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Neuro Final
Large Animal Neurologic Disease
109
Veterinary Medicine
Graduate
03/23/2011

Additional Veterinary Medicine Flashcards

 


 

Cards

Term
True or False, Spinal cord neoplasia in horses is most commonly primarily neural in origin
Definition
False,

usually direct extension of primary soft tissue or bone tumors/mets
Term
What bacteria is most commonly associated with spinal cord abscesses in foals?
Definition
Rhodococcus equi, abscesses form as an extension of septic process
Term
Chronic progressive LMN disease involving sacrococcygeal and cranial nerves in mature horses
Definition
Cauda Equina Neuritis aka polyneuritis equi

paralysis of tail, poor anal tone, bladder atony with overflow incontinance, fecal obstipation)

no tx, mononuclear pleocytosis on CSF (granulometous process)
Term
Caudal spinal cord disease, especially prevalant in southern USA and associated with ingestion of sorghum
Definition
Sorghum cystitis and ataxia

symmetrical ataxia and hypoalgesia of pelvic limbs, urinary incontinance
Term
Rare disorder associated with short stride and stiff gait when excercising, only pelvic limbs affected
Definition
Aortic iliac thrombosis,

increased oxygen demand during exercise results in ischemic pain in hindquarters
Term
What are two parasites that can cause traumatic spinal cord injury in ruminants?
Definition
Hypoderma bovis (cattle)
Paralaphostrongylus tenuis (sheep, camelids)

DX both with CSF tap --> eosinophilia
Term
What is the most common cause of spinal cord compression in adult cattle?
Definition
lymphosarcoma

progressive paresis, paralysis and ataxia +/- lymphadenopathy(rectal palpation/rads)
Term
What is the most common spinal cord disorder in calves?
Definition
Vertebral body abcesses due to hematogenous spread of Actinobacillus pyogens

also traumatic fractures and rickets
Term
Asymmetric spasticity of pelvic limbs in calves, normal when recumbent
Definition
Elso heel: spastic paresis

extreme extensor tone when standing, idiopathic - potentially hereditary, permanent
tx: tibial nerve neurectomy
Term
Intermittent pelvic muscle spasticity in adult cows
Definition
Crampy cow: periodic spasticity

hunched back with legs extended caudally, decreased milk production and progressive weight loss
Term
True or False, Clostridium tetani spores are extremely resistant to adverse environmental conditions
Definition
True
Term
What neurons are affected by the exotoxin produced by vegetative C. tetani organisms?
Definition
bind irreversibly to inhibitory interneurons (glycine) in the ventral horn of the spinal cord gray matter

--> unimpeded muscle contraction, extensor muscles oppose gravity and tend to be more powerful --> increased extensor tone
Term
muscle stifness (esp. jaw), tense facial muscles, prolapsed 3rd eyelide, colic, bloat
Definition

early signs associated with tetanus

 

Term
What are the later clinical signs associated with tetanus?
Definition
tetanic spasms triggered by noise, opisthotonus, sawhorse stance

NO deffinative diagnosis
Term
Horses with marked weight loss despite ravenous appetite, muscle fasiculations, constantly shifting weight from one hind limb to the other, stance with all four limbs close together, managed without access to pasture
Definition
Generalized equine motor neuron disease, associated with chronic vitamin E defficiency
Term
What is the diagnostic test of choice to identify equine motor neuron disease?
Definition
biopsy of the sacrocaudalis dorsalis muscle, look for evidence of neurogenic atrophy
Term
True or False, botulism in adults is usually caused by ingestion of preformed toxin in the feed
Definition
True,

in foals with gastric ulcers spores may be ingested and toxin produced within the GI tract (aka Shaker foals, extreme muscle weakness results in violent trembling and recumbency)
Term
What is the pathogenesis of botulism?
Definition
toxin impairs all peripheral cholinergic neurotransmission, especially at the neuromuscular junction --> results in progressive flacid paralysis of skeletal muscle
Term

loss of prehensile ability in lips, decreased tongue tone, may mimic choke, constapation and ileus, flacid tetraparesis death usually from respiratory arrest

