Lecture 6: Equine nervous system: all other things Flashcards
CSF flows in a ___circulation
craniocaudal
if you have a patient with suspected thoracic melanoma where do you want to take CSF from Atlanto-occipital space or lumbar
lumbar because CSF flows craniocaudal
you perform an atlantooccipital CSF tap if the lesions is above __
foramen magnum (cranial to 2nd vertebrae)
How do you perform an atlantoocipital CSF tap
insert needle at a line between the cranial borders of the atlas, direct needle towards lower jaw with horses head flexed, advance until dura penetrated at about 5cm in 1000lb horse
can draw __mls in 1000lb horse but only __cc in foals for CSF tap
90mls, 1-2ccs
what is the queckenstedts maneuver
hold off the jugular to increase flow—> increase back pressure in brain and increase CSF flow to brain
you perform a lumbosacral CSF tap if lesion is located ___
below the foramen magnum (caudal to second vertebrae)
How do you perform LS CSF tap
palpate LS space, insert ventrally through the sub lumbar muscles until penetrates ligament I’m flavum and then dura
What space is a lateral standing CSF performed between
C1-C2
what are some complications from a C1-C2 lateral CSF tap
stiff necks, fever, tachycardia
what should you do after performing a C1-C2 lateral CSF tap to avoid complications
give banamine and keep head above heart until sedation wears off
what produces the toxin swainsonine
fungus in the seeds: undilum oxytropis
what does swainsonine/ locoweed poisoning cause
inhibits alpha mannosidase causing lysosomal storage disease
what are some signs of locoweed/ swainsonine toxicity
slow staggering gait, emaciation, ataxia, nervousness that worsens with handling, death
what is tx for locoweed poisoning
no effective tx, mild cases resolve in 1-2 weeks once ingestion ceases
what is the toxic in nigropallidal encephalomalacia
repen
what two plants cause nigropallidal encephalomalacia
- Yellow star thistle
- Russian knapweed
what are some clinical signs of nigropallidal encephalomalacia
sudden onset twitching of lips, tongue, flicking, involuntary chewing, poor prehension, weight loss, incoordination, muscle tremors, facial paralysis
how do you dx nigropallidal encephalomalacia
clinical signs and exposure, MRI, necropsy
what is tx for nigropallidal encephalomalacia
no treatment, may stabilize but not recover most do poorly
lead poisoning results in a __ from __
peripheral neuropathy from demyeliantion
what are some clinical signs of lead poisoning
dysphagia, aspiration, pneumonia, dysphonia, altered mentation, weight loss, severe incoordination
how do you dx lead poisoning
- CSF mild nonspecific increase in cells and protein
- Plasma lead levels >0.3ppm
what is tx for lead poisoning
- Remove lead source
- Chelation with EDTA 75mg/kg IV daily for 3-5 days
- Supportive care
What dz does moldy corn poisoning cause
leukoencephalomalacia
what toxin from moldy corn causes leukoencephalomalacia
fumonisins
what is the mechanism of action of fumonisins causing leukoencephalomalacia
interfere with shingolipid biosynthesis- critical for cell growth, differentiation and transformation
what are the clinical signs of leukoencephalomalacia
confusion, obtundation, ataxia, sudden blindness, sweating, head pressing, circling, seizures, recumbent, death within 5 days
how do you dx leukoencephalomalacia
- Clinical signs and exposure to moldy corn
- CSF high protein and normal cell count
- Liver values high
- Liquefactive necrosis of the white matter of brain, grossly visible fluid fill cavities
What sign of leukoencephalomalacia is pathognomonic
liquefactive necrosis of the white matter of the brain, leaving grossly visible fluid filled cavities
what is tx for leukoencephalomalacia
no treatment successful, prognosis poor
Can attempt supportive care with anti-inflammatories, anti-oxidants
what is fluphenizine
neuroleptic agent, antipsychotic human drug
toxic reactions from fluphenizine seem with what dose
> 3-39ng/ml
what are some signs of fluphenizine toxicity
extrapyramidal neurological signs, agitation, sweating, violent pawing, self-mutilation, Parkinsonism
what is tx for fluphenizine
- discontinue drug
- diphenhydramine or benztropine
what is equine dysautonomia also known as
grass sickness
what is equine dysautonomia
acquired degenerative polyneuropathy that predominantly affects the neurons of the autonomic and enteric nervous systems
