Large Animal Sx- Conditions of the equine foot (specific probs) 2

wilsbach's version from 2015-11-04 18:54


Question Answer
what is Laminitis?Inflammation of the laminae within the hoof
what is founder?Layman's term for laminitis, often the chronic form of the disease, usually with rotation of the distal phalanx (P3)
what's so special about hoof vasculature?Special plexuses of blood. lots of anastamosis. walking on the hoof puts pressure upon the valveless venous plexuses, and venous blood forced proximally into digital veins (latter have valves). On lifting foot, negative pressure inside it brings in arterial blood. These plexuses help keep the foot from freezing, but present problems in laminitis
Pathophysiology of Laminitis? (4 things)complex dz which has interaction of: inflammation, metabolic derangement, endothelial and venous dysfunction, and matrix degradation.
Causes of Laminitis--->Systemic factorsCarbohydrate overload, Grass founder, Endotoxemic states, Obesity, hypothyroidism, Pituatary Pars Intermedia Disease (Cushings disease), Metabolic syndrome, Corticosteroids / stress???, Black walnut, Cold water ingestion immediately after exercise
what is Grass founder?put out on green grass in the spring--> tons of easily digestible carbs (like carb overload). happens in ponys all the time.
what are some Endotoxemic states which can lead to laminitis?colic, enteritis, diarrhea, pleuropneumonia
Pituatary Pars Intermedia Disease is basically horse _________ ...cushings
explain metabolic syndromedz charaterized by insulin resistance, fat deposits, laminitis
what did he mention about the steroids and laminitis relationship?cant give a normal horse laminits from a bunch of steroids. but usually they start with laminits but then steroids make it worse (he doesn't think it causes it....most likely steroids made laminits worse)
what should you know about black walnut and laminitis?toxin in it-- if bedded on black walnut shavings they can get toxic laminitis
Causes of Laminitis--> Local factors?Mechanical overload on one limb (can cause "Supporting limb laminitis"), Mechanical overload on both limbs (Road founder)
how does overload on a limb affect a foal vs an adult?foals: usually lead to tendon and lig problems. Adults: laminitis
how does a horse stand with laminitis?hind feet beneath the body (camped out in front, camped under in back)
Clinical Signs of ACUTE laminitis?Typical stance (hind feet beneath the body), Reluctant to move /shifting weight / lame, Bounding digital pulses, Heat in the dorsal hoof wall, Pain to hoof testers over the toe region, Depression at the coronary band, Increased pulse, anxiety, sweating, tremors
**if it is laminitis, where are you going to get a response with hoof testers?TOE REGION
how does a horse with lamintis walk?walk gingerly, exaggerated heel-toe walking
Clinical Signs of CHRONIC laminitis?Lameness (heel to toe foot placement), Distorted hoof shape/ abnormal hoof growth, Hoof tester exam (+/-), Relapses result in severe lameness and recurrence of acute signs
once a horse has had laminitis, it will....always have high risk to get it again
what is going on in this pic? laminitis causes this abnormal growth of hoof-- the toe is all pissed off so it grows slow. so the heel grows faster than the toe, causing this weird shape
most important thing to dx laminitis?RADIOGRAPS! lateromedial view +/- DP
if you wanted to block for lamintis, which block would you use?laminitis in the toe, so need a abaxial sesmoidean block (thats what blocks the whole foot- digital block doesnt get dorsal hoof)
DDX for lamintis? (what makes horses not move well?)Colic, Tying up (myositis), Pleuritis, Tetanus
how should P3/hoof wall relate? with laminitis?on lateral view, dorsal slope of P3 should run parallel with the hoof wall. In laminitis, the P3 "sinks" and is no longer parallel going on here? take a ratio of middle of coffin bone to hoof wall and measure from tip of toe to coffin bone and take a ratio...should be less than 29%. (a/b ≤ 29%)
what might you do with a shoe to help relive some pressure with laminitis?reverse the shoe to dec pressure on toe
If you see a horse walking with a super hypermetric gait in the back legs, what do you think is going on?the FRONT feet were super painful from lamintis so back were hypermetric
