Human pancreatic tissue concentration of bactericidal antibiotics

Optimising outcomes in acute pancreatitis

Acute pancreatitis is a common cause for presentation to emergency departments. Common causes in Western societies include biliary pancreatitis and alcohol (the latter in the setting of chronic pancreatitis). Acute pancreatitis also follows endoscopic retrograde pancreatography in 5 to 10% of patients, a group that could potentially benefit from prophylactic treatment. Although episodes of pancreatitis usually run a relatively benign course, up to 20% of patients have more severe disease, and this group has significant morbidity and mortality. Therefore, attempts have been made to identify, at or soon after presentation, those patients likely to have a poor outcome and to channel resources to this group. The mainstay of treatment is aggressive support and monitoring of those patients likely to have a poor outcome. Pharmacotherapy for acute pancreatitis (both prophylactic and in the acute setting) has been generally disappointing. Efforts initially focused on protease inhibitors, of which gabexate shows some promise as a prophylactic agent. Agents that suppress pancreatic secretion have produced disappointing results in human studies. Infection of pancreatic necrosis is associated with high mortality and requires surgical intervention. In view of the seriousness of infected necrosis, the use of prophylactic antibacterials such as carbapenems and quinolones has been advocated in the setting of pancreatic necrosis. Similarly, data are accumulating to support the use of prophylactic antifungal therapy. Recently, it has become apparent that the intense inflammatory response associated with acute pancreatitis is responsible for much of the local and systemic damage. With this realisation, future efforts in pharmacotherapy are likely to focus on suppression or antagonism of pro-inflammatory cytokines and other inflammatory mediators. Similarly, animal studies have demonstrated the importance of oxidative stress in acute pancreatitis, although to date there is a paucity of information regarding the efficacy of antioxidants. Although the clinical course for most patients with acute pancreatitis is mild, severe acute pancreatitis continues to be a clinical challenge, requiring a multidisciplinary approach of physician, intensivist and surgeon.

Antibiotic prophylaxis and treatment of surgical abdominal sepsis

The incidence of surgical abdominal sepsis is related to the operation, patient and skill of the surgeon, ranging from <2-3% for laparoscopic cholecystectomy to >35-40% in overt peritonitis. Aged, obese, diabetic, neoplastic, acute patients have the highest incidence of sepsis. Antibiotic prophylaxis significantly reduces the incidence of postoperative infections for Class II and II operations. The proper timing (30-60 min before incision), choice of antibiotic (related to possible pathogens) and correct duration are essential. Ultra-short prophylaxis (only one administration) may be effective in most class II procedures and a cephalosporin can be used. Class II operations (colorectal) may require a booster dose soon after surgery or during surgery exceeding 3 h. The most effective regimen may include: ampicillin, clindamycin, I- II- III- or IV-generation cephalosporins, amoxycillin, aminoglycosides, metronidazole have been used alone and in combination. Combination prophylaxis should be active against aerobic and anaerobic bacteria. Treatment of surgical abdominal sepsis may be primary, seconday or tertiary. Surgery should remove the pathologic lesion, and antibiotics reduce the general effects of sepsis and infectious complications. This article presents information on the general rules for correct prophylaxis and treatment.

Management of antimicrobial use in the intensive care unit

Indications for the use of antimicrobials in critically ill patients are similar to those for other hospitalised patients. However, the selection of agents depends on the particular characteristics of patients in the intensive care unit (ICU), the form of presentation of infection, the type of infection and the bacteriological features of the causative pathogens. The use of antimicrobials in patients admitted to medical-surgical ICUs varies between 33 and 53%. The selection of empirical antimicrobials to be included in treatment protocols of the most common infections depends on the strong interrelationship between patient characteristics, predominant pathogens in each focus. and antimicrobials used for treatment. Epidemiological studies carried out in the past have identified the microorganisms most frequently responsible for community-acquired and nosocomial infections in patients admitted to ICUs. Susceptibility to antimicrobial agents may be different between each geographical area, between each hospital and even within the same hospital service. In addition, susceptibility patterns may change temporarily in relation to the use of particular antimicrobials or in association with other unknown factors so that assessment of endemic antimicrobial resistance patterns is very useful in order to tailor the antimicrobial regimens of therapeutic protocols. Antimicrobial use should not be a routine procedure. The clinical course of the patient (an indicator of effectiveness) should be closely monitored as well as the possible appearance of adverse effects and/or multiresistant pathogens. Controls are based on the assessment of plasma drug concentrations and microbiological surveillance to detect the presence of multiresistant strains or new antibacterial-resistant pathogens. Prevention of the development of multiresistant pathogens is the main goal of the ICU antimicrobial policy. Although a series of general strategies to reduce the presence of multiresistant pathogens have been proposed, the implementation of these recommendations in ICUs requires the cooperation of a member of the intensive care team.

Necrotizing pancreatitis: contemporary analysis of 99 consecutive cases

OBJECTIVE

To analyze the impact of a conservative strategy of management in patients with necrotizing pancreatitis, reserving intervention for patients with documented infection or the late complications of organized necrosis.

SUMMARY BACKGROUND DATA

The role of surgery in patients with sterile pancreatic necrosis remains controversial. Although a conservative approach is being increasingly used, few studies have evaluated this strategy when applied to the entire spectrum of patients with necrotizing pancreatitis.

METHODS

The authors reviewed 1,110 consecutive patients with acute pancreatitis managed at Brigham and Women's Hospital between January 1, 1995, and January 1, 2000, focusing on those with pancreatic necrosis documented by contrast-enhanced computed tomography. Fine-needle aspiration, the presence of extraintestinal gas on computed tomography, or both were used to identify infection.

RESULTS

There were 99 (9%) patients with necrotizing pancreatitis treated, with an overall death rate of 14%. In three patients with underlying medical problems, the decision was made initially not to intervene. Of the other 62 patients without documented infection, all but 3 were managed conservatively; this group's death rate was 11%. Of these seven deaths, all were related to multiorgan failure. Five patients in this group eventually required surgery for organized necrosis, with no deaths. Of the 34 patients with infected necrosis, 31 underwent surgery and 3 underwent percutaneous drainage. Only four (12%) of these patients died, all of multiorgan failure. Of the total 11 patients who died, few if any would have been candidates for earlier surgical intervention.

