Term
| What is the load distribution ratio of fore:hind limb weight bearing in a horse? |
|
Definition
|
|
Term
| What is the most common location for equine forelimb lameness? |
|
Definition
| distal to the carpus (95% of forelimb lameness problems) |
|
|
Term
| If forelimbs are affected, how can you identify the lame leg during an active lameness exam? |
|
Definition
| head nod (down) when weight bearing on sound limb, head bob (up) when weight bearing on lame limb |
|
|
Term
| If hindlimbs are affected, how can you identify the lame leg during active lameness exam? |
|
Definition
| Pelvis drops on the lame side and hikes on the sound side OR greatest overall excursion on lame side |
|
|
Term
| How do local anesthetics block pain transmission? |
|
Definition
| local anesthetics block sodium channels in nerve cell membranes --> inhibition of sodium influx prevents neuronal depolarization and blocks conduction along nerves transmitting painful sensation |
|
|
Term
| What is the most commonly used local anesthetic for localization of lameness issues in horses? |
|
Definition
Lidocaine (fast onset, duration 1-3 hours)
if you want another fast onset local anesthetic with a longer duration can use Mepivacaine |
|
|
Term
| In what senario should you AVOID using nerve blocks in a horse? |
|
Definition
| Avoid nerve blocks if fracture is suspected |
|
|
Term
| When utilizing perineural approach for lameness localization what region of the leg should be anesthetized first? |
|
Definition
| always start distal and move proximal *** any tissue distal the the block should lose sensation, if you start applying anesthetic proximally multiple regions of the limb will loose sensation and localization of the lesion will not be possible |
|
|
Term
| T/F when doing an intrarticular, intrathecal (tendon sheath), or intrabursal block it is important to prep the injection site as for surgery |
|
Definition
TRUE
also use sterile equipment and a new bottle of anesthetic |
|
|
Term
| What is the most common side effect associated with diagnostic anesthesia for lameness localization? |
|
Definition
soft tissue swelling (needle trauma, hematoma, cellulitis)
although generally safe, non-septic or septic synovitis is possible, as well as lidocaine toxicity |
|
|
Term
| What could be some reasons that a horse fails to respond to a diagnostic nerve block? |
|
Definition
| chronic pain, habit, atypical neuroanatomy |
|
|
Term
| What are the anatomic landmarks associated with the palmar/plantar digital nerve block? |
|
Definition
| axial (towards the medial surfaces) to collateral cartilages of the hoof, as distal as possible |
|
|
Term
| Which structures are blocked by the palmar/plantar digital nerve block? |
|
Definition
| navicular bone and bursa, deep digital flexor tendon, heel, sole, frog, palmar/plantar aspect of distal interphalangeal joint (ie. joint btwn P2 and P3) |
|
|
Term
| Which nerve block is especially useful for evaluating lesions associated with navicular structures |
|
Definition
| palmar/plantar digital nerve block (navicualr bone and bursa, DDFT, heel, sole, frog, palmar/plantar aspect of DIPJ (joint btwn P2 and P3) |
|
|
Term
| What are the anatomic landmarks for the abaxial sesamoid never block? |
|
Definition
| palmar aspect of fetlock, abaxial (lateral margins)to sesamoid bones and axial to artery and vein |
|
|
Term
| What structures are blocked by the abaxial sesamoid nerve block? |
|
Definition
| entire foot, pastern joint (joint btwn P1 and P2), distal sesmoidean ligaments |
|
|
Term
| What anatomic landmarks are associated with the low 4-point block? |
|
Definition
front limb --> distal aspect of the splint bones and between DDFT and suspensory ligament
****careful to avoid tendon sheath and fetlock joint |
|
|
Term
| What structures are blocked by the low four point block? |
|
Definition
| Everything distal to and including the fetlock joint |
|
|
Term
| What additional nerve must be blocked in the hind limb when anesthetizing the fetlock? |
|
Definition
|
|
Term
| What are the three options for proximal metacarpal/metatarsal anesthesia? |
|
Definition
high 4 point (medial and lateral plantar and metacarpal nerves)
local infiltration of suspensory origin
lateral palmar nerve block |
|
|
Term
| When performing the high 4 point block on the forelimb to anesthetize the entire distal limb which structure is at risk of being penetrated? |
|
Definition
The carpal metacarpal joint (CMC)
***do sterile prep for high 4 point block |
|
|
Term
| When performing the high 4 point block on the hind limb to anesthetize the entire distal limb which structure is at risk of being penetrated? |
|
Definition
tarsal sheath
*** do sterile prep for high 4 point block |
|
|
Term
| What are the most proximal forelimb nerve blocks that can be performed in the horse? |
|
Definition
| ulnar and median nerve blocks |
|
|
Term
| If you are suturing or debriding a wound on the antebrachium what nerve is important to block in addition to the median and ulnar nerves? |
|
Definition