***which drug should you NEVER use in laminitis?NEVER USE STEROIDS
Treatment for Acute lamintits? (basic principals)Remove initiating cause(s). Control laminar inflammation. Break the pain-hypertension cycle. Restore laminar perfusion. Prevent progressive laminar necrosis/damage. Prevent rotation / sinking of P3
Treatment Acute Disease--> specific drugs? specific actions?NSAIDs: Bute, Equioxx. Remove long overgrown toes on hoof wall. Test for metabolic disease and treat if present
how can you provide Support for the Foot with a lamintis case?Deeply bedded stall, Sand, Foam support on sole, Wedge to reduce tension on DDFT
how can temperature help laminitis?ICE HELPS! Can use ice boots. Ice Controls inflammation and reduces damage
why does ice help laminitis?part of laminitis is losing O2 to tissues-- if you cool the tissues, need less O2
Treatment for Chronic laminitis?Re-establish correct alignment of P3, Promote healing of digital lesions, Reduce hypertension, Treat metabolic diseases
what can you do to help Re-establish correct alignment of P3 in chronic laminitis?Trimming, Shoeing, Coronary grooving, ICLD or tenotomy of DDFT
what can you do to help reduce hypertension in horses suffering from chronic laminitis?Analgesia/ anti-inflammatory– NSAIDs (NEVER STEROIDS IN LAMINITIS)
so you have a rotated P3 and a overgrown hoof with chronic laminitis. How can you trim and shoe to help with this?
what kinda shoes do you use for laminitis?Heart bar shoe (helps support frog)
what is coronary grooving?cut the hoof wall under the coronary band, so that fresh horn can grow down at a fresh new angle- put on a raised up shoe so the growth has somewhere to go
what are some things that affect the prog of laminitis?Duration of acute phase, Body weight of horse, Degree of P3 rotation, if there is sinking (poor), if there is Septic laminitis
what is prog like for diff degrees of P3 rotation?less than 11* is fair, more than 11* is poor
why no steroids in laminitis?steroids alter vasoactive response by messing with amines (neg response to vasculature in foot)

Navicular Disease

Question Answer
Lameness caused by pathology of what structures?navicular bone, navicular bursa, impar ligament, Navicular suspensory ligament (CDSL--cruciate distal sesamoidean ligament), DDFT in foot region
where is the impar ligament?
where is the Navicular suspensory ligament? (aka cruciate distal sesmoidean ligament)
Clinical Signs of navicular dz? what makes it worse?Forelimb lameness (often bilateral), Lameness often worse when turning, Lameness often worse on hard surface. Pointing or stumbling
what might a horse do with its foot that would make you think navicular dz?"pointing" the foot out
what Foot conformation might indicate navicular dz?Broken back Hoof-Pastern Axis
what foot shape might indicate navicular dz?Contracted Heels-- contracting inward (narrower heel) because horse is keeping pressure off of them
how do the heels look like in nav dz?Low/Weak Heels ("underrun")
which flexion test might come back postitive with nav dz?Lower Limb Flexion Test
which 4 hoof tester tests will come back positive with navi dz?Across heels, Across frog, Each heel, Over mid-frog
what does the "wedge test" do?In the wedge test, the foot is placed on a wedge of wood, forcing the foot into a hyperextended position while the opposite leg is held in the air; after a period of time, the horse is trotted off in a straight line and watched for an increase in lameness (if subtle navi dz lameness, this will bring it out)
what does the "reverse wedge test" do?elevate heel while weight bearing-increases tension on DDFT
which block do you want to do to see if it is navicular dz?palmar digital nerve block (more specific to back of foot)
Nerve Supply of Navicular Region comes from what 3 things?(1) Palmar digital nerves (2) Branches within the DIP/Nav bursa reflection (3) Branches within the impar ligament
what are the 4 blocks which can numb out the navicular problems?(1) palmar digital (non-specific but best block) (2) Distal Interphalangeal (3) Navicular Bursa (4) Abaxial Sesamoid (will elim navi and lami)
so the L foot is all messed up when you walk the horse. Then you block the left foot, and walk them, and then the RIGHT foot is lame. did you just mess up??no this is common...BOTH feet hurt, but the L hurt more. When you block the L, then the horse shows you the R hurt too