CONCLUSIONS

These results suggest that conservative strategies can be applied successfully to manage most patients with necrotizing pancreatitis, although some will eventually require surgery for symptomatic organized necrosis. Few if any patients seem likely to benefit from a more aggressive strategy.

Acute and chronic pancreatitis

Acute pancreatitis has multiple causes, an unpredictable course, and myriad complications. The diagnosis relies on a combination of history, physical examination, serologic markers, and radiologic findings. The mainstay of therapy includes aggressive hydration, maintenance of NPO, and adequate analgesia with narcotics. Antibiotic and nutritional support with total parenteral nutrition should be used when appropriate.

Incidence, spectrum and antibiotic sensitivity pattern of bacterial infections among patients with acute pancreatitis

BACKGROUND AND AIM

Secondary infection of pancreatic necrotic tissue and peripancreatic fluid is a serious complication of acute pancreatitis resulting in significant morbidity and mortality. The aim of this study was to find out the spectrum of bacterial infections, and their antibiotic sensitivity pattern in patients with acute pancreatitis.

METHODS

All consecutive patients with acute pancreatitis were studied prospectively. Detailed investigations were carried out to identify bacterial infections and their antibiotic sensitivities in patients with suspected infection. These investigations included cultures of various body fluids, throat swabs, indwelling cannula and catheter tips. Pancreatic tissue was obtained by using needle aspiration or at surgery for Gram's stain, culture and sensitivity. All cultures were repeated until the presence of infection was confirmed or excluded.

RESULTS

A total of 169 patients with acute pancreatitis were studied during the period between January 1997 and June 2000 (mean age 41.3 years; 116 males and 53 females). Of the 169 patients, 63 had infections at various sites. A total of 80 cultures were positive, and 12 different bacterial isolates were cultured from samples taken from these 63 patients. Polymicrobial infection was seen in 32% of patients. Twenty-four patients had a confirmed pancreatic infection. Blood cultures had a growth of organisms in 19 patients, with evidence of ongoing or worsening pancreatitis, thus raising a strong suspicion of infected necrosis in them. The commonest organisms were Escherichia coli from 20 cultures and Pseudomonas aeruginosa from 18 cultures. The antibiotic sensitivity pattern showed that most bacteria were sensitive to third generation cephalosporins and quinolones; notably among them were cefotaxime, ceftazidime, and ciprofloxacin.

CONCLUSION

Bacterial infections were seen in 37% of patients with acute pancreatitis. The commonest organisms were Pseudomonas aeruginosa and Escherichia coli. Most bacterial isolates were sensitive to third generation cephalosporins and quinolones.

Pancreatic concentrations of cefepime

The concentrations of cefepime in pancreatic pseudocyst fluid (n = 4), pancreatic tissue (n = 4) and pancreatic fistula fluid (n = 1), and simultaneous plasma concentrations, were measured after intravenous administration of a single 2 g dose to nine patients. Mean plasma concentration was 27.4 mg/L between 120 and 200 min after the end of infusion. Mean pancreatic cefepime concentration was 6.3 mg/L in pseudocyst and 10.7 mg/L in pancreatic tissue. Cefepime was detected by 30 min after the end of the perfusion in pancreatic fistulae fluid, and persisted at 8 h. We conclude that cefepime is a potentially useful antibiotic in prevention and treatment of pancreatic infection.

Update on the management of acute severe pancreatitis

Acute severe pancreatitis is an aggressive disease with a mortality rate of up to 30 percent. In recent years therapy has shifted away from early surgery to intensive medical care. This article focuses on several issues of the management of acute severe pancreatitis emphasising evidence from recent clinical trials and recommendations from recent consensus conferences. Since a correct assessment of the severity of the disease is mandatory as early as possible in the treatment, several multiple scoring factor systems and individual risk factors are explained. The indications and the optimal timing of ERCP are discussed. Prophylactic administration of antibiotics, intravenously or by means of a selective digestive decontamination scheme, seems to be beneficial in decreasing morbidity but not mortality. Adequate nutritional support, preferably achieved by enteral feeding, is an important component in the supportive therapy. Protease inhibitors and anti-secretory drugs have not proven to be of benefit in improving outcome. Immunomodulating substances like platelet activating antagonists are promising but further studies are necessary to confirm the results of the early studies. Finally, indications for surgery are discussed.

Prophylactic antibiotics and pancreatic necrosis

Recent controlled clinical studies suggest a positive effect of early antibiotic treatment on late morbidity and mortality in severe acute pancreatitis. In contrast, widespread use of antibiotics may lead to an increased number of fungal infections and multiresistant bacteria. Optimal choice, duration, and route of administration of the antibiotic agent(s) are far from being established. The additional administration of an antifungal agent with prophylactic intention cannot be supported by the currently available data.

Acute necrotizing pancreatitis: treatment strategy according to the status of infection

OBJECTIVE

To determine benefits of conservative versus surgical treatment in patients with necrotizing pancreatitis.

SUMMARY BACKGROUND DATA

Infection of pancreatic necrosis is the most important risk factor contributing to death in severe acute pancreatitis, and it is generally accepted that infected pancreatic necrosis should be managed surgically. In contrast, the management of sterile pancreatic necrosis accompanied by organ failure is controversial. Recent clinical experience has provided evidence that conservative management of sterile pancreatic necrosis including early antibiotic administration seems promising.

METHODS

A prospective single-center trial evaluated the role of nonsurgical management including early antibiotic treatment in patients with necrotizing pancreatitis. Pancreatic infection, if confirmed by fine-needle aspiration, was considered an indication for surgery, whereas patients without signs of pancreatic infection were treated without surgery.

