Septic Arthritis Flashcards
What are 3 types of causes of septic arthritis?
- Naturally occurring
- Iatrogenic
- Usually bacterial (sometimes viral, mycobacterial, fungal)
What can cellular infiltrates such as degradative enzymes and cytokines create?
Create a cycle of cartilaginous matrix destruction.
What are 5 general aspects of the pathogenesis of septic arthritis?
- Decreased HA synthesis
- Loss of PG
- Joint effusion
- Painful
- Compromise synovial blood flow
What are 4 overall consequences involved with septic arthritis?
- Acute synovitis with suppurative effusion
- Cartilage destruction via cellular and bacterial enzymes and cytokines
- Capsular fibrosis/ankylosis
- DJD
What are 2 examples of complications that can be seen with septic arthritis?
- Contralateral limb laminitis
- Euthanasia
How can septic arthritis be caused in foals?
Failure of passive transfer
In checking for FPT, normal IgG levels should be over what?
What can be used to get this value?
- Over 800
- SNAP test
What are 3 types of septic arthritis seen in foals?
- S-Type
- E-Type
- P-Type
What is affected in the S-Type of septic foal arthritis?
Joint space - synovial membrane, synovial fluid
What age of foal is more commonly affected by the S-Type of septic arthritis in foals?
Less than 1 week
What type of joints are more commonly affected with S-Type septic arthritis in foals?
What are 2 examples of these?
- Larger joints
- Stifle, tibiotarsal
What is the most common joint affected by S-Type septic arthritis in foals?
Tibiotarsal
Is it more common the see one joint or multiple joints affected with S-Type septic arthritis in foals?
Multiple joint involvement more common.
What are 3 clinical signs seen with S-Type septic arthritis in foals?
- Acute onset
- Severe lameness
- Effusion
What are is affected by E-Type septic arthritis in foals?
Bone adjacent to articular cartilage.
What are 2 changes seen with E-Type septic arthritis in foals?
- Expanding epiphysis
- Subchondral lysis
What age range is most commonly affected by E-Type septic arthritis in foals?
Weeks old
History of what 2 conditions can indicate E-Type septic arthritis in foals?
- Failure of passive transfer (FPT)
- Other disease (pneumonia, diarrhea)
Is it more common to see one or multiple joints affected by E-Type septic arthritis in foals?
Multiple joints
What are 4 examples of areas that can be affected by E-Type septic arthritis in foals?
- Distal femur
- Talus
- Tibia
- Radius
What is a pattern of clinical signs commonly seen with E-Type septic arthritis in foals?
Mild intermittent lameness with or without fever followed by acute exacerbation lameness/effusion.
What area is affected by P-Type septic arthritis in foals?
Physis of long bones
What should be checked when physitis is present?
Check the joint space.
What age range is most commonly affected by P-Type septic arthritis?
Weeks to months
How can foals with P-Type septic foal arthritis often present?
Seemingly healthy with no history of prior disease.
What are 3 common locations of P-Type septic arthritis in foals?
- Distal physis of MC3/MT3
- Radius
- Tibia
Does P-Type septic arthritis in foals more commonly affect one or multiple joints?
One
What clinical signs can be seen with P-Type septic foal arthritis?
Premonitory lameness THEN acute severe lameness/swelling.
Periarticular swelling usually without effusion can be seen with what type of septic arthritis in foals?
P-Type
What are 3 types of diagnostics that can be used to detect P-Type septic foal arthritis?
- Radiographs
- US guided aspirate of physis (submit for culture)
- Possible bone biopsy
What should not be done due to the risk of damaging the physis and causing premature closure?
Do NOT debride!
Generally speaking
With which 2 types of septic arthritis in foals can you see lameness, effusion and sometimes fever?
- S-Type
- E-Type
If performing synovial fluid analysis, a cell count over what level and a neutrophil count over what level are indicative of suppurative inflammation?
- Greater than 50,000 cells
- Greater than 90% neutrophils
What are 2 possible findings on blood work for a foal with septic arthritis?
