Jeremy van de Rijn, MS4

The Article: Levine, et al. “The use of point of care ultrasound in the evaluation of pediatric soft tissue neck masses.” American Journal of Emergency Medicine 2019; 37: 1466-69.

Background: Pediatric neck masses are a fairly common entity in the emergency department. Most of the causes are infectious and inflammatory, but the differential can also include congenital and malignant causes. Ultrasound evaluation in the emergency room is an emerging, non-invasive, imaging modality that can aid in diagnosis and clinical decision making. Several prospective studies have evaluated how POCUS can improve medical decision making in pediatric soft tissue infections, but none of these have studied pediatric neck masses. The neck is of particular interest because most of the pathology seen is superficial and amenable to this modality. This study was created to compare the evaluation of pediatric neck masses with ultrasound to radiologic imaging, the gold standard.

The Study: The study was a prospective pilot study involving a convenience sample of patients 1 month to 18 years of age presenting to a tertiary pediatric ED with a soft tissue neck mass.

Inclusion Criteria: patients ages 1 month to 18 years old with soft tissue neck mass.

Exclusion Criteria: excluded if these patients had an unstable airway, had any hemodynamic instability, or failed antibiotic therapy.

There were 2 primary investigators in the study doing the POCUS, both peds EM and ultrasound fellowship trained. Once the patient with neck mass arrived, they were evaluated by a managing ED provider. This provider did a history and physical exam and decided if they wanted to get lab work or radiologic imaging after the POCUS. The study investigator would then come in and perform the POCUS using a standardized protocol. Protocol included: axial and sagittal planes of the mass. Specific sonographic details were overall appearance of the mass, singular lymph nodes vs. conglomeration of lymph nodes, normal lymph node architecture (which is when long axis > short axis and there is doppler flow). They also evaluated if the mass was more consistent with a phlegmon, abscess, cyst, or of unclear etiology (there is specific criteria in the paper for this differentiation).

Then, the study investigator was to make a diagnosis based on the results of the POCUS, which was relayed to the managing provider. If radiologic imaging was ordered by the managing provider, the radiologists were blinded to the results of the POCUS. Of those who received POCUS but not RI, they received a follow up call in 7-10 days after ED discharge.

Primary Endpoint: to assess agreement between POCUS diagnosis and radiologic imaging diagnosis.

Statistical Analysis: Cohen’s kappa statistic performed to determine agreement between diagnosis based on POCUS vs radiologic imaging.

Results: 45 patients were enrolled. 27 patients received both POCUS and radiologic imaging of their soft tissue neck masses. 22 received radiologic ultrasound, 3 received CT, and 2 received both radiologic ultrasound and CT. 21 (78%) of the patients demonstrated agreement in diagnosis between POCUS and radiologic imaging. Lymphadenitis and abscesses as diagnoses had the highest level of agreement. In 18 of the 27 patients receiving both POCUS and RI, the study investigator was not aware of any history or physical exam findings prior to POCUS. Of the other 9, the managing provider and study investigator were the same person. Subgroup analysis showed no difference in results between these groups.

Of the 18 patients who received POCUS but not radiologic imaging, on day 7 phone call, 16 were compliant with treatment plan and were clinically improving, 1 returned to ED with abscess misdiagnosed as lymphadenitis, and 1 was lost to follow up.

The Takeaway: This paper showed that the diagnosis is often unchanged (78% of the time) when evaluating a soft tissue neck mass with POCUS vs radiologic imaging. In the cases where no radiologic imaging was obtained, follow-up with initial diagnosis and management plan was generally good. These results suggest that POCUS is a useful tool in evaluating soft tissue neck masses due to its diagnostic accuracy, ease of use, conservation of resources, and non-invasive modality without radiation.