Clinical and laboratory findings:
(1) sudden onset of restricted joint motion (including limp)
(2) sudden onset of muscle spasm
(3) capsular distention on joint X-ray or ultrasound
(4) leukocytosis with left shift
(5) elevated erythrocyte sedimentation rate (ESR)
(6) fever and a systemic reaction
Situations where the clinical findings may be masked:
(1) in newborn infants
(2) after therapy with antibiotics, anti-inflammatory agents and/or antipyretics
In these situations a high index of suspicion is needed to make the diagnosis.
Aspiration of the joint with smear and culture is the preferred method for making the diagnosis.
Anytime that suppurative arthritis is in the differential diagnosis it must be excluded early, since delay can have devastating effects on the child.