| musculocutaneous nerve --> provides sensation to the skin, not necessary to block when doing lameness exam |
|
|
Term
| Which nerve block can be used to desensitize the entire hind limb from the hock down? |
|
Definition
|
|
Term
| T/F the only region of the joint that is innervated is the synovial membrane |
|
Definition
|
|
Term
| What is the function and composition of the joint capsule? |
|
Definition
| composed primarily of collagen and functions to provide joint stability (along with the collateral ligaments) |
|
|
Term
| What are the two layers of the synovial membrane and what are their composition? |
|
Definition
Intima: epithelial-like layer, 1-3 cells thick composed of type A (macrophage derived) and type B (fibroblast derived) synoviocytes
subintima- layer of loose irregular connective tissue that contains blood vessels |
|
|
Term
| What are the functions of type A and type B synoviocytes respectively? |
|
Definition
Type A synoviocytes are derived from macrophages and clear debris from the synovial fluid
Type B synoviocytes are fibroblast derived and produce hyaluronan and lubricin (these secretions remain localized near the surface of the intimal layer creating a lubricant boundry |
|
|
Term
| What important function of the synovial membrane contributes to joint stability? |
|
Definition
| negative intra-articular pressure |
|
|
Term
| what are four important functions of the synovial membrane? |
|
Definition
| acts as a low friction lining during joint movements; formation of synovial fluid; blood synovial barrier; maintains negative intra-articular pressure to help stabilize the joint |
|
|
Term
| T/F Articular cartilage is richly vascular and richly innervated |
|
Definition
FALSE
because the articular cartilage must be compressible blood vessels and nerves would be crushed (blood vessels and nerves are located in the subintimal layer of the synovial membrane) |
|
|
Term
| What is the function of synovial fluid? |
|
Definition
nourishment of articular cartilage (remember articular cartilage is AVASCULAR)
creates an adhesive seal (negative pressure) --> joint stability
Lubrication (hyaluronate and lubricin produced by type B synoviocytes) |
|
|
Term
| What is the major component of articular (aka. hyaline) cartilage? |
|
Definition
| WATER (70-80%) <-- this allows the articular cartilage to be compressed and cushion the joint |
|
|
Term
| What are the main components of the extracellular matrix of articular cartilage? |
|
Definition
| type II collagen, proteoglycans and glycoproteins (extracellular matrix is produced by the chondrocytes) |
|
|
Term
| How are the type II collagen chains of articular cartilage arranged to provide maximum tensile strength? |
|
Definition
| alpha chain polypeptides (3 alpha chains of collagen form a triple helix, which are orderly arranged into a fibril) |
|
|
Term
| What is the composition of proteoglycans in articular cartilage? |
|
Definition
| aggrecan is the primary protein core with side chains (ex. chondroitin sulfate)that are negatively charged - this attracts water molecules providing good resistance to compression |
|
|
Term
| Which zone (zone 1 is most superficial- ie. closest to synovial membrane, and zone 4 is deepest ie. closest to bone) of the articular cartilage has the greatest cellular density? |
|
Definition
| Zone 1 has the greatest number of cells |
|
|
Term
| How does the arrangement of collagen fibrils within the articular cartilage change depending on the zone? |
|
Definition
| The more superficial zones (ie. closer to the synovial membrane) have fibrils arranged parallel to the surface to provide the greatest amount of tensile strength at the articular surface. Fibrils are randomly oriented through the middle layers and eventually end up perpendicular to the bone at the deepest layers |
|
|
Term
| Which component of the articular cartilage is responsible for resisting tensile forces across the joint? Which is responsible for resisting compressive forces? |
|
Definition
tensile forces are resisted primarily by collagen
compressive forces are resisted primarily by the osmotic pressure provided by proteoglycans (negative side chains off of aggrecan cores attract water molecules) |
|
|
Term
| What classification of inflammation is primarily implicated in equine joint disease? |
|
Definition
|
|
Term
|
Definition
| enzymes that break down proteins/peptide bonds via hydrolysis |
|
|
Term
| What is the major type of protease producing during an inflammatory event? |
|
Definition
| matrix metalloproteinases |
|
|
Term
| T/F matrix metalloproteinases are released in latent form and require activation |
|
Definition
|
|
Term
| What are three types of matrix metalloproteinases that can degrade articular cartilage during inflammatory events? |
|
Definition
Collagenase (MMP 1,8,13) --> cleaves collagen triple helices
Gelatinase (MMP 2, 9) -> further degrades the type II collagen fibrils
Stromelysin (MMP 3) --> degrades proteoglycans |
|
|
Term
| What is the effect of aggrecanases on the integrity of articular cartilage? |
