It is a rare but highly lethal local complication of a severe episode of pancreatitis. It manifests late and is characterized by high fever, increasing abdominal pain, leukocytosis, and a palpable mass in 1/3 of patients.
Diagnostic imaging methods can detect the lesion, but the only way to determine the presence of infection is by analyzing the discharge obtained by percutaneous aspiration or surgery .
The germs involved are those belonging to the intestinal flora , especially coliforms. The only effective treatment is drainage, be it percutaneous or surgical, accompanied by good antibiotic coverage.
Form of presentation
Pancreatic abscess is usually a very serious local complication that occurs after a severe episode of pancreatitis . In particular, patients with postoperative pancreatitis are at high risk of developing pancreatic abscesses.
The incidence of abscess formation ranges from 3 – 22%, depending on the patient population. Most patients present 2-4 weeks after the onset of symptoms, deterioration in general condition, high fever, pain, palpable mass, and leukocytosis. Late death is generally the result of sepsis. Eighty-five percent of patients present a fever greater than 38 ° C, 80% suffer from increasing pain, up to 33% present a palpable lesion, and in almost 100% of cases a leukocytosis greater than 10,000 cells / mm3 is observed. Patients appear toxic, with tachycardia, chills, and hypotension. However, these findings can also be seen in an episode of severe pancreatitis without infection, therefore, they are not always reliable and it is necessary to resort to other methods to arrive at an accurate diagnosis. Abscesses not only,They are located in the pancreatic or peripancreatic area, but they can develop anywhere in the abdominal cavity and even in the pelvis, so when the diagnosis is suspicious, imaging studies of the abdomen and pelvic cavity should be performed.
Diagnosis
The presence of a pancreatic abscess left to its free evolution rapidly progresses to sepsis with a high mortality rate of around 100%, hence a precise and timely diagnosis, at the beginning of the picture, is of special importance.
Hematological tests are not of great diagnostic help because they are very nonspecific. In practically all cases, a leukocytosis greater than 10,000 cells / mm3 with a marked left deviation is observed. Blood cultures are not always positive, and if they are, they are not specific to the site of infection. Serum amylase levels often do not increase after the initial decline, they tend to maintain and even continue to decrease. Other biochemical tests such as serum ribonuclease, phospholipase A2, C-reactive protein, Alpha1 antitrypsin or Alpha2 macroglobulin have not provided more information that decisively contributes to a diagnosis.
Imaging diagnostic methods play a very important role in the diagnosis of this pathology, since they not only detect the lesion, specifying location, size and relationship characteristics with other organs, but also allow direct observation to perform a directed percutaneous aspiration to document the presence of PA infection.
Imaging studies such as Ultrasonography (US), CrQ Computed Tomography and Magnetic Resonance Imaging (MRI) are of great diagnostic value due to their notable progress and success rates, however the advantages and disadvantages of each of them are not fully defined. and my studies are still required; comparative tests in order to evaluate which of these methods is more effective.
Computed tomography is the diagnostic procedure that has been used the most and continues to be used, having managed to improve the morbidity and mortality of patients with pancreatic abscess by allowing an early diagnosis and by showing anatomical details that optimize surgical treatment.
CT shows the abscess as a low-density fluid collection and may reveal pancreatic edema, fluid within the pancreas, or gas bubbles in the pancreatic bed. The presence of gas in the pancreatic and / or peripancreatic region in a patient with acute necrotizing pancreatitis should be considered as evidence of abscess until proven otherwise.
CT with a rapid bolus of contrast injection is widely accepted as it provides information considering the extent of necrotic tissue that appears as hypoperfused areas. It is important to bear in mind the presence of sub-acute necrotic collections, in these cases magnetic resonance imaging surpasses CT and US as it has a sensitivity and specificity that borders 100% (10). However, none of these procedures helps us to differentiate an abscess from an uninfected liquid collection or an area of old bleeding, so if an abscess is suspected, a percutaneous fine needle aspiration should be performed under ultrasound or tomographic control. and subjecting said sample to a smear, Gram and cultures in aerobic and anaerobic media, which will allow an early diagnosis.
