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what are examples of endocrinopathic laminitis?
- Cushings (Pars Pituitary Intermedia dysfunction)
- Equine metabolic syndrome
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although not proven, what is likely the initiating factor to laminitis?
- inflammatory mediators
- (any process that decreases perfusion or decr. protein synthesis)
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what are inflammatory mediators capable of activating that lead to swelling in the hoof compartment?
- excess metalloproteinases cause laminar attachments to break down even before onset of clinical signs
- (MMPs are normally present for remodeling and epidermal growth)
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what is the primary inflammatory cell that extravasates from laminar capillaries in acute laminitis?
mainly neutrophils which cause oxidative damage w/in laminar interstitium
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what are causes of endocrinopathic laminitis, which is more insidious onset than other forms?
- glucocorticoid excess,
- insulin resistance
- impaired glucose utilization
- inflammatory upregulation
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what are some clinical signs of acute laminitis?
- bounding pulses, heat in hoof wall
- shifting wt/refusing to pick up feet or turn in tight circles
- rotation of P3/sinking of P3 felt as depression at coronary band
- tachycardia/tachypnea
- anorexia/depression
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what should angle of p3 in relation to the ground be in health? greater than what angle is poor prognosis?
- 0-5 degrees in health
- >15 degrees = poor prognosis
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what is Obel score for horse that moves willingly at walk but gait is stilted; foot lifted off ground without difficulty?
- grade 2
- (in grade 1, gait not stilted til the trot)
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what is obel score for horse that moves reluctantly and vigorously resists attempts to have foot lifted?
grade 3 (most common grade from acute laminitis)
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which nerve block would elicit improvement for acute laminitis case?
- *abaxial nerve block *
- (not the digital nerve block since this does not block the toe)
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what are radiographic signs during acute laminitis?
may be normal rads or thickened/inflamed dorsal hoof wall as only indicator (want these for comparison later in later stages)
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what projections do you want? where should markers be placed?
- latero-medial with hoof on block
- marker at coronary band, dorsal wall, apex of frog
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what does it mean to see linear radiolucencies in dorsal hoof wall?
gas/air pockets or abscess formation where corium (hoof wall) has separated from lamina
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what are primary means of prophylactic therapy?
cryotherapy and antiinflammatory treatment (NSAIDs/Lidocaine)
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what dose of flunixin is given for purpose of scavenging endotoxin?
0.25mg/kg IV q 8hr
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what are two other prophylactic therapies that mediate effects of endotoxin?
polymyxin B and DMSO
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What do you need to know about shoes for acute laminitis patient? what about bedding?
- take shoes off!!!
- sand or peet moss so able to bury the toe
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describe the changes seen grossly in chronic laminitis patient?
- flat or dropped sole
- wider white line
- uneven growth on hoof wall; irregular growth rings around hoof
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how can you distinguish a flare up of chronic laminitis vs. acute laminitis?
flare up is usually only associated with one foot and is not often accompanied by anorexia/depression/tachycardia
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what are common problems you have to deal with in chronic laminitis cases?
frequent abscesses, sole bruises, hoof crack/chip and pain
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what type of shoeing is appropriate for chronic patients?
shorten the toe and elevate the heal to ease break over and remove stress on DDF (which pulls on P3)
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what is important to note about nutrition when maintaining chronic laminitis patient?
low CHO/grain is imperative
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do all acute cases that survive, develop into chronic cases?
no
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what findings lead to guarded prognosis? when is it definitely time to humanely euthanize?
- rotation is guarded for return to exercise
- sinking is even worse (only 5-10% ever pasture sound)
- euthanize for sure if complete detachment of hoof capsule from dermal lamina
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