Answer 44

540 - 900 days (ACVIM 2017)

Answer 45

True * Although some of these abnormalities often also produce some degree of scoliosis, this does not seem to have a substantial additional impact on the development of neurologic impairment Doberman Pinscher and German Shorthaired Pointer (Dewey et al)

Answer 46

Block Vertebrae (Vet Clin N America)

Answer 47

Right: Ventral aplasia Left: ventral wedge-shaped (Vet Clin N America)

Answer 48

Left: lateral hemivertebra Right: lateral wedge shape (Vet Clin N America)

Answer 49

Left: Doso-lateral hemivertebra Right: Butterfly vertebra (Vet Clin N America)

Answer 50

* Age at presentation - 60% under 1 year, 40% over 1 year * Sex predilection: none * Most common location: usually between T6 and T9, in one report, T7 was the most commonly affected vertebra, followed by T8 and T12 (Vet Clin N America)

Answer 51

Q alb = CSF albumin / serum albumin x 100 Elevation suggests disrupted BBB Q IgG = CSF IgG / serum IgG x 100 Serum IgG concentrations are at least 1000x higher than those in the CSF - there is a strong association between the 2 values Elevations suggest intrathecal IgG production IgG index = Q IgG x Q alb Elevation suggests intrathecal IgG synthesis and BBB dysfunction Can also use antibody index and the goldman-witmer coefficient - techniques that are believed to be more accurate than the IgG index as they use antigen-specific antibody titers rather than total IgG IgM is not normally found in CSF - presence of IgM in serum and/or CSF is considered more specific than IgG or total immunoglobulin levels for detection of active infectious diseases (De Terlizzi) (De Terlizzi)

Answer 52

CRP - bacterial vs. viral meningoencephalitis Myelin basic protein - suggests active demyelinating process in DM (study also confirmed relationship between MBP level and severity of demyelination) (De Terlizzi)

Answer 53

Hemocytometer is used Chamber is placed in a humidified environment for 10-15 minutes to allow the cells to settle to the surface of the glass Neubauer chamber - total cells in all 9 squares are counted, average of 2 counts x 10⁹ = cells / uL Fuchs-Rosenthal chamber, total cells present in 16 x 1mm2 areas are counted x 10⁹ = cells / uL (De Terlizzi)

Answer 54

Phase microscopy - used to differentiate RBCs from WBCs in the haemocytometer chamber When an unstained specimen is examined, it is necessary to lower the microscope condenser to reduce the light intensity Alternatively, the cells may be stained with a small amount of new methylene blue stain (De Terlizzi)

Answer 55

Viral nonsuppurative encephalomyelitis, neoplastic disease, traumatic, vascular, degenerative, and compressive spinal cord lesions Essentially, nonspecific finding (De Terlizzi)

Answer 56

MMP9 (De Terlizzi)

Answer 57

Slow-speed centrifugation and acceleration to concentrate cells from 100 - 400uL into a small circular area on a glass slide * Cellular detail is excellent because the elements are gently spread out on the slide * Alternative method is sedimentation. Cell morphology considered better with cytocentrifugation, BUT the greater number of cells on sedimentation preparations were thought to be more accurate in calculating leukocyte differential. Cell yield and LDIF on cytocentrifugation preparations is imprecise Artifactual changes in the cells: 1. Increased vacuolation 2. Alteration in structure particularly of monocytoid cells and macrophages Cytospin is air dried and stained with Romanowsky stains (De Terlizzi)

Answer 58

10% or less in dogs (8% or less in cats) (some authors have suggested that the presence of neutrophils or eosinophils in the CSF is indicative of an abnormality) Monocytes \> lymphocytes \> neutrophils \> macrophages \> eosinophils \*\*small lymphocytes and mononuclear cells predominate in dogs; monocytes predominate in cats (De Terlizzi)

Answer 59

1. Trauma 2. Hemorrhage 3. Post myelographic meningitis 4. Bacterial, fungal infections, FIP 5. Immune-mediated disease (SRMA) 6. Neoplasia 7. Severe seizures SRMA and necrotizing vasculitis - neturophilic response Neutrophils well preserved, non-degenerate or hypersegmented CSF culture neg for bacteria Neutrophilic pleocytosis \> 500 cells/uL with neutrophil % between 75 - 100% Of patients that had abnormal CSF w/ meningioma, most had neutrophilic pleocytosis (suspected from tumor necrosis) (De Terlizzi)

Answer 60

\> 70% = mononuclear pleocytosis * Also increase in number of monocytoid/macrophages * Reactive lymphocytes w/ normal TNCC = CNS disease * Ex/ CNS viral dz * Canine distemper - mild to moderate lymphocytic pleocytosis * CSF in CDV may show an increase in macrophages (De Terlizzi)

Answer 61

80% lymphocytes Lymphocytic pleocytosis seen in: * CDV * GME * NLE/NME * CNS lymphoma * Ehrlichiosis * Toxoplasma/Neospora * Bacterial meningitis following treatment (De Terlizzi)

Answer 62

1. GME (most common cause) 2. Chronic SRMA 3. Infections (fungal, ehrlichia, Toxoplasma/Neospora, Protothecosis) 4. Trauma/vascular (Disc, myelomalacia, ischemia/infarction) (De Terlizzi)

Answer 63

1. Steroid-responsive eosinophilic meningitis 2. Infection (Toxo/Neospora, fungal, aberrant parsitic migration, CDV, Rabies) (De Terlizzi)

Answer 64

\<5 cells/uL in the dog \<8 cells/uL in the cat \< 25-30mg/dL for cisternal \< 45mg/dL for lumbar (Sharkey)

Answer 65

* Pigs - hog cholera, swine fever, circovirus * Sheep - BVD and border disease * Cattle - BVD (de Lahunta)

Answer 66

Burmese cats * Observed most often with onset at 2-6 mos old in Burmese kittens * Hypokalemia is from excessive loss through the kidneys * Genetic studies - mutation of WNK4 gene (de Lahunta)