Pseudomonas 8-10% of cases. Enterococci and other streptococcal species are isolated in the same percentage . The isolation of anaerobes is infrequent and the incidence of negative cultures is relatively low (2-10%). On the other hand, there is a high incidence of polymicrobial infection (30-55%), which suggests that contaminated bile, rather than the hematogenous route, is what causes bacterial seeding in the pancreas.
Other studies indicate that E.coli is present in 51% of cases, enterococci in 19%, Proteus, Klebsiella and Pseudomonas species in 10% for each of them, staphylococci in 18%, Streptococcus fecalis in 7% and Bacteroides species in 6%. It is thought that these bacteria would come from the colon, filtering through the intestinal wall, which is more permeable due to the adjacent inflammatory process, followed by local spread through lymphatics (and not blood vessels) to necrotic tissues. The triggering mechanism for this bacterial migration is unknown.
Causes
Pancreatic abscesses develop in patients with infected pancreatic pseudocysts.
Symptoms
- Abdominal mass
- Abdominal pain
- Shaking chills
- Fever
- Inability to eat
- Nausea and vomiting
Signs and tests
Patients with pancreatic abscesses have generally had pancreatitis. However, it takes 7 or more days for the complication to occur. Symptoms generally include:
- Abdominal pain
- Fever
Signs of an abscess can be seen in:
- Computerized tomography
- MRI of the abdomen
- Ultrasound
Treatment
Since most deaths in the late phase of acute pancreatitis are due to abscess formation, diagnosis and treatment must be aggressive. Once the abscess diagnosis has been specified, the treatment, in addition to broad antibiotic coverage and effectively treating the complications associated with bleeding , kidney and liver failure , etc., should be aimed at draining the abscess, either through external drainage or a surgical debridement with removal of purulent material and construction of an adequate drainage.
There are several studies that show the benefits and indications of each of these methods. A group of authors agree that the most appropriate treatment is surgical debridement with a good posterior drainage system and that external drainage would be reserved for patients in critical condition or prior to definitive surgical treatment (12,14,15). However, at present, most authors propose as initial treatment for pancreatic abscess, the placement of a percutaneous drainage catheter, which is effective in around 50% (4). In the rest of the patients, an adequate surgical debridement with early reoperation will be performed if there is a septic state.
A study by Freeny and Col (19) showed success with percutaneous drainage in 15 of 23 patients (65%), the rest required surgery. Van Sonnenberg and Col, reported success in 51 of 59 patients (86%) with a mortality within 30 days of completing the drain of 8%. They recommend that in order to be successful with this method, a good selection of patients is important, the use of catheters of adequate size and number and location, and a careful follow-up with an adequate manipulation of the catheters.
Mithofer and Col performed drainage in 39 patients, obtaining success in 31% of cases in the first attempt, the; The rest required surgery, presenting a residual abscess in 14 patients who were successfully treated with percutaneous drainage. However, despite these and others; Similar reports, there are studies such as those by Snape and Schoelf (2,20) that report that although there are very promising results in the percutaneous drainage of pseudocysts, this is not applicable to an abscess whose content is denser and frequently causes obstruction of the the drainage catheters and, on the other hand, the abscess may be septate, not allowing adequate drainage.
They state that in most cases a timely and well-indicated surgical intervention is superior to any percutaneous drainage and that this should only be performed when the surgery is limited by some circumstance. Internal drainage is not indicated in the treatment of abscess, it should only be attempted in the case of uncomplicated pancreatic pseudocyst.
The prophylactic value of antibiotics is uncertain, in 2 recent studies of imipenem , ofloxacin and metronidazole , high levels of these drugs were observed in the blood of the pancreatic tissue, which were reflected in an apparent clinical improvement and in a not very clear improvement of the survival averages, however further studies will be required to determine the real role of prophylactic antibiotic therapy.
Expectations (prognosis)
How well a person does depends on the severity of the infection . The death rate for pancreatic abscesses that have not been drained is very high.
Complications
- Multiple abscesses
- Sepsis
Prevention
Proper drainage of a pancreatic pseudocyst can help prevent some cases of pancreatic abscess; however, in many cases, this disorder cannot be prevented.