An update on pancreatic pathophysiology (do we have to rewrite pancreatic pathophysiology?)

This review focuses on seven aspects of physiology and pathophysiology of the exocrine pancreas that have been intensively discussed and studied within the past few years: (1) the role of neurohormonal mechanisms like melatonin, leptin, or ghrelin in the stimulation of pancreatic enzyme secretion; (2) the initiation processes of acute pancreatitis, like fusion of zymogen granules with lysosomes leading to intracellular activation of trypsinogen by the lysosomal enzyme cathepsin B, or autoactivation of trypsinogen; (3) the role of genes in the pathogenesis of acute pancreatitis; (4) the role of alcohol and constituents of alcoholic beverages in the pathogenesis of acute pancreatitis; (5) the role of pancreatic hypertension, neuropathy, and central mechanisms for the pathogenesis of pain in chronic pancreatitis; (6) the relation between exocrine pancreatic function and diabetes mellitus; and (7) pathophysiology, diagnosis and treatment of pancreatic steatorrhea.

Severe acute pancreatitis: case-oriented discussion of interdisciplinary management

The clinical course of an episode of acute pancreatitis varies from a mild, transitory illness to a severe often necrotizing form with distant organ failure and a mortality rate of 20-40%. Patients with severe pancreatitis, representing about 15-20% of all patients with acute pancreatitis, need to be identified as early as possible after onset of symptoms allowing starting intensive care treatment early in the disease process. An episode of severe acute pancreatitis progresses in two phases. The first 10-14 days are characterized by a systemic inflammatory response syndrome maintained by the release of various inflammatory mediators. The second phase, beginning about 10-14 days after the onset of the disease is dominated by sepsis-related morbidity due to infected peripancreatic and pancreatic necrosis. This state is associated with septic multiple organ systemic failure. The importance of infection on the outcome of necrotizing pancreatitis has been clearly delineated and the pre-emptive use of broad-spectrum antibiotics that achieve effective tissue concentrations is considered standard management of patients with severe necrotizing pancreatitis, especially if associated with organ failure or extended necrosis. Patients with infected necrosis should undergo a surgical intervention. The standard open technique consisting of an organ preserving necrosectomy followed by a postoperative concept of lavage and/or drainage to evacuate necrotic debris occurring during the further course has recently been challenged by various minimally invasive approaches.

The role of the glucocorticoid-dependent mechanism in the progression of sodium taurocholate-induced acute pancreatitis in the rat

The effects of glucocorticoids on acute pancreatitis (AP) have remained contradictory. The aim of this study was to investigate the time courses of the effects of the exogenous glucocorticoid agonists dexamethasone (DEX) and hydrocortisone (HYD) and a glucocorticoid antagonist (RU-38486) and to characterize the local and systemic responses in AP in rats. The glucocorticoid antagonist and agonists were administered just before AP induction. Serum amylase activity determinations, IL-6 bioassays, pancreatic weight/body weight ratio measurements, and survival analysis were performed. Liver and lung injuries were assessed via neutrophil leukocyte infiltration in myeloperoxidase (MPO) assays, tissue adenosine triphosphate (ATP) level determinations, and histology. In the glucocorticoid agonist groups, the survival rate increased, while the serum amylase level, the IL-6 activity, and the pancreatic weight/body weight ratio decreased significantly as compared with the control and RU-treated groups. AP resulted in significant decreases in tissue ATP levels in both the liver and the lung. In the DEX- or HYD-treated groups, the liver ATP levels were significantly elevated, while both the liver and the lung MPO levels were attenuated as compared with the AP and RU-treated groups. These results suggest that glucocorticoids may play important roles in mitigating the progression of the inflammatory reaction during the early phases of AP.

Cefepime tissue penetration in experimental acute pancreatitis

INTRODUCTION

Antibiotic treatment represents a cornerstone in the management of severe acute pancreatitis. However, different antibiotic substances are currently used. In this study, we analyzed penetration of cefepime into pancreatic tissue in two models of acute pancreatitis.

AIMS AND METHODOLOGY

Following induction of acute pancreatitis, animals were treated with a single intravenous dose of cefepime (0.1 mg/g of body weight). At two different time points, blood and tissue samples were obtained for determination of cefepime concentration and microbiologic analysis.

