Diagnosis and discussion:
The ultrasound image on the previous page shows a deep tissue abscess in the patient’s thigh. On ultrasound, an abscess within the tissue of the thigh appears as a dark or hypoechoic structure. Areas of mixed echogenicity may be seen inside the abscess cavity, representing the consistency of pus. Surgical incision and drainage will be needed to optimally treat the infection.
The middle image at left details the loss of normal tissue planes due to generalized cellulitis of the skin. The bottom image demonstrates advanced cellulitis with islands of edema. Over time, this edema can coalesce to form an abscess.
Interestingly, studies have shown that clinical examination is not an extremely sensitive means of differentiating cellulitis from abscess. Ultrasonography, on the other hand, allows physicians to determine whether an infected area is an abscess pocket that will need drainage or simply cellulitis that is better treated with antibiotics and elevation. It can also be used to determine the depth of an abscess, as well as to clearly visualize the important anatomical structures in close proximity to the area needing incision. Arteries, veins, and nerves can be seen with ultrasound, permitting an approach that avoids these structures.
This patient underwent procedural sedation with midazolam and fentanyl and a large amount of pus was removed from her thigh during the incision and drainage procedure. |