Answer 67

Centronuclear (Type II deficiency) Autosomal Recessive Polymyopathy in labrador retrievers * Muscle biopsy: * Variation in muscle fiber size * Depletion of type II muscle fibers * Few cells with centrally positioned nuclei but no necrosis of cells * Light and EM show progressive changes in: * Internal tubuloreticular and sarcolemmal membranes * Triads * Mitochondria * Mutation in PTPLA gene * ABSENT PATELLAR REFLEX * Serum CK is normal/slightly elevated * EMG - few denervation potentials or bursts of CRD

Answer 68

1. Coral snake 2. N American rattlesnake * Both cause postsynaptic blockade of neuromuscular junction * Rapid onset of clinical signs (de Lahunta)

Answer 69

Chlorpyrifos and fenthion - acetylcholinesterase inhibitors * Accumulation of ACh --\> blockade at the receptor --\> LMN paralysis * Clinical signs within minutes to hrs of exposure * Diagnosis via history and decreased levels of cholinesterase in the blood * Tx: atropine for muscarinic signs, pralidoxime chloride for nicotinic signs * In some toxicities, diphenhydramine may help block action of the toxin (de Lahunta)

Answer 70

Sex-linked muscular dystrophy * Deficiency of dystrophin * * Hypertrophy of: * Pharyngeal and laryngeal muscles * Caudal thigh * diaphragm * Atophy of: * Most axial and appendicular muscles * Diagnosis: * Dystrophinopathy - muscle fiber necrosis is severe - elev CK (severe), AST, ALT * * Muscle biopsy: * * Extensive muscle cell necrosis * * Lg accumulation of macrophages * * Fibrosis * * Satellite cells = regeneration * * Immunohistochemistry - lack of dystrophin in the muscle cell membrane * * Sex-linked recessive gene * * Only male dogs clinically affected * * Carrier female - may have elev. CK but rarely clinical signs * * Young male dogs presented for fatigue while exercising, inactivity, slow growth * * * * (de Lahunta)

Answer 71

Collapse after vigorous exercise Juvenile or young adult dogs when they are engaging in strenuous activity with a high level of excitement Mutation in dynamin 1 gene (deLahunta)

Answer 72

Lymphoma (de Lahunta)

Answer 73

Radial nerve (de Lahunta)

Answer 74

Suprascapular nerve * May cause a slight lateral deviation, abduction or lateral buckling of the shoulder when weight is borne on that limb * Denervation atrophy of the supraspinatus and infraspinatus (de Lahunta)

Answer 75

Autosomal recessive, more common in males Onset of clinical signs from 1-3 years Dying back neuropathy - sciatic and recurrent laryngeal (de Lahunta)

Answer 76

Autosomal recessive in Tibetan Mastiffs Clinical signs start between 7-12 weeks and progress rapidly Nerve biopsy - Widespread demyelination and Schwann cell hyperplasia, onion bulb formation with minimal axonal degeneration (deLahunta)

Answer 77

Gracilis, semitendinosus, semimembranosus (de Lahunta)

Answer 78

Tibial nerve dysfunction (innervates extensors of the tarsus) Rupture of part or all of the common calcanean tendon Fracture of the calcaneus Disrution of the long plantar ligament Rupture of the gastroc tendon with the SDF spared --\> tarsus overflexes and the digits flex because of stress put on intact superficial digital flexor that attaches to the calcaneus DDx w/ ultrasound

Answer 79

Rhabdomyolysis On BW - severe elev. CK/muscle enzymes (de Lahunta)

Answer 80

1. Hypokalemia 2. Thiamine deficiency 3. Hyperthyroidism 4. MG 5. Diabetes mellitus 6. Polymyositis 7. Organophosphate toxicity 8. Cervical myelopathy CBC/Chem including CK, thyroxine, AXR, TXR, cervical rads, AChR titer, serology for FeLV/FIV, cryptococcus, T. gondii (de Lahunta)

Answer 81

Deviation of the nose Narrowed palpebral fissure - suggests the levator anguli oculi medialis muscle plays a significant role in the eyelid elevation in horses and farm animals Occasionally, this fissure is slightly smaller on the affected side (de Lahunta)

Answer 82

Ipsilateral spinal nucleus of the trigeminal nerve --\> GSE neurons of BOTH facial nuclei (de Lahunta)

Answer 83

Otitis media

Answer 84

Dysphagia - involvemet of pharyngeal branches of CN 9 and 10 Epistaxis - erosion of the internal carotid or maxillary artery Other neurologic signs: * Laryngeal hemiparesis (vagus involvement) * Horner (cranial cervical ganglion or its postganglionic axons on the internal carotid nerve) * Facial nerve paresis * Hypoglossal paresis * Vestibular (rare) (de Lahunta)

Answer 85

Auditory tube Dorsocaudal aspect of the medial compartment * Pharyngeal branches of 9 and 10 course ventrally adjacent to this medial compartment --\> pharyngeal muscles (de Lahunta)

Answer 86

Microscopic study of the recurrent laryngeal nerves shows an axonal degeneration and demyelination that is most pronounced at the larynx and decreases in the retrograde direction * Current hypothesis is that this is a dying back neuropathy, unable to maintain such long axons * Both nerves are affected * Denervation atrophy occurs on both sides but is worse on the left side * Similar lesions may be seen in the distal branches of the sciatic nerve where they innervate the crural muscles Left recurrent laryngeal nerve has a longer course, passes around the ligamentum arteriosum and aortic arch before continuing cranially along the trachea to the larynx Right only has to pass around the right subclavian artery (de Lahunta)

Answer 87

Innervates: extrinsic tongue muscles, intrinsic tongue muscles, geniohyoideus Clinical signs: impaired function of the tongue in prehension, deglutittion, mastication and phonation Most reliable clinical sign in unilateral dysfunction is unilateral tongue atrophy, may have muscle fasiculations (de Lahunta)

Answer 88

Moldy corn poisoning - ingestion of fumonisin B1 (mycotoxin produced by Fusarium moniliforme) Sudden destruction of cerebral white matter sometimes results in dysphagia (de Lahunta)

