Pancreatic abscess: an unresolved surgical problem

Outcome of severe acute pancreatitis

BACKGROUND

The treatment of severe acute pancreatitis has been evolving from routine operative management to nonoperative care for patients without evidence of pancreatic infection.

METHODS

Retrospective chart review of patients with severe acute pancreatitis at a single institution during a 9-year period.

RESULTS

Sixty consecutive patients had severe pancreatitis. Forty-two had pancreatic necrosis on computed axial tomography (13 infected and 29 sterile). Patients with infected necrosis and 8 with sterile necrosis had operative debridement; the remaining patients were managed without operation (n = 39). The overall mortality was 15%. Mortality was directly related to the Acute Physiology and Chronic Health Examination II and Marshall organ failure scores (P <0.001). Patients who died had a greater incidence of nosocomial infection.

CONCLUSIONS

Patients with infected pancreatic necrosis require early operative debridement, whereas those with sterile necrosis or severe pancreatitis without necrosis can usually be managed safely without surgery.

Infectious complications of acute pancreatitis

Disease severity in patients with acute pancreatitis varies from mild disease with minimal morbidity, to severe disease in which a whole spectrum of local and systemic complications may occur. Infectious complications frequently arise, and especially infection of pancreatic necrosis is an important risk factor for mortality. Several strategies have been devised to reduce this risk, and the use of prophylactic therapy, e.g. selective digestive decontamination, can be considered in patients with documented necrosis fo the pancreas. Pancreatic abscesses and infected pseudocysts arise later in the course of disease, and should be considered as separate entities, due to differences in therapy and outcome of these patients. When infection occurs, source control using either surgical or percutaneous drainage techniques, is essential to avoid systemic complications.

Interventional and surgical treatment of pancreatic abscess

Pancreatic abscess is one of the infectious complications of acute pancreatitis. It is a collection principally containing pus, but it may also contain variable amounts of semisolid necrotic debris. Most of these abscesses evolve from the progressive liquefaction of necrotic pancreatic and peripancreatic tissues, but some arise from infection of peripancreatic fluid or collections elsewhere in the peritoneal cavity. Included also are abscesses found after surgical débridement and drainage of pancreatic necrosis. Although open surgical treatment of infected necrosis is the established treatment of choice, percutaneous drainage of abscesses is successful in some circumstances. We used percutaneous catheter drainage in 39 patients during 1987-1995. Only 9 of 29 (31%) attempts at primary therapy were successful; 2 patients died, and 18 required subsequent surgical drainage. On the other hand, 14 of 14 patients with recurrent or residual abscesses after surgical drainage were successfully drained percutaneously. Percutaneous catheter drainage of pancreatic abscesses may be useful for initial stabilization of septic patients, drainage of further abscesses after surgical intervention (especially when access for reoperation will be difficult), associated abscesses remote from the pancreas, and selected unilocular collections at a sufficient interval after necrotizing pancreatitis to have allowed essentially complete liquefaction.

Pancreatic infection complicating acute pancreatitis

Pancreatic infection is the leading cause of death from acute pancreatitis. Patients with severe necrotizing pancreatitis are most at risk. Early computed tomography and percutaneous fine-needle aspiration microbiology of areas of pancreatic necrosis enable early diagnosis. Pancreatic infection should be treated surgically, although sterile necrosis may be managed conservatively. The role of antimicrobial drugs is uncertain.

Acute necrotizing pancreatitis: management by planned, staged pancreatic necrosectomy/debridement and delayed primary wound closure over drains

We reviewed our recent experience with management of 23 consecutive patients with acute necrotizing pancreatitis. All patients had documented necrotizing pancreatitis with parenchymal or peripancreatic necrosis. Our method of treatment has evolved from our previous approach of controlled open lesser sac drainage (marsupialization) to staged necrosectomy/debridement with delayed primary closure over drains. With this latter approach, hospital mortality was 4 of 23 patients (17 per cent), but significant morbidity still occurred in 12 of 23 patients (52 per cent). However, recurrent intra-abdominal abscess before discharge occurred in only one patient. We believe that this operative approach toward the severely ill patient with acute necrotizing pancreatitis who requires operative intervention will minimize the occurrence of intra-abdominal sepsis.

