Acute Hip pain in a child

John is a 6 years old child who suddenly developed a limp on his right side and walked around with a painful gait. He was happily cycling with his cousins and even went shopping with his family a day earlier. 5 days earlier he had a bout of 'flu' which subsided on it's own.

Hip pain is a frequent cause for limping in children. According to Gicquel et al (2006)the cause depends on the age of the child, trauma or infection, the child's morphology and ethnic origin. However, most of the diagnoses may require only an X-ray and an ultrasound of the hip to be confirmed. Eich et al (1999)suggested that investigation of painful hips in children, based on hip ultrasound, body temperature, Erythrocyte Sedimentation Rate (ESR) and C-reactive protein level (CRP), may allow cases for hip joint aspiration to be selected efficiently and may reduce the number of radiographs and hospital admissions. Michelle et al (2006) found that fever (an oral temperature >38.5°C) was the best predictor of septic arthritis followed by an elevated CRP, an elevated ESR, refusal to bear weight, and an elevated serum white blood-cell count. In his study group, a CRP of >2.0 mg/dL (>20 mg/L) was a strong independent risk factor and a valuable tool for assessing and diagnosing children suspected of having septic arthritis of the hip.

The three main causes to be considered in children of less than 10 years of age are septic arthritis, transient synovitis and Perthes disease. Septic arthritis will require an urgent treatment, whereas Perthes disease will need a long care and follow up in order to watch for a poor outcome that will necessitate a surgical treatment to restore containment of the femoral head. In the adolescent, especially in case of the overweight, the commonest cause to be considered is slipped femoral capital epiphysis, a condition that requires an early and adequate surgical treatment (in situ screw fixation), in order to avoid further displacement and femoral head deformity of poor prognosis. Olivieri et al (2007) reported that Staphylococcus aureus may cause myositis of the Obturator internus Muscle seen in 2 rare cases.

John was afebrile and had full hip range of motion, was sitting comfortably but a bit hesitant to place his weight on his right lower limb. He had mild pain with hip joint Internal rotation and External rotation. His preliminary diagnoses was transient synovitis and he given mild analgesic and advised to avoid excessive walking or running. After discussing the differential diagnoses and management with the parents, we decided to do a thorough investigation and treatment with a paediatric Orthopaedic Surgeon.

Links you need to know:-
Differentiating Between Septic Arthritis and Transient Synovitis of the Hip in Children
Septic Arthritis:Paediatric Hip
Investigations and treatment of Septic Arthritis
Transient Synovitis
Factors Distinguishing Septic Arthritis from Transient Synovitis of the Hip in Children