Laminitis

Question 1

What is laminitis?

Answer 1

inflammation of the lamellae of the inner hoof CAPSULE

• painful (hoof wall lamellae is inflamed)
• usually associated w/ systemic disease
• clinical syndrome rather than a morphologic diagnosis

Question 2

What organ systems are commonly involved in laminitis?

Answer 2

• GI
• Respiratory
• Reproductive
• Endocrine
• Musculoskeletal
• Integument
• Immune System
• Renal

Question 3

What are risk factors when a horse has laminitis?

Answer 3

• endotoxemia/sepsis or SIRS
• endocrinopathies
• trauma ‘road founder’
• drug induce
• toxin induce

Question 4

What factors could lead to inflammation and disorganization of lamellar anatomy if the lamellar tissues are exposed to them?

Answer 4

• blood supply (hypoxia and nutrient delivery)
• Inflammatory cells
• bacteria
• imbalanced glucose metabolism
  exact mechanism not known

Question 5

When does laminar leukocyte infiltration and epithelial stress occur with regard to laminitis?

Answer 5

at the onset of lameness in the CHO model

Question 6

What do leukocytes in the extravascular tissue produce?

Answer 6

cytokines, matrix metalloproteases (MMPs) (degrade extracellular matrix), and reactive oxygen species

Question 7

What is the vascular hypothesis of Laminitis?

Answer 7

unique vascular digital circulation with numerous AV shunts

• poor perfusion and ischemia during developmental stage due to vasoconstriction
• swelling in response to inflammation -> compartmental system
• reperfusion injury (production oxygen radicals that contribute to cellular injury and inflammation

Question 8

True or false? Laminitis can be caused by insulin.

Answer 8

True. Prolonged Hyperinsulinemia can cause horses to develop laminitis within 48hrs

Question 9

What can cause laminitis?

Answer 9

• inflammation (Bacterial, viral, etc)
• Reperfusion injury
• Hyperinsulinemia
• Contusion or excessive weight loading
• Vasocompression

Question 10

What is the weight load on the front and back legs of the horse?

Answer 10

front 60%, back 40%

Question 11

What is the dominating force for displacement in the hoof?

Answer 11

vertical load

Question 12

What is the dominating force for rotation in the hoof?

Answer 12

tensile forces

Question 13

Why is there a high risk for failure when treating laminitis?

Answer 13

• sensitive structures in hoof may fail to regenerate properly
• Injured structures may fail to support apparatus
• Dead cells hard to exfoliate

Question 14

How should laminitis be evaluated?

Answer 14

• Physical exam (HR, RR, rectal temp.)
• External examination of foot
• Radiographs
• Other

Question 15

What are the characteristics of Obel grade I laminitis?

Answer 15

shift weight from one foot to other, but will move relatively freely

Question 16

What are the characteristics of Obel grade II laminitis?

Answer 16

lameness more obvious, when turning, stilted gait and shuffling
- one foot can be lifted without causing extreme discomfort in contralateral foot

Question 17

What are the characteristics of Obel grade III laminitis?

Answer 17

reluctant to move and resists any attempt to lift foot because of the pain this will induce in contralateral foot

Question 18

What are the characteristics of Obel grade IV laminitis?

Answer 18

most severe grade. immobile and often recumbent

Question 19

What is the best way to diagnose laminitis?

Answer 19

radiographs

Question 20

What are the phases of laminitis?

Answer 20

• developmental
• Acute
• Chronic

Question 21

What is the developmental phase of laminitis?

Answer 21

medical or systemic condition

Question 22

What is the Acute phase of laminitis?

Answer 22

first signs of pain. Radiographic evidence

- subacute: prolong acute stage with out compromised structures

Question 23

What is the chronic phase of laminitis?

Answer 23

compromised structures

• compensated (stable)
• Uncompensated (unstable)

Question 24

How is the developmental phase of laminitis treated?

Answer 24

• treat primary cause

- cryotherapy

Question 25

How is the acute stage of laminitis treated?

Answer 25

• primary condition resolved?
• assess pain level and treat (severe: butorphanol, lidocain CRI, morphine, ketamine CRI)
• understand client goals, expectations and financial situation
• prognosis
• nursing care and after care?
• NSAIDs (phenylbutazone, flunixin meglumine, Previcox)
• DMSO, pentoxifylline, atropine
  cryotherapy

Question 26

What are treatment options for laminitis at the hoof level?

Answer 26

• decrease tension of the DDFT on the coffin bone
• Unloading the laminar interface
• reducing inflammation
• easing break-over
• Protecting sensitive tissue

Question 27

What does the prognosis of laminitis depend on?

Answer 27

• amount lamellar damage (sinkers)
• Hoof conformation
• Duration (bone reabsorption, infection)
• Coronary band damage (shear lesions)
• Vascular damage

Question 28

What are the characteristics of chronic compensated laminitis?

Answer 28

• coffin bone has displaced and stabilized to some degree

- hoof growth is often slowed or distorted

Question 29

What are the characteristics of chronic uncompensated laminitis?

Answer 29

• coffin bone continues to displace

- usually suffering from severe pain

Question 30

What does rehabilitation of the foot after laminitis depend on?

Answer 30

health of the coffin bone

Question 31

What are potential complications of laminitis?

Answer 31

• coffin join subluxation
• over correction
• under correction
• seroma formation
• coronary band pathologies
• infections/osteomyelitis
• flexor tendon contracture
• marginal rim fractures