what's some stuff you can see on rads which would be like "hey navi dz here"cysts in the navi bone
If you wanna view the navi bone from the top, which rad angle to use?Dorsoproximal-palmarodistal 60 degree oblique
if you wanna view the navi from the side, which rad angle to use?Palmaroproximal-palmarodistal oblique (skyline)
radiographic lesions of navi dz?Flexor cortex roughening, lots of lysis on bone on cortex, Medullary sclerosis / poor demarcation with cortex, Medullary lysis / cyst formation, Enthesiophyte formation at insertion of Nav. Susp. Lig, Mineralization within the DDFT, Distal border synovial invaginations
what is going on here? this is Enthesiophyte formation at insertion of Nav. Susp. Lig...can indicate navi dz
what's going on here? Medullary lysis / cyst formation
what's going on here? Medullary sclerosis / poor demarcation with cortex
what's going on here? Mineralization within the DDFT
what's going on here? Distal border synovial invaginations
explain how Nuclear scintigraphy helps dx navi dz?use Technitium 99 which has a Soft tissue and bone phase. Once it has had time to go to the site take rads of the foot. This method is very sensitive but not specific
how do you position the ultrasound to look at the navi bone? what structures can you see?go through the frog-- you will be able to see Imaging of bursa, DDFT, collateral distal sesamoidean ligament and impar ligament
Why is ultrasound a very important and viable tool in the dx of navi dz? Soft tissue lesions are part of the disease process with Navicular Disease
**Differential Diagnoses for navicular dz? (7)Nav bursitis, Nav bone pain/edema, DDF tendinitis, Nav. Susp. Desmitis, Impar ligament desmitis, Adhesions DDFT/bone, Combination injuries
Differential Diagnoses for similar foot lameness?DIPJ collateral desmitis (inflammation of a ligament), DDAL (distal digital annular ligament) desmitis, Cyst of the P2/P3, DIPJ osteoarthritis, PIPJ osteoarthritis, Distal sesamoidean desmitis
explain the correct shoeing which can help treat navicular dz?Reduce forces on navicular bone / heels, Balance the foot, Correct / reduce conformational faults, Ease breakover forces (Rolled toe, raised heels)
options for pain control treatment of navi dz?Analgesic (NSAID most commonly), Intra-bursal / intra-articular– HA( hyaluronic acid)/CCS(corticosteroids), Extra-corporeal shock wave therapy, Tiludronate/ chlodronate diphosphonate (Tilden, OsPhos), PSGAGs / IV hyaluronic acid, Temporary chemical or cryoneurectomy (to desensitize palmar digital nerve)
which analgesics and antiinflammatories are usually used for navi dz? analgesic is usually NSAID. To reduce inflammation, Intra-bursal / intra-articular– HA( hyaluronic acid) or CCS(corticosteroids) (Decreases synovitis, Inhibits migration of inflammatory cells to the joint, can provide pain relief)
what are the biphosphanates used in navi dz, and why are they used?Tiludronate/ chlodronate diphosphonate (Tilden, OsPhos)....Bisphosphonates are a class of drugs that prevent the loss of bone mass, used to treat osteoporosis and similar diseases
why do you want to use Injectable polysulfated glycosaminoglycans (PSGAGS) in navi dz?Protects cartilage and enhances HA production
why would you want to give hyaluronic acid to a navi dz horse?Lubricates joint, reduces influx of inflammatory cells, and protects cartilage
what 2 nerve procedures can you try on WHAT nerve? Temporary chemical or cryoneurectomy (to desensitize palmar digital nerve)
5 surgical treatment options for navi dz?(1) Navicular Bursoscopy (2) Desmotomy of navicular suspensory ligament (3) Inferior check ligament desmotomy (4) Extracorporeal shockwave therapy (5) Surgical neurectomy
what should you know to tell the owner if you are going to perform a Surgical neurectomy?can be useful for some but will not be permanent. (cut nerves at level of block-- usually legal.) but never last forever. if get a few years youre lucky
when would navi dz be a POOR prognosis? Poor for return to athletic soundness if lameness > 6 months. Poor for severe pathologic radiographic lesions
when would navi dz be a FAIR prognosis?good for return to soundness if lameness < 6 months