Nutrition in severe acute pancreatitis

Severe acute pancreatitis is a two-phase systemic disease. The first phase is a clinical response resulting from systemic effects of proinflammatory mediators called SIRS (systemic inflammatory response syndrome), that may lead to multiple organ failure and death. The second phase, if the process is not reversed by natural defences or treatment, may be accompanied by local complications such as infected pancreatic necrosis. The severity of the disease must be established early to identify patients requiring intensive monitoring and support. The clinico-biochemical score (Ranson score) is about 80% accurate at 48 hours but is not accurate before this time; the APACHE II system has the sensitivity to predict severe pancreatitis in 61% of patients on admission. Although not perfect, the prognostic systems of severity remain better than clinical judgement. SIRS followed by local complications is accompanied by increased energy requirements and, with the absence of oral intake, a persistently negative nitrogen balance and mineral and micronutrient deficiencies. Thus, early nutritional support is indicated. Formerly, total parenteral nutrition was the standard practice for providing exogenous nutrients avoiding pancreatic stimulation. The use of early enteral feeding has recently been evaluated. Gastric atony and obstruction of the duodenum by pancreatic oedema or necrosis have been overcome by delivering enteral nutrition to the jejunum, distal to the ligament of Treitz; in this position, regular diets do not stimulate pancreatic secretions. The efficacy, tolerance, clinical outcome and cost of enteral nutrition suggest that this feeding route should be preferred in patients with severe acute pancreatitis.