RESULTS

Between January 1994 and June 1999, 204 consecutive patients with acute pancreatitis were recruited. Eighty-six (42%) had necrotizing disease, of whom 57 (66%) had sterile and 29 (34%) infected necrosis. Patients with infected necrosis had more organ failures and a greater extent of necrosis compared with those with sterile necrosis. When early antibiotic treatment was used in all patients with necrotizing pancreatitis (imipenem/cilastatin), the characteristics of pancreatic infection changed to predominantly gram-positive and fungal infections. Fine-needle aspiration showed a sensitivity of 96% for detecting pancreatic infection. The death rate was 1.8% (1/56) in patients with sterile necrosis managed without surgery versus 24% (7/29) in patients with infected necrosis (P <.01). Two patients whose infected necrosis could not be diagnosed in a timely fashion died while receiving nonsurgical treatment. Thus, an intent-to-treat analysis (nonsurgical vs. surgical treatment) revealed a death rate of 5% (3/58) with conservative management versus 21% (6/28) with surgery.

CONCLUSIONS

These results support nonsurgical management, including early antibiotic treatment, in patients with sterile pancreatic necrosis. Patients with infected necrosis still represent a high-risk group in severe acute pancreatitis, and for them surgical treatment seems preferable.

Therapeutic efficacy of continuous arterial infusion of an antibiotic and a protease inhibitor via the superior mesenteric artery for acute pancreatitis in an animal model

The major cause of death in acute pancreatitis is severe infection owing to bacterial translocation. As a new strategy, we investigated the effects of continuous intra-arterial infusion of an antibiotic (imipenem) or protease inhibitor (nafamostat mesylate) via the superior mesenteric artery (SMA) on bacterial translocation in acute pancreatitis. Infusion of saline (group I), nafamostat mesylate (group II), or imipenem (group III) was started 6 hours after inducing acute pancreatitis in dogs by infusing autologous gallbladder bile into the main pancreatic duct. The survival rate in group III was significantly improved compared to group I(100 vs. 30% at 24 hours), and bacterial infection of the peritoneal fluid, mesenteric lymph nodes, and pancreas was completely prevented in group III. Intestinal damage assessed by light and scanning electron microscopy and by biochemical parameters (mucosal protein content and myeloperoxidase activity) was also significantly mitigated in group III, which showed milder pancreatic necrosis as well. There was little beneficial effect in preventing bacterial translocation in group II, although the survival rate at 24 hours (70%) was improved. Continuous arterial infusion of an antibiotic via the SMA is effective in mitigating intestinal mucosal damage and preventing bacterial translocation in acute pancreatitis, thereby improving survival.

Long-term effects of nafamostat and imipenem on experimental acute pancreatitis in rats

Long-term effects of nafamostat mesylate, a protease inhibitor, and imipenem, an antibiotic, on trypsintaurocholate-induced acute pancreatitis were studied in rats. Sham-operated rats infused with a buffer solution into the pancreatic duct served as controls. Nafamostat (1 mg/kg), imipenem (10 mg/kg), or imipenem + nafamostat in saline was injected subcutaneously 0.25, 3, 24, and 48 hours after the induction of pancreatitis. In untreated rats and control rats, saline was injected at the same intervals as in the treated rats. All rats in an untreated group died within 3.5 days (median survival, 1.25 day) after the induction of pancreatitis. The 2-week survival rate was significantly (p < 0.05) improved by a combination of nafamostat and imipenem (42%), but not by nafamostat (17%), or imipenem (8%) alone. Bacterial culture at 24 hours revealed infection of necrotic pancreatic tissues and ascites by intestinal bacteria in all untreated rats but not in control rats. Bacterial counts were significantly reduced by imipenem, but not by nafamostat. In conclusion, bacterial infection occurred within 24 hours after the induction of trypsintaurocholate pancreatitis in rats. Early treatment with nafamostat + imipenem, but not nafamostat or imipenem alone, improves long-term survival.

Fluconazole penetration into the pancreas

Because of antibiotic prophylaxis for necrotizing pancreatitis, the frequency of fungal superinfection in patients with pancreatic necrosis is increasing. In this study we analyzed the penetration of fluconazole into the human pancreas and in experimental acute pancreatitis. In human pancreatic tissues, the mean fluconazole concentration was 8.19 +/- 3.38 microg/g (96% of the corresponding concentration in serum). In experimental edematous and necrotizing pancreatitis, 88 and 91% of the serum fluconazole concentration was found in the pancreas. These data show that fluconazole penetration into the pancreas is sufficient to prevent and/or treat fungal contamination in patients with pancreatic necrosis.

Prophylactic antibiotic therapy in the management of acute pancreatitis

Studies done in the early 1970s came to the conclusion that antibiotic prophylaxis was not useful in the management of acute pancreatitis. However, these studies suffered from the drawback of using antibiotics that had poor penetration into the pancreas. In addition, the design of these trials were faulty. With the advent of new information and the availability of better antibiotics, the picture is changing. Recent studies have suggested that antibiotic prophylaxis is useful in decreasing the incidence of infection in patients with severe pancreatitis. Of the antibiotics that have been tested, imipenem appears to be the most promising.

Necrotizing pancreatitis: pathophysiology, diagnosis, and acute care management

Severe acute necrotizing pancreatitis is a disease that is caused by premature activation of pancreatic enzymes. Cytokine release contributes to systemic manifestations such as systemic inflammatory response syndrome (SIRS), multiple organ dysfunction syndrome (MODS), adult respiratory distress syndrome (ARDS), and sepsis. Diagnosis is based on a history of abdominal pain, laboratory values such as serum amylase and lipase levels, and CT scan. Medical management focuses on fluid and electrolyte balance, antibiotic therapy, pain control, and decreasing systemic complications. Surgery is indicated when infectious pancreatic necrosis has been identified. This article addresses incidence and etiology; pathophysiology; clinical manifestations; diagnostics; and medical and surgical patient care management.

Continuous arterial infusion therapy for severe acute pancreatitis: correlation between CT arteriography and therapeutic effect

PURPOSE

This study evaluates the relationship between the therapeutic effect of arterial infusion therapy for severe acute pancreatitis and drug distribution on CT-arteriography (CTA).