 

Definition

botulism

 

No definitive Dx, isolating toxin from the feed is the best chance

Term
atrophy of supraspinatus and infraspinatus muscles, abduction of limb during forward motion and lateral deviation of the humerus when walking, little lameness observed
Definition
damage to the suprascapular nerve
Term
single limb extensor paralysis with dropped elbow, limb usually carried due to lack of carpal extension
Definition
Damage to the radial nerve
Term
Post calving cow with unilateral to bilateral abduction of the hind limb(s)
Definition
obturator (and sciatic ie. peroneal)nerve damage
Term
Paralysis of the quadriceps muscle with no weight bearing by the stifle, limb flexed and toe dragged
Definition
damage to the femoral nerve
Term
Knuckling over onto the wall of the hoof, inability to extend digit or flex hock, associated with calving/foaling and long periods of recumbency
Definition
peroneal nerve paralysis
Term
Weak at fetlocks, esp. post calving
Definition
tibial nerve paralysis
Term
What are the two most frequently diagnosed conditions associated with acute recumbency and cervical spinal cord disease in horses?
Definition
trauma
cervical vertebral malformation
Term
short neck, reduced ability to flex the neck, palpable malformations to atlas and axis, variable degrees of tetraparesis and ataxia, especially arabian/saddlebred/appaloosa foals
Definition
occipitoatlantoaxial malformation

DX with rads, no TX
Term
Rapidly growing animals, older horses with osteoarthritis of the articular facets, slowly progressive to acute with trauma UMN signs (stiff/spastic) to all limbs, pelvic limbs may be more severely affected, difficulty backing (ie. coordination deficits)
Definition
Cervical vertebral malformation
Term
Sagittal diameter corresponds to what anatomic location on a radiograph?
Definition
sagital diameter corresponds to the diameter of the vertebral canal

sagital diameter divided by the width of the vertebral body should be over 50%
Term
traumatic spinal cord lesions in horses and foals commonly involve the cervical vertebrae, but foals also commonly have injuries in what other region of the spinal cord?
Definition
thoracic

adults: cervical
foals: cervical and thoracic
Term
young growing horses without access to grass, potential familial predisposition, lesions may be most prominent mid-thoracic (ie. pelvix limbs more affected) --> symmetric ataxia, paresis, hypometria, poor paniculus
Definition
Equine degenerative myelopathy (EDM)

poor prognosis, vit E supplementation may help and also preventative for horses not displaying clinical signs
Term
What are the 5 most common viral diseases of horses that result in diffuse CNS disease?
Definition
EEE, WEE, VEE, WNV, rabies
Term
What are the 5 most common viral diseases in cattle that result in diffuse CNS disease?
Definition
Rabies, pseudorabies, IBR, BSE, MCF
Term
Unilateral, dropped ear, keratitis, muzzle assymetry
Definition
facial nerve paralysis (CN 7)
Term
Head tilt, ataxia, horizontal nystagmus
Definition
Vestibular disease
Term
ataxia without weakness, dysmetria, jerky head bobbing and intention tremor
Definition
Cerebellar disease
Term
What breeds of horses and cattle are predisposed to develop cerebellar abiotrophy?
Definition
Arabian

Jersey, shorthorn, angus, holstein

inherited and associated with BVD infections in utero
Term
What disease is associated with:
septicemia in neonates
dehorning/sinusitis in cattle
traumatic skull fractures in horses
Definition
Bacterial meningoencephalitis
Term
What organisms are most frequently implicated in association with bacterial meningoencephalitis in horses?
In cattle?
Definition
Strep equi in horses
actinomyces and fusibacterium in cattle
Term
Recently arrived feedlot cattle with diffuse CNS signs, other animals have pneumonia and arthritis
Definition
thrombotic meningoencephalitis (TME)

etiology: histophilus somnus
Term
outbreaks of meningitis in young ruminants (more rapid severe clinical course in sheep than cattle), sporatic in adults, diffuse CNS disease, fed poorly cured (pH> 5.6) silage
Definition