RESULTS

Mean pancreatic tissue concentrations +/- SEM 30 minutes after drug administration were significantly higher in animals with either mild acute pancreatitis (113 +/- 22 mg/kg) or severe acute pancreatitis (75 +/- 22 mg/kg) than in control animals (30 +/- 6 mg/kg) (p < 0.005). The minimal inhibitory concentrations (MIC90) for organisms usually isolated from infected pancreatic necrosis vary between 0.05 and 8 mg/L, which is between nine and 1,500 times lower than the mean peak concentration found in necrotic pancreatic tissue. Seven hours 30 minutes after antibiotic administration, pancreatic cefepime concentrations were still above the MIC90 in 100% and 83% of animals with mild and severe disease, respectively. The infection rate of pancreatic tissue was significantly lower after antibiotic treatment and was similar after imipenem/cilastatin or cefepime treatment.

CONCLUSION

Because of its antibacterial coverage and proven tissue penetration in acute pancreatitis, cefepime should be studied in patients with severe acute pancreatitis.

Macrophage migration inhibitory factor is a critical mediator of severe acute pancreatitis

BACKGROUND & AIMS

Macrophage migration inhibitory factor (MIF), originally described as an inhibitor of the random migration of macrophages, has been shown recently to be involved in the pathogenesis of several inflammatory diseases such as sepsis. The aim of this study was to clarify the role of MIF in acute pancreatitis (AP).

METHODS

Hemorrhagic necrotizing pancreatitis and edematous pancreatitis were induced by the injection of taurocholic acid (TCA pancreatitis) and cerulein (cerulein pancreatitis), respectively, on male Wistar rats. MIF levels in ascitic fluids, serum, and the organs were determined. The effects of anti-MIF antibody were examined on the prognosis of rats with TCA pancreatitis and of female CD-1 mice with choline-deficient, ethionine-supplemented, diet-induced model of severe AP. In addition, serum MIF levels in AP patients and in healthy controls were measured.

RESULTS

Serum and ascitic MIF levels in TCA pancreatitis were increased rapidly and decreased gradually thereafter. Ascitic MIF levels were also increased in cerulein pancreatitis, but to a lesser degree. MIF level was increased in the lung in TCA pancreatitis, but not in the pancreas and the liver. Prophylactic (1 hour before and immediately after induction) administration of anti-MIF antibody significantly improved the survival rate of rats with TCA pancreatitis. The survival rate of mice with severe AP was also improved significantly by the antibody treatment. Serum MIF levels were higher in severe AP patients than mild AP patients and healthy controls.

CONCLUSIONS

These results suggest a role of MIF in the pathogenesis of severe AP.

Early debridement for necrotizing pancreatitis: is it worthwhile?

BACKGROUND

The timing for debridement of necrotizing pancreatitis is controversial. We reviewed our experience with early and delayed surgical debridement in patients with necrotizing pancreatitis.

STUDY DESIGN

The records of patients diagnosed with acute necrotizing pancreatitis from January 1993 through June 2000 were reviewed retrospectively. Data were analyzed with respect to Ranson's, APACHE II, and multiple organ failure scores, etiology, presence of infection, overall and ICU length of stay, time to first debridement, number of debridements, fluid requirements, days to enteral feeding, transfusion requirements, complications, and mortality.

RESULTS

Twenty-six patients (18 males, 8 females, mean age 51 years) were diagnosed with acute necrotizing pancreatitis. The admission Ranson's score was 4.8, the APACHE II score was 11.7, and multiple organ failure score was 4.2. All but one patient underwent pancreatic debridement (4.3 debridements per patient). Eighteen patients (69%) had infected pancreatic necrosis. The timing of debridement was based on patients' condition and surgeon's preference. The presentation and demographics of patients who underwent early (<2 weeks) or late (>2 weeks) debridement did not differ significantly. Patients debrided early had a trend toward higher mortality (29% versus 18%) and experienced a higher number of major complications (p < 0.05). The six patients (23%) who died were older, had multiple organ failure scores, and more often had Candida in the infected necrosis (p < .05).

CONCLUSIONS

Early debridement for acute necrotizing pancreatitis might not improve survival and might even be associated with increased number of complications. Most patients diagnosed with necrotizing pancreatitis eventually need debridement, but it might be beneficial to delay debridement if the patient's condition allows for it.

Pancreatic sepsis: prevention and therapy

Except for a minority of early fatalities, most deaths in acute pancreatitis occur after the first 7 to 10 days due to infective complications, particularly infected necrosis. Hence, preventing this risk factor seems to represent a major step forward in the clinical management of severe pancreatitis. Consequently, antibiotics emerged as a cornerstone of the treatment of severe acute pancreatitis. The duration of such treatment, the route of administration and the substance(s) of choice need to be carefully selected. Surgical debridement is the treatment of choice of infected necrosis, while percutaneous drainage is successful in some patients.

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.