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111 Cards in this Set
- Front
- Back
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What are your two goals of a neuro exam?
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Confirm its a neuro peoblem then locate the lesion (eg peripheral vs central)
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What neuro disease do tall lanky young thoroughbred racehorses get?
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Wobblers
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What neuro disease do Arabian foals get?
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Cerebellar abiotrophy
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What kins of diet could predispose to wobblers and how?
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High CHO diet --> fast growth and abnormal cartilage formation in neck --> Wobblers
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What is an example of a neuro disease that could affect horses on a herd level?
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Botulism
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Describe a central lesion vs peripheral?
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Central (eg cerebral or ascending RAS) = abnormal mentation, eg obtunded. Head pressing.
Peripheral = the horse sees you and walks over to you but is all ataxic |
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Where do you localize the lesion to when a horse has seizures?
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Seizures mean there is a primary brain lesion in the cerebrum
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When you have a horse with history of seizures, you know its a central disease. What diagnostic test will you perform?
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CSF tap
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Where do you test a horse's Panniculus response?
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Neck skin
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How did she describe testing facial nerve paralysis?
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Clamping a hemostat to the horses muzzle and him not caring (in that pic you also see that the left lip is hanging low)
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You are doing a neuro exam and check the anal and tail tone. Instead of the horse's tail being hard to lift, you can pick it up with no resistance...where do you localize the lesion to?
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Caudal lesions cause decreased tail and anal tone.
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What are some clinical signs of caudal disease?
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Decreased tail and anal tone
Urinary and fecal retention Perineal staining (this is something youll see with Herpes) |
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What causes fast muscle atrophy? Give an example.
What causes slow muscle atrophy? |
Fast = neuronal injury like Sweeney
Slow = disuse atrophy |
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How do you assess autonomic function?
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Defectaion
Sweating Horner's signs |
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Where are lesions causing Horner's?
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T1-T3
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What causes Horners?
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Damage to the sympathetic fibers (in the neck or brachial plexus)
Brachial plexus avulsion Injury to cranial thoracic spinal cord Cervical sympathetic trunk injury (like perivascular injection in the neck could cause) Guttural pouch disease |
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What are the 5 CS of Horners in a horse?
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Ptosis
Enophthalmos TE prolapse Miosis Sweating on the affected side |
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Which receptors cause sweating in horses?
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Beta2
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If a horse is walking, can she have a cerebral lesion?
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Yes! The cerebrum is NOT required for a horse to walk...theyll jus show deficits when asked to perform complex maneuvers that require some "higher brain activity"
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Gait defiits from a neurological perspective....describe the different grades of gait deficits..
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0 = none
1 = subtle, the owner probably wont even notice 2 = everyone notices theres something wrong with the gait but its hard to say whether its lameness or neuro 3= these are obvious neuro deficits 4 = so bad the horse may easily fall over himself 5 = recumbency |
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What are the 5 "normal gait" requirements?
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1. Musculature
2. Motor & sensory peripheral nerves 3. Local spinal reflexes (very impt) 4. Asc & desc pathways of the spinal cord 5. Motor centers in the brainstem |
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Is the cerebrum necessary for normal gait?
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No!
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Horses should be able to stop on a dime. With neuro disease, what will he do when you ask him to stop?
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Probably continue moving forward and get tangled up in his feet.
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Who goes deaf?
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Horses with vestibulocochlear disease (VIII)
(some Paints with congenital deafness) |
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If you suspect a horse is deaf due to VIII damage, what test will you perform to confirm the nerve is fucked up?
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Blindfold that horse and he will immediately lose his balance
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What are 3 signs of VIII disease?
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Deaf
Nystagmus Head tilt |
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What are some abnormal gait descriptive terms? (5)
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Paresis
Ataxia Hypometria Hypermetria Proprioceptive deficits |
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What is paresis?
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Weakness
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How do you test for paresis/weakness?
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Back the horse up and he will drag his back feet (youll also see wear on the toes from him dragging them)
Bouncy stride Muscle fasciculations (like how my leg muscles start to fail after having to walk up the hill) Sway test whatever that means Pull on his tail--a noemal horse wont practically fall over like one with paresis will Walk him up an incline DONT try to hop the horse like we do in small animals...they are definitely too big lol |
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T/F. Ataxia = paresis.
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False
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What is ataxia?
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Ataxia is incoordination....like theyre drunk
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Why do they get ataxix?
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Cause they cant fine tune their muscle acticity during movement
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What are some things you look for to determine a horse is ataxic?
