Young Senegalese men with acute abdomen and located collections

A 26-year-old male Senegalese patient consulted primary healthcare for epigastric pain, vomiting and diarrhoea, diagnosed with acute gastroenteritis. A week later, he came to the emergency department with bad general condition, febricula, leukocytosis of 20*10⁹ cells/mL and coagulopathy (INR=1.35, Prothrombin Activity=64%). An abdominopelvic enhanced computed tomography (APE-CT) was performed.

The APE-CT in the axial plane, from cranial to caudal directions (figures 1, 2 and 3), sagittal oblique planes (figures 4 and 5) and coronal planes (figures 6 and 7) highlighted several large communicating collections distending the lesser sac (LS), some of them with an air-fluid level. The pancreatic gland was normal. There were no gallstones. The findings in the inframesocolic abdominal cavity were unremarkable.

A sagittal oblique (video 1- figure 15) and coronal plane (video 2- figure 16) movies have been added.

The case illustrates an unusual expression (abscesses in LS) of an uncommon presentation (perforation) of a common disease (peptic disease). 

Peptic ulceration (PU) represents the common end-point of the balance disruption between gastric acid production and protective mucosa mechanisms. Helicobacter pylori is the common causative agent (positive in our patient). Since the development of anti-acid medications, it is rare in western populations, being more frequent in males (3:1) and in the older population. Upper gastrointestinal haemorrhage is the most common complication (14%). Perforation affects up to 6%, debuting as generalized acute abdominal pain, peritonism and shock. Gastric outlet obstruction is only seen in 1%, present in our case [1,2,3].

CT is the choice modality facing a hollow-viscera perforation suspicion, but usually, this suspicion is unclear. Hollow-viscera perforation commonly shows free pneumoperitoneum and abundant fluid whether proximal perforations. A discontinuity in the stomach or duodenal wall is sometimes visible at CT [1,2,3].

Our key findings were air-fluid collections involving exclusively the LS (figures 8-10). An air-fluid level collection implies an abscess or communication with surrounding hollow-viscera.

The abscesses, completely distending the LS in our patient, allow us to review the LS anatomy (figures 11-14). The LS is a unique peritoneal space that extends behind the stomach and anterior to the pancreas and the left kidney. It is collapsed at normal times.  Their superior recess surrounds the caudate lobe and communicates with the peritoneal cavity through the foramen of Winslow (FW). The lesser omentum (LO) covers the LS anteriorly and delimitates the FW (figures 11-14) [4, 5, 6].

A PU perforation stating as an abscess in LS is rare, but it is the more frequent cause of an LS abscess. Perforation of the posterior wall of the intraabdominal oesophagus also extends directly into the LS. The LS is not usually contaminated in generalized peritonitis [7].

PU perforation is a surgical emergency. In our patient, the surgery highlighted a PU perforation in the duodenal bulb wall, filtering its content through the FW into the LS, leading to a purulent abscess. Streptococcus constellatus grew-up in the cultures. The patient received intravenous Meropenem and Vancomycin at Intensive Care Unit. Radiological drainage was required for two collections developed later. The patient fully recovered.

The radiological involvement is essential for reaching the origin of an acute abdomen. Radiological drainage enables a minimally-invasive management.

Teaching point: abscesses exclusively placed in the LS commonly imply a posterior gastric or duodenal bulb perforation, or pancreatitis.