Utility of other investigations for children and adolescents with musculoskeletal symptoms

Note: Synovial fluid aspiration should only be performed in children or adolescents with suspected septic arthritis, as part of acute hospital management.

Synovial fluid aspiration should only be performed in children or adolescents with suspected septic arthritis as part of acute hospital management. Local or general anaesthesia may be required, depending on the child or adolescent’s age and the affected joint. Detection of a pathogen on culture of synovial fluid is diagnostic of infection. Nucleic acid amplification testing (NAAT) (eg polymerase chain reaction [PCR]) of synovial fluid can identify microorganisms not detected by synovial fluid culture.

Synovial fluid aspiration for microscopy alone is not usually helpful in the differential diagnosis of inflammatory arthritis in children or adolescents. Crystal deposition disease (eg gout, calcium pyrophosphate deposition) is extremely rare in childhood.

If a sexually transmitted infection is suspected as a cause of reactive arthritis, seek expert advice regarding the most appropriate investigations and treatment. This is pertinent for sexually active children and adolescents, and may be an alerting feature (‘red flag’) for sexual abuse1. See also STIs in infants and children if sexual abuse is suspected.

Urinalysis is important to detect proteinuria or haematuria in children or adolescents with suspected kidney disease associated with immunoglobulin A (IgA) vasculitis or inflammatory connective tissue disease such as SLE; sterile pyuria may be present in reactive arthritis.

1 If nonaccidental injury (child abuse) is suspected, immediately refer patients for paediatric and forensic expert advice. Hospital paediatric services can often provide initial phone advice and directions for follow-up and care. In some jurisdictions, it is mandatory to report nonaccidental injuries in infants and children to state authorities.Return