Answer 89

Listeriosis * L. monocytogenes * Predominance of lesions are in the pons * Various combinations of facial paralysis and vestibular ataxia are the most common clinical signs (ddx otitis media internal) * Treated with high doses of penicillin, fair prognosis if the cow is still standing (de Lahunta)

Answer 90

GVE dysfunction - dilated pupil that is unresponsive to light GSE dysfunction - ptosis and ventrolateral strabismus. Does not adduct well on testing normal nystagmus (de Lahunta)

Answer 91

* Congestion of the bulbar conjunctiva * Fundic exam - congested retinal blood vessels * Warmer, pinker skin on the side affected * Due to peripheral vasodilation of the head * Nasal mucosa - * Vasodilation --\> decreased airflow --\> increased tissue rigidity * Disinhibition --\> increased nasal gland secretion * Results in accumulation of dried secretion (crusts) within the naris * Sympathetic innervation to the nose: * Cr. cervical ganglion --\> internal carotid artery --\> sympathetic fibers leave as the deep petrosal nerve --\> join the major petrosal nerve (parasympathetic fibers from the facial nerve) --\> nerve of the pterygoid canal (sympathetic and parasympathetic fibers) --\> pterygopalatine ganglion (only parasympathetic fibers synapse here) --\> caudal nasal nerve --\> nasal cavity Loss of parasympathetic innervation to the nasal mucosa --\> loss of moisture from the lateral nasal gland --\> hyperkeratosis (de Lahunta)

Answer 92

All domestic animals except the horse, sweating is decreased on the surface of the body that is deprived of its sympathetic innervation * Called hypohydrosis or anhidrosis * Difficult to appreciate except on the nasal planum of the ox (de Lahunta)

Answer 93

Sympathetic paralysis --\> excessive sweating (hyperhidrosis) in the area of the skin that is denervated * Often the initial clinical sign that is observed (especially if the disorder is acute) * If the paralysis persists, sweating may decrease with time (may remain present at the base of the ear) * ( loss of sympathetic innervation to the head may be an early sign of equine grass sickness ) (de Lahunta)

Answer 94

Smaller palpebral fissure Palpable hyperthermia of the ear Miosis and protrusion of the third eyelid are subtle Cattle - less sweating occurs on the planum nasolabiale on the affected side Vasodilation in the nasal mucosa --\> narrow airway --\> difference felt on expiration (de Lahunta)

Answer 95

Starts at the cervicothoracic ganglion --\> follows vertebral artery into the transverse foramen of C6 and continues cranially through these foramina to C1 All axons are ganglionic axons As it passes between each cervical vertebra, it supplies a ramus to the cervical spinal nerve at each of the intervertebral foramina (de Lahunta)

Answer 96

Tropicamide Atropine (Slatter)

Answer 97

Direct acting (stimuate adrenoreceptors same way norepinephrine would) * Epinepherine (penetrates eye poorly, causes systemic effects) * Phenylephrine * Dipivefrin (epinephrine prodrug) Indirect acting * Hydroxyamphetamine - facilitates neuronal release of norepinephrine * Cocaine - prevents reuptake of norepinephrine (Slatter)

Answer 98

Direct-acting * Pilocarpine - directly stimulates the muscarinic receptors on smooth muscle cells of the pupillary sphincter and ciliary body * Effective even in the denervated eye * Increased lacrimal production * Side effects - salivation, vomiting, diarrhea Indirect acting * Physostigmine - cholinesterase inhibitor * Organophosphate - inhibit cholinesterase (rarely used due to potential for toxicity, especially if OP flea/tick preventative) * ex/ Demecarium, carbachol (Slatter)

Answer 99

Instill 0.2 - 1% pilocarpine into the conjunctival sac of both eyes * If the eye w/ horner responds (pupil dilation) BEFORE the contralateral (normal) eye --\> denervation hypersensitivity --\> suggests ganglionic neuron (after cr. cervical ganglion) is abnormal * If the eye w/ horner responds slowly - suggests preganglionic lesion Denervation hypersensitivity - following sympathetic denervation of the ocular muscles, there is increased sensitivity of the iris muscle to neurotransmitters (Slatter)

Answer 100

Mild compression of the rostral brainstem --\> miosis (increased activity of oculomotor GVE) Continued compression --\> mydriasis (loss of oculomotor GVE) (de Lahunta)

Answer 101

Cat - slips of striated muscle from the lateral rectus and levator palpebrae superiors attach to the 2 extremities of the eyelid and may actively contribute to its protrusion Experimental medullary lesion that affect the cerebellar nuclei --\> protruded third eyelid but the clinical signs of cerebellar ataxia predominate (de Lahunta)

Answer 102

Clinical syndrome that involves dysfunction of the cutaneous distribution of sympathetic nerves * Chronic pain with localized hyperalgesia * Clinical signs of dysregulation of the cutaneous sympathetic innervation include * Hyperthermia, hypothermia * Hyperhidrosis, hypohidrosis * Edema * Trauma of some sort is usually a precipitating event at some time in the history of the patient * Reported in horse and dog (de Lahunta)

Answer 103

0.6 - 0.75% (Task Force)

Answer 104

Seizure (Task Force)

Answer 105

Epileptic seizure (Task Force)

Answer 106

Reactive seizure A provoked seizure is considered synonymous with reactive seizure (Task Force)

Answer 107

Epilepsy This definition is usually practically applied as having at least 2 unprovoked epileptic seizures \> 24h apart (Task Force)

Answer 108

Idiopathic epilepsy: * Genetic epilepsy - causative gene for epilepsy has been identified/confirmed genetic background * Suspected genetic epilepsy - a genetic influence is supported by: * A high breed prevalence \> 2% * Genealogical analysis * And/or familial accumulation of epileptic individuals * *"It seems very likely that the genetic influences in idiopathic epilepsies probably are complex involving multiple genes and interactions between genes (epistatic) and between genes and the environment (epigenetic)"* * **Epilepsy of unknown cause - epilepsy in which the nature of the underlying cause is as yet unknown, and with no identification of structural epilepsy (Task Force)

Answer 109

Structural epilepsy (Task Force)