- Increased fibrinogen
- +/- leukocytosis
If there is septic arthritis, fibrinogen levels in the blood work can get over what?
Greater than 900 mg/dL
What can be seen on US with foal septic arthritis?
Hypercellular fluid
It is important to identify what when dealing with septic arthritis in foals?
Must ID all joints involved.
What part of the foal should be examined with US due to it being a source of infection?
Umbilicus
What part of the patient should be evaluated when a foal is suspected of having septic arthritis?
Evaluate the entire patient!
What is the prognosis for foals with septic arthritis?
77% survival rate
What are 3 potential risk factors for septic arthritis in adult horses?
- Iatrogenic
- Trauma
- Bacteremia
What are 3 types of procedures where septic arthritis can be caused iatrogenically?
- Synovial surgery
- Fracture repair
- Arthrocentesis
Is hematogenous spread a rare or common cause of septic arthritis in adult horses?
Rare
What is a common bacterial source of septic arthritis with arthrocentesis in adult horses?
Staphylococcus
An open joint is a what?
An open joint is an INFECTED JOINT.
Septic arthritis in adult horses is similar to what?
Similar to foals without bone involvement.
The is an acute onset of what clinical sign with septic arthritis in adult horses?
Severe lameness
What are 2 clinical signs that can be seen per-articular with septic arthritis in adult horses?
- Heat
- Swelling
What is a clinical sign that may or may not be seen with septic arthritis in adult horses?
Fever
What is the gold standard for diagnosis sepsis in adult horses?
Microbiology using a joint tap.
What are 3 factors of synovial fluid to grossly examine?
- Color
- Clarity
- Viscosity
What are 3 aspects of clinicopathological fluid joint evaluation with septic arthritis in adult horses?
- Total protein
- Cell count differential
- Staining of smears
A joint should be tapped for evolution distant to what?
Distant to the wound.
What are 2 types of media that can be used for culturing and sensitivity of a joint tap for septic arthritis in adult horses that can give a much better yield?
- Enrichment media
- Blood culture media
If the initial sample from a joint tap looking for septic arthritis in adult horses comes back negative, what should be done?
Repeat culture
When evaluating joint fluid, what color is considered normal?
What is considered abnormal?
- Pale yellow
- Serosanguinous, orange
When evaluating joint fluid, what clarity is considered normal?
What is considered abnormal?
- Clear
- Turbid
When evaluating joint fluid, what WBC count is considered normal?
What is considered abnormal?
- Less than 500 cells/dL
- Thousands +
When evaluating joint fluid, what neutrophil differential is considered normal?
What is considered abnormal?
- Less than 10% neutrophils
- Greater than 90%, usually degenerated
When evaluating joint fluid, what total protein level is considered normal?
What is considered abnormal?
- Less than 2 g/dL
- Greater than 3.5 g/dL
Cultures should be taken before what happens?
Before antibiotics are given.
Can you still culture if antibiotics have been initiated?
Yes
Why is it important to do the joint tap away from the wound?
Don’t want to introduce anything into joint.
What are 3 radiographic signs that can be seen with septic arthritis in adult horses?
- Marked effusion
- Soft tissue swelling
- Osseous involvement
For treatment of septic arthritis to be successful, what 2 things need to take place?
- Rapid recognition of disease
- Immediate aggressive treatment
Treatment goals for returning cartilage to a normal environment include what 3 aspects?
- Eradicate infection
- Eliminate inflammation
- Minimize matrix loss and cartilage damage
If treatment goals for septic arthritis are not accomplished what can happen?
Irreversible structural damage and decreased prognosis for return to function.
While waiting for results of septic arthritis samples, what can be done?
Begin broad spectrum antibiotics such as penicillin or gentamicin.
What is the mainstay of treatment for septic arthritis?
How often should it be done?
- Lavage with large volumes (5-10 L)
- Early and often
What type of lavage is ideal?
What is another type that could be used?
