Acute Pancreatitis

Although alcohol abuse is the major cause of acute pancreatitis in the middle aged, it is less common as a cause in the elderly. Acute pancreatitis, however, occurs with increasing frequency in the elderly because of an increased prevalence of gallstones. A recent English study showed that hospital admission rates for acute pancreatitis had doubled over a 30 year period in all age groups but the case fatality rates had not altered.2 Hospital admissions for acute pancreatitis per 100 000 were 13 or more for both men and women over 65 years of age and the case fatality rates were 8 per 100 patients at 29 days after presentation and 7.4 at 30–364 days after presentation. Corresponding rates in the over-75 years old age group were even higher. In addition to alcohol and gallstones, other predisposing factors for acute pancreatitis in the elderly include hypercalcaemia (usually due to hyperparathyroidism), hypertriglyceridaemia and obstruction to pancreatic flow such as that caused by tumours, endoscopic pancreatography and uraemia. Acute pancreatitis occurs in up to 30% of patients following cardiac bypass surgery, perhaps because of the administration of large doses of intravenous calcium chloride. Acute pancreatitis is also associated with biliary sludge and cholecystectomy or endoscopic papillotomy may prevent recurrence. Elderly patients are more likely to be taking prescribed medication, but whether drugs are a major cause of acute pancreatitis is debatable. Most reports of drug-related pancreatitis are anecdotal and the potential severity of the disease precludes drug challenges. A large retrospective German study of acute pancreatitis implicated drugs as a possible cause in only 1.4% of the patients. The disease was mild and ran a benign course.3 It is now recognized that autoimmune pancreatitis is not rare in older persons.4 On imaging, it is characterized by pancreatic enlargement with an irregular narrow pancreatic duct. Histologically there is lymphoplasmacytic infiltrate with swirling fibrosis and obliterative phlebitis. The tissue stains positive for IgG4-positive cells. Serum levels of IgG4 are also elevated. It can be associated with biliary structures, retroperitoneal fibrosis, parotid infiltration and mediastinal lymphadenopathy. The condition is highly sensitive to steroid therapy.

Pathophysiology of Acute Pancreatitis

The basic underlying pathophysiological mechanism in acute pancreatitis is pancreatic duct obstruction. This allows autodigestion of the gland by its own enzymes. Reflux of bile and duodenal juices into the pancreatic duct are also important. In the majority of patients, the process is self-limiting but in some the disease becomes fulminating. This leads to pancreatic necrosis and activation of inflammatory cytokines, which can result in generalized organ failure (systemic inflammatory response syndrome). If the necrosed pancreas becomes infected by gut bacteria, the disease is often fatal.

Presentation of Acute Pancreatitis

The illness characteristically presents with severe abdominal pain, often leading to acute hospital admission. The pain usually occurs in the epigastrium and radiates through to the back and is often relieved by sitting forward. This presentation, however, may differ in the elderly when the illness may be confused with myocardial infarction or a perforated abdominal viscus.

The physical signs are those of an acute abdomen. Jaundice, vomiting, fever, tachycardia and hypotension may occur. If severe, haemorrhagic pancreatitis supervenes with retroperitoneal haemorrhage, which leads to bruising in the flanks (Grey Turner’s sign), around the umbilicus (Cullen’s sign) or even below the inguinal ligament (Fox’s sign).

Diagnosis of Acute Pancreatitis

The diagnosis is supported by the finding of high levels of amylase in the serum. Elevated levels of serum lipase are more specific than elevated amylase levels. The serum lipase rises within 4–8 h, peaks at 24 h and returns to normal in 8–14 days.

Radiological examinations are increasingly important and sophisticated. Straight abdominal X-rays may show a sentinel loop—an area of small bowel ileus adjacent to the inflamed pancreas. In severe pancreatitis, the chest X-ray can reveal a pleural effusion, areas of atelectasis and pulmonary oedema. These appearances occur in patients of all ages.