Monoarthritis

Monoarthritis

1. Complete history and examination

   • Suspect joint trauma / injury
     • Effusion/synovitis present
       • Arthrocentesis
         • Crystals
           • MSU
             • Gout
           • CPPD
             • Pseudogout
         • WBC <2000
           • Suspect non-inflammatory conditions eg. OA
         • WBC >2000
           • Suspect inflammatory causes eg. RA, JIA, spondyloarthropathies, SLE, septic arthritis etc.
             • Synovial fluid gram stain, culture, sensitivity
               • Pathogens
                 • Septic arthritis
               • No pathogens
                 • ESR and CRP
                   • Patterns indicative of certain disease vs generalised elevation
                 • RF and CCP
                   • Positive
                     • Suspect rheumatoid arthritis
                   • Negative
                     • Rheumatoid arthritispossible but consider other aetiologies
                 • ANA
                   • Positive
                     • ENA and dsDNA
                       • Positive
                         • Suspect SLE
                       • Negative
                         • SLE unlikely, consider other aetiologies
                   • Negative
                     • SLE unlikely, consider other aetiologies
         • Haemarthrosis
           • Imaging
           • Coagulopathy profile
     • No effusion/synovitis
       • Radiograph
         • Fracture, tumour, osteonecrosis
   • Suspect soft tissue problem
     • Ultrasound
   • Suspect mechanical joint problem
     • RA, CCP, arthrocentesis, ESR
       • Positive
         • Osteoarthritis unlikely, consider other aetiologies
       • Negative
         • Suspect osteoarthritis
     • Radiograph
   • Suspect inflammatory joint problem

2. Findings

3. Investigation

4. Condition