Surgical strategies in the treatment of pancreatic necrosis and infection

Controversy still surrounds the management of necrotic and septic complications of acute pancreatitis. A review of the literature of the past decade dealing with the surgical treatment of pancreatic necrosis, pancreatic abscess and infected pancreatic necrosis has been undertaken. Three main patterns of management could be identified: (1) 'conventional treatment', consisting of pancreatic resection or necrosectomy with drainage; (2) 'local lavage', consisting of necrosectomy followed by regional lavage; and (3) 'open management', with resection or necrosectomy followed by planned multiple re-explorations. From this review it appears that local lavage and open management offer better survival prospects than conventional treatment. Open abdomen techniques, however, are associated with an increased risk of complications, such as colonic necrosis, intestinal fistula, and intra-abdominal bleeding. Excellent results can be achieved in specialized centres with any of the three methods, provided adequate debridement and prompt reoperations are undertaken if the septic state persists.

Pancreatic abscess and other pus-harboring collections related to pancreatitis: a review of 108 cases

This is a report on 108 cases collected from 1970 to 1987, in the same department, of surgically-detected pancreatic abscesses or pus-harboring collections. The purulent areas were either of a spreading pattern or represented a clearly localized mass. To the spreading pattern belong 47 cases of necrotizing pancreatitis, without discontinuity in the clinical course from the early toxic to the late septic phase, 4 cases of acute pancreatitis, initially in remission and later complicated by septic collections, and 4 cases which developed after an acute attack of chronic pancreatitis. The abscess pattern was made up of 19 each of pseudocysts and predisposing pancreatitis, 10 cases of chronic pancreatitis, and only 5 necrotizing "nonstop" pancreatitis. The surgical treatment in all cases consisted of multiple drainages and postoperative irrigation. We exclude 3 cases of associated open packing. The etiological, clinical, and biochemical features of each group of patients are reported and discussed. Computed tomography availability seems to be the most important improvement reported as regards diagnosis and surgical tactics. The overall mortality rate was 15.7% with a significant difference between the 2 patterns (23.6% for the spreading pattern versus 7.5% for the abscess pattern). On the basis of this experience, it is possible to establish a relationship between the gross appearance of the collection and the underlying pancreatic disease with differences in terms of prognosis, morbidity, and mortality. Finally, a simple nomenclature can be chosen which is capable of distinguishing between the diverse pancreatic purulent collections. While the presence of pus may characterize the course of severe acute pancreatitis in many cases, the low incidence of "true" pancreatic abscess is emphasized.

Surgical management of acute pancreatitis

This review examines the lack of improvement in terms of mortality and outcome in patients with acute pancreatitis. Energetic fluid replacement is the only treatment of proven value. There is a strong case for identification of patients with severe disease who may benefit from early operative intervention. Eradication of gallstones may prevent further attacks in patients with gallstone pancreatitis. The benefits of pancreatic resection and necrosectomy still require full evaluation.

Intestinal fistula complicating necrotizing pancreatitis

Eight of 17 patients with necrotizing pancreatitis (47 percent) developed 12 intestinal fistulas. Pancreatitis occurred most often secondary to alcohol abuse, and fistula complicated controlled open drainage of the lesser sac more often than sump or Penrose drainage of the lesser sac. Fistulas appeared more often in patients with two or more drainage operations than in those with a single drainage procedure. Most duodenal fistulas closed with nonoperative therapy, whereas jejunal and colonic fistulas required operative closure. Operative techniques included both simple suture closure and resection with anastomosis. Five patients (29 percent) died. Thus, although frequent debridement and controlled open drainage may reduce the mortality rate of necrotizing pancreatitis, it appears to increase the likelihood of intestinal fistulas, which may require operative treatment.

Debridement and closed cavity irrigation for the treatment of pancreatic necrosis

Pancreatic and peripancreatic debridement combined with a closed cavity system of drainage was used to manage necrotic sequelae of severe acute pancreatitis in 14 patients. Intravenous contrast-enhanced computed tomography, or latterly incremental dynamic computed tomographic angiography, accurately detected and localized necrotic tissue. Operation was delayed where possible to permit demarcation of the necrotic area and the development of a 'capsule' of inflammatory tissue. A retrocolic route of access to the necrotic area was used in nine cases, and purpose-made silicone elastomer tubes with an outside diameter of 20 mm were positioned so that drainage was assisted by gravity when the patient was supine. The cavity was irrigated with saline (initially 2 litres daily), and in the last seven patients Trasylol was included in the irrigation fluid (5 x 10(6) kallidinogenase inactivator (KI) units/litre) for the first postoperative week. Three elderly patients died (mean age 72 years) but all patients aged less than 68 years survived. Planned reoperation was carried out in two patients, but further reoperations were not required in the remaining 11. Drainage tubes were removed when contrast studies showed the cavity to be small and superficial; the median duration of drainage was 28 days. Although sinograms demonstrated fistulae between cavity and small bowel (n = 4) or small bowel and colon (n = 2), no clinical problems resulted and all closed spontaneously. Closed drainage may be as effective as techniques of marsupialization, but avoids the need for frequent relaparotomy.