Listeriosis (gram +, hardy in environment, intracellular parasite)

 

ZOONOTIC potential

Term
What is the pathogenesis of listeriosis?
Definition
enters through mucosal abrasions--> trigeminal (CN 5) --> forms microabscesses in the brain stem (is. no gross lesions on necropsy)
Term
staggering, blindness, rapid death in feedlot sheep
Definition
clostridial enterotoxemia

CNS path: focal symmetrical encephalomalacia
Term
What serotype of clostridium is responsible for encephalomalacia in sheep?
Definition
clostridium perfringens type D

Vaccinate!
Term
feedlot calves, diarrhea, INTERMITTENT seizure-like CNS signs
Definition
nervous coccidiosis

Tx: amprolium, fluid and electrolytes
Term
cattle, muscle twitching--> hyperesthesia and convulsions, low serum Mg
Definition
hypomagnesemic tetany
Term
sporatic to herd distribution, major management/husbandry changes, young animals, blindness (normal PLR), muscle tremors, incoordination, recumbency with opisthotonos
Definition
polioencephalomalacia
Term
How does a high concentrate ration diet promote the development of polioencephalomalacia in ruminants?
Definition
high concentrate ration helps thiaminase producing bacteria thrive --> thiamine deficiency results in neuronal degeneration and intracellular edema in the cerebrum, additionally the thiaminase bacteria produce hydrogen sulfide gas that can distend the rumen
Term
INTERMITTENT CNS signs: ackward stance, licking, head pressing, responds to IV glucose therapy
Definition
nervous ketosis
Term
Young growing animals, drought conditions, poor quality feed, blindness, clonic tonic convulsions, progressive paresis/paralysis
Definition
hypovitaminosis A

DX: serum vit A, analysis of feed
Term
diffuse CNS signs with concurrent liver disease
Definition
hepatic encephalopathy
GRAVE prognosis
Term
Non-specific cerebral signs, consumption of mold corn +/- liver enzyme elevations
Definition
fusarium moniliform toxin --> leukoencephalomalacia
Term
difficulty prehending food/water, history of ingestion of yellow star thistle
Definition
nigropallidal encephalomalacia
Term
True or False, lead poisoning in horses is often associated with a single large ingestion of lead resulting in blindness, ataxia, head pressing and abdominal pain
Definition
FALSE lead poisoning in horses is the result of chronic exposure --> peripheral neuropathies Cattle may present with acute toxicity as described
Term
How do organophosphates cause toxicity?
Definition
organophosphates inactivate cholinesterases resulting in overstimulation of paraysmpathetic nerves --> SLUD and miosis
Term
dyspnea, diarrhea, miosis, drooling, bloat, collapse, access/exposure to insecticides
Definition
organophosphate toxicitiy

TX: atropine and activated charcol
Term
What organisms are responsible for equine protozoal myeloencephalitis (EPM)?
Definition
Sarcocystis neurona and Neospora hughesi
Term
True or False, most horses exposed to sarcocystis neurona and/or neospora hughesi develop CNS signs
Definition
FALSE

