BY Mike Mallory
A 3-year-old comes to your office with a fever and a limp. Parents noticed a little discomfort yesterday, but it’s worse today and now the child doesn’t want to bear weight. What is the work up that we need to do? That is the question that the recently finalized Musculoskeletal (MSK) Infection clinical practice guideline attempts to answer.
The first question that the guideline asks us is to determine our level of suspicion for risk of MSK infection. The following historical and exam features should raise suspicion of MSK infection.
Pain, fever, inability to bear weight, gait disturbance/limp, limited use of extremity, immobility of extremity, travel to area with endemic Lyme disease.
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Limited range of motion, swelling, tenderness, warmth at site, fever, erythema, psoas sign.
After that, the guideline helps to split the population into those with high suspicion for bacterial infection and those with low suspicion for bacterial infection. Then it suggests evaluation and treatment.
For those with fever, and refusal to bear weight, focal pain, limited use and/or mobility, laboratory and imaging evaluation is recommended. Plain films of the affected region should be performed and then blood drawn. The results of these tests help to determine the actual risk of bacterial infection.
If the child has an elevated WBC (>12,000), CRP>2 or ESR>40 then they are considered at high risk for bacterial infection. If they do not meet these any of these criteria, then the child is thought to be a low risk for bacterial infection and a trial of nonsteroidal anti-inflammatory medication is recommended. This can be achieved with ibuprofen in the outpatient setting, or may be done with a dose of Toradol in the ED. If the child improves (becomes afebrile and is able to ambulate) and you can arrange outpatient follow up, then they may be safely discharged to home for follow up in the next 24-48 hours.
If any of the child’s labs trigger the high-risk designation, then a cascade of other considerations is made to determine if the child should undergo joint aspiration in the ED or if they will be admitted for imaging as an inpatient.
Because the child may undergo aspiration or sedation in short order after arriving in the ED, it is important for all children referred to the ED for concern of MSK infection to be made NPO as soon as the possibility that they may need to go to the ED is apparent.