|
Definition
cleaves aggrecan
*** If aggrecan molecule is cleaved close to it's attachment to hyaluronan the osmotic pressure supplied by the proteoglycan side chains is significantly compromised |
|
|
Term
| Which pro-inflammatory cytokines are important in the pathophysiology of osteoarthritis? |
|
Definition
| IL-1 and TNF-alpha ---> stimulate production of matrix metalloproteinases by chondrocytes and synoviocytes (degrade collagen and proteoglycans) |
|
|
Term
| Which anti-inflammatory cytokines can limit production of inflammatory cytokines (IL-1, TNF-alpha) and therefore limit production of matrix metalloproteinases? |
|
Definition
|
|
Term
| How do inflammatory prostoglandins affect articular cartilage? |
|
Definition
| prostoglandins deplete proteoglycans from ECM (reduce osmotic cushioning effect) and enhance pain perception |
|
|
Term
| Why do oxygen free radicals (ie. ischemia/reperfusion injury) have less effect on joints than they do on other tissues? |
|
Definition
| articular cartilage is avascular, and the entire joint is relatively avascular, so the effects of free radicals do not have a great an effect on these tissues |
|
|
Term
| T/F growth factors may signal many pro- and anti-inflammatory effects |
|
Definition
|
|
Term
| What is osteochondrosis (OC)? |
|
Definition
| failure of endochondral ossification in some regions of the bone results in focal areas of thickened articular cartilage |
|
|
Term
| What is osteochondritis dissecans (OCD)? |
|
Definition
| thickened cartilage (as a result of failure of endochondral ossification, ie. osteochondrosis) cracks and creates a cartilage/bone flap |
|
|
Term
| What is the classic signalment and clinical signs associated with developmental orthopedic disease? |
|
Definition
| young animal with joint effusion and mild to moderate lameness ex. osteochondritis dessecans, subchondral cysts, delayed ossification |
|
|
Term
| What are the three main ways large animals can develop septic joint disease? |
|
Definition
direct penetration of a joint (most common cause in adults ex. step on a nail)
extension from adjacent tissues (usually physis <- very vascular structure)
hematogenous spread (more common in young animals) |
|
|
Term
| What is the definition of osteoarthritis? |
|
Definition
| progressive deterioration of the articular cartilage accompanied by changes in the bone and soft tissue of the affected joint |
|
|
Term
| What are some signs of osteoarthritis appreciable on arthroscopy? |
|
Definition
| grooves/wear lines in the articular cartilage, loss of smooth shiny surface, osteophyte formation, variable synovial inflammation |
|
|
Term
| Where are the majority of bovine lameness problems localized to? |
|
Definition
70-80% of lameness issues in cows occur in the digits
**can r/o using low regional nerve blocks |
|
|
Term
| What is the morbidity, location, and degree of lameness associated with interdigital phlegmon (foot rot)? |
|
Definition
| sporatic to endemic, entire crevice and coronary band affected, affected animals present with acute severe lameness |
|
|
Term
| What is the morbidity, location, and degree of lameness associated with interdigital dermatitis (heel horn erosion)? |
|
Definition
| high morbidity (50-100%), heel and interdigital crevice affected, animals present with mild lameness |
|
|
Term
| What is the morbidity, location, and degree of lameness associated with digital dermatitis (hairy heel warts)? |
|
Definition
| Very high morbidity, lesions are located on the heel, animals present with marked lameness |
|
|
Term
| What is the morbidity, location, and degree of lameness associated with interdigital hyperplasia (corns)? |
|
Definition
| sporadic morbitidy (4-6%), lesions located on dorsal aspect of the interdigital crevice, animals present with none to moderate lameness |
|
|
Term
| What is the etiologic agent associated with interdigital phlegmon (foot rot)? |
|
Definition
Fusibacterium necrophorum, occurs in association with excessive moisture and maceration of the skin
** very distinctive rotten odor |
|
|
Term
| How do you treat and prevent interdigital phlegmon (foot rot)? |
|
Definition
important to treat with systemic antibiotics to prevent extension of the infection into deeper structures (ie. coffin joint, DDFT, fat pad) Foot baths can be used in conjunction with systemic therapy but important to keep the feet DRY
control is aimed at managing the environment to minimize excessive moisture and abrasive bedding. |
|
|
Term
| What is the treatment of choice for interdigital dermatitis (heel horn erosion)? |
|
Definition
clean and debride lesions, apply topical antibiotics (because lesions don't penetrate the dermis systemic antibiotics are not as effective)
control by maintaining good environmental hygiene and weekly prophylactic foot baths |
|
|
Term
| What is the treatment of choice for digital dermatitis (hairy heel warts)? control? |
|
Definition
debride lesions and apply topical oxytetracycline and antimicrobial foot baths.
