Causes of Lameness: Foot Flashcards
What are the causes of laminitis?
Can affect all types and ages of horses
Many causes:
* Carbohydrate overload - large ingestion of grain
* Lush grass consumption
* Cold water ingestion after exercise
* Septicemia/endotoxemia from infection - diarrhea, retained fetal membranes, pneumonia
* Excessive concussion/impact - contralateral limb, road founder
* Hormonal - Cushing’s Disease, Metabolic Syndrome
* Viral - high fever
* Pharmacologically induced - corticosteroid administration
What is the pathophysiology of Laminitis?
blood supply to laminae get compromised (vasoconstriction) –> increased arteriovenous shunting –> decreased capillary perfusion –> pain –> more vasoconstriction –> more shunting –> more necrosis
What are the consequences of necrosis?
PIII suspended in hoof by interdigitating laminae
necrosis of laminae –> PIII lacks suspending support –> PIII moves distally (sinking)
DDFT pulls PIII palmarly/plantarly (rotation)
What are the three phases of laminitis?
developmental phase
acute phase
chronic phase
Describe the developmental phase of laminitis
exposed to causative factors
ends when signs begin
Describe the acute phase of laminitis
1-4 feet affected
increased digital pulse, pain, heat, rotation, and/or sinking
Describe the chronic phase of laminitis
can last days to years
What are the signs of laminitis?
walking on eggshells, rocked back
hesitant to pick up a foot
shifting weight
increased digital pulses and heat
increased HR, RR, and temp
positive to hoof testers at solar margin
chronic - hoof rings, flat sole, widened white line (seedy toe), bruised soles
How do you diagnose laminitis?
clinical signs
radiographs
How do you treat laminitis?
○ Anti-inflammation - banamine/bute, DMSO, ice therapy
○ Anti-endotoxin - banamine, polymixin B, pentoxifylline, plasma
○ Anticoagulation - aspirin
○ Vasodilation - isoxsuprine, ace, nitroglycerine
○ Red blood cell deformability - pentoxifylline
○ Frog pressure and foot support - deep bedding, lily pads, Styrofoam, heart bar shoes, elevated heel
○ Deep digital flexor tenectomy or distal check ligament
○ Dorsal hoof wall resection
What is navicular syndrome?
○ AKA podotrochleosis
○ 4-9 years old
○ Forelimb > hindlimb
○ Bilateral > unilateral
○ Males > females
○ QHs and SBs
○ Coffin joint, navicular bone, navicular burse, DDFT involved
What are the causes of navicular syndrome?
○ Poor conformation (small feet, low heels, long toe) and concussion –> bursitis –> inflammatory reaction –> alters bone
○ DDFT stresses the bone –> bone remodeling
○ Arterial constriction within foot –> thrombosis –> ischemic necrosis of the bone
What are the signs of navicular syndrome?
○ Intermittent, progressive lameness that improves with rest
○ Shortened stride
○ Positive hoof testers across heels
○ Positive distal limb flexion
○ Contracted raised heels, concave sole, narrow quarters
How do you diagnose navicular syndrome?
○ Hoof testers
§ Positive across heels
○ Palmar digital nerve block
○ Radiographs (~50% have changes)
§ Enlarged vascular foramina along distal border (lollipop lesions)
§ Cysts on flexor surface
§ Osteophytes or spurs on wings
○ Intrabursal anesthesia
How do you treat navicular?
○ Corrective shoeing and trimming
§ Heels raised, toes shortened and rolled, bar shoes, pad
○ Medications
§ Isoxsuprine - vasodilator
§ NSAIDs
§ Tildren and Osphos - decrease bone resorption
§ Legend, Adequan, oral supplements
§ Intrabursal injections of corticosteroids and HA
○ Alleviation of pain
§ Palmar digital neurectomy (consider complications)
What is street nail?
○ Puncture into navicular bursa
§ Often from nail or stick (DON’T PULL)
§ Results in septic bursitis
What can be affected by street nail?
Can affect navicular bone, PIII, coffin joint, and/or DDFT
How do you treat street nail?
Treatment: surgical debridement, topical and systemic antibiotics, NSAIDs, etc.
What is side bone?
Ossification of collateral cartilages of PIII
What causes side bone?
Causes: poor conformation, improper shoeing and trimming
What are the signs of side bone?
Signs: lameness, hard and painful cartilages on palpation
How do you diagnose side bone?
Diagnosis: rads and clinical signs
How do you treat sidebone?
Treatment: corrective shoeing/trimming, NSAIDs
What is quittor?
