Equine Foot Flashcards
1
Q
what is a hoof abscess?
A
focal accumulation of purulent exudate that most often occurs between germinal and keratinized epithelium; also known as septic pododermatitis
2
Q
describe the etiology/pathophysiology of hoof abscess?
A
etiology: bacterial invasion through keratinized epithelium via
- defects in hoof wall lead to microcracks and white line separation or
- traumatic damage from foreign body penetration or sole bruising
- environmental factors: moisture and moisture inconsistency (drought to sudden rain, etc).
- predispositons: laminitis, poor hoof structures
pathogenesis:
1. rapid increase in pressure causes
2. separation from germinal layer of epithelium (subsolar, subcuneal, submural) and involvement of deeper structures
3
Q
what is the clinical presentation of a hoof abscess?
A
- acute severe lameness (top differential for this plus fractures)
- variable lameness with duration and extent of abscess
4
Q
what are 5 differential diagnoses for hoof asbcess?
A
- coffin bone fracture
- navicular bone fracture
- sepsis of deeper structures
- severe bruising
- severe soft tissue injury
5
Q
describe diagnosis of hoof abscess
A
- physical exam:
-increased digital pulses
-increased hoof capsule pressure
-coronary band/heel bulb will be swelling, painful to touch, have purulent discharge
-hoof tester response - visual exam of solar surfaceL look for dark discoloration and further eval that area but avoid excessive pairing (hole making)
- radiographs: usually not on first visit; if still can’t find draining tract on second visit, do a radiograph and look for dark spot
6
Q
describe treatment/management of hoof abscess
A
- facilitate drainage: make sure hole you make is big enough to allow drainage
- foot bandage: keep area soft after drain to prevent sealing back up before all infection is drained or will reabscess
- pain management: some type of NSAID (phenylbutazone is most effective; make horse more comfortable, bear more weight on affected foot, push infection out of capsule)
- antibiotics: not generally use systemic antibiotics bc concentrations really can’t reach affected tissue; but if involvement of deeper structures (infection migrated to cause septic area of coffin bone may use Ab; region limb perfusion
- tetanus prophylaxis: boost!
7
Q
describe prognosis for hoof abscess
A
- uncomplicated: good
- deeper structure involvement: depends on affected structure but generally if can establish drainage within 3 days generally good
8
Q
what is white line disease?
A
keratoyltic condition that affects deeper layers of stratum medium of hoof wall, causing crumbling decomposition of the horn at the white line and can lead to separation of the hoof wall
9
Q
describe the etiology/pathophysiology of white line disease
A
- unknown agent, but suspect involvement of fungi or anaerobic bacteria that causes a keratolytic process that creates cavities within the hoof wall
- can have single OR multiple hoof wall, so examine all 4 hooves
- inflammation of underlying tissues is uncommon
- coffin bone displacement is possible but also uncommon
- can be an incidental finding/asymptomatic; the lameness observed is due to debris in the created cavity putting pressure on sensitive lamellae or coffin bone displacement
10
Q
describe differential diagnoses for white line disease
A
- laminitis
- abscess
11
Q
describe diagnosis of white line disease
A
- soft and chalky horn
- can use hoof wall percussion (tap around and see if can hear a hollow spot)
- radiographs!!
12
Q
describe treatment/management of white line disease
A
- removal of undermine hoof wall
- hoof wall capsule stabilization: after removal of hoof wall, don’t want to cover area bc want to expose to air, so stabilize by boot or other creative means; exposure to oxygen is key!
- topical medications
13
Q
describe prognosis of white line disease
A
- return to previous performance if coffin bone not displaced
- time to return is dependent on extent of hoof wall resected and growth rate of hoof wall (average horse takes about a year to grow from coronary band to ground)
- recurrence is uncommon: usually owners on alert after diagnosis and better care following
14
Q
what are hoof cracks?
A
vertical or horizontal fissures in the hoof wall
15
Q
describe etiology/pathophysiology of hoof cracks
A
1, causes by excessive forces on hoof wall/coronary band
- classified by:
-orientation
-location
-depth
-length - predisposing factors:
-hoof wall imbalance
-coronary band trauma/defect
-poor quality hoof wall
-inadequate/infrequent trimming
16
Q
describe clinical presentation of hoof cracks
A
- visual exam- clients notice these
- could present with lameness if unstable or infected full-thickness crack
17
Q
describe diagnosis of hoof cracks
A
- coronary band palpation: if not sensitive in area of crack, is likely not the source of any lameness
- diagnostic analgesia on side of foot with crack
- radiographs; can tell depth and severity of crack
18
Q
describe treatment/management of hoof cracks
A
- identify and treat underlying cause if possible; if severe hoof wall imbalance, address, if coronary band defect and just the way the horse is made, can’t really change
- stabilization of crack
- unloading hoof wall under crack: keep pressure off it
-use epoxy and stainless steel wire to bridge the crack to stop movement, bridge hoof wall on either side of crack to decrease movement
19
Q
describe prognosis of hoof cracks
A
depends on location, depth, underlying cause (if can address or not)
20
Q
what are keratomas?