Morbidity is very high so it is important to isolate affected animals |
|
|
Term
| What is the treatment of choice for interdigital hyperplasia (corns) and how can you prevent this condition? |
|
Definition
first confirm source of pain (corns can be asymptomatic), resect lesion and wire claws together (excessive spreading of the claws results in chronic irritation that initiates corn formation)
diligent claw trimming can help to prevent interdigital hyperplasia but large, heavy animals are predisposed to developing the condition |
|
|
Term
| What type of stance is suggestive of acute laminitis in cattle? |
|
Definition
| rapid onset of pain/lameness --> crossed legs (reduce amount of pressure on affected digits) |
|
|
Term
| What changes to the feet are associated with chronic laminitis? |
|
Definition
| thickened or irregular coronary band --> slipper foot, double soles, white line disease |
|
|
Term
| What factors increase the risk of developing laminitis in cattle? |
|
Definition
| abrupt feed changes, rapid growth, endotoxemia |
|
|
Term
| What are the primary lesions associated with pododermatitis circumscripta? |
|
Definition
| sole ulcer at the sole-bulb junction over the P3 prominence, these lesions occur on the medial fordigits and lateral hind digits (primary weight bearing digitis) and occur especially in heavy high producing cows |
|
|
Term
| What is the treatment for sole ulcers (pododermatitis circumscripta)? |
|
Definition
| trim claws, debride any exuberant granulation tissue, block non-affected claw (removes pressure off of the affected digit) |
|
|
Term
| What is the prognosis for cattle with digital fractures? |
|
Definition
guarded, P3 heals really slowly
can block opposite claw, cast the limb, amputate the affected digit or arthrodese the joint |
|
|
Term
| What is the etiology and treatment for corckscrew claw? |
|
Definition
| hereditary disorder, usually affects lateral claw --> can be managed with frequent hoof trimmings. These animals should be culled from the breeding herd |
|
|
Term
| Other than direct penetrating injury what is the most common source of septic arthritis in adult cattle? |
|
Definition
| contiguous infection from adjacent soft tissue infections (ex. interdigital phlegmon, sole ulcers, soft tissue injuries adjacent to joints) |
|
|
Term
| Other than direct penetrating injury what is the most common source of septic arthritis in neonatal cattle? |
|
Definition
| hematogenous spread, tends to affect larger joints and occur in multiple sites |
|
|
Term
| How can you diagnose septic arthritis? |
|
Definition
| suggestive clinical signs (non-weight bearing lameness), cytology of joint fluid (WBC >40,000/uL, degenerative PMNs, bacteria are rarely seen on cytology but would be definitive for septic arthritis if present) |
|
|
Term
| What are the principles of treatment for septic arthritis? |
|
Definition
volume lavage with sterile isotonic solution, regional IV antibiotics + systemic antibiotics, NSAIDs to reduce inflammation, controled excercise (esp. neonates, can develop contracted tendons if recumbant for long periods of time)
if chronic can amputate affected claw or arthrodese affected joint |
|
|
Term
| What are the four most common causes of acute non-weight bearing lameness in a 2 year old heifer? |
|
Definition
| septic arthritis, long bone/weight bearing bone fracture, septic tenovitis, sole abcesses (more common in horses) |
|
|
Term
| What is the most common location for a hygroma? |
|
Definition
| tarsal/carpal, associated with chronic soft tissue trauma (may reflect poor husbandry/bedding), cosmetic treatment is hard to achieve but these lesions generally do not cause lameness |
|
|
Term
| What stance is associated with DDF tendon laceration? |
|
Definition
|
|
Term
| What stance is associated with SDF tendon laceration? |
|
Definition
|
|
Term
| What is the treatment for flexor tendon lacerations in cattle? |
|
Definition
debride and clean soft tissue wounds, cast/splint affected limb for 4-12 weeks
No need to suture the ends of the tendon together, prognosis is better than for equine patients with the same injury |
|
|
Term
| What stance is associated with ruptured gastrocnemius? |
|
Definition
dropped hock
too distal to cast, prognosis is poor |
|
|
Term
| Which animals are predisposed to developing osteochondrosis? |
|
Definition
| Bulls and fattening steers (disease is associated with high CHO diet), lesions primarily affect the large joint |
|
|
Term
| T/F spastic paresis (Elso heel) is a hereditary condition that usually affects the gastrocs resulting in progresive hock extension |
|
Definition
| TRUE tx to reach slaughter only |
|
|
Term
| What is the treatment of choice for femoral/obturator neuritis? |
|
Definition
| NSAIDS and support lift (usually there is no axonal damage, just inflammation) |
|
|
Term
| What is the presentation and treatment associated with radial nerve/brachial plexus paresis? |
|
Definition
often associated with trauma that results in rapid abduction of the forelimbs +/- humeral fractures -> recumbency
tx with splints (fix the carpus in place to allow the cow to bear weight), NSAIDs, and swim/lift (to reduce pressure myositis associated with recumbancy) |
|
|
Term
| What is the treatment for cannon bone fractures associated with inappropriate application of traction during dystocia? |
|
Definition
Colostrum/plasma because often unable to stand to nurse (treat failure of passive transfer)
full limb cast, changed every 2-3 weeks to allow for bone and hoof growth |
|
|
Term
| What calving injury is most common in calves that are born in anterior position with hip lock? |
|
Definition
| slipped capital femoral epiphysis (prognosis is fair with surgery, poor with medical treatment) |
|
|
Term
| What important clin path test should be assessed in all neonates with calving injuries? |
|
Definition
| check serum immunoglobulin levels as all neonates with calving injuries may be unable to nurse, and may have poor intestinal immunoglobulin absorption |
|
|
Term
| What type of calf injury is associated with posterior/breach presentation dystocias? |
|
Definition
| rib fractures, if fractured in multiple places --> flail chest --> dyspnea |
|
|
Term
| What is the most common location for jaw fractures in calves that required assisted delivery? |
|
Definition
| bilateral interdental space, prognosis is good if addresses quickly |
|
|
Term
| Why is rest an essential component of treating equine joint disease? |
|
Definition
| rest allows for a reduction of acute inflammation -> reduction in inflammatory cytokines and MMPs -> less destruction of articular cartilage |
|
|
Term
| What is the function of physical therapy in treatment of equine joint disease? |
|
Definition
| goal of PE is to strengthen the muscles associated with the affected joints -> increase joint stability |
|
|
Term
| What is the most important element of nutritional treatment for equine joint disease? |
|
Definition
| Weight control (increased body weight --> increased load on joints --> increased incidence of disease) |
|
|
Term
| What is the mechanism of NSAID treatment in equine joint disease? When is the use of NSAIDs contraindicated? |
|
Definition
NSAIDs reduce inflammation and pain sensation by inhibiting cyclo-oxygenase and therefore reducing prostaglandin formation.