Value of contrast-enhanced computerized tomography in the early diagnosis and prognosis of acute pancreatitis. A prospective study of 202 patients

Two hundred two patients admitted with the clinical suspicion of acute pancreatitis underwent computerized tomography scanning within 36 hours of admission. The diagnostic value of the computerized tomography findings was excellent, with a sensitivity of 92 percent and a specificity of 100 percent. One hundred seventy-six patients with acute pancreatitis defined according to the overall clinical course were included in the prognostic study. The pancreatitis was fatal in 21 patients, severe in 47 patients, and mild in 108 patients. The computerized tomography findings were classified into the following three groups on the basis of the extent of phlegmonous extrapancreatic spread: Group I, no phlegmonous extrapancreatic spread (100 patients, none died); Group II, phlegmonous extrapancreatic spread in one or two areas (28 patients, mortality rate 4 percent); and Group III, phlegmonous extrapancreatic spread in three or more areas (48 patients, mortality rate 42 percent) (p less than 0.0001). The following three scores from prognostic clinical and laboratory data were also obtained: Score 1, zero or one positive sign (82 patients, none died); Score 2, two to four positive signs (54 patients, mortality rate 13 percent); Score 3, five or more positive signs (40 patients, mortality rate 35 percent) (p less than 0.001). The combination of computerized tomography findings and prognostic signs had the best predictive value. Patients in Group III, Score 3 (24 patients) or Group III, Score 2 (19 patients) had mortality rates of 58 percent and 32 percent, respectively, and complications developed in all of the survivors. In addition, all except two acute pancreatitis patients in whom pancreatic abscess developed were found in Group III (p less than 0.0001). Furthermore, for Group III patients, the prediction of death associated with abscesses was enhanced by the number of prognostic signs. The mortality rate increased from 17 percent for Score 2 patients to 81 percent for Score 3 patients (p = 0.0078). As a result of this study, we recommend early computerized tomography for all Score 2 and Score 3 patients, since it allows prompt recognition of patients at high risk for systemic and local complications. Adequate therapy can then be directed to the group of patients to whom it is best suited. Serial computerized tomographies should be reserved for those patients presenting with phlegmonous extrapancreatic spread.

Early diagnosis of pancreatic infection by computed tomography-guided aspiration

We performed 92 computed tomography-guided percutaneous needle aspirations of pancreatic inflammatory masses in 60 patients suspected of harboring pancreatic infection. Thirty-six patients (60%) were found by Gram stain and culture to have a total of 41 separate episodes of pancreatic infection. Among 42 aspirates judged to be infected by computed tomography-guided aspiration, all but one were confirmed by surgery or indwelling catheter drainage. Among 50 aspirates judged to be sterile, no subsequent evidence of infection was found. All patients tolerated the procedure well and no complications were noted. As a result of this technique, we observed that pancreatic infection occurs earlier than has been previously appreciated (within 14 days of the onset of pancreatitis in 20 of the 36 patients) and that infection may recur during prolonged bouts of pancreatitis. We conclude that guided aspiration is a safe, accurate method for identifying infection of the pancreas at an early stage.

Pancreatic abscess and infected pancreatic necrosis. Different local septic complications in acute pancreatitis

