LA MS 14: Septic OA Flashcards
(44 cards)
Septic OA
EMERGENCY
Painful - support limb laminitis
IFX –> IFM
–bacteria: hyaluronidase, cytolytic toxins
–Synovial cells: IL-1B, prostaglandins
Eliminating IFX early = key
Irreversible cartilage degeneration - tx goal is to minimize OA
Classification of Septic Arthritis - hematogenous
SEPTic S type = synovium E type = epiphysis P type = physis T type = tarsal bone
Classification of Septic Arthritis - Non hematogenous
Puncture wound
Contiguous soft tissue
Septic Arthritis in Foals - Neonatal blood supply
In the growth plate, have transphyseal vessels that communicate btw primary and epiphysis artery. Predisposes IFX at growth plate (physis) in foals
- -over time, lose these connections
- -Bacteria more likely to lodge in small capillaries
- -as being vessels, being degraded, bacteria more likely to get stuck so more challenging to dx and treat
Type S
Synovial
Septic arthritis resulting from inoculation of the synovial membrane
Often see gas-producing bacteria or open communication to outside world
Type E
Subchondral bone IFX present
epiphysis
Type P
Physis
Physeal IFX on the metaphyseal side of the growth plate
Often appears lytic
–remember RAD changes always lag behind
Type T
Tarsal bones (or carpal bones)
IFX of small tarsal or carpal bones esp in premature foals
Sequela
–collapse and angular limb deformity
Foal vs Adult
Prog usually worse in foals
- -hematogenous
- -complications from the septicemia
- -multiple jts = decreased racing prognosis
- -also osteitis, osteomyelitis, physitis
Other complications assoc w/ foals
May have
–septic arthritis only
–septic physitis only
–septic arthritis and physitis
–septic osteomyelitis, physitis
–septic arthritis, physitis and osteomyelitis
BEWARE - premature closing and angular limb deformities
Dx - hx (foals)
FOALS ARE OFTEN FEBRILE Hematogenous >>> penetrating Prematurity FPT Usually <1mo
Etiologic Agents
Aerobic/facultative anaerobes in 91% of cases Anaerobic - Clostridium Mycoplasma Rhodococcus Fungal agents --Scendosporium prolificans --Candida
Etiologic Agents: Aerobic/Facultative Anaerobes
Salmonella Strep zoo E. Coli Actinobacillus equili Staph aureus Borrelia
Dx Considerations
Hx, PE --assess entire P --Articular swelling, lameness, cellulitis +/- predisposing hx Synovial fluid analysis --cytology, gram stain --culture and sensitivity RADS
Dx Hx - Adults
ADULTS ALMOST NEVER FEBRILE Iatrogenic --Staph or Strep either post-op or post jt INJ Trauma Nearby IFX --foot abscess --cellulitis Idiopathic
Dx Sample Collection
Minimize blood contamination
Sample away from open wounds
Avoid cellulitis
Sample Types
Cytology/Gram Stain --EDTA, heparin Culture --Blood culture vials --Anaerobic/aerobic --NO ANTICOAG --fluid, fibrin, or synovium can be cultured Have dose of ABX ready to infuse
Synovial fluid analysis
Translucent yellow
Normal viscosity - mucin, HA –> string btw fingers
Cloudy fluid suggests >30,000 cells/uL
Normal Synovial Fluid
TP <2.0 to <2.5 g/dL
WBC <450 to <5000
Cell type <10% neutrophils
Synovial fluid - IFM
TP 2.5 to 4 g/dL
WBC 500 to 20,000
Cell type 10-50% neutrophils
Synovial fluid IFX
TP >4.0 g/dL
WBC >30,000/uL
Cell type >80% neutrophils
Serum Amyloid A
Not specific to sepsis
Synovial Fluid Cytology
Gram stain --ID bacteria in 25% --Rapid guidance for ABX selection Neutrophils --normally <10% synovial fluid --usually non-degenerate in early IFX -->80% usually always IFX'd --degenerate neutrophils ALWAYS bad
Dx: culture and sensitivity
No growth does not mean not infected
Single organism indicative of IFX
Pos culture correlates w/ decreased prof
Blood culture media increases likelihood of a positive culture
