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Flashcards in Septic Arthritis Deck (27)
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1
Q

What are some causes of septic arthritis?

A

Naturally Occurring - hematogenous (seen in foals), traumatic

Iatrogenic - arthroscopy, arthocentesis, fracture repair, etc

Usually bacterial but can viral/ mycobacterial/ fungal

** Can prevent with lavages, antibiotics, effective drainage

2
Q

What processes occur that damage cartilage in septic arthritis?

A
  • Fibrin is deposited
  • Degradative enzymes ( colagenase, stromelysin, MMP) and cytokines (IL-1, 6, TNF) enter capsule

-Result is a loss of PG, decreased HA synthesis, joint effusion, pain, decreased synovial blood flow

3
Q

What are the different types of septic arthritis in foals?

A

S (synovial), E (epiphysis), P

Must ID all joints when diagnosing

4
Q

What is S-type foal septic arthritis?

A

Affects synovial fluid and synovial membrane

Occurs in foals < 1 week old

Affects larger/ multiple joints (stifle, tibiotarsal)

CS: acute severe lameness and effusion

5
Q

What is E-type foal septic arthritis?

A

Affects bones next to articular cartilage –> appears as subchondral lysis on rads)

 Age: weeks old
 Hx: FPT, other dz (pneumonia, diarrhea)
Joints:
 Multiple
 Distal femur, talus, tibia, radius
 CS: mild intermittent lameness +-fever…THEN acute exacerbation of lameness/effusion

6
Q

What is P-type foal septic arthritis?

A

Occurs on physis of long bone, may include joint

Will appear healthy without disease history

Affects distal physis of MC/T III, radius, tibia –> only one site though

CS: Premonitory lameness THEN acute severe
lameness/swelling, and periarticular swelling without effusion

7
Q

How do you diagnose P-type septic arthritis?

A

Radiographs

Physis aspirate

Bone biopsy

DON’T DEBRIDE –> DAMAGES AND CLOSES PHYSIS

8
Q

What values would you see on a blood work in foal septic arthritis?

A

Synovial fluid
 >50,000 cell count, >90% neuts
 Color –normal to cloudy, red, orange, pink

Bloodwork:
Increased fibrinogen +-leukocytosis
 Fibrinogen usu. >900 mg/dL with bone involvement

US –> hypercellular fluid detail (hyperechoic)

9
Q

What is the prognosis for septic arthritis in foals?

A

77% –> pretty good

10
Q

What can predispose foals to septic arthritis?

A

Failure of passive transfer leads to bacteremia, resulting in septic arthritis

11
Q

What is the difference between swelling and joint effusion?

A

Effusion is the accumulation of fluid within the joint

Swelling is an accumulation of fluid outside the joint

12
Q

What risk factors can predispose adult horses to septic arthritis?

A

Iatrogenic –> Staph usually infects joint

Trauma –> many different possibilities, Enterobacteriaceae most commonly infects (Staph, pseudomonas, sometimes fungi)

** an open joint is an infected joint

13
Q

What are the clinical signs of septic arthritis in adults?

A

Similar to foals

Acute severe onset of lameness (important)

Synovial effusion

Peri-articular heat and swelling

May or may not have fever

14
Q

How do you diagnose septic arthritis?

A

Joint tap and microbiology –> GOLD STANDARD

Gross exam

TP, cell count, smear stains

C/ S –> Enrichment culture and blood culture *better yield

**In foals, aspirate physis for physitis potential

15
Q

T/F

When tapping a septic joint, you should tap TOWARDS the wound

A

FALSE

Tap AWAY from the wound to get a false reading

16
Q

What Imaging modalities do you want to run to diagnose septic arthritis?

A

Radiograph –> effusion, soft tissue swelling, osseous involvement

US –> guide for aspirate, hypercellular fluid, umbilicus check in foals

Nuclear scintigraphy

17
Q

Why do you not want to add chlorhexidine/ povidone iodine in septic arthritis lavages?

A

Kills healthy cells and doesn’t do anything to fix the disease

18
Q

What are consequences of septic arthritis?

A
  • Acute synovitis w/ suppurative effusion
  • Cartilage destruction
  • Capsular fibrosis/ ankylosis
  • Degenerative joint disease
  • Contralateral limb laminitis
  • Possible euthanasia
19
Q

How do you want to treat septic arthritis?

A
  • Start off with broad spectrum ABs locally–> pen/gen (give for at least 30 days and continue to give 2 weeks after resolution)
  • Lavage early and often in large volumes (5-10 L) –> VERY IMPORTANT!!!!!
  • Arthroscopic lavage ideal but can use large needle lavage
  • Sedate and give local anesthesia (2% mepivacaine in jiont) for arthoscopy/ -otomy
20
Q

What type of lavage solutions do you want to use for lavage solutions?

A
  • Balanced electrolyte solutions –> LRS, normosol
  • DON’T USE CHLORHEXIDINE, POVIDONE-IODINE
  • Maybe DMSO
21
Q

How often do you want to lavage and when should you stop?

A
  • Perform daily if severe enough

- Stop once lameness, effusion/ swelling, other signs resolve

22
Q

What antibiotics are septic arthritis susceptible to?

A

Aminogylcosides –> concentration dependent AB

  • Give 50 mg Amikacin
23
Q

How do you perform regional limb perfusion?

A
  • Give local anesthesia and sedation
  • Apply tourniquet above and below joint if possible
  • Inject solution slowly with butterfly catheter
  • Leave tourniquet for 30 min
  • Give 1/3 of systemic dose
24
Q

What antibiotic do you want to use in a regional limb perfusion in cows?

A

Florfenicol - effective againts F. necrophorum and A. pyogenes

25
Q

How do you give intra-osseous antibiotics

A
  • Local anesthesia
  • Apply Esmarch tourniquet
  • Inject solution slowly and leave tourniquet on for 30 min
26
Q

What other drugs do you want to give for septic arthritis?

A
  • Morphine/ opiates –> very painful condition
  • NSAIDs (give GI protectants too)
  • Lidocaine and ketamine CRI
  • Epidural for hindlimb –> opiates and detomidine
27
Q

What is the most important way to measure the effectiveness of treatment?

A
  • Clinical lameness and pain

– NSAIDs can mask pain