Exam 1 - Equine Musculoskeletal/Joint Infections Flashcards
what are the different pathways in which synovial infections can happen?
hematogenous - foals
traumatic/wounds
post injection
what are the different pathways in which osteitis/osteomyelitis can happen?
hematogenous
traumatic/wounds
post-fracture fixation
what are examples of direct inoculation resulting in synovial infections?
wound associated or iatrogenic from infection/sx
affects joints/tendon sheaths/bursa
what are some potential complications of a resolved synovial infection?
lame horse with OA/DJD & support limb issues
what happens if you have a synovial infection that is unresolved?
fatal to the horse
T/F: an infected synovial structure always results in severe lameness
true
T/F: if you have a peri-synovial wound without any lameness, it is unlikely that there is any synovial penetration
true
T/F: a neonate with a swollen joint may be because the mare stepped on it & not due to infection
true
what is the pathogenesis of synovial infections?
animal is inoculated & there is colonization, inflammation, & degradation by proteases/cytokines/free radicles that occurs (can either be hematogenous or direct inoculation)
what are some examples of direct inoculation resulting in a synovial infection?
periarticular cellulitis, post intra-articular injection, & post-op patient
infection in the synovium of a joint leads to __________ and/or ___________
synovitis/tenosynovitis
what happens if there is bacterial colonization in the epiphysis or physis of a bone?
osteomyelitis
what is the common signalment of a horse with a synovial infection?
peri-natal horse that is lame (focal lameness) & has swollen joint(s) - swelling may be effusion, or periarticular cellulitis
INFECTED UNTIL PROVEN OTHERWISE
history/physical exam shows prior sepsis or perisynovial injury that is considered open until proven otherwise
how is a synovial infection diagnosed?
physical exam, imaging, & joint fluid cytology
what imaging modalities are commonly used for diagnosing synovial infections?
rads
ultrasound - hyperechoic fluid
mri
what parameters of synovial fluid analysis are consistent with a synovial infection?
WBC > 30,000/uL
neutrophils > 90% of total cell population
TP > 3 gm/dL
what components make up a synovial wash?
fluid analysis for cytology
checking for wound communication
when may you use a contrast study for a horse with a suspected synovial infection?
use to evaluate, joints, tendon sheaths, & draining tracts
how are synovial infections managed?
eliminate/prevent infections - abx, can be systemic/intra-articular, regional perfusion, choose empirically because cultures take 3-10 days (pick based off of expected pathogens/post-inj-sx/open wounds)
preserve joint function - normalize synovial environment
debride/drain
how can you normalize the synovial environment?
synovial lavage or open synovial therapy
what provides the cortical blood supply?
periosteal bone - external 1/3
endosteal bone - internal 2/3
what location do we commonly see osteitis/sequestration in the distal limb?
mc/mt from avulsion injuries - affects the skin/fascia/periosteum & can be non-repairable with exposed bone/bacterial colonization
why do we commonly see osteitis/sequestration in the coffin bone of horses?
sole penetration - can affect distal phalanx, navicular apparatus
key is early recognition
what is most important if there is sole penetration affecting the navicular apparatus?
early & acute management
