Ultrasound in Pediatric Emergencies

Gaurav Saigal, MD, Jennifer Runco Therrien, MD, and Frank Kuo, BS


Appl Radiol. 2014;43(8) 

In This Article

Musculoskeletal Pathology

US applications in MSK pathology include evaluation of joint effusions (particularly of the hip), guidance for percutaneous drainage and localization of non-radiopaque foreign bodies.

Hip Effusion

Hip effusions have various etiologies. However, when a pediatric patient presents with fever, pain, and refusal to bear weight on one limb, septic arthritis or transient synovitis are the most likely diagnoses. Transient or toxic synovitis is a self-limiting inflammation of the joint space precipitated by a prior infection (classically an upper respiratory infection) or allergy.[36] A hip effusion may or may not always be present in transient synovitis (Figure 17). In septic arthritis, it is extremely important to diagnose and treat quickly due to the potential devastating consequence of joint destruction.[37] Usually, joint effusions are clear in transient synovitis and contain debris (due to purulent fluid) in cases of septic arthritis.[38] However, this may not always be the case and the currently accepted mode of practice is US- guided aspiration of fluid, even if clear, to exclude the possibility of septic arthritis.[39,40] If no fluid is seen on the US, the cause is presumed to be due to transient synovitis, particularly if other clinical signs and symptoms favor the diagnosis and no invasive procedure is necessary.

Figure 17.

Male child presenting at 1 yr refusing to walk on the left lower extremity following history of a viral infection a few days before. Longitudinal US views of the hips side-by-side for comparison demonstrate a left-sided hip effusion (white arrows). Note that the effusion usually collects just anterior to the neck of the femur in a dependent portion of the joint. No effusion is noted in the contralateral joint space.