Hemorrhagic and necrotising acute pancreatitis with septic abscess

Clinical History

A 57-year-old man with a history of alcoholism and acute pancreatitis (AP) presented to the hospital with persistent severe epigastric pain radiating widely in the abdomen.

Imaging Findings

MRI showed a diffuse enlargement of the pancreas with widespread edema of the glandular parenchyma and areas of necrosis. Areas with high signal intensity on T1w were considered as indicative of hemorrhage. There was increased peripancreatic fluid. Pararenal fluid collections, subdiaphragmatic and perihepatic effusions were als noticed. The dilated gall-bladder contained sludge and sand.
A CT examination 10 days later demonstrated again the enlargement of the pancreatic parenchyma with edema and areas of necrosis. In addition to the pararenal and perihepatic fluid, CT visualized a fluid collection between the rectum and the bladder. CT also showed an extensive amount of gas withihn the areas of tissue necrosis in the anterior pararenal space.

Discussion

Acute pancreatitis (AP) is related to an inflammatory etiology secondary to organ autodigestion from release of pancreatic enzymes [4]. It is burdened with numerous potential complications and associated with significant mortality. The disease assumes a malignant course in 20-30% of cases, with the development of massive necrosis of the pancreatic and peripancreatic tissues, infection, hemorrhage, and endogenous intoxication with lesions of the lungs, kidneys, heart and liver [4]. Necrosis of the glandular parenchyma is an important predictor of prognosis [3]. The possible outcomes of pancreatic necrosis are resolution, pseudocyst, or abscess.
In uncomplicated cases of AP imaging is not typically acquired. In patients suspected of having complicated AP, CT is usually the method of choice. MR-cholangiopancreatography with fluid-sensitive sequences and fat suppression can depict early signs of pancreatitis[ 2]. MRI has the added value of demonstrating possible choledocholithiasis, distention, disruption or leakage of the pancreatic duct, and visualizing a possible communication of a pseudocyst with the pancreatic duct.
At the admission of the patient in our hospital we performed first an MR examination, because we had at our disposal the results of a CT-scan executed 7 days earlier in another center, by which AP had already been diagnosed. Moreover, MRI better demonstrates local hemorrhage in or around the pancreas and helps to assess the internal consistency and drainability of fluid collections [1].
The imaging findings of the subsequent CT study 10 days later were found to correspond to severe AP. In severe AP two CT features are significantly correlated with mortality: the number of the parts of the pancreas (head-corpus-tail) exhibting areas of necrosis and the presence of distant fluid collections (posterior pararenal space and/or paracolic gutter). According to the literature, mortality is 42% and 20% if two/all three parts or none/one part of the pancreas exhibit necrosis, respectively. Mortality is 46% and 22% if distant fluid collections are present or absent, respectively [5]. These two morphologic features on CT are considered to be helpful to predict the prognosis in patients suffering from severe AP [5].
Patients with symptomatic sterile or infected pancreatic necrosis are managed traditionally by open surgical debridement and removal of necrotic tissue. In our patient surgery confirmed the presence of a septic abscess and the bacterial culture yielded the presence of Klebsiella pneumoniae and Acinetobacter baumannii.
During the last decade, however, reports of endoscopic pancreatic necrosectomy as an alternative minimally-invasive approach, have demonstrated high success rates and low mortality [6].
In critically ill patients with organized pancreatic necrosis we perform endoscopic US drainage. The preliminary good results encourage us to extend the use of this technique.

Differential Diagnosis List

Final Diagnosis

Hemorrhagic and necrotising acute pancreatitis with septic abscess

URL:	https://www.eurorad.org/case/9305
DOI:	10.1594/EURORAD/CASE.9305
ISSN:	1563-4086