***contraindicated in dehydrated patients --> acute renal failure |
|
|
Term
| What is the treatment of choice for equine osteoarthritis? |
|
Definition
intra-articular corticosteroids
**inhibit degradative enzymes (phospholipase A2) |
|
|
Term
| Which corticosteroid would you use to treat osteoarthritis in a low motion joint, or a hard to reach joint (ex. hip)? |
|
Definition
methylprednisolone acetate
*** LONG duration of action |
|
|
Term
| Which corticosteroid would you use to treat osteoarthritis in a high motion joint? |
|
Definition
triamcinolone acetonide
** most chondroprotective activity |
|
|
Term
| What is the term used to describe a lateral deviation of the limb? |
|
Definition
|
|
Term
| What is the term used to describe a medial deviation of the limb? |
|
Definition
|
|
Term
| What is the most common cause of angular limb deformity in large animals? |
|
Definition
asynchronous physeal growth
** may also arise from ligamentous laxity (premature foals), tarsal/carpal cuboidal bone collapse or fractures |
|
|
Term
| T/F if the only musculoskeletal abnormality is an angular limb deformity the animal will NOT be lame |
|
Definition
|
|
Term
| What are the three most common angular limb deformities? |
|
Definition
carpal and tarsal valgus
fetlock varus
**singular and in combination |
|
|
Term
| What is a clinical finding associated with angular limb deformities secondary to crushed carpal/tarsal cuboidal bones? |
|
Definition
| the affected limb will be shorter than the unaffected limb |
|
|
Term
| How should you assess a horse for angular limb deformities? |
|
Definition
| look straight on with each limb, not straight on from the front of the horse |
|
|
Term
| How can you localize the nidus of an angular limb deformity on radiographs? |
|
Definition
| draw a straight line down the middle of each bone , where the lines intersect is a rough indicator of the source of the problem |
|
|
Term
| What are two surgical treatments that can be used to correct angular limb deformities? |
|
Definition
periosteal stripping (cut periostium on the side that the deformity is angled towards, relieves pressure against the physis on this side)
transphyseal bridging (applied to side opposite the angular deformity to slow growth at this physis giving the other side time to catch up <-- must be removed once limb is straight) |
|
|
Term
| What region of the long bones is most prone to inflammation in young growing animals? |
|
Definition
| metaphysis provides much of the longitudinal growth and has a greater blood supply than the epiphysis; therefore, this region is most prone to inflammation |
|
|
Term
| What is the etiology of physitis in young growing animals? |
|
Definition
abnormal bone that cannot withstand normal stresses
OR
normally growing bone that is exposed to excessive stress secondary to conformational abnormalities (asymmetrical physitis) or excessive exercise or weight gain (symmetrical physitis) |
|
|
Term
| How can you differentiate physitis from tendon problems in a horse that is exhibiting buckling forward at the carpus or fetlock? |
|
Definition
| if physitis the feet will be flat on the ground, if tendons are involved toe will be tipped forward (DDF) |
|
|
Term
| What radiographic abnormalities are consistent with the diagnosis of physitis? |
|
Definition
| region of increased lucency (bone lysis) surrounded by a thin zone of increased opacity (fibrosis) at the physis |
|
|
Term
| What is the pathophysiology of metacarpal exostoses (aka splints)? |
|
Definition
inflammation and tearing of the interosseus ligament (where splint bones attach to MC III/cannon bone) secondary to conformational abnormalities or external trauma -> new bone is produced at the site of injury to stabilize, this is a painful condition
**most commonly occurs at the medial aspect between MC II and cannon |
|
|
Term
| How is metacarpal exostoses (splints) diagnosed and what is its prognosis? |
|
Definition
dx based off rads (need to r/o splint bone fracture), lameness and pain on palpation
prognosis is generally good but large exostoses may cause persistent lameness secondary to irritation of the suspensory ligament |
|
|
Term
| Why is stabilization the central element in management of equine long bone fractures? |
|
Definition
stabilize the limb -->
relieves anxiety
keeps the bone from penetrating the skin and protects any existing wound from further contamination
minimize further damage to the fractured ends of the bone and surrounding soft tissues
minimize neural and vascular injury |
|
|
Term
| T/F in cases of suspected/known long bone fracture splint should be applied prior to shooting radiographs |
|
Definition
TRUE
it is imperative to stabilize the limb |
|
|
Term
| Once limb has been stabilized what other treatments should be considered prior to surgical referral for treatment of long bone fracture in horses? |
|
Definition
Broad spectrum antibiotics (if concurrent skin damage)
IV fluids if severe hemmorhage/sweating (hypovolemic shock)