Chronic inflammation and infection of collateral cartilages of PIII
What are the signs of quittor?
Signs: lameness, purulent discharge at coronary band, heat, swelling, pain
How do you diagnose quittor?
Diagnosis: contrast radiographs
How do you treat quittor?
Treatment: radical surgical excision with distal drainage
What is gravel?
Opening in white line –> Infection within sensitive laminae –> Cannot drain distally –> Infection travels to band for drainage
What causes gravel?
Causes: dry foot, sequel to laminitis, puncture wound
What are the signs of gravel?
Signs: lameness, drainage tract at band, changes to white line, heat
What is the diagnosis of gravel?
Diagnosis: hoof testers, clinical signs
What is the treatment of gravel?
Establish drainage for infection
□ Dremel
□ Soaking with Epsom salts
□ Hoof resection
Prevent secondary infection
□ Bandaging
□ Soaking in dilute betadine solution
What is white line disease?
More widespread than gravel
What is the cause of white line disease?
Cause: poor foot hygiene, opportunistic bacterial/fungus proliferate in stratum medium (part of hoof capsule)
What are the signs of white line disease?
Signs: +/- lameness, dark black line along sole-wall junction with foul odor, separation of outer hoof wall
What is the diagnosis of white line disease?
Diagnosis: clinical signs
What is the treatment for white line disease?
Treatment: proper hygiene, cleaning with antiseptic, hoof wall resection, soaking, bandaging, White Lightening
What is a foot abscess?
Most common cause of lameness!
What causes foot abscesses?
Cause: puncture from foreign object entering sensitive areas of foot –> bacteria invade and reproduce –> abscess
What are the signs of a foot abscess?
Mild to non-weight bearing lameness
What is the diagnosis for a foot abscess?
Hoof testers
Hoof knife exploration w/ location of small, dark spot
Rads to rule out bone involvement
How do you treat a foot abscess?
Cleaning of area
Establishing drainage
Protection lesion until healing occurs - soaking in dilute betadine, wrapping with icthammol or magnapaste, gauze, diaper, and vet wrap, NSAIDs, shoe w/ removable plate, protective boot
What is sole bruising?
Very common
Take longer to heal than abscess
What causes a sole bruise?
Cause: impact onto sole or frog w/ out puncture
What are the signs of a sole bruise?
Signs: mild to severe lameness, +/- visible bruise
What is the diagnosis of a sole bruise?
Diagnosis: hoof testers, rads to rule out bony changes or abscess
What is the treatment for a sole bruise?
Treatment: alleviate cause; provide protection - bar shoe, pad; soaking in cold water, NSAIDs
What is thrush?
Infection within sulci of frog
Due to dirty, moist conditions
Often Fusobacterium necrophorum
Often affects more than one foot
What are the signs of thrush?
Characteristic odor
Black purulent discharge
Lameness if infection erodes into sensitive tissue
How do you diagnose thrush?
clinical signs
How do you treat thrush?
Proper hygiene
Cleaning with antiseptic (betadine, Kopertox)
antibacterial/antifungal medications (tomorrow, cephalasporin)
Thrush buster
White lightening
What is canker?
Chronic hypertrophy of horn-producing tissues of foot
§ Often in hind feet of draft horses
What are the causes of canker?
○ Cause: moisture, poor hygiene
What are the signs of canker?
Foul smelling
Necrotic horn covered with caseous
Cream-colored exudate
Oily ragged frog
What is the diagnosis of canker?
clinical signs
What is the treatment of canker?
debridement of necrotic tissue, soaking or bandaging with antiseptic
What is a keratoma?
Excessive keratin produced by epidermal cells of coronary band
Grow distally, sandwiched between wall of hoof and PIII
What causes a keratoma?
Cause: associated with chronic irritation, infection or trauma
What are the signs of a keratoma?
Cause little discomfort until grow down to weight bearing surface of hoof
What is the diagnosis of a keratoma?
○ Diagnosis: clinical signs
What is the treatment of a keratoma?
complete surgical removal
What are hoof cracks?
○ Common cause of lameness
○ Quarter and heel cracks often involve sensitive laminae –> more painful than toe cracks
○ Can start at ground and extend proximally or at coronary band and extend distally
What are the causes of hoof cracks?
Causes: foot imbalance, too wet or too dry, coronary band injury
What are the signs of hoof cracks?
+/- lameness
How do you diagnose hoof cracks?
clinical signs, hoof testers
How do you treat hoof cracks?
stabilize with clips, bar shoes, patch
