Foor Pathologies

Question 1

what is sole bruise

Answer 1

• most common cause of transient lameness in horses
• characterized by sudden onset mild to severe lameness
• lameness is typically transient although longer term lameness can result if the bruise develps into an abscess

Question 2

what is a sole bruises pathogenesis

Answer 2

• blunt trauma
• damage to internal tissue
• blood vessel rupture

Question 3

what causes sole bruises

Answer 3

• rocky or ice-covered ground
• ill-fitting shoes
• laminitis

Question 4

what is a corn

Answer 4

• sole bruise occuring at the seat of corn or just the buttress if the hoof wall

Question 5

what is a hoof abscess

Answer 5

• most common cause of severe acute lameness in the horse
• characterized by internal infection of the foot accompanied by inflammation
• pain and damage are exacerbated because ( Horse bears weight continuously on the affected area and the swelling is confined by a solid hoof wall )
• typically presents as sudden acute lameness although some horses may demonstrate minimal lameness and others may show no signs

Question 6

what causes hoof abscess

Answer 6

• bruise
• sole puncture
• white line disease
• quicking

Question 7

what is the pathology of hoof abscess

Answer 7

• debris invades foot
• inflammation reaction inside hoof capsule
• pressure on surrounding tissues
• lameness, enzamatic tissue destruction and infection moves through tissue

Question 8

what is the treatment of hoof abscess

Answer 8

• establish drainage tract from the abscess to the solar surace of the foot
• encourage drainage using foot baths of water and magnesium sulfate and or a foot poultice
• whe the abscess is completely drained, the area must be kept clean until drainage tract has healed
• phaenicia sericata fly larvae may be used to remove necrotic tissues (larval debridement) = they will secrete liquefy and break down dead tissue while disinfecting the area and stimulating wound healing

Question 9

what are potential complications of abscess

Answer 9

• untreated abscess follows the path of least resistance, this usually runs along dermal/ epidermal laminar junction and eventually the abscess will break out at the coronet band (consequent damage to the coronet band can compromise the integrity of the hoof wall and allowing the abscess to proceed = more painful for the horse)
• untreated may also migrate to other interior structures of the foot such as collateral cartilage and/or the distal phalanx resulting in perminant unsoundness

Question 10

what is WLD

Answer 10

• white line disease
• occurs when mechanical stresses, genetic weakness, environmental conditions affecting the inner hoof wall attachement or toxins such as selenium cause separation of the hoof wall from the sole of the foot at the white line
• separation allows debris and pathogens (bacteria and or keratinophilic fungi) to invade sole of the foot = invasion proceeds along the epidermal/dermal laminar junction towards the coronet band causing death of laminar tissue
• seedy toe is white line disease originating at toe of the foot

Question 11

what is the treatment of white line line disease

Answer 11

• hoof wall debridement
• removal of c=necrotic tissue
• and corrective shoeing to redistribute pressure on the roof wall

Question 12

what is Quittor

Answer 12

• infection of the collateral cartilages of the distal phalanx
• usually results from puncture wounds or lacerations that create a patheay for invading pathogens to enter into the soft tissue of the foot
• affected horses present with lameness and a chronic wound above the coronet band that intermittently exudes a purulent and putrid discharge
• location within the soft tissue of the foot make it difficult to treat effectively and surgery is usally required along with extensive post - operative treatment
• prognosis is guarded

Question 13

what is thrush

Answer 13

• bacterial infection of lateral and central sulci of the frog
• opportunistic fungal infections may follow
• treatment involves antibacterial cleansing
• untreated, thrush can potentially invade the softer tissue with the foot making it important to not ignore the condition

Question 14

what is keratoma

Answer 14

• a rare tumour of the keratin producing epidermal cells of the inner goof wall originating from the horn-producing cells of the coronet band
• results in a mass between the hoof wall and the distal phalanx which must be surgically removed

Question 15

what are hoof cracks

Answer 15

• considered to be stress fractures
• cracks that develop on the top of the hoof occur as a result of damage to the coronary corium (hoof capsule generating tissue )
• superficial cracks involve the pigmented and unpigmented stratum media (do not affect the integrity of the hoof of the soundness of the horse)
• deep cracks involve the stratumm medium as well as the stratum internum and the dermal parietis (must be rectified to avoid exposing laminar tissue to potential pathogens or weakening the hoof wall)
• hoof cracks are usually dealth with by therapeutic shoeing
• foot cracks extended upward from the distal region are a result of inadequate farrier care and overly long hooves that become weak and separate from the sole; may be accompanied by white line disease