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Inconsistent foot motion (the foot lands anywhere)
Side-to-side foot motion Circling exaggerates how bad he is at foot placement They cant get thru obstacle courses Incline.... |
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What can you do to make their ataxia worse?
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Put a blindfold on them or elevTe their neck when you have them move
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What does a hypometric gait look like? What disease does it resemble?
Is hypometria a common neuro deficit? |
Stiff gait
Navicular disease Rare |
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Hypermetria is a commoner gait deficit than hypometria.
What is a disease that causes hypermetria? |
Stringhalt
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Blindfolding worsens which two conditions?
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VIII disease
Ataxia |
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Does blindfolding worsen proprioceptive deficits?
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No. Proprioceptive deficits are independent of vision.
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What are clinical signs of proprioceptive deficits?
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Teuncal sway
Crircumduction of limbs Abnormal stance (standing with legs abducted or crossed) Abnormal or inconsistent and/or placement |
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Whaere are the receptors for proprioception located?
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Skin, joints, muscles
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What does circumduction of the limbs mean?
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Proprioceptive deficits...they just swing their leg out with no idea where it is or where its landing
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Will cerebral or vestibular disease cause weakness (paresis)?
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No.
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In which two locations will a lesion NOT cause hypermetria?
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LMN or MSk
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What is most important when collecting a CSF tap?
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Good restraint (and no increase in ICP)
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What are the two sites to collect CSF in a horse?
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AO space and LS space
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Describe how you would perform an AO tap on a horse
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First put them under GA
3.5" spinal needle (which sounds long but really isnt in the grand scheme of things) |
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What is an advantage of using the AO space for CSF collection?
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The cistern is shallowly located, so there is minimal risk of contamination with blood
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What is a disadvantage of using the AO space?
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Horse must be under GA
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When is performing a CSF tap contraindicated and why?
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With increased ICP because sticking something into the spinal cord can cause just enough oressure to herniate the brain thru the back of the skull
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How do you perform LS CSF tap?
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Put the horse in stocka if its gonna be done standing
Or do it in lateral recumbency Use a very long spinal needle (over 9") Pump the tail up and sown to locate the divot Stick |
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Which space do you have to enter to find CSF?
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Subarachnoid space
(congrats to everyone that didnt have to google that like i just did) |
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Ok so we said we woulsn't perform CSF tap if a horse has evidence of elevated intracranial pressure.
What are some CS of this (4)? |
Extensor rigidity
Strabismus (when the pupils are looking different directions) Edema in the back of the eye Bilateral mydriasis |
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What does normal CSF look like/contain?
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Clear
Low cellularity < 6 WBCs) Low protein (<100) No RBCs |
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What is xanthochromia?
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When the CSF is yellow brown
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What does xanthochromia mean?
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That theres too much protein or there was hemorrhage into the subarachnoid space.
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What causes xanthochromia?
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Trauma (including iatrogenic hemorrhage)
Herpes (causes endothelial damage and therefore leakage of RBCs and protein into the CSF) |
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What disease coud you get a false positive for if you had contamination of CSF with blood?
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EPM....apparently this is ubiquitous in the environment so most/many orses have Ab against it.
If blood got into the CSF when you were doing your tap, so could Ab (which travel in blood). This could lead you to believe the horse has EPM. |
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What the heck xouls black CSF mean?
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CNS melanoma
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How many cervical vertebrae do horses have?
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7
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Where is the horse's last cervical vertebra located?
What is the clinical significance of this? |
Thoracic inlet
Hard to see on rads |
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How would you go about taking contrast rads of a horses neck?
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First do plain aka scout films
Give NSAIDs Inject contrast under GA Take films with neck flexed then extended |
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How many films do yiu have to shoot to get a picture of the entire neck?
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3-4...their necks are long!
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What ais a risk of myelography?
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If a horse has a compressive lesion, flexing and extending it can make it worse but its usually transient
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Most horses have compression od the dorsal or ventral plane.
Can you see compressions in these planes? |
Yes.
(you cannot see compressions in the horizontal plane) |
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What two diagnostic tests are contraindicated if a hose shows evidence of increased ICP?
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CSF tap
Myelography |
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When is compression of the ventral dye column normal?
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If the nrck is flexed
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When is compressiom of the dorsal dye colum normal?
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Never (means he has a dorsal compressive lesion)
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What is the name of the photosensitizing porphyrin derived from plants?
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Phylloerythrin
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When do clinical signs of liver disease occur?
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After 75-80% loss of liver function aka we wont see it until really late in the disease process
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When is icterus common?
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More common with acute disease...it isnt always seen in late stages
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Why does liver disease cause diarrhea?
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They dont know, but remember that it can cause diarrhea
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Why dos liver disease cause hemorrhaging?
