- Most common between 2-8 years of age. However, this condition can affect children up to 15 years old. The male to female ratio is 1.9:1. It is a benign condition with the presence of small amount of fluid in the joint. Often follows viral illness. Etiology speculated to be post infectious reactive arthritis. It is important to rule out a bacterial infection of the joint and bone. It is also important to rule out avascular necrosis (Legg-Perthes disease). The best way to do this is with a bone scintigraphy.
- Child may refuse to stand and limp. There may be pain on maneuvering the hip joint. The child does not usually appear ill, only low grade fever, and the ESR, CRP, and WBC count are normal or slightly elevated.
- This disease usually starts with a characteristic skin leasion, erythema chronicum migrans.
- Radiograph is normal or only small effusion present. Fluid is sterile.
- Treatment is reassurance and following carefully to be sure that there is no septic process, analgesics, and rest as needed. Lasts for a few days.
- Children with this condition often present with acute arthritis which if left untreated can turn into the chronic form.
- Transient synovitis typically has an acute onset, and spontaneously recovery with no radiological abnormality or systemic upset. It occurs between the ages of 2 and 10 years (peaking between 5 and 6 years) and is more common in boys, often preceded by viral infection.
(6, 7, 21)