Question 16

what is navicular syndrome (podotrochleosis)

Answer 16

• the cause of more than 1/3 of chronic front limb lameness ( misdiagnosis is common

Question 17

what type of presentation does navicular syndrome show

Answer 17

• intermittent from limb lameness that increases in frequency and is characterized by a short strided gait; horse may stand with toe pointed
• lameness is bilateral but asymmetric an severity increase with exercise
• lameness is more apparent when horse is circuling

Question 18

what diagnosis navicular syndrome

Answer 18

• predisposing factors
• characteristic lameness history
• no obvious injury or trauma
• contracted heels

Question 19

what can diagnostic testing indicators show

Answer 19

• hoof testers = heel pain
• nerve blocks = change in previously lame foot from left to right or right to left
• radiographs = alterations in navicular bone
• thermographs = heat in the heal area
• ultrasound = alterations to bone and or surrounding soft tissues
• MRI = alterations to bone and or surrouding soft tissues

Question 20

how can you treat navicular syndtome

Answer 20

• therapeutic hoof care and shoeing in conjunction with chemotherapeutic agents to relieve pain and inflammation
• acupuncture treatment as well as a number of nutraceuticals are availabale for horses with navicular
• and extreme treatment is surgical denerving which alleviates pain from the navicular area by serving the sensory nerves that come from heel area

Question 21

what is laminitis

Answer 21

• non infectious inflammation of the laminae ( suspensory apparatus of the distal phalanx ( SADP)

Question 22

possible causes of laminitis

Answer 22

• carb overload
• hyperinsulinemia
• cushings
• endotoxemia
• sepsis
• shock
• some medications
• fever
• management causes = exercise/feed imbalance, poor or negligent foot care, excessive concussive force (road founder) overly soft ground

Question 23

what causes laminitis

Answer 23

• vasoconstriction of the capillaries that nourish the laminae and increases arteriovenous stunting
• decrease capillary perfusion of the laminae which become necrotic from lack of oxygen and nutrients and this weakens the laminar bond between the distal phalanx and the hoof wall causing pain to the area which further causes vasoconstriction

Question 24

what are the phases of laminitis

Answer 24

• exposure
• acute on set and progression of lamness
  grade 1: horse shows signs of pain, trot is choppy
  grade 2 : horse is lame at the walk and reluctant to trot
  grade 3: horse refuses to have leg lifted
  grade 4 : horse is in extreme pain and refuses to move ; the coronet band and the hoof wall are very warm to the touch ; a bounding digital pulse is easily discerned
  chronic - founder

Question 25

what are the steps in lamanitic events

Answer 25

1. laminar inflammation results in separation of the epidermal and dermal laminae
2. the seperation creates space between epidermal and dermal laminae referred to as the laminar wedge
3. the loss of connection between epidermal and dermal allows the coffin bone to rotate, specifically, the distal end of the coffin bone drops downward toward the sole of the foot
4. as the coffin bone rotates, it pulls away from the hoof wall resulting in deflexion of the coronary papillae and bending of the juvenile horn tubules
5. the proximal end of the coffin bone puts pressure on the coronary corium causing it to become compressed further disrupting horn tubule formation ad alignment
6. as the distal end of the coffin bone sinks in, it causes compression of the sole
7. compression of the sole are compresses the blood vessels that supply nutrients to the tissues of the sole, comprimising blood flow
8. as a result of the lack of blood supply, the tissue of the sole die and lose the ability to support internal structures
9. the coffin bone, with a compremised connection of the hoof wall and insufficient support from tissue of the sole, related firther and the distal end can penetrate the sole of the foot

Question 26

treatments of laminitis

Answer 26

• cold therapy
• vasodilators
• anti-coagulates
• anti-inflammatories
• sand footing
• bandaging
• therapeutic shoeing

Question 27

what can you do for post laminitis management

Answer 27

• depends on the cause
• carful farrier and therapeudic shoeing