Differentials
Loculated intra-abdominal hematoma
SIGNS / SYMPTOMS
A loculated hematoma can be very challenging to differentiate from an IAA.
INVESTIGATIONS
Hemoperitoneum is usually accompanied by a drop in hematocrit.
Fluid sampling and culture is usually diagnostic. Measurement of fluid density by CT scan may be helpful.
Pancreatic pseudocyst
SIGNS / SYMPTOMS
Usually accompanied by a recent history of pancreatitis. A challenging part in the workup of a pancreatic pseudocyst is the exclusion of an infection.
INVESTIGATIONS
Air-fluid level on CT scan will help identify an infected pancreatic pseudocyst. Fluid sampling usually confirms the diagnosis.
Absence of debris on CT scan is helpful to exclude an abscess.
Diverticular or appendiceal phlegmon
SIGNS / SYMPTOMS
A phlegmon is an inflammatory mass with some associated exudates, and therefore not an actual abscess. Phlegmon may become an abscess if not treated. Both may have the same clinical picture.
INVESTIGATIONS
Sometimes very hard to differentiate from an abscess. CT scan may be helpful.
Intra-abdominal serum or lymph collection
SIGNS / SYMPTOMS
Other fluids that collect in the peritoneal cavity are lymph or serum (seroma). Sometimes very hard to differentiate from an abscess.
INVESTIGATIONS
CT scan may be helpful to evaluate the character of the fluid in the collection. Fluid sampling and culture is usually diagnostic.
Normal postoperative changes or postoperative fluid collections
SIGNS / SYMPTOMS
Differentiation of an early IAA from normal postoperative changes and fluid collections can be challenging. Most postoperative fluid collections are not infected and resolve spontaneously. However, infected fluid collections are associated with significant morbidity and mortality, and require percutaneous or surgical drainage.
INVESTIGATIONS
Imaging features that indicate infection include the presence of gas where none was seen previously, the development of a discrete abscess wall, and rim-shaped enhancement in the abscess wall, with either single- or double-ring signs.
Use of this content is subject to our disclaimer