foot lesions Flashcards
foot lesions are split into what causes? name the 4 most common foot lesions and tell me what their general cause is.
Digital dermatitis - infection
sole ulcer - claw horn
sole hemorrhage - claw horn
white line dz - claw horn
what is the cause of digital dermatitis?
Treponema spp (3 groups) + opportunistic/secondary bac t
what are the risk factors for digital dermatitis?
group of cattle housed together
unsure of transmission, maybe direct and fomites, maybe genetic component too
what is the main and possibly only reservoir of digital dermatitis?
lesions on infected animals
what are the C/S of digital dermatitis?
- mild-severe lameness
- interdigital area behind heel bulbs
- small circular moist browny grey exudative areas of epidermal liquefaction
- matting of surrounding hair
- raw dermal granulation tissue if diphtheritic debris cleaned (painful!)
- occasionally skin above 1 heel bulb only
- interdigital space b/t claws, coronary band at front of foot, around accessory digits
- papilliform or hairy warts
how is digital dermatitis classified? briefly explain it
M scale
M0 = healthy, normal
M1 = early, small, <2cm
M2 = acute, active, bright red/granulomatous, >2cm
M3 = healing stage w/i 1-2d after topical tx, where acute lesion has covered itself with a firm scab
M4 = late chronic lesions (dyskeratotic)
M4.1= chronic lesion w/ subacute components
how do you dx digital dermatitis?
clean and examine –> C/S
how do you tx digital dermatitis?
clean/dry, topical Ab (oxytetracycline) or bandage w/ Abs
what are the other names for sole ulcer?
pododermatitis, circumscripta
what are the causes of sole ulcers?
- movement of P3, claw overgrowth, external pressure –> pinching of corium & germinal epithelium b/t P3 and hoof capsule
- pinching around bony protrusion where flexor tendon attaches (caudal edge of pedal bone)
- changes in structure/function of digital cushion –> poor/inadequate cushioning and formation of new bone on P3 (exacerbates problem)
tell me about mild, moderate, and severe sole ulcers
mild: blood in horn as sole is produced = sole hemorrhage
mod: partial/intermittent interruption of horn production at sole ulcer site
severe: horn production completely stops at sole ulcer site for long time
what are the C/S of sole ulcers/sole hemorrhage?
- slight-severe lamenss
- often both hind feet (one worse than the other)
- predominantly on lateral claw of hindfeet, medial claw of forefeet
- hemorrhagic discolouration to complete cessation of horn prod. at ulcer site
- possible secondary infection
- deep digital sepsis in extreme cases
how do you dx sole ulcers?
clean/trim foot, C/S are pathognomonic
how do you tx sole ulcer/sole hemorrhage?
corrective trimming + reduce height of affected claw and dish site
remove underrun horn and granuloma if present
apply foot block to sound claw + NSAIDs
parenteral ABs if infection
place on deep straw if severe
want to decrease pressure on pinched corium
what is the px of sole ulcers/sole hemorrhage?
good if simple, poor if multiple claws affected/severe/deep digital sepsis is present
tell me the pathogenesis of white line dz.
- junction of sole + wall = area of weakness
- causes similar to sole ulcers –> initial hemorrhage in white line, which may then separate
- separation exacerbated by standing on concrete, dirt/stone impaction –> infection through to corium
- white line seals over –> infection trapped –> pus produced expands within potential space –> under sole pain!
- abscess forms under sole, infection can tract up wall, eventually pus breaks out, usually at heel or less commonly at coronary band
what are the C/S of white line disease?
- mod-severe lameness
- lat claw more commonly affected
- swelling = advanced ± large abscess
- leg abducted to bear weight on medial claw
- always on white line, more frequently on abaxial wall closest to heel, then going to tip of claw to axial side
how do you dx white line dz?
- pain if “tweak” claw
- white line impaction and abscess when trimming/exploration
- small pin prick sized holes to large areas of impaction on white line (ALWAYS BLACK)
how do you tx white line dz?
- trim/balance both claws
- explore impacted white line
- drain abscess
- remove underrun sole
- if tracked ip wall, remove entire section of wall
- Ab dressing (max 48h)
- foot block sound claw + NSAIDs
- parenteral Abs if necrotic corium found
in bovines, 90% of lameness is in the ____, and 90% of those lesions are in the ____.
foot, hind feet
what is the other name for foot rot?
interdigital necrobacillosis
what is the cause of interdigital necrobacillosis?
acute necrotising inflammation of interdigital skin –> F. necrophorum ± T. pyogenes, Strep AND damage to skin
what are the C/S of interdigital necrobacillosis?
- sudden onset
- mod-sev lameness
- swelling of ST above/around coronary band and between digits (digits forced apart)
- swollen/hot/enflamed/painful
- split in interdigital space which discharges pus/necrotic tissue
- F. necrophorum SMELLS
how do you dx foot rot?
C/S
