COTW 3/27: 82-year-old woman presents after an MVC

An 82-year-old woman with an unknown past medical history presents to the ED after striking multiple cars in a parking lot. The patient is extremely hard-of-hearing and presents without her hearing aids, so initial history is limited. Per EMS, glucose is >600. Vitals are normal.

The patient initially presented with history concerning for trauma so a trauma primary survey was performed. Upon exposure, a right lower extremity wound was revealed.

Right lower extremity wound

The patient reports that the wound has been worsening over the past several days. Her mentation is altered, and this appears to have been a contributing factor for her motor vehicle collision. An ultrasound of the tissue surrounding the wound was performed:

The unaffected left limb above shows normal subcutaneous tissue and musculature while the right limb above shows a hazy subcutaneous layer with a hyperechoic white fascial plane and areas of posterior shadowing that obscure the deeper tissues. This shadowing is sometimes referred to as “dirty” shadowing because it does not completely obscure structures far-field to it like other hyperechoic structures such as bone or gallstones. This shadowing is caused by gas in the subcutaneous tissue.

The appearance of the patient’s wound and the presence of subcutaneous gas raised significant concern for a necrotizing soft tissue infection (NSTI). Orthopedics was consulted and they evaluated the patient at bedside. While surgical subspecialties often request x-rays or CT scans of the affected areas prior to surgery, due to the patient’s concerning physical exam and presence of gas on the ultrasound, the patient was taken to the OR emergently without imaging other than the bedside ultrasound. The patient initially went to the OR for irrigation and debridement but required an above-the-knee amputation later in her hospitalization for better source control. She was discharged from the hospital in stable condition one week later.

If a necrotizing soft tissue infection is suspected, surgical consultation should be obtained immediately and should not be delayed by imaging or awaiting laboratory values. Bedside ultrasound can increase an Emergency Physician’s suspicion for NSTI and subcutaneous gas in the setting of infection is highly specific but it is an insensitive finding and its absence should not delay definitive management if clinical suspicion is high. The mortality for NSTI is ~20% and delay in diagnosis and definitive management can be deadly.