Scott Herskovitz MD, Inova Children’s Hospital

The Case
A 3yo female presents to the ED with right hip pain of two weeks’ duration, then re-presents 2 days later with systemic symptoms in addition to her hip pain.

Here’s How You Answered Our Questions:

Discussion:
One interesting point in our discussion today was on the utility of an ultrasound in this case. While many respondents said that an ultrasound of the hips would be the most clinically useful test, a few argued that it was unlikely to yield useful information. It seemed as though everyone who wanted an ultrasound was planning to use it to rule out a septic hip, but this was an unlikely diagnosis in this case as the hip pain was bilateral. Shireen Atabaki, our teaching attending this week, explained that a septic hip was one of the few diagnoses that needed to be ruled out emergently for this case, and that even though the diagnosis was unlikely, a negative ultrasound would remove it from the differential completely, allowing the patient to be admitted for further workup. Jo Cohen, our ultrasound expert, added that a negative ultrasound would be useful for ruling out a septic hip, as it is sensitive for detecting a hip effusion, but that a positive ultrasound could be the result of a number of other diagnoses (e.g. hemarthrosis, myositis).

The rationale for obtaining an orthopedics consult was far less exciting: nearly everyone agreed that they would likely have little to add at this point, but would need to be involved prior to admission due to institutional guidelines.

Thanks to Dave, Maybelle, and Shireen for clearly outlining their thinking and differential diagnoses.

Denouement:
The patient was admitted to the hospitalist service for an MRI of the hips to evaluate for osteomyelitis. The results did not demonstrate signs of osteomyelitis. Below is a single cut of the MRI.

This demonstrated diffuse abnormal bone marrow enhancement of the R>L pelvis and R femur with possible etiologies including leukemia/lymphoma, with less likely etiologies including multi-focal osteomyelitis, Langerhans histiocytosis or sickle-cell. A bone marrow biopsy was performed which showed B-cell ALL.

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