Chapter 86 - Synovial and Osseous infection Flashcards
What are the main causes of orthopedic infection in horses?
Penetrating wounds, hematogenous spread, and iatrogenic introduction (surgical intervention or intrasynovial injection).
Why is the distal limb of a horse at higher risk for infection?
Due to poor muscle and soft tissue coverage with reduced vascular supply.
What can the strong inflammatory response in a synovial cavity lead to during infection?
Significant cartilage damage and subsequent osteoarthritis.
Why is fracture fixation in horses associated with a high risk of surgical site infection?
How can orthopedic infections affect a horse’s future performance?
They can cause chronic pain, joint stiffness, and reduce future performance.
Why are neonate foals more susceptible to infection compared to adults?
Due to their immature immune system and potential failure of passive transfer of immunity (IgG).
What is the role of failure of passive transfer in foals developing septic arthritis and osteomyelitis?
It leads to bacteremia and septicemia, which can localize in bones and joints via hematogenous spread.
What percentage of foals in neonatal intensive care units are affected by septic arthritis and osteomyelitis?
Up to 13%.
Which bacteria are commonly isolated from the joints of foals with septic arthritis?
Gram-negative bacteria like Escherichia coli, Actinobacillus spp., and Klebsiella spp..
What factors are associated with a negative outcome in foals with septic arthritis?
Multiple septic joints and the presence of multisystemic disease.
What is an S-type infection?
An infection associated with the synovial membrane and fluid, typically in very young foals under 2 weeks old.
What is the prognosis of foals with multiple septic joints?
Negative outcome in the presence of multisystemic disease
Which joints are most commonly affected in S-type infections?
Tarsocrural, stifle, and metacarpo-/metatarsophalangeal (MCP/MTP) joints.
What is an E-type infection?
An infection localized to the articular epiphyseal complex or the bone adjacent to the articular cartilage.
Which joints are commonly affected by E-type infections?
Distal femur, talus, proximal and distal radius, distal tibia, and patella.
In what age group of foals do E-type infections typically occur?
Older foals with multiple joints affected and often with a prior history of illness.
What is a P-type infection?
An infection that localizes in the long bone physes of older, generally healthy foals.
Which bacterial isolates are commonly found in P-type infections?
Streptococcus, Rhodococcus, Actinobacillus, and Escherichia coli.
What are the typical clinical signs of S- and E-type infections?
Joint effusion, lameness, synovial distension, periarticular edema, and pain on palpation.
What additional clinical findings are common in P-type infections?
Periarticular swelling with marked sensitivity to palpation and intermittent lameness.
What hematological change is a reliable indicator of osteomyelitis in E- and P-type infections?
Plasma fibrinogen levels of 900 mg/dL or higher.
What imaging modality is used as a baseline to assess bone involvement in these infections?
Radiographs.
What are the common causes of synovial infections in adult horses?
Penetrating traumatic injury, iatrogenic causes following surgery, or intrasynovial injections
What is the most commonly isolated bacterium in synovial infections in adult horses?
Staphylococcus aureus.