(Infection)

Overview

• Infection of the joint space caused by pathogenic inoculation of microbes
• Routes of Spread → Haematogenous (Most Common - spread from a distant site, eg. abscess, wound infection, septicaemia) or Direct Contamination (Iatrogenic from arthrocentesis or Trauma leading to open wounds around joint)
• Risk Factors → underlying joint disease (OA/RA), prosthetic joint, age>80, immunosuppression, diabetes, IV drug use
• Causative Organisms → staphylococcus aureus most common in adults and children >2 yrs (in young adults who are sexually active, neisseria gonorrhoeae is most common). Staph. epidermidis may be cause if prosthetic joint.
  • S.Aureus ⇒ gram positive
  • Neisseria Gonorrhoea ⇒ gram negative diplococci

Making Diagnosis

Clinical Features:

• Acute Onset → symptoms present for <2 weeks
• Hot, swollen, painful, restricted joint (Unilateral) → septic arthritis until proven otherwise
• Fever
• Most commonly affected joint is the knee, followed by hip, wrists, shoulders and ankles

<aside> 💡 Triad → FEVER, JOINT PAIN, RESTRICTED RANGE OF MOTION

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Investigations:

• Arthrocentesis (Joint Aspiration) → procedure in which synovial fluid is aspirated from a joint using a sterile needle

  <aside> 💡 JOINT ASPIRATION + CULTURE BEFORE ANTIBIOTICS

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