NSAIDs (analgesic and anti-inflammatory, only give to well hydrated patients otherwise --> ARF) |
|
|
Term
| What type of splint should be used in the case of fractures to the phalanges up to the mid-metacarpus? |
|
Definition
| place phalanges in extension (horse will be standing on its toe) and apply a dorsal splint up to the proximal limit of the the metacarpus (cannon bone) |
|
|
Term
| What type of splint should be used in the case of fractures to the phalanges up to the mid-metatarsus? |
|
Definition
| place the phalanges in extension and apply splint to the plantar surface of the limb (flexion from reciprocal apparatus makes plantar splint application easier than dorsal) up to the proximal limit of the metatarsus (cannon bone) |
|
|
Term
| What type of splint should be used in the case of fractures to the mid-metacarpus to the distal radius? |
|
Definition
| apply robert jones bandage (1 inch thick) up to the elbow with one caudal and one lateral splint (important to stabilize in both directions because of minimal muscle coverage over the cannon bone) |
|
|
Term
| What type of splint should be used in the case of fractures to the mid-radius up to the elbow in the forelimb, and fractures of the tarsus or tibia in the hind limb? |
|
Definition
apply a lateral splint as high over the thorax as possible (planks of wood work well)
goal is the prevent abduction of the limb --> penetration of the bone through the skin |
|
|
Term
| What type of splint should be used in the case of fractures proximal to the elbow or femoral fractures? |
|
Definition
| these bones are protected and stabilized by heavy muscle cover, application of a caudal splint to the elbow can lock the carpus to provide support and allow the horse to put weight on this leg <-- reduces anxiety) |
|
|
Term
| Which anatomic feature is important to include when splinting fractures affecting the middle and proximal metatarsus? |
|
Definition
| must ensure that splints (caudal and lateral) extend to the point of the calcaneous (can conform the caudal splint over the calcaneous, ie. point of hock, up to the stifle) |
|
|
Term
| T/F large trailers are preferred over small trailers when transporting a horse following stabilization of long bone fracture |
|
Definition
TRUE
larger trailers allow you to choose the direction the horse is facing, when braking the weight is concentrated on the limbs facing forwards in respect to the direction the vehicle is traveling |
|
|
Term
| Horses with forelimb fractures should be hauled facing what direction? |
|
Definition
| forelimb fractures should be hauled facing backwards (weight on hindlimbs when vehicle is breaking) |
|
|
Term
| horses with hind limb fractures should be hauled facing which direction? |
|
Definition
| hind limb fractures should be hauled facing forwards (weight is concentrated on forelimbs when vehicle is braking) |
|
|
Term
| What clin path findings are consistent with muscle necrosis? |
|
Definition
elevated AST, LDH and CK
r/o liver disease (AST and LDH are not muscle specific) |
|
|
Term
| What elevation of which serum enzyme is a good indicator of chronic muscle necrosis? |
|
Definition
| elevated AST, delayed lymphatic leakage and prolonged clearance of this enzyme indicated chronicity |
|
|
Term
| trends in which serum enzyme are important for assessing response of muscle to treatment? |
|
Definition
| CK, is eliminated from the serum rapidly following muscle damage, recheck every 3-7 days to assess ongoing necrosis |
|
|
Term
| What are some ultrasonographic features of muscle necrosis? |
|
Definition
| swelling and hypoechoic (due to edema +/- hemmorage) |
|
|
Term
| which muscle group should be biopsied when motor neuron disease is suspected? |
|
Definition
sacrocaudalis muscle;
>20% slow twitch fibers, most consistently atrophied |
|
|
Term
| which muscle group should be biopsied when exertional myopathy is considered? |
|
Definition
| semimembranosus or gluteal |
|
|
Term
| Which muscle group should be biopsied when immune-mediated myopathy is suspected? |
|
Definition
|
|
Term
| Why is it important to assess renal function in patients with rhabdomyolysis? |
|
Definition
| extensive muscle necrosis can cause pigment nephropathy |
|
|
Term
| What is the etiology and clinical signs associated with hyperkalemic periodic paralysis (HYPP)? |
|
Definition
inherited autosomal dominant -> point mutation in sodium channel prevents it from closing -> increased neuronal depolarization and muscle contraction
most significant clinical feature are muscle fasciculations, also sweating, prolapsed 3rd eyelid and dyspnea/stridor (esp. homozygotes) |
|
|
Term
| T/F HYPP is associated with elevated serum potassium and CK |
|
Definition
FALSE
CK is Normal
Potassium is elevated during an episode and normal between episodes |
|
|
Term
| What is the treatment for an acute episode of HYPP? What management changes can help reduce incidence of HYPP episodes? |
|
Definition
during and episode karo syrup/grain can help induce intracellular translocation of potassium and lower serum levels.