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Cause the liver isnt making globulins/proteins, and clotting factors
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Who produces gamma globulins?
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Plasma cells--not the liver
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Enzymes that elevate with hepatocecllular injury are located ______.
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In the cytosol
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What is the most specific indicator of hepatocellular injury in horses?
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SDH
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Do we measure ALT in horses or other large animals?
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No
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So what are our two cytosolic enyzmes that measure hepatocellular injury in horses?
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SDH & AST
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What three things are AST related to?
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Hepatocellular injury
Muscle damage RBC lysis |
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Ourembrane-bound, _______ enzymes are an indicator of biliary disease.
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Cholestatic
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What are the two hepatobiliary enzymes?
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GGT* and alk phos
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When we look at liver enzymes, what kind of elevation are we looking for before considering it significant?
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>3x
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Where is alk phos found?
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Bone
Intestine Colostrum Hepatobiliary tree |
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What are the four liver function tests in horses that we see on a chemistry?
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Albumin
Glucose BUN bilirubin |
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Qhat are the 3 liver function tests we need to run separately from a chemistry?
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Bile acids
Serum ammonia level Coag tests |
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Why dont we see hypoalbuminemia in a horse with liver disease?
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Because albumin has a half-life of 19 days (aka a really long half life) we dont see a drop in levels til the horse is pretty much dead (or we never see the drop)
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Why dont horses in liver failure get ascites like dogs do?
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Cause they dont become hypoalbuminemic.
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Is fasting hyperbilirubinemia a primary liver disease?
Which bilirubin increases? |
No of course not
Indirect (the one we dont worry about as much) |
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Why does fasting cause an increase in indirect aka unconjugated bilirubin?
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Because ligandin (the enzyme reaponsible for conjugating bilirubin) has a really short half-life and is only gotten from the food)
Makes sense |
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Can fasting hyperbilirubinemia cause a horse to be icteric?
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Yep
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When do we worry about an increaee in direct/conjugated bilirubin?
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When direct is more than 25% of total bilirubin, it indicates there is biliary obstruction
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In small animal med, do we run bile acids if the animal is icteric?
Do we in horses? |
No
Yes. |
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Whats normal bile acids in the horse?
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Under 20...some say under 14
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T/F. Bile acida is highly specific for liver disease, but not soecific for the type of liver disease.
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True. We know this
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Do you have to fast a horse before running bile acids test?
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Nope. Theyd on have a gallbladder so it doesnt matter
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What does hepatic encephalopathy indicate?
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Reduced liver mass or shunting of blood around the liver
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What do we have to remember about running a blood ammonia test?
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Ammonia is very labile, so the test must be run immediately after collecting your sample
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T/F. The higher the blood ammonia levels, the worse the hepatic encephalopathy.
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False. They do not correlate
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What are the three significant clinical signs of hepatic encephalopathy?
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Head pressing
Seizures Abnormal, possibly aggressive behavior |
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How can you tell parenchymal detail of the liver without doing surgery?
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By its echogenicity on ultrasound
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T/F. The liver should always be within the costochondral junctions.
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True...look at pics on pg4....bottom left shows normal liver and bottom right shows enlarged liver (its extending past those black shadows whixh are the CCJs)
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If you perform liver biopsy and find fibrosis, what is the prognosis?
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Dead horse
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Where do you look for the liver on U/S?
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Ventral to the lungs....on the left 7-9 ICS
Right = 6-15th |
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What are our landmarks for obtaining a liver biopsy?
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On the right side of the horse draw 2 lines from the tuber coxae: one to the point of the shoulder, and the other to the point of the elbow.
In this region, direct your needle thing cranio-ventral in the 11-14th rib spaces to get your sample Goal = avoid lungs |
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What do we always do before we poke livers?
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Coag tests.
Is PT >30% prolonged, we don't poke the liver |
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Why hepatic encephalopathy? What is the peotein byproduct that is toxic to the CNS?
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NH3+ aka ammonia
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What is our first and foremost goal when presented with an HE horse?
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Prevent him from hurting himself or others (remember their behavioe changes and they can get aggressive) via sedatives!
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What drug do we want to avoid using in an HE horse?
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Benzodiazepines
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How do benzodiazepines work?
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GABAergic aka inhibiltory effects on the CNS
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Why do some clinicians give Flumazenil to horses with HE?
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Flumazenil may inhibit GABA (thus inhibiting the inhibition of the CNS)
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Hwhat are the two sedative drugs we give to horses with HE?
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Flumazenil and Detomidine
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What is our choice of long-term treatment for HE?
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Dietary management
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