Lecture 29 4/8/25 Flashcards
Which sedative medications can be used to safely restrain an equine patient and limit secondary trauma?
-xylazine
-detomidine
-acepromazine
-butorphanol
What are potential systemic problems that can occur in patients with musculoskeletal issues?
-hypovolemic shock due to hemorrhage
-fluid and electrolyte losses with sweat
-resp. compromise with head, neck, and thoracic injuries
-systemic infection and/or endotoxemia with severe and/or chronic infections
What is most important regarding the musculoskeletal exam?
-localizing the injury and identifying affected anatomy
-determine the level of weight bearing
Which diagnostics are primarily used for musculoskeletal problems in equine?
-radiographs
-ultrasound
-advanced imaging
What are the causes of non-weight bearing lameness in horses?
-foot abscess* (most common)
-fracture*
-septic synovial structure*
-luxation
-lacerations of support structures
-lacerations/punctures of hoof
-laminitis
What are the characteristics of fractures in equine patients?
-present with acute, severe, non-weight bearing lameness
-diagnosed with rads
-most require referral
-prognosis varies with location, open vs closed, and athletic ability/expectations
-must be stabilized prior to transport
What are the characteristics of synovial sepsis?
-common emergency
-causes significant inflammation
-osteoarthritis and cartilage damage are common outcomes
-potential for loss of function or life
-commonly caused hematogenously in foals and via penetrating wounds in adults
What are the types of septic arthritis based on structure involved?
-synovitis: joints
-tenosynovitis: tendon sheaths
-bursitis: bursas
Why are the distal limbs prone to synovial infections?
combination of many synovial structures and poor soft tissue coverage; even small wounds can lead to infection
How can iatrogenic septic arthritis best be prevented?
adequate disinfection, aseptic technique, and client communication with every joint surgery or injection
What is the pathogenesis of septic arthritis?
-direct introduction of bacteria
-low fluid shear
-bacteria adhere, reproduce, and cause infection
What are the potentiating factors for septic arthritis?
-foreign material
-devitalized tissue
-number and nature of organism
-immune response
What is the pathophysiology of septic arthritis?
-colonization incites inflammation
-degradation of hyaluronan, collagen, and proteoglycan
-synoviocytes and chondrocytes are activated
-effusion forms
-fibrin formation
-pannus tissue formation
-cartilage matrix breakdown
-chondrocyte death
-persistent osteoarthritis
What are the clinical signs of septic arthitis?
-acute, severe, non-weight bearing lameness
-joint effusion
-possibly elevated digital pulses
-elevated acute phase proteins (fibrinogen, SAA)
Why is synoviocentesis done in joints with suspected septic arthritis?
-evaluation of wound communication
-fluid collection and analysis for cytology
-sample collection for culture (gold standard)
What is assessed on synovial fluid analysis?
-color and quality
-nucleated cell count and cytology
-total protein
-SAA
-culture and sensitivity
What is normal vs abnormal for synovial fluid color and quality?
*normal:
-yellow
-clear
-viscous
*abnormal:
-red, orange, or bright yellow
-opaque
-fibrinous
-non-viscous
What is normal vs abnormal for synovial fluid nucleated cell count and cytology?
*normal:
-</= 3,500 cells/uL
-primarily mononuclear cells on cytology
*abnormal:
-5,000 to 30,000+ cells/uL
*definitive for sepsis:
-> 90% neutrophils
-bacteria present
What are the characteristics of total protein in synovial fluid?
-normal is less than 2 g/dL
-animals are more likely to survive if TP is less than 6 g/dL
When should infection be suspected based off cell count and total protein results?
total nucleated cell count of 20,000 cells/uL or more combined with a TP greater than 3.5 g/dL
What are the characteristics of SAA?
-increases with both non-infectious and septic arthritis
-not affected by repeat centesis
-peripheral SAA typically used to evaluate clinical course rather than diagnose
What are the characteristics of culture and sensitivity of synovial fluid?
-gold standard for diagnosis
-poor sensitivity
-also possible to do PCR
-Staph. aureus and mixed infections are most common
What is evaluated on rads when concerned about septic arthritis?
-look for fractures and osteomyelitis
-gas indicates communication
-can use contrast for better results
What is evaluated on ultrasound when concerned about septic arthritis?
-soft tissue injury
-joint capsule thickening
-synovial effusion
-fibrin accumulation in fluid
