Musculoskeletal diseases Flashcards
What is the causative agent of wooden tongue?
Actinobacillus lignieresii
Describe the pathophysiology of wooden tongue
Actinobacillus lives in the oral cavity and penetrates the tongue following a wound, causing granulomatous infection
What are the clinical signs of wooden tongue?
Anorexia, dehydration, hypersalivation, enlarged firm tongue +/- ulcers, regional lymphadenitis, submandibular swelling
How is wooden tongue diagnosed?
Clinical signs + aspirate with gram negative rods with sulfur granules. Response to treatment indicates diagnosis as well.
How is wooden tongue treated?
10-20% sodium iodide IV twice, 7-10d apart
Oxytetracycline for severe cases
Should improve within 48hrs
What is the causative agent of lumpy jaw?
Actinomyces bovis
Describe the pathophysiology of lumpy jaw
Actinomyces is commonly found in the oral cavity and infects tissues following a wound. Infection spreads and can cause osteomyelitis.
What are the clinical signs of lumpy jaw?
Painless bony immovable swelling of jaw -> decreased appetite and abnormal chewing, weight loss, hypersalivation -> eventual destruction of jaw, periosteal response, and fibrous tissue reaction +/- draining tracts
How is lumpy jaw diagnosed?
Clinical signs, gram stain of aspirate or biopsy showing gram negative branching rods +/- sulfur granules, osteomyelitis on radiology, culture of organism, response to treatment
How is lumpy jaw treated?
Consider culling
If animal is valuable treat with 10-20% sodium iodide IV every 7-10 days until signs of iodism appear + procaine penicillin. You can debulk/curette, flush and pack lesions and remove loose teeth as well. Lesion won’t get smaller but with care might not get bigger.
What is the most common location for lameness in cattle?
Lateral claw of rear feet
What are the steps of a lameness examination?
Observe at rest- stance, muscle atrophy, conformation
Observe during walk- from side then rear
Closely examine affected foot- swelling, look after trimming or on foot table, might need lateral recumbency
How frequently should hoof trimming be performed?
At least once a year for dairy cattle
What are predisposing factors for sole ulcers?
Lateral claw longer than medial claw, lateral claw less concave than medial claw, lateral claw carrying more weight, hard environment, under-conditioned cow
What are the clinical signs of a sole ulcer? How is it diagnosed?
Painful hoof
Diagnosed by direct examination
How is a sole ulcer treated?
Decrease focal pressure with corrective trimming or by applying a wooden block, debride and control granulation tissue
How are sole ulcers prevented?
Annual foot trimming, maximize cow comfort
What clinical signs are associated with subclinical laminitis?
Yellow waxy discoloration of solar horn, chalkiness and widening of sole-wall junction
What clinical signs are seen in chronic laminitis?
Lameness, parallel ridges in hoof wall with long misshapen claws, white line disease can occur
How is laminitis treated/prevented?
Regular corrective trimming, correct diet to prevent rumen acidosis
What are predisposing factors for subsolar abscesses?
Solar penetration- anything that softens the hoof, excessively worn soles, foreign bodies
How are subsolar abscesses treated?
Hoof trimming, drainage of the abscess
Describe white line disease; how is it treated?
Sequelae of laminitis- widening of white line most commonly at heel to sole junction in lateral rear claw, often complicated by infection of distal interphalangeal joint and navicular bursa
Treated with corrective trimming
Describe pedal bone fractures
Most common in large adult cattle (beef), usually associated with trauma, present with severe lameness and pain, positive on hoof testers. Diagnose with radiographs. Treat with wooden block on the unaffected claw and confinement for 8 weeks minimum.
Which animals most commonly develop interdigital fibromas?
Heavy, older cattle, primarily bulls
How should interdigital fibromas be treated? How do you know if they need to be treated?
Treat if they are lame
Surgically excise lesion, apply pressure bandage
What is the difference between scissor claws and corkscrew claws?
Scissor claws are overgrown and overlap
Corkscrew claws are overgrown and claw rotates on long axis
Which cattle (dairy or beef) are more predisposed to digital dermatitis?
Dairy
What is the causative agent of digital dermatitis?
Treponema- a spirochete bacteria
What are risk factors for developing digital dermatitis?
Large herds with purchased cows, grooved concrete floor, high moisture floor, hoof trimming equipment used on other farms, hoof trimming equipment that isn’t disinfected
What are the clinical signs of digital dermatitis?