MATERIALS AND METHODS

Eleven patients with severe acute pancreatitis were treated by arterial infusion with use of protease inhibitor and antibiotics. Ten patients had an inflammation of the entire pancreas, while one had pancreatitis localized to the body and tail of the pancreas. The arterial infusion drugs were infused into the celiac artery, splenic artery, inferior pancreaticoduodenal artery, and common hepatic artery. The drug distributions were evaluated by CTA in 10 patients. The duration of arterial infusion ranged from 3 to 39 days. The relationship between the distribution on the CTA and the change in clinical grading of pancreatitis as evaluated by an APACHE II score was studied.

RESULTS

Of the nine patients with inflammation of the entire pancreas, six showed the distribution of contrast material to the entire area of pancreatic inflammation (a good distribution) on the CTA, and the remaining three did not show the distribution of contrast material to cover the entire area of pancreatic inflammation (a poor distribution). One patient with localized pancreatitis showed a good distribution. In seven patients with a good distribution, the APACHE II score was decreased from 11.7 points to 4.3 points during follow-up. In the remaining three patients with a poor distribution, the APACHE II score was decreased from 12.3 points to nine points, but was decreased to five points after the additional interventions. One patient without CTA showed a marked improvement in the APACHE II score. No clinically important complications were observed.

CONCLUSION

The present study findings suggest that arterial infusion is effective in the treatment of severe acute pancreatitis. A good drug distribution to the area of inflammation is needed to ensure a proper therapeutic effect.

Review article: the treatment of acute biliary pancreatitis

World-wide, gallstones are the commonest cause of acute pancreatitis (AP), a potentially life-threatening condition. Scoring systems based on radiologic findings and serologic markers help predict which patients may have retained bile duct stones. Endoscopic decompression of the biliary tree (by sphincterotomy and stone extraction during ERCP) is safer than surgery, which carries high morbidity and mortality in AP. Four prospective, randomized clinical trials confirm the utility of this approach, however careful patient selection is necessary. Medical therapy for AP is supportive; no agent or medical intervention has been shown consistently to abort or ameliorate the course of AP. Drugs that inhibit inflammatory cytokine production, however, are showing promise.

Surgical approach in patients with acute pancreatitis. Is infected or sterile necrosis an indication--in whom should this be done, when, and why?

The morbidity and mortality rates of severe acute pancreatitis are related to the degree of pancreatic necrosis that accompanies the attack and to the presence of infection. The decision about whether and when to operate on these patients is often difficult, and it requires mature clinical judgment. Proven infection of pancreatic necrosis is an absolute indication for surgical intervention, at which time surgical doffebridement and drainage should be performed. Most patients with sterile necrosis eventually respond to conservative nonsurgical medical management. In patients who remain critically ill for weeks or whose clinical course deteriorates despite maximal intensive care, surgery may be appropriate. Even when these guidelines are followed, the mortality (15% to 40%) and morbidity (approximately 80%) rates remain high.

Quantification of horseradish peroxidase delivery into the arterial wall in vivo as a model of local drug treatment: comparison between a porous and a gel-coated balloon catheter

PURPOSE

To quantify horseradish peroxidase (HRP) delivery into the arterial wall, as a model of local drug delivery, and to compare two different percutaneous delivery balloons.

METHODS

Perforated and hydrophilic hydrogel-coated balloon catheters were used to deliver HRP in aqueous solution into the wall of porcine iliac arteries in vivo. HRP solutions of 1 mg/ml were used together with both perforated and hydrophilic hydrogel-coated balloon catheters and 40 mg/ml HRP solutions were used with the hydrogel-coated balloon only. The amount of HRP deposited in the arterial wall was then determined photospectrometrically.

RESULTS

Using the 1 mg/ml HRP solution, the hydrogel-coated balloon absorbed 0.047 mg HRP into the coating. Treatment with this balloon resulted in a mean vessel wall concentration of 7.4 microg HRP/g tissue +/- 93% (standard deviation) (n = 7). Treatment with the hydrogel-coated balloon that had absorbed 1.88 mg HRP into the coating (using the 40 mg/ml HRP solution) led to a mean vessel wall concentration of 69.5 microg HRP/g tissue +/- 74% (n = 7). Treatment with the perforated balloon using 1 mg/ml aqueous HRP solution led to a mean vessel wall concentration of 174 microg/g +/- 81% (n = 7). Differences between the hydrogel-coated and perforated balloons (1 mg/g solutions of HRP) and between hydrogel-coated balloons (0.047 mg vs 1.88 mg absorbed into the balloon coating) were significant (p < 0.05; two-sided Wilcoxon test).

CONCLUSIONS

The use of a perforated balloon catheter allowed the delivery of a higher total amount of HRP compared with the hydrogel-coated balloon, but at the cost of a higher systemic HRP application. To deliver 174 microg HRP per gram of vessel wall with the perforated balloon, 6.5 +/- 1.5 mg HRP were lost into the arterial blood (delivery efficiency range = 0.2%-0.3%). With 0.047 mg HRP loaded into the coating of the hydrogel balloon, 7.4 microg HRP could be applied to 1 g of vessel wall (delivery efficiency 1.7%), and with 1.88 mg HRP loaded into the coating of the hydrogel balloon, 69.5 microg HRP could be applied per gram of vessel wall (delivery efficiency 0.6%).

Pancreatic surgery

According to epidemiologic studies, the incidence of acute and chronic pancreatitis and carcinoma of the pancreas are increasing worldwide. This is the result not only of improved diagnostic methods introduced in the last decades (eg, contrast-enhanced computed tomography, "all-in-one" magnetic resonance imaging, single-photon emission computed tomography, and endoscopic retrograde cholangiopancreatography) but also of changes in the environment and nutritional behavior. Once a specific diagnosis has been made, the first-choice interventions in acute and chronic inflammatory pancreatic diseases are predominantly organ-and organ function-preserving surgical procedures. In pancreatic cancer, extended radical surgery and multimodal therapies seem to offer the most benefit. This article provides an overview of recently published articles focusing on surgical treatment options in acute and chronic pancreatitis and carcinoma of the pancreas.

