SEPTIC ARTHRITIDES

Question 1

KEY CONCEPTS

Answer 1

RISK FACTORS
Prosthetic Joint
Immunocompromise
HIV
IVDU
Sickle Cell
High Risk Sexual Activity

PATHOGENS
Staph Aureus
Steptococcus
Gram -ve bacteria
N. Gonorrhoeae MC sexually active adults

Question 2

DDx

Answer 2

Non-septic Arthritis
Cellulitis
Nectrotizing Fasciitis
Periarticular Disease: bursitis, tendinopathy, tenosynovitis
Hemarthrosis
Occult Trauma

Question 3

MANAGEMENT

Answer 3

DOCUMENTATION

Acute Joint:
Warmth and Erythema
Effusion (78%)
Pain with aROM and pROM (85%)
Limited Range of Motion
Micro-motion tenderness
Fever (57%)

INVESTIGATIONS

CBC
CRP, ESR
Blood Cultures
XRAY: r/o concurrent joint disease, does NOT rule out an infection

Arthrocentesis with synovial fluid analysis:
Cell Count
Gram Stain
Culture
Crystals

Relative c/i:
Overlying cellulitis
Coagulopathy

EMPIRIC MANAGEMENT

Vancomycin:
Loading Dose 25-30 mg / kg IV
followed by 15 mg/kg IV q 8-12 hrs

Clindamycin: Vancomycin Allergy
600-900 mg IV q 8 hrs

Discontinue Vancomycin once susceptibilities allow:

Cefazolin 2 g IV q 8 hr

Gram Negative:
Ceftriaxone 2 g IV if gram

Add ciprofloxacin 400 mg IV if sickle cell / risk of salmonella

DISPOSITION
Orthopedic Consultatoin
Admission

Question 4

SYNOVIAL FLUID ANALYSIS

Answer 4

SEPTIC: NON-GONOCOCCAL
Cloudy, opaque
WCB > 50,000
Neutrophils > 90%
Gram Stain + < 2/3
Culture + (70-90%)
Crystals -

SEPTIC: GONOCOCCAL
Cloudy, opaque
WCB > 25,000
Gram Stain +
Culture +
Crystals -

SEPTIC: PROSTHETIC
Cloudy, opaque
WCB > 11,000
Neutrophils > 64%
Gram Stain + < 2/3
Culture + (70-90%)
Crystals -

INFLAMMATORY
Cloudy
WCB 20,000-50,000
Neutrophils > 50%
Gram Stain -
Culture -
Crystals +