Prevention involves regular turnout/excercise, low potassium diet +/- acetazolamide (oral diuretic --> increase urinary potassium excretion) |
|
|
Term
| Which form of myotonia is mild and non-progressive? Which is severe and progressive? |
|
Definition
myotonia congenita is mild and non-progressive
myotonia dystrophica is more severe and progressive (associated with structural derangements in addition to biochemical abnormalities within the muscle) |
|
|
Term
| What is the etiology of myotonia? |
|
Definition
| defect in skeletal muscle chloride channel --> muscles cannot relax |
|
|
Term
| What are three potential etiologies for nonexercise associated inflammatory rhabdomyolysis? |
|
Definition
bacterial (clostridium)
viral (influenza A2)
parasitic (sarcocystis) |
|
|
Term
| T/F clostridial myositis associated with IM injections is due to direct innoculation as needle passes through contaminated skin |
|
Definition
| FALSE clostridial spores may be ingested and remain dormant in the muscle, injections or muscle trauma that cause ischemia create an anaerobic environment in which sporulation occurs -> endotoxins cause extensive muscle necrosis |
|
|
Term
| what type of infections predisposes horses to developing immune mediated myositis? |
|
Definition
respiratory infections (esp. Strep sp.)
**associated with rapid onset of muscle atrophy |
|
|
Term
| What dietary deficiencies are associated with nutritional myodegeneration (aka white muscle disease)? |
|
Definition
| deficiencies in vitamin E and selenium in young growing animals |
|
|
Term
| What clinical and laboratory findings are consistent with nutritional myodegeneration (white muscle disease)? |
|
Definition
weakness, stiffness, hunched +/- recumbant
tachyarythmias (heart may be primarily affected, or may be secondary to pain)
laboratory findings include elevated serum CK and AST and myoglobinuria
can also evaluate blood levels of vitamin E and selenium |
|
|
Term
| What is the prognosis for patients with nutritional myodegeneration? What are two important preventative measures that can be taken especially in endemic areas? |
|
Definition
prognosis is good if standing after 48hrs. If one animal comes down with nutritional myodegeneration check the entire herd!
In endemic areas can inject neonates and pregnant dams with vitamin E and selenium as preventative |
|
|
Term
| What types of muscle can be affected by toxic rhabdomyolysis causes by ionophores and white snake root/rayless goldenrod? |
|
Definition
| both skeletal and cardiac muscle are affected |
|
|
Term
| T/F animals with signs of excertional rhabdomyolysis should be hand walked to reduce clinical signs |
|
Definition
FALSE (hand walk HYPP horses -muscle fasiculations but NO pain)
use tranquilizers to relieve anxiety + analgesia, can also use NSAIDs but only if well hydrated (dehydration + NSAIDs = ARF) |
|
|
Term
| What are three syndromes classified as traumatic rhabdomyoysis? |
|
Definition
capture myopathy
postanesthetic myoneuropathy
downer cows (trauma, parturient paresis, malnutrition, sepsis) |
|
|
Term
| What are some nutritional elements associated with cases of sporatic tying up? |
|
Definition
vit e and selenium deficiency -> weakness
inadequate electrolyes -> cramping and pain |
|
|
Term
| In cases of sporatic (extrinsic) exertional rhabdomyolysis which element of exercise is more influential in inducing episodes, duration or intensity of exercise? |
|
Definition
|
|
Term
| What kind of diet is best for horses prone to exertional rhabdomyolysis? |
|
Definition
| diets low in starch and sugars (NSC) are ideal |
|
|
Term
| What is the etiology and outcome of horses affected by malignant hyperthermia? |
|
Definition
dominant mutation in RYR1
episode is often instigated by anesthesia --> extreme rhabdomyolysis +/- sudden death |
|
|
Term
| What signalment is most commonly associated with recurrent excertional rhabdomyolysis? |
|
Definition
usually fillies, esp. TB/arabian/standardbreds
Excitment, nervousness and stress are key triggers |
|
|
Term
| What is the etiology of type 1 PSSM? |
|
Definition
| dominant gain of function mutation in glycogen synthase 1 --> abnormal glycogen accumulates in muscle |
|
|
Term
| What clin path finding is consistent with PSSM? How can you definitively diagnose PSSM? |
|
Definition
persistently elevated CK (>800 u/L)
definitive dx via muscle biopsy |
|
|
Term
| How should horses with PSSM be managed? |
|
Definition
NO grain, minimize intake of starch and sugar (NSC)
daily exercise and turnout (at least 15min/day) |
|
|
Term
| What type of collagen predominates in tendons and ligaments? |
|
Definition
Type 1 (densely packed/well arranged --> great tensile strength but limited stretch capacity)
** remember, type 2 collagen is most predominant in articular cartilage |
|
|
Term
| How do tendons and ligaments heal? |
|
Definition
| healing occurs through fibroplasia, never regain 100% strength or structure |
|
|
Term
| What is the best therapy to promote greatest healing and regain of function in the event of a tendon/ligament injury? |
|
Definition
| passive motion exercises promote earlier parallel-fiber healing than inactivity (ie. stall rest) |
|
|
Term
