Emergency Bedside Ultrasound for Pediatric Soft Tissue Infections

Skin and soft tissue infections, particularly abscesses caused by community-acquired
methicillin resistant Staphylococcus aureus (CA-MRSA) are a growing public health problem.
The treatment of a skin abscess usually requires incision and drainage or needle aspiration.
In addition to providing definitive therapy, appropriate drainage can allow for organism
identification and antibiotic susceptibility testing should antibiotics be utilized. A skin
cellulitis, which is treated with systemic antibiotics and supportive care alone, may be
hard to distinguish from an abscess, as both have similar clinical features. Therefore, as
the presence or absence of purulent material may be difficult to determine, children may
undergo an unnecessary drainage procedure. If drainage is avoided, the patient may require
a subsequent ED visit if the diagnosis is missed on initial examination. This can lead to
worsened clinical outcome, an extra financial burden for the family, and added emotional
distress for the patient.

Emergency ultrasound (EUS), which has been used since the mid-1980s is being used in adults
to detect fluid collections such as soft tissue abscesses. Studies in adult patients have
shown that EUS adds useful information to the history and physical examination and may even
alter physicians' clinical impressions and management of patients. Currently, it is not
known whether children represent a different population for EUS than adults and how EUS
would perform in the pediatric outpatient setting. With improved diagnosis of soft tissue
infections, better epidemiologic data about organism prevalence, improved and more prompt
treatment, and more appropriate use of antibiotic therapy can be done.

To date, no study exists evaluating its utility specifically for the evaluation of soft
tissue infections. The primary goal of this study is to evaluate the test characteristics of
EUS in pediatric patients presenting with evidence of soft tissue infection. Secondary aims
include evaluating the prevalence of soft tissue abscesses and MRSA infections specifically
in the study population.

Inclusion Criteria:

- Evidence of at least one of the following: skin elevation, induration, tenderness,
fluctuance, or history of purulent drainage from the lesion

Exclusion Criteria:

- Suspected paronychia or felon

- Lesion involving the face, perirectal, or vaginal area

- Surgical wound infection

- Underlying immunodeficiency

- Non-soft tissue infectious mass (e.g. lymphadenitis)

- Suspected non-infectious mass (e.g. hernia, lymph node)