Laminitis Flashcards
What is laminitis?
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
What organ systems are commonly involved in laminitis?
- GI
- Respiratory
- Reproductive
- Endocrine
- Musculoskeletal
- Integument
- Immune System
- Renal
What are risk factors when a horse has laminitis?
- endotoxemia/sepsis or SIRS
- endocrinopathies
- trauma ‘road founder’
- drug induce
- toxin induce
What factors could lead to inflammation and disorganization of lamellar anatomy if the lamellar tissues are exposed to them?
- blood supply (hypoxia and nutrient delivery)
- Inflammatory cells
- bacteria
- imbalanced glucose metabolism
exact mechanism not known
When does laminar leukocyte infiltration and epithelial stress occur with regard to laminitis?
at the onset of lameness in the CHO model
What do leukocytes in the extravascular tissue produce?
cytokines, matrix metalloproteases (MMPs) (degrade extracellular matrix), and reactive oxygen species
What is the vascular hypothesis of Laminitis?
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
True or false? Laminitis can be caused by insulin.
True. Prolonged Hyperinsulinemia can cause horses to develop laminitis within 48hrs
What can cause laminitis?
- inflammation (Bacterial, viral, etc)
- Reperfusion injury
- Hyperinsulinemia
- Contusion or excessive weight loading
- Vasocompression
What is the weight load on the front and back legs of the horse?
front 60%, back 40%
What is the dominating force for displacement in the hoof?
vertical load
What is the dominating force for rotation in the hoof?
tensile forces
Why is there a high risk for failure when treating laminitis?
- sensitive structures in hoof may fail to regenerate properly
- Injured structures may fail to support apparatus
- Dead cells hard to exfoliate
How should laminitis be evaluated?
- Physical exam (HR, RR, rectal temp.)
- External examination of foot
- Radiographs
- Other
What are the characteristics of Obel grade I laminitis?
shift weight from one foot to other, but will move relatively freely
What are the characteristics of Obel grade II laminitis?
lameness more obvious, when turning, stilted gait and shuffling
- one foot can be lifted without causing extreme discomfort in contralateral foot
What are the characteristics of Obel grade III laminitis?
reluctant to move and resists any attempt to lift foot because of the pain this will induce in contralateral foot
What are the characteristics of Obel grade IV laminitis?
most severe grade. immobile and often recumbent
What is the best way to diagnose laminitis?
radiographs
What are the phases of laminitis?
- developmental
- Acute
- Chronic
What is the developmental phase of laminitis?
medical or systemic condition
What is the Acute phase of laminitis?
first signs of pain. Radiographic evidence
- subacute: prolong acute stage with out compromised structures
What is the chronic phase of laminitis?
compromised structures
- compensated (stable)
- Uncompensated (unstable)
How is the developmental phase of laminitis treated?
- treat primary cause
- cryotherapy
How is the acute stage of laminitis treated?
- 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
What are treatment options for laminitis at the hoof level?
- decrease tension of the DDFT on the coffin bone
- Unloading the laminar interface
- reducing inflammation
- easing break-over
- Protecting sensitive tissue
What does the prognosis of laminitis depend on?
- amount lamellar damage (sinkers)
- Hoof conformation
- Duration (bone reabsorption, infection)
- Coronary band damage (shear lesions)
- Vascular damage
What are the characteristics of chronic compensated laminitis?
- coffin bone has displaced and stabilized to some degree
- hoof growth is often slowed or distorted
What are the characteristics of chronic uncompensated laminitis?
- coffin bone continues to displace
- usually suffering from severe pain
What does rehabilitation of the foot after laminitis depend on?
health of the coffin bone
What are potential complications of laminitis?
- coffin join subluxation
- over correction
- under correction
- seroma formation
- coronary band pathologies
- infections/osteomyelitis
- flexor tendon contracture
- marginal rim fractures
