Acute pancreatitis: assessment and management

Acute lung injury in two experimental models of acute pancreatitis: infusion of saline or sodium taurocholate into the pancreatic duct

OBJECTIVE

To compare acute pulmonary changes secondary to sodium taurocholate hemorrhagic pancreatitis with those changes secondary to a less severe pancreatitis induced by saline infusion into the biliopancreatic duct.

DESIGN

Prospective, randomized controlled trial.

SETTING

University pulmonary laboratory.

SUBJECTS

A total of 110 male Wistar rats.

INTERVENTIONS

Pancreatitis was induced by either 0.5 mL of a 4% solution of sodium taurocholate (TAU group) or 0.5 mL of normal saline (SAL group) injection into the biliopancreatic duct. Data were compared with data from control (sham-operated) animals (SHAM group).

MEASUREMENTS AND MAIN RESULTS

The severity of pancreatic and pulmonary injuries was evaluated 1, 3, and 8 days after the induction of acute pancreatitis by morphometric and pulmonary mechanical studies. Biliopancreatic duct pressure was measured during infusion of solutions in SAL and TAU groups. SAL and TAU groups developed an intense necrohemorrhagic pancreatitis on day 1 without differences in biliopancreatic duct pressures (134.0+/-45.1 cm H2O vs. 123.3+/-23.4 cm H2O). Acute pancreatic lesions were still intense on day 3 in the TAU group only. Pulmonary resistance in SAL and TAU groups was significantly greater than in the SHAM group on day 3 only. On day 1, there was an increase in intraalveolar edema in both groups (p < .02). There was an increase in polymorphonuclear cells in alveolar septa on day 1 only in the TAU group (p < .001). In contrast, both experimental groups presented greater values of PMN cells on day 8 compared with the SHAM group (p < .001). Both groups with pancreatitis showed an increase in alveolar distention and collapse on day 1 that persisted only in the TAU group on days 3 and 8. No deaths were observed in the control (SHAM) group. In contrast, the SAL group had lower mortality than the TAU group in the first two days (17% and 52%, respectively, p = .03).

CONCLUSION

High-pressure infusion of normal saline into the biliopancreatic duct of rats results in significant pancreatic and lung alterations. These changes are worse in the presence of sodium taurocholate.

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.