Answer 110

Focal epileptic seizures. Focal epileptic seizures are characterized by lateralized and/or regional signs (motor, autonomic or behavioural signs, alone or in combination). The ictal onset is consistent from one epileptic seizure to another. They may be discretely localised or more widely distributed. Focal epileptic seizures may originate in subcortical structures, with preferential propagation patterns that can involve the contralateral hemisphere. With focal epileptic seizures, the abnormal electrical activity arises in a localized group of neurons or network within one hemisphere. The clinical signs reflect the functions of the area or areas involved. (Task Force)

Answer 111

Motor: episodic focal motor phenomena Autonomic: parasympathetic and epigastric components Behavioral: Focal epileptic seizure which in humans can represent psychic and/or sensory seizure phenomena, may in animals represent a short-lasting episodic change in behavior such as anxiousness, restlessness, unexplainable fear reactions, abnormal attention seeking/clinging to the owner (Task Force)

Answer 112

Generalized epileptic seizures * May occur alone, or evolve from a focal epileptic seizure start * Dogs and cats - generalized epileptic seizure predominantly present as tonic, clonic, or tonic-clonic epileptic seizures. * As a rule the animal will loose consciousness during convulsive epileptic seizures (myoclonic seizures excluded) * Salivation, urination and/or defecation furthermore also occur (myoclonic seizures excluded)

Answer 113

Generalized convulsive * Tonic-clonic * Tonic * Clonic * Myoclonic (jerking movements usually affecting both sides of the body) Generalized non-convulsive * Atonic (also called drop attacks) * Sudden loss or diminution of muscle tone without an apparent preceding myoclonic or tonic event lasting 1-2 seconds or more, involving head, trunk, jaw or limb musculature (Task Force)

Answer 114

Trick question - they should not. Consciousness should always be a subjective interpretation in animals, therefore it is not meaningful to subclassify focal epileptic seizures using consciousness. (Task Force)

Answer 115

Ictus (Task Force)

Answer 116

Tonic: a sustained increase in muscle contraction lasting a few seconds to minutes Versive: A sustained, forced conjugate ocular, cephalic, and/or truncal turning/rotation or lateral deviation from the midline Dystonic: Sustained contractions of both agonist and antagonist muscles producing athetoid or twisting movements, which when prolonged may produce abnormal postures (Task Force)

Answer 117

Myoclonic/myoclonus Clonic: myoclonus which is regularly repetitive, involves the same muscle groups, at a frequency of about 2-3 seconds and is prolonged (synonym - rhythmic myoclonus) (Task Force)

Answer 118

Automatism * Oroalimentary - lip smacking, lip pursing, chewing, licking, teeth grinding or swallowing * Pedal - principally distal component involvement, bilateral or unilateral. Usually running movement (Task Force)

Answer 119

Aura: a subjective ictal phenomenon that, in a given patient, may precede an observable seizure; If alone, constitutes a sensory seizure. This can result in behavioral changes such as fear, aggression, searching behavior, attention, body sensation What is an aura - Commonly owners report that they can forsee a motor seizure when specific and well-known signs repeatedly appear within seconds or minutes prior to convulsions. The term has been used to describe a forewarning of convulsions. The group recommends the term aura is not used in veterinary medicine. The signs occurring as the first indication of seizure activity (marking beginning of ictus) and interpreted by the dog owner as a warning sign is indeed a focal seizure onset, and should be referred to as such. (Task Force)

Answer 120

Incidence: refers to the number of epileptic seizures within a time period, or the number of seizures days per unit of time * Regular - consistent or predictable intervals between such events * Irregular - inconsistent interval * Cluster - Incidence of epileptic seizures within a given period (one or a few days) which exceeds the average incidence over a longer period for the patient. Cluster seizures can be divided clinically as 2 or more seizures within a 24 hour period * Provocative factor - transient and sporadic endogenous or exogenous element capable of augmenting seizure incidence in the patient with chronic epilepsy and evoking seizures in susceptible non-epileitic individuals (Task Force)

Answer 121

Status epilepticus "An epileptic seizure which shows no clinical signs of arresting after a duration encompassing the great majority of seizures of that type in most patients or recurrent epileptic seizures without resumption of baseline central nervous system function interictally" (Task Force)

Answer 122

Lateralizing phenomenon = TODD's phenomenon = bravais' phenomenon (Task Force)

Answer 123

1. T2W hyperintensities predominantly in the piriform and temporal lobes, cingulate gyrus and hippocampus 2. Mild contrast uptake +/- ``` CSF analysis (can be unhelpful because post-ictal pleocytosis can occur) - if abnormal, repeat in 6 weeks \*\* a study in idiopathic epileptic dogs identified an association between CSF WBC count and time interval between the last seizure and the collection of CSF ``` Repeat imaging in the postictal period and assess changes in brain volume/atrophy Post-ictal MRI changes usually resolve within 16 weeks (Task Force)

Answer 124

Post-ictal changes in the temporal and parietal lobe. Images obtained in a 1.5 T Siemens Symphony, Erlangen, Germany. Post-ictal oedema in the temporal lobe (short white arrow), hippocampus (long white arrow) and cingulate gyrus (yellow arrow) in a 2 year male English Bulldog that presented in status epilepticus

Answer 125

* Atrophy * Asymmetry in size * Loss of defined morphologic structure * Increased T2W/FLAIR signal * Decreased T1W signal Reduced volume of the hippocampus/hippocampal atrophy has been demonstrated in epileptic dogs Hippocampal T2W hyperintensity is well correlated with pathology and hippocampal sclerosis Volumetric studies would be beneficial however it is labor intensive and not routinely done (Task Force)

Answer 126

Tier I: * History of 2 or more unprovoked epilepic seizures occurring at least 24h apart * Age at epileptic seizure onset of between 6m and 6y * Unremarkable inter-ictal physical and neurological examination * No significant abnormalities on minimum data base blood tests and urinalysis Tier II * Factors listed in tier I and * Normal fasting and post-prandial bile acids * MRI of the brain (based on epilepsy specific brain protocol) * CSF analysis Tier III * Factors listed in tiers I and II * Identification of electroencephalography abnormalities characteristic for seizure disorders (Task Force)

