Society for Pediatric Urgent Care

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Society for Pediatric Urgent Care

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SEPTIC ARTHRITIS

BASICS

DESCRIPTION

  • Infectious inflammation of synovial space that can affect any joint.
  • In children, more commonly progresses to osteomyelitis because of presence of intracapsular metaphyses.

RISK FACTORS

  • Recent fractures or injuries can provide an entry point for infection.
  • Consider gonococcal arthritis in sexually active patients.

PATHOPHYSIOLOGY

  • Infectious agents enter joint space allowing for infection. Infection can easily spread to adjacent bone in children with intracapsular metaphyses.

ETIOLOGY

  • A variety of of organisms are implicated, including Staph aureus, coagulase negative staphylocci (associated with implants and prostheses), enteric organisms (associated with gastrointestinal infections).

COMMONLY ASSOCIATED CONDITIONS

  • Sickle cell disease associated with salmonella osteomyelitis as well as Strep pneumo arthritis

DIAGNOSIS

HISTORY

  • Acute onset of fever and joint pain, swelling and limited range of motion.

PHYSICAL EXAM

  • Fever and malaise
  • Hip: No swelling palpable. May notice asymmetry of gluteal fold.
  • Other joints: swelling, warmth, redness and tenderness at affected joint. Limited range of motion.
  • Pain with compression of joint spaces.
  • Usually only one joint involved. Involvement of multiple joints argues against septic arthritis.

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Initial Lab Tests

  • CBC demonstrates increased WBC
  • ESR elevated
  • CRP has high negative predictive value
  • Blood culture

Imaging

  • Xray to rule out occult fracture and to look for periosteal reaction.
  • Ultrasound, especially of hip joint, to determine presence of effusion.
  • MRI to look for surrounding osteomyelitis in joints with intracapsular metaphyses (elbow, hip, shoulder, ankle)

Diagnostic Procedures / Other

  • Synovial fluid aspiration necessary, but not particularly sensitive or specific. Send for WBC and culture (requires special culture or PCR testing for Kingella)

Pathological Findings

DIFFERENTIAL DIAGNOSIS

  • Occult fracture
  • SCFE, avascular necrosis
  • Autoimmune or viral Arthritis
  • Cellulitis overlying a joint

TREATMENT

MEDICATION

First Line

  • Antibiotics: tailored to specific organisms. If no risk factors identified, most likely Gram positive cocci.

SURGERY / OTHER PROCEDURES

  • Surgical wash out

DISPOSITION

Admission Criteria

  • Critical care admission criteria
  • Requires admission for IV antibiotics and surgical wash out

Discharge Criteria

  • Arrangements for prolonged IV antibiotic course

Issues For Referral

  • Requires emergent orthopedic consultation secondary to risk for long term disability

FOLLOW UP

FOLLOW-UP RECOMMENDATIONS

  • Discharge instructions and medications
  • IV antibiotics until afebrile x 24 hours
  • Activity
  • Physical therapy for rehabilitation of joint

PROGNOSIS

  • Early diagnosis and wash out may prevent long term disability in affected joint

COMPLICATIONS

  • Osteoarthritis or mobility loss from joint erosion
  • Sepsis

See Also (Topic, Algorithm, Electronic Media Element)

  • Kocher criteria

CODES

ICD9

  • PUBLISHER WILL ENTER

SNOMED

  • PUBLISHER WILL ENTER

PEARLS AND PITFALLS

  • In neonates may present with multiple joint involvement and systemic illness as is usually blood-borne.
  • If high suspicion for septic arthritis, patient should be treated regardless of synovial fluid results.