The role of antibiotic prophylaxis in the treatment of acute pancreatitis

Infected necrosis in acute pancreatitis is one of the most dreaded complications of acute pancreatitis. Whereas selection of an appropriate antibiotic treatment of the infection poses no problem, prophylactic application of antibiotic remains controversial in the absence of symptoms of infection, but where contrast-enhanced CT scan clearly proves necrosis. This article discusses the present state of the art of the role of antibiotic prophylaxis in the treatment of acute pancreatitis and provides clinical guidelines.

Nonsurgical management of acute pancreatitis. Use of antibiotics

In severe AP, infected necrosis is the leading cause of death. Prevention of pancreatic infection is the major goal in the treatment of patients with necrotizing pancreatitis. Adequate early antibiotic therapy seems to be promising in these patients. Their role and the optimal timing of the antibiotic therapy (e.g., benefit of prophylactic application) are discussed. Preliminary results of a study in patients with infected pancreatic necrosis and exclusively or primarily conservative treatment also are presented.

Prophylactic antibiotics for severe acute pancreatitis: the beginning of an era

Death from acute severe pancreatitis results from infection and multiple organ system failure occurring late in the course of illness. Patients with necrotizing pancreatitis involving at least one-third of the organ are at highest risk of secondary infection and death. We conducted a MEDLINE search to identify human trials of prophylactic antibiotics in acute pancreatitis. Results of early studies of prophylactic ampicillin to avoid secondary infection and death were negative, but the studies included patients with mild disease who are at low risk for infection. Antibiotics were beneficial in four recently completed studies: imipenem significantly reduced pancreatic and nonpancreatic sepsis (p< or =0.01); cefuroxime reduced all infectious complications (p<0.01) and deaths (p=0.0284); a regimen of ceftazidime, amikacin, and metronidazole reduced all infectious complications (p<0.03); and protocol use of imipenem significantly reduced pancreatic infection compared with nonprotocol antibiotics (p=0.04) and no antibiotics (p<0.001). Based on these results, we suggest early antibiotic prophylaxis in patients with necrotizing pancreatitis, but the best drug and duration of therapy are unknown.

Controlled clinical trial of pefloxacin versus imipenem in severe acute pancreatitis

BACKGROUND & AIMS

Antibiotic prophylaxis in severe pancreatitis has recently yielded promising clinical results, with imipenem significantly reducing the incidence of infected necrosis compared with an untreated control group. On the bases of pefloxacin's spectrum of action and pancreatic penetration, we investigated whether such drugs represent a valid alternative to imipenem.

METHODS

In a multicenter study, 60 patients with severe acute pancreatitis with necrosis affecting at least 50% of the pancreas were randomly allocated to receive intravenous treatment for 2 weeks with pefloxacin, 400 mg twice daily (30 patients), or imipenem, 500 mg three times daily (30 patients), within 120 hours of onset of symptoms. Age, sex, body weight, Ranson and Apache II scores, C-reactive protein, etiology, and time from onset of symptoms to treatment were well matched in the two groups.

RESULTS

The incidences of infected necrosis and extrapancreatic infections were 34% and 44%, respectively, in the pefloxacin group and 10% and 20% in the imipenem group. Imipenem proved significantly more effective in prevention of pancreatic infections (P </= 0.05). Mortality was not significantly different in the two groups.

CONCLUSIONS

Despite its theoretical potential, pefloxacin is inferior to imipenem in the prevention of infections associated with severe pancreatitis.

Difference in microbes contaminating pancreatic necrosis in biliary and alcoholic pancreatitis

CONCLUSION

There are differences in the microbiology of infected pancreatic necrosis in alcoholic and biliary pancreatitis. One possible explanation may be different routes of contamination.

BACKGROUND

Infection is a severe complication in acute pancreatitis. Bacteria are found in 40-70% of all patients suffering from necrotizing pancreatitis. We investigated whether there were any differences in microbes isolated from pancreatic necrosis in biliary and alcoholic pancreatitis.

METHODS

Microbiological tests were conducted on necrosis taken at the operation for pancreatitis with the etiology of (group A) alcoholic pancreatitis (n = 47) and (group B) biliary pancreatitis (n = 23). Patients with simultaneous cholecystitis were excluded. The time from the first symptoms to the operation or the extent of necrosis did not differ between the groups.

RESULTS

Microbes were isolated more often in the cultures from group B than group A (17/23 = 74% vs 15/47 = 32%, p = 0.001). The most common were Gram-positive bacteria in group A and Gram-negative bacteria in group B. From the first week, from the onset of symptoms to the operation. Gram-negative bacteria were isolated significantly more often in the cultures from group B patients than from group A patients (8/10 = 80% vs 1/5 = 20%, p = 0.04). In multivariate analysis, we found that biliary pancreatitis was an independent risk factor (adds ratio 5.5, 95% confidence interval [CI] 0.59-52.10) of contamination of necrosis with Gram-negative bacteria.

Alcohol and the pancreas

Alcoholic pancreatitis may be one of the most serious adverse consequences of alcohol abuse. Its diagnosis, as it has for many years, depends primarily on clinical acumen in interpreting properly the symptoms and signs of abdominal distress, buttressed by elevated pancreatic enzymes (amylase and lipase). More recently, the use of computerized tomography (CT) in selected situations has been both of confirmatory and prognostic value. Severity of abnormality by CT correlates reasonably well with a variety of clinical-laboratory clusters (APACHE system, Ranson's criteria, etc.) and aids in therapy. The pathogenesis of alcoholic pancreatitis is not fully defined. The ultimate picture is one of tissue autolysis by activated proteolytic enzymes. The triggers for such activation, however, are still not known. They are represented by three main theories: (1) large duct obstruction and/or increased permeability relative to pancreatic secretion, (2) small duct obstruction due to proteinaceous precipitates, and (3) a direct toxic-metabolic effect of ethanol on pancreatic acinar cells. While not mutually exclusive, we favor the last hypothesis as being most consistent with the effects of ethanol on other organ systems. The direct effects of ethanol and/or its metabolites may be mediated, at least in part, via oxidative stress or the generation of fatty acid ethyl esters. Autolysis (regardless of proximate mechanism(s)) leads to inflammation likely mediated via release of various cytokines. It also should be appreciated that "acute" pancreatitis (the topic of this chapter) likely represents an acute process within a chronic pancreatic exposure and injury from alcoholic abuse. The key question of why pancreatitis develops in only a small number of alcohol abusers is not resolved. Therapy depends on the severity of alcoholic pancreatitis, which is defined by clinical-laboratory and often CT criteria. Mild pancreatitis usually resolves acutely with alcohol abstention and supportive therapy. Severe pancreatitis has a significant morbidity and mortality, mainly related to the degree of pancreatic necrosis and infection. It requires meticulous combined medical-surgical care.