Answer 127

Excitatory: glutamate, aspartate, acetylcholine Inhibitory: GABA, glycine, norepi, taurine (de Lahunta)

Answer 128

1. Imipramine - inhibits reuptake of norepi, anticholinergic 2. Selegiline - MAOI that results in an increase in concentration of norepi in the CNS 3. Methylphenidate for excessive sleepiness 4. Yohimbine - alpha 2 adrenergic antagonist - increases release of norepi (de Lahunta)

Answer 129

Ca channel disorders - paralysis Cl channel disorders - myotonia Na channel disorders - both (Vet Clin N America)

Answer 130

It has been reported but not as common in acquired MG (approximately 90% of acquired MG dogs have megaesophagus) Tendon reflexes usually normal (may be fatigable) (VCNASAP Shelton)

Answer 131

Demonstration of serum autoantibodies against muscle AChR by immunoprecipitation of serum autoantibodies against muscle AChR by immunoprecipitation radioimmunoassay * Seronegative myasthenia occurs in approximately 2% of the dogs with generalized MG * False positive results are rare * A species specific assay should be used ELISA - uses oligopeptide from the canine AChR-alpha subunit protein fraction * Potential for false negative (if autoantibodies do not recognize denatured antigen) * Potential for false positive - The peptides are produced in an E. coli expression system, may be contaminated with E. coli proteins (VCNASAP Shelton)

Answer 132

Shelton - focal, generalized and acute fulminating MG treated with anticholinesterase (or no meds at all) - 47/53 (88.7%) went into spontaneous remission The 6 dogs that did not go into remission developed neoplasia (thymoma, melanosarcoma, thyroglossal duct papillary cysadenocarcinoma) 1-3y after diagnosis (VCNASAP Shelton)

Answer 133

Ampicillin + aminoglycoside Ampicillin - exacerbated MG in humans Aminoglycoside - reported to antagonize neostigmine

Answer 134

1. Clinical signs consistent with MG 2. Consistent pharmacologic (positive derophonium response) and electrophysiologic (decrement) findings 3. Normalization of limb muscle weakness after anticholinesterase therapy 4. At least 2 negative serum AChR antibody titers by radioimmunoassay * Seroconversiom may occur, thus antibody titers should be repeated 1-2 months after a negative AChR antibody titer Shelton (VCNASAP)

Answer 135

1. Antibodies directed against non-AChR end-plate determinants 2. Antibodies directed against the toxin binding site, such that patients with antibodies to this site would seem to be seronegative 3. Antibodies are bound to the endplates without detectable circulating serum antibodies (antigen excess) 4. Antibodies are directed against antigenic determinants that may be lost during the AChR extraction procedure

Answer 136

Stiff rigid gait, muscle tremors, fasiculation Peripheral neuropathy may occur some time after exposure Fenthion toxicity - differs from classic OP poisoning with weakness predominating and little evidence of autonomic dysfunction Chronic exposure may occur before clinical signs appear, and the onset of signs may be delayed (VCNASAP Shelton)

