“Coxitis Simplex” Transient Synovitis Hlynur Georgsson 24/11/2003

Etiology Remains obscure Inflammation of synovial lining Post-traumatic, allergic, infectious Inflammation of synovial lining Often after URTI (32-50%) or virosis 4x increase in viral titers seen in 45% Elevated interferon levels seen in 43% No association shown with B-19 or HHSV6 History of Trauma in 17-30%

Epidemiology Bilateral 5% Most common cause of non-traumatic hip pain in children Annual incidence 0.2% 0.4-0.9% of pediatric ER admissions lifetime risk 3% Typically children aged 3-8y Boys>girls 2:1 Seasonal increase in Autumn? Bilateral 5% Symptomatically unilat. show bilat. effusions in 25% Recurrence within 6 months in 4-15%

Presentation/History 6 year old non-febrile boy with a limp and uni- or bilateral hip-pain Onset Acute, typically less than one week at presentation Pain Partial flexion and external rotation to minimize intraarticular pressure Internal rotation especially restricted during Hip or groin region, occasionaly referred to ant. Thigh or medial knee Typically no fever or low-grade

Workup Bloodstatus + WBC, ESR X-ray Ultrasonography Arthrocentesis maybe unspecific soft-tissue changes Ultrasonography Can detect as little as 2-3ml of fluid Arthrocentesis Ddx. Septic arthritis Three-phase bone scanning Ddx. Osteomyelitis, osteoma, occult fracture

Treatment NSAID Aspiration therapeutic? Ibuprofen, Celebrex Aspiration therapeutic? Full activity as tolerated vs. no weight-bearing? ? Traction ? ? Antihistamine, i.m. Steroids ? Full recovery 1-4w 1-2% may go on to develop Perthes disease with avascular necrosis of femoral head, Higher risk if delayed bone age Recurrence within 6m = 4-15%