- Arthroscopic lavage
- Needle (Through and through) lavage
What are 3 reasons that arthroscopic lavage is ideal?
- Rapid accurate delivery
- Removal of fibrin clots
- Targeted debridement
What size needles are used for needle lavage?
Where are they placed?
- 18-16 gauge needle
- Needles placed in all compartments
What are 2 necessary parts of treatment for septic arthritis if the horse is to remain standing?
- Sedation
- Local anesthesia
What is an example of a local anesthetic used for septic arthritis?
2% mepivacaine
What are 2 types of balanced electrolyte solutions that can be used to lavage joints for septic arthritis?
- LRS
- Normosol
What are 2 things not to add in a lavage used for septic arthritis?
Why?
- Chlorhexidine, Povidone-iodine
- Shown to be inflammatory, effective concentrations would cause damage to tissue
How often should a septic joint be lavaged?
Daily initially if not fully responsive.
When should lavage treatment for a septic joint be stopped?
Timing is specific to the individual.
What are 3 signs that indicate it might be time to stop lavage with septic arthritis?
- Resolution of lameness
- Resolution of effusion/swelling
- Able to discontinue use of NSAIDs/analgesics
Which type of antibiotic is more important in the treatment or septic arthritis: local or systemic?
Local
When is it ok to stop antibiotics?
Minimum 30 days and 2 weeks beyond resolution of clinical signs.
What are 4 routes of administration for local antibiotics with septic arthritis?
- Intra-osseous
- Intra-articular
- Regional limb perfusion
- Impregnated biomaterials
When can antibiotics be administered intra-articularly?
After completion of lavage
Intra-articular administration of antibiotics can lead to a very high concentration of the drug where?
At site of sepsis (joint)
500 mg of Amikacin provides a concentration greater than MIC for most common pathogens for how long when given intra-articularly?
72 hours
What do you have to be careful about when dealing with septic arthritis in multiple joints?
Not to exceed the daily total systemic dose.
How often is regional limb perfusion performed?
4 times a day
Proper tourniquet placement is essential for what type of dosing?
Regional limb perfusion
What size catheters are used for regional limb perfusion?
Why?
- 25-27 gauge
- Use smaller size to try and make the vein last.
How should a regional limb perfusion be injected?
Slowly over 5-10 minutes
How long should the tourniquet be left of for with regional limb perfusion?
30 minutes
What is an example of an anti-inflammatory that can be given topically with regional limb perfusion that has less perivascular swelling and edema?
Surpass
What is the general rule of thumb when dosing for regional limb perfusion?
1/3 of systemic dose
What drug is used for regional limb perfusion in cattle?
What are 2 bacteria that is acts against?
- Florfenicol
- F. necrophorum and A. pyogenes
When using regional limb perfusion, it is important to not do what?
Not to exceed the total daily systemic dose.
What size hole is drilled for intra-osseous antibiotic administration?
What can fit into this size hole?
- 4 mm
- Male end of lure tip extension
What should be used and then left on for at least 30 minutes after IO antibiotic administration?
Tourniquet
What can be excruciatingly painful?
Septic arthritis
What is a reason for using analgesia in conjunction with septic arthritis?
Contralateral limb laminitis
What are 4 possible consequences as a result of excessive time in recumbency?
- Decubital ulcers
- Respiratory disease
- GI disease
- Weight loss
What are 2 examples of GI protectants that can be used in horses?
- Omeprazole
- Sucralfate
What are the 2 most reliable and important measures to assess response to treatment for septic arthritis?
- Clinical lameness
- Pain
What is something to be careful of when evaluating effectiveness of a treatment for septic arthritis?
NSAIDs and other analgesics can mask pain and give a false impression of success.
Never discharge any antibiotics or lavage until what occurs?
Until horse is evaluated AFTER analgesics have been reduced or discontinued.
What are 3 goals of adjunct treatment for septic arthritis?
- Eradicate infection
- Eliminate inflammation
- Return cartilage to it’s normal environment
What is an example of an adjunct treatment that can be used with septic arthritis?
HA