| What location and specific tendon are most commonly implicated in cases of tendonitis (bowed tendon)? |
|
Definition
| most commonly affect the SDF in the forelimbs, middle bow (mid-metacarpus) is the most common location |
|
|
Term
| T/F animals with tendonitis may present as lame or sound |
|
Definition
TRUE
acute tendonitis --> mild to moderate lameness, usually self limitin
chronic phase -> may be sound at the walk and trot |
|
|
Term
| What is the key to successful treatment of tendonitis? |
|
Definition
early diagnosis
-> heat, swelling, and pain on PE
-> ULTRASOUND (decreased echogenicity correlates with fiber disruption) <-- evaluate response to treatment via serial ultrasound |
|
|
Term
| What limb position is common in lacerations of extensor tendons (ie. lesions over dorsal to lateral limb, generally over metacarpus)? |
|
Definition
| horse is unable to extend the toe --> may knuckle over on the toe <-- apply caudal splint to point of elbow for support |
|
|
Term
| What limb position is seen with lacerations of the SDF tendon? With the DDF tendon? |
|
Definition
SDF laceration --> dropped fetlock
DDF lacteration --> toe tips up
** poor prognosis for soundness if both are transected |
|
|
Term
| What is the leg position that positively identifies rupture of the peroneus tertius? |
|
Definition
ability to extend the hock while the stifle is flexed
**prognosis is favorable is no avulsion fracture at the femur |
|
|
Term
| What is the leg position that positively identifies disruption of the caudal component of the reciprocal apparatus? |
|
Definition
hock flexed and stifle extended during weight bearing
**most commonly occurs in foals following dystocia or trauma --> disruption of gastrocnemius and SDF muscle |
|
|
Term
| What anatomic features of the hoof act to reduce concussive forces? |
|
Definition
Frog, digital and coronary cushions, lateral cartilages of the foot = shock absorbers
Blood contained in the plexuses of the corium produces a hydraulic cushion
Laminae dissipate concussions due to increased surface of attachment |
|
|
Term
| What is the most common etiologic agent associated with thrush? |
|
Definition
Degenerative condition of the epidermis of the central and collateral sulci of the frog associated with (but not necessarily caused by) Fusobacterium
Necrophorum
Disease of poor hygiene associated with moist conditions, especially feces and urine |
|
|
Term
| What is the pathophysiology of laminitis? |
|
Definition
| Disturbance of the blood flow to the foot -> Subsequent separation of the laminae -> Breakdown of the attachment between sensitive and insensitive laminae |
|
|
Term
| T/F degree of abnormality on radiographs does not correlate with clinical severity of laminitis |
|
Definition
TRUE
Radiographic signs DO NOT correlate with the clinical picture, degree of rotation is questionable as a prognostic indicator
** Sequential radiographic study is more helpful in monitoring response to therapy than a single film |
|
|
Term
| What type of shoe is useful in the therapeutic management of laminitis? |
|
Definition
Any shoe that elevates the heel
ex. heart bar, egg bar, reverse shoe
** in extreme situations casts may be used |
|
|
Term
| describe the etiology and clinical presentation of a horse with palmar foot syndrome. |
|
Definition
Slowly developing intermittent lameness (localized to caudal hoof) which is aggravated by exercise
due to chronic degenerative condition of the navicular bone associated surrounding soft tissue
**pathogenesis is unknown |
|
|
Term
| What are the weight bearing surfaces of the hoof? |
|
Definition
ground border of hoof wall, bars,
white line, frog, ½ inch of sole on inner side of white line |
|
|
Term
| What is the reasoning behind shoeing horses hooves? |
|
Definition
Protect foot from excessive wear associated with normal exercise
Help with conformational problems
Therapeutic (tx laminitis etc.) |
|
|
Term
| Which nerve blocks and joints blocks are used to diagnose lameness related to foot problems? |
|
Definition
nerve blocks:
Palmar/plantar digital
Abaxial
Joint-Bursa blocks
Distal interphalangeal joint (ie. coffin block)
Navicular bursa |
|
|
Term
| What is the difference between a sole bruise and a sole corn? |
|
Definition
Bruise: subsolar hematoma
Corn: bruise in angle of sole |
|
|
Term
| What is the medical term for canker and how does this disease present? |
|
Definition
Chronic infectious pododermatitis
presents with a characteristic odor and
caseous exudate on cauliflower-like proliferative lesion |
|
|
Term
| T/F sidebone is not a common cause of lameness in horses |
|
Definition
TRUE
***sidebone is the calcification of collateral cartilages |
|
|
Term
| What is the etiology and clinical presentation associated with quittor in horses? |
|
Definition
Quittor is necrosis of the collateral cartilages of P3 secondary to local trauma
horses are intermittently lame and lesion appears as a draining tract
associated with the coronary band |
|
|
Term
| What is the treatment and prognosis for a fractured navicular bone? |
|
Definition
Conservative treatment involves stall rest (6 months), bar shoes, +/- wedge shoes
More aggressive therapy may include internal fixation: screw in lag fashion
or palmar digital neurectomy
Prognosis is guarded to poor |
|
|