30-60% of exposed animals seroconvert, of these individuals a few will go on to develop CNS signs (stress is an important predisposing factor)
Term
True or False, 80% of cases of equine protozoal myelitis affect the spinal cord only
Definition
TRUE, tends to by ASSYMETRIC and multifocal, ventral horn gray matter --> muscle atrophy
Term
What two diagnostics are most informative for equine protozoal myelitis?
Definition
Western Blot (+ indicates exposure)
IFAT (+ confirms disease)

both from serum (can also use CSF)
Term
TRUE or FALSE, early diagnosis of EPM results in improvement of clinical signs in 75% of horses
Definition
True
Term
What's the tx of choice for EPM?
Definition
ponazuril

also NSAIDS, DMSO, Trimethoprim/sulfa (dihydrofolate reductase inhibitors)
Term
respiratory disease, abortion, neurologic disease (symmetric pelvic ataxia, urinary bladder paralysis, sporatic in adult horses
Definition
Equine herpes virus 1
Term
What is the diagnostic test of choice for equine herpes virus 1
Definition
throat swab and PCR

also..CSF: high titers, high protein, xanthochromic
Term
change in mental status, bizarre behaviors, seizures are neurologic signs that can be localized to ____
Definition
cerebral cortex
Term
inability to coordinate motor movements like eating and drinking is associated with lesions in _____
Definition
basal ganglia
Term
cranial nerves 3-12 arise from which anatomical region of the brain?
Definition
brain stem
Term
loss of consciousness implies damage to ____
Definition
reticular formation (located in the brain stem)
Term
which physical exam test can be performed to assess the integrity of the visual pathway and optic nerve?
Definition
menace response
Term
position of the pupil, size and symmetry of the pupil are all controled by which cranial nerve?
Definition
occulomotor (CN III)
Term
the presence of strabismus indicates a lesion affecting which cranial nerve?
Definition
trochlear (CN 4)
Term
inability to chew, dropped jaw, loss of sensation to the head indicates a lesion affecting which cranial nerve?
Definition
Trigeminal (CN 5)
Term
dropped ear and corneal ulcers suggest lesions affecting which cranial nerve?
Definition
Facial (CN 7)
Term
paralysis of the pharynx/larynx indicates a lesion affecting which cranial nerves?
Definition
glossopharyngeal (CN 9)
Vagus (CN 10)
Accessory (CN 11)
Term
How can forelimb UMN signs can be exaggerated if subtle?
Definition
forelimb UMN signs are exaggerated when the patient walks up an incline
Term
What neurologic abnormality does the tail pull support on physical exam?
Definition
weakness
Term
describe the features of a hypometric gait
Definition
stiff movement with little flexion of the joints
Term
describe the features of a hypermetric gait
Definition
increased range of motion, overstepping
Term
describe the features of a weak gait
Definition
dragging the limbs, worn hooves, low arc to the swing phase of the stride
Term
describe the features of an ataxic gait
Definition
irregularly irregular, poor coordination, swaying from side to side, weaving of the limbs, abducted/adducted foot placement (also can try testing conscious proprioception this way), circumduction when turning
Term
Clinical signs associated with spinal cord lesions in C1-C6
Definition
ataxia, weakness, all four limbs but worse in the rear, hyperactive reflexes
Term
Clinical signs associated with spinal cord lesions in C6-T2
Definition
ataxia, weakness (forelimbs severely affected), depressed forelimb reflexes
Term
clinical signs associated with spinal cord lesions affecting T2-L3
Definition
normal forelimbs, ataxia and weakness in hindlimbs
Term
clinical signs associated with spinal cord lesions affecting L4-S2
Definition
normal forelimbs, ataxia and paresis in the rear limbs
Term
clinical signs associated with spinal cord lesions affecting S1-S3
Definition
distended bladder, dilated anus, loss of tail tone
Term
Myelography is useful to diagnose what type of lesion
Definition
compressive (where the flow of dye is disrupted --> dark area on rads = compressive lesion)
Term
foals with deranged cerebral function (loss of suckle reflex, hyperesthesia/hyperexcitability, jerky stiff movements, sometimes dyspnea ---> hypothermia, acidosis, seizures, coma)
+/- limb weakness, extensor spasms, clonic convulsions
Definition
Neonatal maladjustment syndrome
Term
What neuroendocrine factors are implicated in neonatal maladjustment syndrome?
Definition
Allopregnalone (produced by placenta, keeps foals somnolent in utero)

