TS: transient synovitis: looks like septic but with less symptoms
| Transient Synovitis | Septic Arthritis | |
|---|---|---|
| Clinical presentation | Well-appearing Afebrile or low-grade fever Able to bear weight |
Ill-appearing Febrile Non–weight-bearing |
| Diagnosis | Normal or mildly elevated WBC, ESR, CRP Unilateral/bilateral ultrasound effusion Diagnosis of exclusion |
Moderately elevated WBC, ESR, CRP± Positive blood culture Unilateral ultrasound effusion Synovial fluid WBC >50,000/mm3 |
| Treatment | Conservative | Joint drainage & antibiotics |
A 3-year-old boy is brought to the emergency department by his mother for hip pain that has worsened over the last week. The mother states, "My son initially had occasional pain while playing and would point to his left hip, but now he limps and says that his right thigh hurts as well." She reports that he is usually very active but now only wants to lie down and watch television. There is no known history of trauma, and the child has been well recently except for a runny nose that his mother attributes to allergies. The patient's 7-year-old sister had an upper respiratory illness last week, but no other family members have been sick. Temperature is 37.8 C (100 F). The patient is well-appearing and cooperative. Cardiac and pulmonary examinations are unremarkable. Testicular examination shows normal male external genitalia with the testes descended bilaterally. When lying down on the examination table, the child keeps his left hip flexed and externally rotated. He winces when his hips are internally rotated, and there is decreased range of motion on examination. There is a small abrasion on the left shin but no bruising or petechiae. The rest of the examination is unremarkable.