Answer 137

``` Pralidoxime chloride (2-PAM), or protopam chloride - work by breaking up the OP-ChE complex and increasing OP excretion via the urine Work best when combined with atropine ``` Should NOT be used in carbamate toxicity Pralidoxime chloride has also been useful in cases of chlorpyrifos toxicity in cats Diphenhydramine has been recommended to relieve muscle weakness and tremors in fenthion toxicity (VCNASAP Shelton)

Answer 138

Several drugs have been shown to reduce the safety margin of neuromuscular transmission, including a**minoglycoside antibiotics, antiarrhythmic agents, phenothiazines, and magnesium**, given parenterally or in cathartics Methimazole these agents can potentiate neuromuscular blocking agents used during surgical procedures, and may worsen or unmask preexisting disorders of neuromuscular transmission (VCNASAP Shelton)

Answer 139

1. Dysuria 2. Regurgitation 3. Purulent nasal discharge 4. Photophobia 5. Anorexia 6. Weight loss Average duration of clinical signs - 2 weeks Clinical signs predominantly reflect loss of parasympathetic dysfunction (sympathetic dysfunction also present) (VCNASAP O'Brien)

Answer 140

Documenting sympathetic and parasympathetic dysfunction without significant somatic motor system involvement (except for anal sphincter involvement) or sensory loss Necropsy - autonomic ganglia degeneration with minimal inflammation Pilocarpine - diluted to from 1% to 0.05% with normal saline. 1-2 drops placed in 1 eye. Dogs with dysautonomia should have denervation hypersensitivity and respond rapidly. (normal dog may respond but it will take longer). If no response, can try full strength pilocarpine

Answer 141

Orthostatic hypotension: measure BP with dog in lateral recumbency, then tilted at an angle of 30-45 degrees. Normal dog - this has little effect on BP Dogs with dysautonomia - BP drops in the elevated limbs and increases in the limbs placed downward Other: HR usually within normal limits, but does not increase as expected when BP drops or when the animal becomes excited

Answer 142

* Reduced neuronal density * Degenerate neurons that lack Nissl substance * Longer duration cases - inflammation can be locally pronounced, interstitial clusters of lymphocytes * Neuronal loss may occasionally dominate the histopathologic features * Lesions in parasympathetic postganglionic neurons is less consistent * Involvement among ganglia is not uniform - several ganglia need to be examined (VCNASAP O'Brien)

Answer 143

decreased elbow flexion with the shoulder placed in adduction internal (medial) rotation

Answer 144

Mannitol All cattle treated with thiamine grain slowly replaced with hay fiber As patients respond to treatment, blindness is usually the last deficit to resolve and the one that occasionally persists (de Lahunta)

Answer 145

Parasympathetic - facilitatory GVE LMN input (via pelvic nerves, postganglionic neuron in the wall of digestive tract) Sympathetic - inhibitory (except to the internal anal sphincter) Ganglionic neurons in the caudal mesenteric ganglion Same as urinary bladder/urethra (de Lahunta)

Answer 146

The facilitatory centers in the pontomedullary reticular formation and vestibular system can function autonomously The inhibitory centers in the pontomedullary reticular formation require continual input from the cerebral cortex, basal nuclei, and cerebellum

Answer 147

This abnormality has been observed in dogs with a focal ischemic stroke or ischemic infarction of: * Cerebral extrapyramidal nuclei * Thalamic nuclei * Subthalamus Usually contralateral to the side of the lesion Consist of abnormal head posture (head tilt or turn), neck posture (cervical dystonia/torticollis or pleurothotonus) or both Abnormal nystagmus, strabismus or both (de Lahunta)

Answer 148

just proximal to the tarsus compression of sensory branches of the fibular nerves at this level the GSE LMN axons that innervate the cranial crural muscles have left the fibular nerves, leaving only GP and GSA axons to be compressed Hypalgesia or analgesia of the dorsal surface of the paw may accompany this abnormal paw position (de lahunta)

Answer 149

Consider sensory ganglioneuritis Autopsy - diffuse, nonsuppurative lymphoplasmacytic inflammation of multiple cranial and spinal nerves, and spinal nerve ganglia and dorsal roots * Loss of neuronal cell bodies is recognizable in these ganglia --\> wallerian degeneration of the associated dorsal roots and distal nerves * Inflammation of the trigeminal ganglia --\> inflammation of GSE LMN neurons that pass through this ganglia Diagnosis - biopsy of a spinal ganglion (de Lahunta)

Answer 150

Dorsal root What is seen is Wallerian degeneration of the general proprioceptive axons which directly enter the dorsal funiculi without synapse until they reach the caudal medulla (de Lahunta)

Answer 151

Petrous temporal bone or intracranial/brainstem lesion at that level (de Lahunta)

Answer 152

Spontaneous discomfort related to a thalamic lesion (often neoplasm) Loss of GSA thalamic relay nucleus that modulates pain --\> results in hyperalgesia Report of unilateral thalamic glioma in a dog described spontaneous discomfort on the contralateral side of the body (de Lahunta)

Answer 153

1. Lesions within the dorsal gray column 2. Loss of inhibition of the neurons involved in nociception 3. Pontomedullary lesions that interfere with nuclei of the caudally projecting pathways that are the source of inhibition of neurons involved in nociception 4. Thalamus (thalamic relay nucleus responsible for inhibiting pain signals) (de Lahunta)

Answer 154

L1-5 dorsolateral border of the ventral gray column The axons course cranially in the fasiculus proprius and terminate by synapsing on thoracic limb extensor LMNs in the cervical intumescence Their purpose is to synchronize extension of the pelvic limbs with flexion of the thoracic limbs Schiff-Sherrington - spontaneously resolves in about 10-14 days (de Lahunta)

Answer 155

1. Subacute/chronic OP toxicity 2. MG 3. Hyperthyroidism 4. Thiamine deficiency 5. Hereditary myopathy (Devon rex, sphynx) 6. Polymyositis 7. Hypokalemia (also hypernatremia, hypocalcemia) 8. PSS + HE (also NH3 chloride toxicity) (VCNASAP Dickinson)

Answer 156

Caudal nerve/tail deficits only 100% Caudal nerve deficits + urinary retention + decreased/absent anal tone/perineal sensation + decreased urethral sphincter tone - 50% recovery "Recoveryrates decreased from 100% to 50% for cats in the following order: 1. Caudal nerve (tail) deficits only 2. Caudal nerve deficits plus urinary retention 3. Caudal nerve deficits plus urinary retention plus decreased anal tone/perineal sensation 4. Caudal nerve deficits plus urinary retention plus decreased/absent analtone/perineal sensation plus decreased urethral sphincter tone" \*\* cats that did not recovery normal urinary function within 1 month were likely to have permanent micturition abnormalities of varying severity (VCNASAP Dickinson)

Answer 157