A
benign epithelial tumors of hoof capsule; two variations
- cylindrical: column-like shape, deep to hoof wall, parallel orientation to horn tubules, more common
- spherical: less common, reported in frog, sole, and above coronary band
21
Q
describe etiology/pathophysiology of keratomas
A
- unknown, but possible develop due to localized chronic irritation/inflam or trauma to germinal layers of epothelium hoof capsule
- pressure from mass can lead to coffin bone lysis and/or distortion of voerlying hoof capsule
22
Q
describe clinical presentation of keratomas
A
- change in contour of white line
- lameness associated with infection and/or pressure exerted on sensitive tissues
- recurrent foot abscesses in samel location
23
Q
what are 3 differential diagnoses for keratomas
A
- other rare hoof tumors
- chronic hoof wounds
- hoof abscesses
24
Q
describe diagnosis of keratomas
A
- presumptive:
-visual appearance of hoof capsule
-radiographic evidence
-advanced imaging - definitive:
-biopsy with histopathology
25
describe treatment/management of keratomas
1. surgical removal: approach depends on keratoma location
-standing versus general anesthesia
-usually apply a tourniquet
-post op: bandaging, peri-op antibiotics, NSAIDs, hoof capsule stabilization
26
describe prognosis of keratomas
good after uncomplicated complete surgical excision
if more complicated, be more cautious and consider recurrence as a possibility
27
what is thrush?
degenerative keratolytic condition of the frog
28
describe etiology/pathophysiology of trhush
1. specific agent unknown, anaerobic bacteria thought to play a vital role in the process
2. commonly begins in the central sulcus, spreads to collateral sulci and central portion of the frog
3. generally affects superficial frog tissue before spreading deeper
4. historically associated with poor hoof care or low stable hygiene but some horses can get even in clean conditions
5. predispositions: lack of exercise, foot conformation (upright feet, have a deeper space for the frog so debris can build up)
29
describe clinical presentation of thrush, diff diagnosis, diagnosis
1. lameness usually only present if disease has extended to dermal tissue
2. pain reaction when affected frog is subjected to pressure
3. distinct foul odor and discharge
4. rough appearance/bleeding from from even just from picking hoof
5. a differential diagnosis would be canker
6. diagnosis is visual appearance and odor
30
describe treatment/management of thrush
1. topical therapy goals:
-disinfect
-dessicate
-harden frog horn
2. consider depth of tissue involvement when selecting topical meds
3. environmental management, if dirty clean!
31
describe prognosis of thrush
good with adequate treatment and management
recurrence more likely in horses with predisposing hoof conformations
32
what is canker?
proliferative pododermatitis
33
describe etiology/pathophysiology of canker
1. unknown
2. suspected etiologic agents: anaerobic bacteria, spirochetes, bovine papillomavirus
3. characterized by proliferative inflammation of epidermis and dermis
4. usually starts in central or collateral sulci then spreads rapidly; may spread to sole, heel bulbs, hoof wall, coronary band
5. predisposing factors: poor hygiene, environment (warm, moist), breed
34
describe clinical presentation of canker, differential diagnosis
1. lameness depending on chronicity/severity
2. may occur in multiple hooves
3. frond or finger-like projections covered by caseous exudate
4. painful to palpation
5. differential diagnosis: thrush, exuberant granulation tissue
35
describe diagnosis of canker
1. presumptive (most common): based on characteristic appearance of affected tissue
2. definitive: biopsy and histopathology
36
describe treatment/management of canker
1, combination of surgical and medical therapies
2. surgical debridement of affected tissue; goal is to remove all affected tissue without disruption of germinal layer of epidermis
3. medical therapy:
-topical medication(s) after surgical debridement: antimicrobial, benzoyl peroxide 10% solution
-hoof bandage or treatment plate
-NSAIDs
-environmental management
-rechecks
37
describe prognosis of thrush
1. initially guarded until see what will happen
2. complete recovery with normal horn growth is possible
3. long-term risk of recurrence even if a full recovery if initially achieved
38
describe coffin joint osteoarthritis
progressive degeneration of articular cartilage and the underlying bone
39
give etiology/pathophysiology of coffin joint OA
1. chronic repetitive trauma
2. traumatic
3. fractures
4. osteochondrosis
5. septic/infectious arthritis
40
describe clinical presentaion of coffin joint OA
1. lameness of varying degrees
2. diagnosis:
-lameness exam: IA anesthesia
-imaging: radiographs and MRI
41
describe coffin joint OA treatment
1. use of NSAIDs to inhibit arachidonic acid cascade is a long used mainstay
2. intra-articular corticosteroids
3. biologics: autologous conditioned serum, platelet-rich plasma
42
describe coffin joint OA prognosis
guarded to fair; dependent on severity and response to treatment