Pregnenalone sulphate (produced by placenta, excitatory effects)
Term
What laboratory abnormalities can be seen in foals with neonatal maladjustment syndrome?
Definition
CBC: anemia, inflammation Chemistry: abnormal renal function, liver function, electrolytes Many have normal CSF (can be done to r/o meningitis)
Term
An involuntary alteration of motor activity, consciousness and autonomic function caused by a rapid electrical discharge from the cerebral cortex
Definition
seizure
Term
what are some signs associated with partial seizures in large animals?
Definition
jaw chomping, tachypnea, tremor of facial muscles, jerky head movements
Term
What is a post-ictal phase?
Definition
period of depression and temporary blindness following a generalized seizure, can last minutes to days
Term
True or False, adult horses have a lower seizure threshold than foals
Definition
FALSE
Term
What breed is affected by juvenile epilepsy syndrome? What is the prognosis?
Definition
arabian foals, prognosis is good if seizures can be controled, often outgrow the condition between 12 and 18 months of age
Term
arabian foals with diluted coat color, difficulty standing following birth, episodes of muscle rigidity in limbs, neck and back --> opisthotonus, paddling
+/- nystagmus
Definition
Lavendar foal syndrome (aka coat color dilution lethal), most are euthanized within days of birth
Term
What bones are frequently affected in horses with cranial trauma? What neurologic abnormalities may accompany these injuries?
Definition
basisphenoid, occipital, and basioccipital sutures --> dysfunction of vestibulocochlear (CN 8), glossopharyngeal (CN 9), vagus (CN 10), and accessory (CN 11)
Term
Signs associated with midbrain hemorrhage
Definition
coma, depression, anisocoria, hemorrhage in inner ear cavities, facial and vestibular nerve abnormalities
Term
What CSF abnormalities are supportive of trauma?
Definition
high RBC, high CK, xanthochromia
Term
Of the equine viral encephalomyelitides that occur in the USA which has the highest mortality associated with infection?
Definition

EEE (90% mortality) WEE (10-50%) <-- more common in MN

 

WNV (33%)

Term
Warm weather (ie. mosquito season), fever, stiffness, hyperesthesia, muscle fasciculations, head pressing, seizures, anorexia, recumbency....
Definition
Equine Viral Encephalomyelitides (EEE, WEE, VEE, WNV)
Term
What disease must be considered in any large animal with acute ataxia, lameness, mentation changes, or local hyperesthesia of less than 10 days duration?
Definition
Rabies! EXTREMELY variable clinical signs, invariably fatal, ZOONOTIC
Term
ruminants closely associated with swine, intense pruritis
Definition
pseudorabies --> non-suppurative encephalomyelitis (no gross lesions, virus isolation and IFA from fresh brain)
Term
calves under six months, neurologic and respiratory abnormalities
adults may have pruritis
Definition
Infectious bovine rhinotracheitis
Term
How is the scrapie prion transmitted between individuals?
Definition
ingestion (placenta), prenatally, direct contact
Term
sheep over 18 months of age, pruritis, progressive gait abnormalities, muscle tremors, emaciation
Definition
scrapie
Term
What disease are very treatable BUT early diagnosis is essential for good prognosis?
Definition
Polioencephalomalacia, TME, hypomangnesemic tetany
Term
What diseases are potentially ZOONOTIC and deffinitive diagnosis is a legal liability/client health concern?
Definition
Rabies
Listeriosis
toxoplasmosis
lead poisoning
Term
What diseases are not treatable and must be recognized to avoid unnecessary cost and suffering?
Definition
spinal lymphoma
pseudorabies
viral encephalitis of the goat
Term
What herd health diseases are preventable and deffinative diagnosis allows removal of inciting cause/issue?
Definition
lead poisoning
organoposphate toxicity
hypovitaminosis A
tetanus
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