* Anisocoria with persistent mydriasis and decreased/absent PLR * EM or IFA has revealed a C-type RNA virus localization in the short ciliary nerves or ciliary ganglion of affected cats * Generalized peripheral neuropathy with progressive tetraparesis * Experimental FeLV infection - abnormalities in peripheral nerve conduction velocities * Urinary incontinence - suggested to be a potential manifestation of FeLV infection (VCNASAP Dickinson)

Answer 158

Primarily behavioral and mood changes Neuromuscular - subclinical myopathy reported, decreased MNCV and SNCV reported in experimentally infected cats (VCNASAP Dickinson)

Answer 159

1. Organophosphates 2. Heavy metals 3. Vincristine 4. Salinomycin 5. Acrylamide 6. Pyrethrins (?) (VCNASAP Dickinson)

Answer 160

* Necrosis of CNS neurons --\> ataxia, seizures, tremors * Degeneration of sensory neurons also described Other heavy metal toxicities associated with neuromuscular dz: * Thallium (in rodenticides) - hypotonia and ataxia * Lead poisoning - typically GI and CNS dz, megaesophagus reported (VCNASAP Dickinson)

Answer 161

Sensory-motor neuropathy Pathologic changes predominantly in proximal portions of peripheral nerves (VCNASAP Dickinson)

Answer 162

Persistent influx of Na ions into excitable cells of the nervous system and muscle Clinical signs * Hyperexcitability * Tremors * Convulsions * Neuromuscular weakness (28%) (VCNASAP Dickinson)

Answer 163

Ischemia --\> demyelination and Wallerian-like degeneration Central fibers in a nerve fasicle seem most susceptible than peripheral fibers Muscle: Ischemic myopathy with myofiber necrosis Affects cranial tibial muscles most severely (VCNASAP Dickinson)

Answer 164

1. Hyperglycemia --\> polyol pathway flux --\> depletion of myoinositol and modification of proteins by glycation --\> metabolic nerve changes * One study found an association between functional and structural deficits and increased polyol pathway flux with a decrease in nerve myoinositol levels 2. Vascular changes --\> peripheral nerve oxidative stress (VCNASAP Dickinson)

Answer 165

1. Neoplastic infiltration 2. Generalized neuromuscular disease 3. Lead toxicosis 4. Surgical or ablational procedures involving the thyroid gland 5. Trauma (VCNASAP Dickinson)

Answer 166

Described in experimental cats with dietary restriction of phenylalanine and tyrosine (VCNASAP Dickinson)

Answer 167

Elapid = snake family (coral snakes) * Act @ NMJ * Postsynaptic toxins: curare-like activity - block AChR (can be reversed w/ antiserum) * Presynaptic toxins: irreversible depletion of ACh vesicles in axonal terminal * Presenting clinical signs - PL weakness/ataxia to flaccid tetraplegia and respiratory paralysis * Onset may be delayed for several hours; progression is usually rapid * Pupillary dilation with decreased PLR and glycosuria are common findings in Tiger snake evenomation * EMG usually normal, but reduced/absent CMAP on NCV (VCNASAP Dickinson)

Answer 168

Neurotoxin = alpha-latrotoxin Toxin binds to sympathetic, parasympathetic, and motor nerve terminals --\> influx of Ca --\> nonspecific exocytosis of synaptic vesicles Release of ACh --\> muscle spasm, pain, SLUDD, hypertension, restlessness Spasticity followed within 12-24 hours by flaccid paralysis as a result of the destruction of motor end plates, and prolonged depolarization No specific diagnostic tests are available, bites are not usually apparent Cats reported to be particularly sensitive - 20/22 envenomated cats dying in one report (VCNASAP Dickinson)

Answer 169

OP: irreversible inhibitors of acetylcholinesterase via time-dependent aging process Carbamates are slowly reversible inhibitors Cats are reported to be particularly sensitive to the acute and delayed toxic effects of OPs - a delayed neuropathy has been reported in cats with OP toxicity (not carbamate toxicity) typically 1-4 weeks after exposure Symmetric distal axonal degeneration of peripheral and central nerve fibers --\> LMN paraparesis MOA of delayed toxicity unknown - may involve inhibition of neuronal esterase OP: chlorpyrifos, fenthion (VCNASAP Dickinson)

Answer 170

Determination of acetylcholinesterase levels in plasma, erythrocytes, or whole blood may indicate exposure to acetylcholinesterase-inhibiting toxins There is disagreement as to whether feline RBC ChE activity is measurable ChE activity in whole blood may be the most reliable diagnostic tool - value \< 25% normal - suggested as indicative of toxicity Postmortem - specific identification of compounds can be done using frozen samples of vomitus, skin, hair, fat, brain, or liver (VCNASAP Dickinson)

Answer 171

False - dystrophin deficiency and laminin alpha 2 = merosin deficiency (VCNASAP Dickinson)

Answer 172

Hereditary myopathy of Devon Rex cats - autosomal pattern of inheritance * Onset 3-23 weeks * CK normal * Histopathologic examination of muscle demonstrated alterations consistent with muscular dystrophy * Immunohistochemical staining of muscle biopsy specimens for dystrophin was normal Sphynx cats - Muscular dystrophy * Noninflammatory myopathy (VCNASAP Dickinson)

Answer 173

False - reported in 5 related cats * Onset from 6 mos to 1.5 years of age - reluctance to move, hypermetria, muscle twitching, hyporeflexia, muscle wasting * Most prominent in thee proximal muscles of the forelimbs * Lg but variable numbers of nemaline rods * FIber-size variation with atrophy fo type I and 2A fibers (VCNASAP Dickinson)

Answer 174

Myositis ossificans (VCNASAP Dickinson)

Answer 175

Muscle cramps * Arise from abnormal discharges of nerve terminals in a muscle, can occur with activity or rest * Most are caused by hyperactivity of the peripheral nerve terminals or CNS rather than a primary muscle disease * Can result in myoglobinuria if severe * EMG - high-frequency, high-amplitude discharge of potentials resembling motor unit action potentials * Electrically silent muscle cramps occur with strenuous or ischemic exercise in metabolic myopathies associated with defects of glycolysis of glycogenolysis (VCNASAP Shelton)

Answer 176

Fasiculations * May be seen as transient, longitudinal depressions of the skin surface * Fasiculations potentials are spontaneous discharges of single motor neurons * Most commonly associated with motor neuron diseases * May be found in normal individuals treated with anticholinesterase drugs (VCNASAP Shelton)

Answer 177

Myokymia * Movements are slower and more prolonged than fasciculations * EMG - myokymic discharges are groups of 2-10 potentials, probably arising from motor units and firing at 5-60Hz * They arise in the peripheral axon of chronically damaged nerves and are associated with clinical myokymia or with syndromes of continuous muscle fiber contraction (VCNASAP Shelton)

Answer 178

Characterized by self-propagating rippling of muscles induced by stretch or percussion in which the ripple propagates at approximately 0.6m/s, 10x slower than muscle fiber conduction velocities Muscles are electrically silent - which differentiates them from myokymia and neuromyotonia (VCNASAP Shelton)

Answer 179

Myotonia * important form of spontaneous activity in muscle disease resulting from alterations in the ion channels in the muscle fiber membrane * diagnosis via EMG (VCNASAP Shelton)

Answer 180

