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Flashcards in Septic Arthritis Deck (33)
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1

What are naturally occurring routes of septic arthritis?

Hematogenous or traumatic

2

What are iatrogenic causes of septic arthritis?

Arthroscopy
Arthrocentesis
Fracture repair

3

Pathogenesis of septic arthritis?

Synovitis/capsulitis
Fibrin deposition
Cellular infiltrates
—> degradative enzymes, cytokines
—> collagenases, stromelysin, MMP release
—> IL1, IL6, TNF

Creates cycle of cartilaginous matrix destruction

Decreased HA synthesis
Loss of PG
Joint effusion
Pain
Compromise synovial blood flow

4

What are risk factors in foals for septic arthritis ?

FPT — risk of bacteremia (hematogenous)

5

What are the types of septic arthritis in foals?

S — synovial membrane and fluid

E — epiphysis, bone adjacent to articular cartilage

P — physis of long bones +/- joint

6

Foal <1week with acute, severe lameness, and effusion of the stifle and tibiotarsal joints.

What type of septic arthritis is this?

S type

7

Foal a few weeks old that had a mild lameness and fever. Lameness has acutely worsened in the last day. There is effusion in multiple joints, the distal femur, taus, and radius.

What type of septic arthritis is this?

E type

Can confirm with rads —> subchondral bone lysis

8

Foal a month old that was seemingly healthy that had developed an premonitory lameness which is now acute and severe.

What type of septic arthritis is this?

P type

9

How can you confirm a P type septic arthritis?

Radiographs —> lysis
Aspirate of physis

Possible bone biopsy

DO NOT debride -> will damage physis, causing premature closure

10

How can you confirm diagnosis of S and E type septic arthritis ?

Radiographs

Synovial fluid analysis
>50,000 cell count, >90% PMNs
Colour- normla to cloudy, red, orange, pink

Blood work : increase fibrinogen +/- leukocytosis
Fibrinogen >900mg/dL with bone involvement

US: hypercelluar fuild

11

What is the prognosis for survival for foals with septic arthritis?

77%

12

What is the most common agent involved in septic arthritis of adult horses?

Enterbacteriaceae


Staph, pseudomonas, or fungi can be involved

13

T/F: open joint = infected joint

True

14

Clinical signs of septic arthritis in adults?

Acute onset of severe lameness

Synovial effusion

Peri-articular heat and swelling

+/- fever

15

What is the gold standard for diagnosis of septic arthritis ?

Microbiology

C/S in blood culture bottles
Repeat for culture if initial sample is negative

16

Cytology of a joint.

Color: pale yellow
Clear
WBC 400 cells/dL, <10% neutrophils
TP 2g/dL

Normal or abnormal?

Normal

17

Cytology of a joint.

Colour: orange, turbid
WBC 2000 cells/dL, > 90% neutrophils
TP 3.5g/dL

Normal or abnormal?

Abnormal

Normal WBC <500cells/dL with <10% neutrophils
Normal TP is < 2g/dL

18

What is the most common isolate in septic joints?

Staphylococcus

19

Why do we want to do our tap away from the wound?

Prevent contamination from would surface for culture

20

What are consequences of septic arthritis ?

Acute synovitis with suppurative effusion

Cartilage destruction due to cellular and bacterial enzymes, and cytokines

Capsular fibrosis/ankylosis

DJD

Contralateral limb laminitis

21

What is the treatment for septic arthritis?

LAVAGE- early and often
- large volumes

Broad spectrum antibiotics

22

What are two methods of joint lavage?

Arthroscopic (best)
-rapid and accurate delivery
-removal of fibrin clot
-targeted debridement

Needle (through and through lavage)
-use large guage need (16-18g)
- needles can get clogged easily

Can be done with local anesthesia (2% mepivacaine) and sedation or under general anesthesia

23

What solution do you use in lavage of a joint?

Balanced electrolyte solution — LRS or Normosol

24

T/F: chlorhexidine or poisoned-iodine can be added to lavage solutions to help as an anti-inflammatory and free radical scavenger

F

These are cytotoxic. NEVER use

Can use DMSO for these purposes

25

How often should you lavage a septic joint?

Daily initially

Can stop when there is resolution of lameness or effusion/swelling

26

How long should you give broad spectrum antibiotics for a septic joint? /

Minimum 30days and 2weeks beyond resolution of CS

27

Why must you be cautions of administering IA injections of antibiotics into multiple joints??

Local IA antibiotics can provide high concentration with int he joints but you must be careful not to exceed the daily total SYSTEMIC dose

28

How often can regional limb perfusion be done to treat septic arthritis? And how long do you leave the tourniquet inplace?

Performed QOD

Tourniquet in place (above and below site) for 30mins

29

What is the dosage for regional limb perfusion ?

1/3rd of systemic dose

Diluted to 30ml for distal limb

Diluted to 60ml if above carpus/tarsus

30

In cattle you can do a regional limb perfusion with __________ which provides a high tissue concentration of antibiotics against F. Necrophorum and A. Pyogenes

Florfenicol