Fulminant acute pancreatitis and infected necrosis: results of open management of the abdomen and "planned" reoperations

BACKGROUND

Controversy still surrounds the management of fulminant acute necrotizing pancreatitis. Because mortality rates continue to be high, especially in patients with fulminant acute pancreatitis and infected necrosis, aggressive surgical techniques, such as open management of the abdomen and "planned" reoperations, seem to be justified.

STUDY DESIGN

From 1988 through 1995, 28 patients with fulminant acute pancreatitis and infected necrosis were treated with open management of the abdomen followed by planned reoperations at our surgical intensive care unit.

RESULTS

All patients had infected necrosis with severe clinical deterioration: 12 patients had an Acute Physiology and Chronic Health Evaluation (APACHE) II score > or = 20 and 16 patients had a Simplified Acute Physiology Score (SAPS) > or = 15. Nineteen patients suffered from severe multiorgan failure; the remaining 9 patients needed only ventilatory and inotropic support. The mean number of reoperations was 17. In 14 patients, major bleeding occurred; fistula developed in 7. Later, 9 abscesses were drained percutaneously. The hospital mortality rate was 39%. Longterm morbidity in survivors was substantial, especially concerning abdominal-wall defects.

CONCLUSIONS

Open management of the abdomen followed by planned reoperations is an aggressive but reasonably successful surgical treatment strategy for patients with fulminant acute pancreatitis and infected necrosis. Morbidity and mortality rates were high, but in these critically ill patients, such high rates could be expected. Because management and clinical surveillance require specific expertise, management of these patients is best undertaken in specialized centers.

Percutaneous aspiration for bacteriological studies in patients with necrotizing pancreatitis

BACKGROUND

Percutaneous computed tomography (CT)-guided aspiration of abdominal collections is performed in necrotizing pancreatitis to detect infection of necrosis, which is an adverse prognostic factor and requires surgical drainage. However, in the case of sterile aspirates, the outcome and the optimum management are subject to debate. This study examined the clinical and bacteriological outcome of patients with severe acute pancreatitis with initially sterile necrosis and assessed the efficiency of percutaneous drainage in this setting.

METHODS

Seventeen patients hospitalized for necrotizing pancreatitis with a septic course underwent a preliminary sterile CT-guided aspiration. Eight patients underwent simultaneous percutaneous drainage of the punctured collection. Supportive therapy was continued unless severe clinical deterioration or proven secondary infection of necrosis indicated the need for necrosectomy and drainage.

RESULTS

Secondary infection of necrosis was observed in two patients of nine who had only fine-needle aspiration cytology of the collection, and in seven of eight it was drained percutaneously (P = 0.01). Only one patient drained percutaneously recovered without surgery. Surgical drainage was required in 12 patients. The hospital mortality rate was 29 per cent and was not significantly affected by the bacteriological status of necrosis.

CONCLUSION

Percutaneous drainage of sterile collections predisposed to secondary infection of the necrosis and did not cure the patients. A first sterile percutaneous aspiration did not predict a favourable course and surgery frequently remains necessary.

Antibiotic prophylaxis in the initial management of severe acute pancreatitis

BACKGROUND

The role of antibiotic prophylaxis in the initial management of patients with acute pancreatitis is an area of major controversy. Contrary to earlier clinical trials, recent experimental and clinical studies have accrued evidence that warrants reappraisal of current clinical practice. This article reviews these recent advances in knowledge.

METHODS

All papers derived from a Medline search for the years 1990-1997 inclusive using the text words 'acute', 'pancreatitis', 'antibiotic' and 'antibiotics' were studied. Additional papers were derived from reference lists within papers identified by the Medline search. Only experimental and clinical papers relevant to the issue of prophylactic antibiotic therapy in acute pancreatitis are included in the review.

RESULTS AND CONCLUSION

Current experimental evidence favours the use of prophylactic antibiotics in severe acute pancreatitis. The results of contemporary randomized clinical trials restricted to patients with prognostically severe acute pancreatitis have demonstrated improvement in outcome associated with antibiotic treatment.

Acute pancreatitis: nonsurgical management

The care of patients with severe acute pancreatitis is complex. Although numerous medical therapies have been proposed, few interventions have been shown to be of benefit in patients with severe disease. This review summarizes the nonoperative management of patients with acute pancreatitis, including therapies shown to be of little value, the role of antibiotics in patients with acute pancreatitis, the importance of monitoring and supportive care, and the rationale of endoscopic and surgical intervention.

A critical review of antibiotic prophylaxis in severe acute pancreatitis

The close association between infection and poor outcome in severe pancreatitis has led many investigators to hypothesize that antibiotic prophylaxis might reduce infection and thereby reduce mortality. However, despite this possible relationship, few studies of good quality have been performed in humans. Comprehensive searches using Medline and reviewing relevant published bibliographies of English-language human and experimental literature concerning acute pancreatitis or pancreatic tissue and antibiotic therapy or pharmacokinetics were conducted. Ample experimental evidence indicates that aminoglycosides penetrate pancreatic tissue poorly and that penetration of penicillins is variable, although the relevance of this is debatable, because most tissue that requires debridement in severe pancreatitis is necrotic peripancreatic retroperitoneal fat, not the pancreas itself. Although several animal studies suggest that antibiotic prophylaxis would be beneficial in severe pancreatitis, two recent randomized studies of intravenous antibiotics in humans provide conflicting data. There are insufficient data to recommend the use of selective digestive decontamination. Some justification exists for the use of intravenous antibiotic prophylaxis in severe pancreatitis, but the data are insufficient to mandate prophylaxis or to elevate it to the standard of care. If chosen, prophylaxis with the combination of a fluoroquinolone plus metronidazole, or monotherapy with a carbapenem antibiotic, would be most appropriate. Several other questions-including the minimum degree of severity that will benefit, the validity of endpoints other than mortality, and reduction of the need for surgical drainage-require additional trials.

