Septic Arthritis in Adults - You Can't mIss this

HPI:
33 year old with no prior PMH presents to the ED with left knee pain

Physical Exam:
Swelling over the left knee. Limited range of motion secondary to pain. No overlying laceration or abrasion. Knee is warm to the touch. Overlying cellulitis on the lateral left knee. Palpable DP and PT pulses with intact sensation in the SP, DP and tibial nerve distributions.

Radiology:
Normal knee

Management:
Patient underwent arthrocentesis. Joint fluid analysis showed only 81 cells. Presentation consistent with cellulitis and patient improved with IV antibiotics.

Discussion:
-Most commonly affected joints in descending order: knee, hip, elbow, ankle, sternoclavicular joint
-Joints become infected by 1) bacteremia, 2) direct inoculation 3) contiguous spread from adjacent osteomyelitis
-Why does it matter? It causes irreversible cartilage destruction in the joint
-Involved joint is tender, warm and erythematous
-WBC count, ESR and CRP aid in the diagnosis
-Diagnosis is by joint fluid analysis – TAP THE JOINT!
-Treatment includes early antibiotic treatment and operative irrigation and drainage of the joint

Key Points:
 -Always think of this diagnosis when a patient presents with a tender, warm and erythematous joint
 -Diagnosis is by joint fluid analysis – TAP THE JOINT!
 -THIS IS AN ORTHOPEDIC SURGICAL EMERGENCY – Involve consultants early!