what are the acute clinical signs of equine dysautonomia
small intestinal ileus, massive amounts of nasogastric reflux with minimal colic signs, death from hypovolemia
what are the subacute signs of equine dysautonomia
ileus with minimal reflex, often develop large colon or cecal impaction
what are the chronic signs of equine dysautonomia
cachexia and myasthenia, development of rhinitis sicca
how do you dx equine dysautonomia
necropsy findings consistent with stage of disease an autonomic ganglia and enteric nerve degeneration
what is tx for acute and subacute equine dysautonomia
supportive care until euthanasia
what is tx for chronic equine dysautonomia
Excellent nutritional support
what is prognosis for acute, subacute and chronic equine dysautonomia
acute and subacute: 100% fatal
Chronic: 40-50% survive with long term care
what are some clinical signs of lyme disease
low grade fever, stiffness, lameness in more than one limb, laminitis, anterior uveitis, muscle tenderness, swollen joints, neuroboreliosis
what is neuroborreliosis
neurological disease with muscle atrophy, cranial nerve deficits, ataxia, behavioral changes, hyperesthesia and encephalitis
How does the serum lyme multiplex OSP A/C/F test for Lyme disease
- OSP A elevated with vaccination (no vax for horses)
- OSP C- suggest recent infection
- OSP F: chronic infection
What test is the most sensitive and specific to dx Lyme disease
paired serum: CSF lym multiplex Osp A/C/F
t or f: a negative serology and normal CSF mean horse is negative for Lyme disease
false0 can have normal CSF and serology
what is tx for Lyme disease
- Oxytetracycline- best at eliminating borrelia
- Doxycycline
- Minocycline
what 2 nematodes causes verminous encephalitis
1.hailcephalobus gingivalis
2. Strongylus vulgaris
how do horses get verminous encephalitis
direct extension from masses on the dermis of the head as well as hematogenous spread
what type of infection occurs with verminous encephalitis
severe tissue reaction with abscessation and fulminant pyogranulomatous disease
what are the clinical signs for verminous encephalitis
encephalitis
how do you dx verminous encephalitis
- CSF containing eosinophils is suggestive
- Confirmed on hisopathology
what is tx for verminous encephalitis
- Ivermectin and high dose fenbendazole
- Surgical debunking
strongylus vulgaris usually just migrate through the ___ resulting in clots thrown to the GIT= thromboembolic colic
cranial mesenteric artery
cryptococcal meningitis also has a ___tropism
respiratory
cryptococcus neoformans infects __animals
immunocompromised
cryptococcus gattii infects ___animals
immunocompetent
how do you dx cryptococcal meningitis
- Titer
- Demonstration of organism
what is tx for cryptococcal meningitis
fluconazole
What bacteria in neonates causes bacterial meningitis
E. Coli
what bacteria in adults causes bacterial meningitis
streptococcus spp
how do you dx bacterial meningitis
CSF cytology and culture
what is tx for bacterial meningitis
- Potentiated sulfonamides, enrofloxacin, chloramphenicol or metronidazole
- Steroids
- NSAIDs- ketophen
what are some causes of head shaking
- Neurological- trigeminal neuritis, photic head shaking, EPM
- Behavior- stereotypical behavior, avoidance/discomfort
- Disorders of skull, eyes, ears, oral cavity
how do you tx photic head shaking
UV light protection
how do you tx non-photic head shaking (trigeminal neuritis)
- Nose devices
- Insect/fly control
- DCAB diet- add alfalfa, magnesium citrate/sulfate/oxide, magnesium/boron
- Cyproheptadine
what causes excessive daytime sleepiness
sleep deprivation from:
1. Pain
2. Alpha horses
3. Unsafe surrounds
what is hypersominia
excessive sleepiness
what can cause hypersomnia
sleep deprivation, PPID, encephalopathy, trauma, EPM
what is catalepsy
sudden loss of muscle tone triggered by sudden stimulus and abnormal REM sleep
how do you dx narcolepsy/ catalepsy
- induce with physostigmine- acetylcholinesterase inhibitor
- Low hpyocretin-1 in CSF fluid
what is tx for narcolepsy/ catalepsy
- Imipramine- prevents serotonin reuptake inhibitor
- Atropine- prevents muscarinic blocker
what is a stereotypical behavior
repetitive relatively invariant and apparently functionless behaviors, irreversible
why do horses exhibit stereotypical behaviors
coping mechanisms, endorphin release results in positive training