Antimicrobial activity of human pancreatic juice and its interaction with antibiotics

Pancreatic juice (PJ) should be a factor of variability in the antimicrobial activity of antibiotics eliminated by the pancreas during pancreatic infections. We studied its effects on the activity of antimicrobial drugs with different mechanisms of action. Samples of pure PJ were collected from 16 patients with stabilized external pancreatic fistulas. The antimicrobial activity of the juice at different concentrations (from 1.25 to 100%) alone and in combination with mezlocillin, imipenem, ceftriaxone, gentamicin, ofloxacin, and ciprofloxacin was studied by a microbiological method (continuous turbidimetric recording of bacterial growth). The human PJ showed dose-dependent antimicrobial activity that increased directly with the concentration. The activity of the antibiotics at bactericidal concentrations were not modified by the PJ, while the combination with subinhibitory concentrations produced the following variable and different effects: (i) additivity with mezlocillin, ceftriaxone, gentamicin, and ciprofloxacin and autonomy (no interaction) with imipenem and ofloxacin against Providencia rettgeri and (ii) additivity with ceftriaxone, ofloxacin, gentamicin, imipenem, and mezlocillin and autonomy with ciprofloxacin against Escherichia coli. In the presence of PJ, fluoroquinolones showed constant positive effects, while beta-lactams showed more variable antimicrobial activity. Antibiotic concentrations and PJ pharmacodynamics are the main factors determining the final effect of the interaction in vitro. These results may be useful in choosing antibiotics for the treatment of pancreatic infections when they are supplemented with the pharmacokinetic data for each drug.

Continuous regional arterial infusion of protease inhibitor and antibiotics in acute necrotizing pancreatitis

PURPOSE

This study was conducted to determine whether continuous regional arterial infusion (CRAI) of the protease inhibitor, nafamostat mesylate, in acute necrotizing pancreatitis, would reduce mortality. In addition, the effectiveness of CRAI of the antibiotic imipenem in combination with nafamostat was investigated for its effect in preventing secondary infection of the pancreatic necrotic tissue.

PATIENTS AND METHODS

Fifty- three patients with acute necrotizing pancreatitis were divided into three groups: Group I, 16 patients who were referred >8 days after disease onset, received intravenous nafamostat and antibiotics; Group II, 22 patients referred within 7 days, received nafamostat via CRAI, and antibiotics intravenously; Group III, 15 patients referred within 7 days, received both nafamostat and imipenem via CRAI.

RESULTS

The mortality rates in Group II (13.6%) and group III (6.7%) were significantly reduced, as compared with that in group I (43.8%). The incidence of infection of pancreatic necrosis in group III (0%) was significantly lower than those in group I (50%) and in group II (22.8%).

CONCLUSION

CRAI of nafamostat and imipenem in acute necrotizing pancreatitis was effective in reducing mortality and preventing the development of pancreatic infection.

Imipenem/cilastatin: an update of its antibacterial activity, pharmacokinetics and therapeutic efficacy in the treatment of serious infections

The prototype carbapenem antibacterial agent imipenem has a very broad spectrum of antibacterial activity, encompassing most Gram-negative and Gram-positive aerobes and anaerobes, including most beta-lactamase-producing species. It is coadministered with a renal dehydropeptidase inhibitor, cilastatin, in order to prevent its renal metabolism in clinical use. Extensive clinical experience gained with imipenem/cilastatin has shown it to provide effective monotherapy for septicaemia, neutropenic fever, and intra-abdominal, lower respiratory tract, genitourinary, gynaecological, skin and soft tissues, and bone and joint infections. In these indications, imipenem/cilastatin generally exhibits similar efficacy to broad-spectrum cephalosporins and other carbapenems and is at least equivalent to standard aminoglycoside-based and other combination regimens. Imipenem/cilastatin is generally well tolerated by adults and children, with local injection site events, gastrointestinal disturbances and dermatological reactions being the most common adverse events. Seizures have also been reported, occurring mostly in patients with impaired renal function or CNS pathology, or with excessive dosage. Although it is no longer a unique compound, as newer carbapenems such as meropenem are becoming available, imipenem/cilastatin nevertheless remains an important agent with established efficacy as monotherapy for moderate to severe bacterial infections. Its particular niche is in treating infections known or suspected to be caused by multiresistant pathogens.

Pathogenesis and prevention of early pancreatic infection in experimental acute necrotizing pancreatitis

OBJECTIVE

The authors test antibiotic strategies aimed at either mitigating bacterial translocation from the gut or delivering antibiotics specifically concentrated by the pancreas for prevention of early secondary infection after acute necrotizing pancreatitis.

BACKGROUND

Infection currently is the principal cause of death after severe pancreatitis. The authors have shown that the risk of bacterial infection correlates directly with the degree of tissue injury in a rodent model of pancreatitis. Bacteria most likely arrive by translocation from the colon.

METHODS

Severe acute necrotizing pancreatitis was induced in rats by a combination of low-dose controlled intraductal infusion of glycodeoxycholic acid superimposed on intravenous cerulein hyperstimulation. At 6 hours, animals were randomly allocated to five treatment groups: controls, selective gut decontamination (oral antibiotics and cefotaxime), oral antibiotics alone, cefotaxime alone, or imipenem. At 96 hours, surviving animals were killed for quantitative bacterial study of the cecum, pancreas, and kidney.

RESULTS

The 96-hour mortality (35%) was unaffected by any treatment regimen. Cecal gram-negative bacteria were significantly reduced only by the oral antibiotics. Pancreatic infection was significantly reduced by full-gut decontamination and by imipenem, but not by oral antibiotics or by cefotaxime alone. Renal infection was reduced by both intravenous antibiotics.

