Laminitis

Question 1

What is laminitis

Answer 1

inflammation of lamellae on inner hoof capsule
PAIN
debilitating, economic and welfare consequences
associated with systemic disease

Question 2

Laminitis risk factors

Answer 2

Endotoxemia, sepsis or SIRS
endocrinopathies, trauma (road founder), drug or toxin induced
Systemic disease - lamellar tissues exposed to factors –> inflammation and disorganization of anatomy
hypoxia and decreased nutrient delivery
inflammatory cells, bacteria, glucose metabolism imbalance
laminar leukocyte infiltration and epithelial stress at onset of lameness in CHO model

Question 3

Vascular hypothesis

Answer 3

many AV shunts, poor perfusion and ischemia during development phase due to vasoconstriction –> swelling –> compartmental syndrome
reperfusion injury post vasoconstriction phase - ROS production - cell injury and inflammation, vasodilation

Question 4

Hyperinsulinemia

Answer 4

study showed horses that had glucose infusion to increase insulin, developed laminitis 48h later

Question 5

Trauma and laminits

Answer 5

contusion or weight loading, tearing of tissue, induce vasospasm, fatigue, vasocompression

Question 6

laminitis common in foals?

Answer 6

no, rare
endotoxemia from salmonella
severe endothelial damage to distal limb causing hoof to slough off

Question 7

Pathophysiology

Answer 7

mechanical displacement after disrupted lamina
weight load 60% front feet, 40% hind
Vertical load (weight of horse) - dominant factor for displacement
Tensile forces (from flexor tendons) - dominant factor for rotation

Question 8

Complete case evaluation

Answer 8

PE w/ HR,, RR, rectal temp
HR >100 = pain = severe
external exam of foot, RADS
laminitis stance
check digital pulse at abaxial area, hoof testers to isolate pain location
check for sinking of coronary band

Question 9

Obel Grades of laminitis

Answer 9

1 - shift weight between foot, moves relatively freely
2 - lameness more obvious, when turning, stilted gait and shuffling
- one foot can be lifted without causing extreme comfort in contralateral foot
3 - reluctant to move, resists attempt to lift foot because pain in contralateral foot
4 - most severe, immobile, often recumbent

Question 10

Measurements to Dx laminitis on rads

Answer 10

Hoof wall: should be 18mm top to bottom
coronary and to extensor process: 12mm
sole depth: 10mm

Question 11

4 phases of laminitis

Answer 11

Developmental
Acute
Subacute
Chronic

Question 12

Developmental phase

Answer 12

medical or systemic condition, before clinical appearance or foot pain
PREVENT WITH CRYOTHERAPY
Tx primary cause

Question 13

Acute phase

Answer 13

clinical foot pain and lameness, clinical evidence on rads (hoof wall/lamina measurements) - distance >18mm suspect laminitis
nerve block to test if foot is the problem
Tx:
NSAIDs (phenylbutazone, Flunixin meglumine, can add previcox)
pain: butorphanol, lidocaine CRI, morphine, ketamine (if this painful then poor prognosis)
DMSO, pentoxyfylline, atropine - vasodilatory effects - not preferred by depedro
CRYOTHERAPY, decrease tension of DDFT on coffin, unload laminar surface, decrease inflammation, wrap tow, wooden shoes, sand stall
Prognosis: depends on lamellar damage, duration, hoof conformation, vascular damage

Question 14

Chronic phase

Answer 14

abscesses present, make sure bone not infected, structures compromised
Compensated (stable) = coffin bone displaced and stabilized, slow/distorted hoof growth
- horse can walk but don’t ride
Uncompensated (unstable) = coffin bone continues to displace, severe pain, rehab dependent on health of coffin bone
- Sinkers: displacement in the horizontal plane
- coronary band lesions: shear lesions - bulges due to inflammation
Tx: make new groove on goof
perfusion deficits - dorsal lamina, circumflex vessels, coronary plexus, proximal displacement circumflex vessels

Question 15

Tx of laminitis

Answer 15

based on client goals, finances, after care

many potential complications