Predictive Algorithms in the Diagnosis and Management of Pediatric Hip and Periarticular Infection

A toddler with transient synovitis and COVID-19 infection

Transient synovitis of the hip is a common medical emergency in children. Although reactive arthritis in adults may occur 1-4 weeks after COVID-19 infection or post-vaccination, few reports of transient synovitis in children associated with acute COVID-19 infection have been made. Transient synovitis of the hip occurs most frequently in children 3-8 years of age with a recent upper respiratory infection, bacterial infection, or trauma. This case report presents a unique case of an otherwise healthy 15-month-old girl with right hip pain and the refusal to ambulate associated with COVID-19 infection.

The Limping Child: A Guide for the Trainees

Limping is a common presenting complaint in children. Despite this, it remains to be a diagnostic challenge for treating physicians due to an expanded list of etiologies. It arises from a spectrum of disorders, ranging from physiological variations of gait at different stages of development to systemic causes, such as inflammatory diseases or musculoskeletal infections. On rare occasions, non-musculoskeletal causes could result in limping. The diagnostic challenge increases in younger age children where a detailed physical examination that helps identify the exact source of pathology may not be possible. In older patients who have a well-developed gait cycle, the physical assessment might be easier. Clinical assessment in a child presenting with a limp includes gait analysis, which is essential to guide the appropriate request of diagnostic laboratory tests and imaging studies. In this paper, we provide a practical guide for a trainee in General Pediatric and Pediatric Rheumatology on an approach to a limping child, aiming to identify the common causes of limping and to describe normal and abnormal gait cycles. We also discuss other diagnostic considerations in the assessment of these children.

Transient synovitis of the hip: Current practice and risk of misdiagnosis

INTRODUCTION

Transient synovitis (TS) is a common and benign cause of hip pain in children, but must be distinguished from more serious entities such as septic arthritis, osteomyelitis, and pyomyositis. Our objectives were to determine the risk of missed bacterial musculoskeletal infection and rates of diagnostic testing in children diagnosed with TS.

METHODS

We performed a cohort study using the Pediatric Heath Information System of children 1-10 years diagnosed with TS in the ED. We determined rates of missed bacterial musculoskeletal infection (defined as a new diagnosis of septic arthritis, osteomyelitis, or pyomyositis within 14 days of initial ED visit). We described the initial diagnostic evaluation and ED management of children diagnosed with TS and variability between sites.

RESULTS

We analyzed 6419 encounters from 37 hospitals. 62 (1.0%, 95%CI: 0.7-1.2%) children were diagnosed with a missed bacterial musculoskeletal infection. Children with missed infection were younger than those without (median age 2.6 vs. 4.6 years, p < 0.01). Serum laboratory testing was performed in 76% of encounters with minimal variation across sites. There was significant variation in the rates of hip ultrasound by site (2 to 92%), which has increased in use over time (from 42% in 2016 to 62% in 2021).

CONCLUSION

In this large observational study, missed bacterial musculoskeletal infection in children diagnosed with TS was rare but more common in younger children. The optimal combination of bloodwork and radiographic testing, especially ultrasound, to distinguish TS from more serious disease remains unclear.