CONCLUSIONS

Early pancreatic infection after acute necrotizing pancreatitis can be reduced with a full-gut decontamination regimen or with an antibiotic concentrated by the pancreas (imipenem) but not by unconcentrated antibiotics of similar spectrum (cefotaxime) or by oral antibiotics alone. These findings suggest that 1) both direct bacterial translocation from the gut and hematogenous seeding interplay in pancreatic infection while hematogenous seeding is dominant at extrapancreatic sites and 2) imipenem may be useful in clinical pancreatitis.

Routes of spread of pathogens into the pancreas in a feline model of acute pancreatitis

The routes of spread of pathogens into the pancreas in acute pancreatitis were investigated. Four experiments were performed: (1) cats with and without acute pancreatitis were given 10(7) Escherichia coli (E coli) intravenously, (2) in cats with acute pancreatitis 10(8) E coli was placed in the colon. In half of them the colon was then enclosed in an impermeable bag to prevent transmural spread. (3) E coli (10(4)) was placed in the pancreatic duct in cats with and without acute pancreatitis. (4) In cats with acute pancreatitis 10(5) E coli was placed in the gall bladder. In half of them the common bile duct was ligated to prevent biliary-pancreatic reflux. After 24 hours, intravenous E coli infected the pancreas in six of nine cats with acute pancreatitis and three of 10 controls. After 72 hours E coli spread to the pancreas from the colon in six of nine cats with acute pancreatitis. This was prevented by enclosing the colon in an impermeable bag (p = 0.02). In five of six cats with acute pancreatitis and five of six controls E coli placed in the pancreatic duct colonised the pancreas within 24 hours. Pancreatic colonisation from the gall bladder occurred in five of six cats with a patent common bile duct and in three of six with an obstructed common bile duct. In conclusion, in cats E coli can spread to the pancreas by the blood stream, transmurally from the colon, and by reflux into the pancreatic duct.

Penetration of ciprofloxacin into the human pancreas

The aim of this study was to determine the concentrations of ciprofloxacin in human pancreatic tissue and juice. Concentrations were measured by high-pressure liquid chromatography (HPLC). Two hundred mg of ciprofloxacin were administered as a short i.v. infusion (30 min). The median ciprofloxacin concentrations 140 min (median) after the start of infusion in pancreatic tissue as well as in pancreatic juice were 0.9 mg/kg (mg/l). The penetration ratio was 1.0 for pancreatic tissue and 0.83 for pancreatic juice. With regard to the minimal inhibitory concentrations (MIC) for the respective bacteria, ciprofloxacin seems to be an appropriate drug for the treatment of septic complications in necrotizing pancreatitis. Future clinical trials are necessary to prove this assumption.

Antimicrobial treatment of pancreatic infection in cats

An investigation examined the efficacy of antibiotics in a novel feline model of pancreatic infection in acute pancreatitis. Acute pancreatitis was induced in cats using an established technique. In control animals (no pancreatitis) and cats with pancreatitis, Escherichia coli (10(4) in 0.1 ml) was placed in the pancreatic duct. Reoperation was performed after 24 h in six controls and six cats with pancreatitis. E. coli was cultured from the pancreas in five control animals and five cats with pancreatitis. Reoperation was performed after 1 week in ten controls, in 11 cats with pancreatitis and in nine with pancreatitis that were treated with cefotaxime (50 mg/kg intramuscularly three times daily) started 12 h after the induction of pancreatitis and administration of E. coli. Pancreatic infection developed in eight cats with pancreatitis compared with none of the cefotaxime-treated animals and none of the controls (P < 0.05). Cefotaxime reached bactericidal levels in pancreatic tissue and juice. In conclusion, ductal administration of E. coli caused pancreatic infection only in cats with acute pancreatitis. Early administration of an appropriate antibiotic was effective in treating pancreatic infection in acute pancreatitis.

Behavior of antibiotics during human necrotizing pancreatitis

The aim of the study was to verify whether antibiotics excreted by the normal pancreas are also excreted in human necrotizing pancreatitis, reaching the tissue sites of the infection. Twelve patients suffering from acute necrotizing pancreatitis were treated with imipenem-cilastatin (0.5 g), mezlocillin (2 g), gentamicin (0.08 g), amikacin (0.5 g), pefloxacin (0.4 g), and metronidazole (0.5 g). Serum and necrotic samples were collected simultaneously at different time intervals after parenteral drug administration by computed tomography-guided needle aspiration, intraoperatively, and from surgical drainages placed during surgery. Drug concentrations were determined by microbiological and high-performance liquid chromatography assays. All antibiotics reached the necrotic tissues, but with varying degrees of penetration, this being low for aminoglycosides (13%) and high in the case of pefloxacin (89%) and metronidazole (99%). The concentrations of pefloxacin (13.0 to 23 micrograms/g) and metronidazole (8.4 micrograms/g) in the necrotic samples were distinctly higher than the MICs for the organisms most commonly isolated in this disease; the concentrations in tissue of imipenem (3.35 micrograms/g) and mezlocillin (8.0 and 15.0 micrograms/g) did not always exceed the MICs for 90% of strains tested, whereas the aminoglycoside concentrations in necrotic tissue (0.5 microgram/g) were inadequate. Repeated administration of drugs (for 3, 7, 17, and 20 days) seems to enhance penetration of pefloxacin, imipenem, and metronidazole into necrotic pancreatic tissue. The choice of antibiotics in preventing infected necrosis during necrotizing pancreatitis should be based on their antimicrobial activity, penetration rate, persistence, and therapeutic concentrations in the necrotic pancreatic area. These requisites are provided by pefloxacin and metronidazole and to a variable extent by imipenem and mezlocillin.

Acute pancreatitis

Acute pancreatitis is an inflammatory disease of variable clinical severity. The pathologic conditions that correlate with clinical severity and with local systemic complications range from mild edema to pancreatic an peripancreatic necrosis. This article discusses diagnosis, etiology, laboratory evaluation, and imaging studies with respect to acute pancreatitis. Assessing the prognosis, detecting complications, and therapy are discussed also.