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Reactive Arthritis


Step 1: View clinicals

A 22 year old man presents with pain and swelling of his right knee for 2 weeks. The pain worsens with weight bearing. There is no history of trauma. He was prescribed ciprofloxacin for an urinary tract infection around 3 weeks ago. His medical history is otherwise unremarkable. He is sexually active,

Step 2: Order all relevant investigations

X-Ray R/s Knee Joint

Anteroposterior, lateral and axial patellar images are obtained. These are only significant for mild soft tissue swelling and a moderate effusion.

R/s Knee Joint Aspiration

Appearance: turbid WBC: 7,000/mm3 (< 200) PMN: 80% (< 20%) Glucose: 70 mg/dl (normal: within 10 mg/dl of serum glucose) Protein: 4 g/dl (1 - 3) Gram stain: no organisms Crystals: not seen Random plasma glucose: 80 mg/dl

Urethral swab + Chlamydial NAAT

Positive for Chlamydia.

HLA-B27 assay

The HLA-B27 assay is negative.

Step 3: Select appropriate management

Immobilize joint

Score: ★★☆