Local septic complications in acute pancreatitis need to be exactly characterized and defined in order to develop improved concepts for their prevention, early diagnosis, and therapy. While up to now all local septic complications have been termed abscesses, the present study for the first time delineates the morphologic, clinical, and laboratory criteria needed to distinguish between two separate clinical entities: the infected necrosis (IN) and the pancreatic abscess (PA). IN is defined as a diffuse bacterial inflammation of necrotic pancreatic and peripancreatic tissue, but without any significant pus collections. On the other hand, the morphologic substrate of PA is a localized collection of pus surrounded by a more or less distinct capsula. IN becomes clinically evident during the early phase of acute pancreatitis (AP). The patients with IN present both the signs of sepsis and the laboratory findings of AP. Thus in these patients the most fulminant course of AP is observed; 51.8% and 35.7% of them have pulmonary or renal insufficiency, respectively. The mortality of the patients with IN is high and amounts to 32.1%. Pancreatic abscess, on the other hand, does not develop before the fifth week after onset of symptoms and after subsidence of the acute phase of pancreatitis. In these patients laboratory signs of AP-like amylasemia, hypocalcemia, hyperglycemia, and rise of LDH are rarely observed. Corresponding to the lack of pathophysiologic effects of AP per se, pulmonary and renal insufficiencies occur in only 33.3% and 16.7%, respectively, and mortality in these patients is 22.2%. While an abscess may readily be identified by computed tomography, the differentiation between IN and non-IN can be very difficult.(ABSTRACT TRUNCATED AT 250 WORDS)

Factors contributing to fatal outcome after treatment of pancreatic abscess

The authors analyzed 27 patients with pancreatic abscess treated since 1975 at hospitals affiliated with the University of Louisville School of Medicine. Treatment consisted of careful debridement, abscess drainage, and multiple antibiotics in all patients. Overall mortality was 33%; however, only three of 17 patients treated since 1980 have died. Patients who died were more likely to have bacteremia, a residual abscess, multiple organ system failure, and/or polymicrobial growth on culture of the abscess. The proper use of soft suction drains in a dependent position reduced the rate of residual abscess to 19% compared to 67% in patients not treated in this fashion. The results identify factors that are correlates of death in patients with pancreatic abscess and emphasize the importance of prompt diagnosis and proper treatment.

Improved survival in 45 patients with pancreatic abscess

The reported mortality due to pancreatic abscesses after acute pancreatitis has been 30 to 50%, a statistic that has remained unchanged for decades. This is a report of 45 patients treated over 10 years, showing a dramatic improvement in survival during that period. They represent 2.5% of admissions at the Massachusetts General Hospital for acute pancreatitis. The identifiable antecedents included alcohol (38%), gallstones (11%), and surgical trauma (16%), or were unknown in 24%. Computerized tomography (CT) was clearly the best means of specific diagnosis (unequivocal evidence in 74%, suggestive in 21%). Treatment in 44 patients was surgical debridement and catheter drainage, and in one it was resection of the pancreatic head. Multiple abscesses were present at the first operation in 21 patients. Seven had second drainage procedures for additional abscesses. In the first 5 years (1974-1978), 10 of 26 patients died (38%). In the second 5 years (1979-1983), one of 19 died (5%) (p less than 0.01). Postoperative complications (84%) included wound hemorrhage (9 of 26 vs. 1 of 19), systemic sepsis (7 of 26 vs. 1 of 19), pancreatic fistula (14/45, 13 of which closed spontaneously), colonic perforation (4), duodenal perforation (2), and gastric perforation (1). The causes of death were renal and respiratory failure with sepsis (7), hemorrhage (3), and pulmonary emboli (1). Analysis of the findings shows in the second 5-year period more frequent use of CT to certify the diagnosis of pancreatic abscess earlier, a more aggressive attitude producing earlier surgical intervention, and more extensive drainage and debridement of associated necrotic tissue. Transcatheter arterial embolization was used successfully to control postoperative hemorrhage from the abscess cavity. CT-guided percutaneous catheter drainage was used occasionally for drainage of recurrent abscesses. Neither open packing of major pancreatic abscesses nor lavage of the abscess cavity, as recently advocated, was necessary.

Pancreatic abscesses

This paper presents the clinical features and problems in the management of 34 patients with pancreatic abscesses. In the majority of patients the abscesses developed following an attack of pancreatitis due to alcohol or gallstones. The abscesses were usually multilocular, and often had spread widely in the retroperitoneal space. Invasion into surrounding viscera or the peritoneal cavity occurred in 12 instances, and eight patients developed major bleeding into the abscess cavity. Obstructive complications (affecting bowel, common bile duct and large veins) occurred in eight patients. Twelve of the 34 patients (35 per cent) died, most deaths being due to failure to control sepsis (seven patients) or to massive bleeding from the abscess cavity (three patients). The mortality of this condition is likely to remain high, but may be reduced by better drainage techniques at the initial exploration. The importance of the infra-mesocolic approach for drainage is emphasized.