Neuromyotonia * Caused by hyperexcitability of peripheral nerves * Muscle stiffness at rest, myokymia and delayed muscle relaxation resembling myotonia * EMG recordings - bursts of MUAP firing at high rates WITHOUT typical waxing and waning of myotonia * Abnormal spontaneous activity persists during sleep but is lessened * Blockade of neuromuscular transmission abolishes the abnormal activity (presumably arises in the distal motor nerves or nerve terminals) (VCNASAP Shelton)

Answer 181

Hypertonicity syndrome * Inherited as a recessive trait * Clinical signs most commonly found in Scottish Terriers from 6 weeks to 18 most of age, may be elicited by stress, excitement or exercise * Limbs gradually stiffen until the animal is unable to move * Arching of the lumbar spine and PL stiffness may progress to somersaults and falling (do not lose consciousness) * Clinical signs resolve within 10 minutes * Thought to be associated with serotonin deficiency * Methylsergide - serotonin antagonist --\> exercise 2h later will induce clinical signs (VCNASAP Shelton)

Answer 182

Clonazepam TID Tolerance may develop By 2 years of age, resolution of clinical signs can occur and dog may no longer need medication (VCNASAP Shelton)

Answer 183

Border Terrier * Hypothesized to represent a form of paroxysmal non-kinesigenic dyskinesia * First episodes usually occur before 3 years of age * Occur spontaneously, excitement, or when waking up from sleep * Attacks last 2-30 min, up to 3x daily, often associated with mild tremor and borborgymi * GI upset before or after in 50% of dogs * Antiepileptic drugs ineffective * Response to gluten-free diet * Affected border terriers had increased serum titers of antitransglutaminase 2 and angigliadin antibodies, normalized when fed gluten free diet

Answer 184

Hereditary paroxysmal dyskinesia * Heterogeneous group of movement disorders * Young adult onset * Autosomal recessive * Episodes of hyperkinesia and dystonia lasting from several minutes to several hours could occur up to 10 times daily * Not associated with strenuous exercise or fasting, sometimes triggered by excitement * A mutation in PIGN gene identified Kolicheski et al

Answer 185

Malignant hyperthermia syndrome All clinical and laboratory manifestations of MHS derive from a **breakdown of calcium sequestration** in the sarcoplasmic reticulum of skeletal muscle --\> unopposed muscle contracture, release of cations and enzymes (CK) into circulation, and production of heat and acid VCNASAP

Answer 186

RYR1 ryanodine calcium channel (VCNASAP)

Answer 187

Increased production of CO2 MH in dogs not typically characterized by early onset of lactic acidosis or muscle rigidity Use of dantrolene - shown to be efficacious in reversing signs of the canine sydnrome (VCNASAP)

Answer 188

Avoid volatile anesthetics - halothane, isoflurane, sevoflurane and depolarizing neuromuscular blocking agents (succinylcholine) Safe anesthetic drugs include: benzodiazepines, phenothiazine, barbituates, etomidate, propofol, dissociative agents, opioids, NO, nondepolarizing neuromuscular blockers, local anesthetics Total IV anesthesia or regional/local anesthetic techniques can be safely used (VCNASAP)

Answer 189

MOA - inhibition of 50s ribosomal subunit Dosage for protozoal infections are often higher than those used for susceptible aerobic bacterial disease Completely absorbed after oral admin, widely distributed due to high lipophilicity Low concentrations in CSF, high concentration in parenchyma (high lipid solubility) (VCNASAP Kent)

Answer 190

V/d Decreased vitamin K absorption --\> clotting factors Neuromuscular blocking agents - potentiate nondepolarizing neuromuscular agents during anesthesia (VCNASAP Kent)

Answer 191

MOA: TMP inhibits tetrahydrofolate reductase Sulfonamide acts as an analog for PABA The combination has a greater affinity for bacterial enzymes than for mammalian enzymes Adverse: Hypothyroidism, Hypersensitivity reactions (hepatotoxicity), KCS, blood dyscrasias Used for treatment of protozoal disease - Neospora, Toxoplasma, and Hepatozoon (VCNASAP Kent)

Answer 192

14-day course of TMP SDZ + Clindamycin + Pyrimethamine Followed by decoquinate - stops formation of sporozoites in the intestinal tract (VCNASAP Kent)

Answer 193

* Rigidity - Increased resistance to change in position or angle of joints * Spasm - Brief, automatic jerking movement * Tremor - Abnormal repetitive shaking movement of the body * Tetany - Sustained muscular contraction without relaxation * Tetanus - Intermittent tonic muscular contractions * Spasticity State of increased tone of a muscle (Dewey)

Answer 194

Jack Russel Terrier * Neuromyotonia is clinically characterized by muscle twitching or myokymia, persistent muscle contraction, muscle stiffness or cramps, and impaired muscle relaxation * Episodes of severe myokymia + collapse * Homozygosity of this gene --\> spinocerebellar ataxia (hereditary ataxia) * KCNJ10 --\> Kir4.1 K+ channel (Dewey)

Answer 195

13 - 16Hz Seen only when dog is weight bearing (Dewey)

Answer 196

1. Bichon frise 2. Scotty cramp 3. CKCS - episodic hypertonicity 4. Irish Wolfhound - startle disease 5. Labrador retriever - generalized muscle stiffness 6. Chinooks - paroxysmal dyskinesia 7. Miniature wirehaired dachshund - Lafora disease (Dewey)

Answer 197

* Neuron specific enolase - found in the cytoplasm of neurons (also localized in neuroendocrine cells, oligodendrocytes, thrombocytes, and erythrocytes) * An increase of the CSF NSE might be useful for detecting evidence of neuronal damage in the CSF * Myelin basic protein - produced by oligodendrocytes, major constituent of the axonal myelin sheath * Predicted to be a marker of white matter injury * Higher CSF MBP in dogs with thoracolumbar IVD that had unsucessful outcome * Increased in CSF of DM patients * GFAP - intermediate filament in astrocytes * Serum GFAP - high specificity for predicting myelomalacia (75% sensitivity) * Serum GFAP - Sn 67%, Sp 100% for diagnosing NME * Cleaved tau protein - binds to axonal microtubules, part of the axonal cytoskeleton * Dogs with IVDH, ROC analysis showed a moderate correlation between CSF c-tau concentration and prognosis * Did not correlate with T2W spinal cord hyperintensity on MRI (which is known to be associated with functional outcome) * Phosphorylated neurofilament heavy chain - cytoskeletal component in axons * Paraplegic dogs with absence of DPP - ROC analysis revealed a weak correlation between the serum pNF-H concentration and prognosis * MMPs * MMPs are Zn-dependent endopeptidases that degrade various components of the extracellular matrix * Dogs with thoracolumbar IVDH - paraplegic at admission, significantly higher elevated MMP than those with voluntary motor activity * VEGF * Strongly expressed in canine meningiomas, the degree of VEGF associated with survival times * Intratumoral VEGF expression may be a useful marker for predicting prognosis of meningiomas (VCNASAP)

Answer 198

1. Superficial cervical muscles 2. Brachiocephalicus (cervical cleidocephalicus) 3. Trapezius - cervical part 4. Splenius Cut through - rectus capitus exposed (Slatter)