Lesion on plantar area of rear feet, can be ulcerative, erosive, or proliferative (wart-like), usually well-demarcated with hyperemic edge and possibly necrotic center, lesion is painful and doesn’t extend above dewclaws
What is the treatment for digital dermatitis?
Topical antibiotics, individual animal treatment is most efficacious but labor intensive
Debulk if lesion is very large
Describe the bandaging used for digital dermatitis
Bandage with oxytetracycline or LS-50 soaked cotton ball
Describe the spray used for digital dermatitis
Only used in herringbone parlors- rinse hind feet then spray with tetracycline HCl powder mixture (or LS or copper peroxide)
Why are footbaths not recommended for digital dermatits?
Difficult to keep clean, have questionable efficacy, expensive to maintain, environmental hazard
How is digital dermatitis controlled?
Oral biotin (20mg/head), vaccine (unclear if efficacious), spraying hind feet, disinfect hoof trimming equipment
What is another name for interdigital dermatitis?
Foot rot
Describe the etiology of interdigital dermatitis
Localized bacterial cellulitis with deep tissue invasion
Usually non-motile, anaerobic, gram-negative organisms (Fusobacterium necrophorum and Dichelobacter nodosus)
Which cattle get interdigital dermatitis most commonly?
Yearling beef cattle
Describe the pathophysiology of interdigital dermatitis
Traumatic injury to interdigital area which gets softened due to water is invaded by bacteria causing necrotizing, deep, invasive infection
What are the clinical signs of interdigital dermatitis?
Rapid onset of moderate to severe lameness with significant symmetrical swelling and erythema between and above digit
How is interdigital dermatitis treated?
Procaine penicillin (IM), oxytetracycline (IM), ceftiofur (SQ)
What is the causative agent of infectious foot rot of sheep?
Dichelobacter nodosus (also Fusobacterium necrophorum)
Describe the pathophysiology of infectious foot rot in sheep
Carrier sheep discharges bacteria to the ground which infects other sheep and infiltrates interdigital wounds
Wet, warm pastures are ideal and there is some genetic resistance after infection
What are the clinical signs of infectious foot rot in sheep?
Rapid onset of moderate to severe lameness in multiple sheep (kneeling to graze), separation of horn, usually more than one foot affected, small amount of foul smelling exudate
How is infectious foot rot diagnosed in sheep?
Clinical exam, identification of the organism
How is infectious foot rot in sheep treated?
Historically- paring of all feet, topical application of zinc sulfate, foot bath
Now- antibiotics (oxytetracycline, gamithromycin), keep dry environment
How is infectious foot rot in sheep controlled?
Vaccination for short-term resistance (4-12w), needs to contain the right pilus antigen
Describe the pathophysiology of septic arthritis of the distal interphalangeal joint
Usually an extension from adjacent cellulitis, may affect other sites (navicular bursa or bone, DDFT, P3)
What are the clinical signs of septic arthritis of the distal interphalangeal joint?
Severe unilateral pain and lameness with asymmetrical swelling and drainage abscess on lateral coronary band
How is septic arthritis of the distal interphalangeal joint diagnosed?
Clinical signs, radiographs to confirm osteomyelitis
How is septic arthritis of the distal interphalangeal joint treated?
Digit amputation- (high amputation with Gigli wire), best if smaller cow
Curettage and local antibiotic administration- must establish drainage, apply wooden block to other claw, can use local and systemic antibiotics, long recovery time and labor intensive
What tendon develops septic tenosynovitis?
Deep digital tendon- see swelling caudodorsal of fetlock with tipped claw
What direction is hip luxation most common?
Dorsocranial
Describe hock hygromas
Commonly form in dairy cattle due to repeated trauma, treatment is not recommended, if cow becomes lame, salvage
What is the prognosis of different limb fractures?
The more distal the fracture the better the prognosis
How do you treat a metacarpal/metatarsal fracture?
Sedate animal and cast (6 weeks)
How is a radial/ulnar fracture treated?
Poor prognosis- can attempt internal fixation on valuable animal <800lbs, otherwise euthanize/salvage
How is a humeral fracture treated?
If animal can still stand/walk, place in a box stall for >3 months
How is a tibial fracture treated?
Thomas splint and cast- prognosis fair to good if animal will stand with splint
How is a femoral fracture treated?
Can attempt internal fixation in a valuable calf, otherwise place in box stall for 3 months
