acute pancreatitis

Last edited 12/2018 and last reviewed 07/2021

Acute pancreatitis (AP) is inflammation of the pancreas triggered by release of activated exocrine enzymes into the substance of the organ (1).   

It is relatively common and has shown a 10 fold increase in many Western countries in the last two decades (1,2)

• annual incidence varies in different parts of the world, it may range from 10 to 80 new cases per 100,000 inhabitants annually
• a low incidence rate can be observed in the Netherlands and UK (10 and 24 pts/100,000 inhabitants/year) while in the Scandinavian countries and USA, the incidence rate is higher (35 to 73 pts/100,000 inhabitants/year).
• in the UK, hospitals serving a population of 300 000-400 000 people admit about 100 cases each year
• accounts for approximately 1% of acute surgical admissions (1,2,3)

Alcohol abuse and gallstone migration are the most common causes with the latter being more common in women than in men (3). AIDS patients are affected more commonly than other groups.

NICE state (4):

• acute pancreatitis is acute inflammation of the pancreas and is a common cause of acute abdominal pain
• incidence in the UK is approximately 56 cases per 100,000 people per year
• around 50% of cases are caused by gallstones, 25% by alcohol and 25% by other factors
• in about 25% of cases, acute pancreatitis is severe and associated with complications such as respiratory or kidney failure, or the development of abdominal fluid collections
  • in these more severe cases, people often need critical care and a prolonged hospital stay, and the mortality rate is 25%
  • overall mortality rate in acute pancreatitis is approximately 5%.

The condition may vary from mild (around 80% of cases) with recovery within a few days to severe (20%) acute pancreatitis with the need of prolonged hospital stay and critical care support. Severe AP is also associated with a 15-20% risk of death (1).

According to the Atlanta classification, acute pancreatitis can be divided into:

• interstitial oedematous pancreatitis
• seen in 80-90% of patients
• usually a milder variant
• characterized by the presence of acute inflammation of pancreatic parenchyma and perpancreatic tissue but without pancreatic or peripancreatic necrosis on imaging
• usually resolves itself quickly within a week
• necrotizing pancreatitis
• 5-10% of cases
• a severe variant
• pancreatic parenchymal necrosis or peripancreatic necrosis, or both are present (1,5)

The condition is rare in children.

Presentation and Diagnosis (4):

• people with acute pancreatitis usually present with sudden-onset abdominal pain
• nausea and vomiting are often present and there may be a history of gallstones or excessive alcohol intake
• typical physical signs include epigastric tenderness, fever and tachycardia. Diagnosis of acute pancreatitis is confirmed by testing blood lipase or amylase levels, which are usually raised
  • if raised levels are not found, abdominal CT may confirm pancreatic inflammation.

Do not assume that a person's acute pancreatitis is alcohol-related just because they drink alcohol (4):

If gallstones and alcohol have been excluded as potential causes of a person's acute pancreatitis, investigate other possible causes such as:

• metabolic causes (such as hypercalcaemia or hyperlipidaemia)
• prescription drugs
• microlithiasis
• hereditary causes
• autoimmune pancreatitis
• ampullary or pancreatic tumours
• anatomical anomalies (pancreas divisum)

• nutrition
  • ensure that people with acute pancreatitis are not made 'nil-by-mouth' and do not have food withheld unless there is a clear reason for this (for example, vomiting)
  • enteral nutrition should be offered to anyone with severe or moderately severe acute pancreatitis. Start within 72 hours of presentation and aim to meet their nutritional requirements as soon as possible
  • anyone with severe or moderately severe acute pancreatitis should be offered parenteral nutrition only if enteral nutrition has failed or is contraindicated

Reference:

• (1) Johnson CD, Besselink MG, Carter R. Acute pancreatitis. BMJ. 2014;349:g4859
• (2) Lankisch PG, Apte M, Banks PA. Acute pancreatitis. Lancet. 2015;386(9988):85-96.
• (3) Gomez D et al. Retrospective study of patients with acute pancreatitis: is serum amylase still required? BMJ Open. 2012;2(5)  
• (4) NICE (September 2018). Pancreatitis
• (5) Sureka B et al. Imaging lexicon for acute pancreatitis: 2012 Atlanta Classification revisited. Gastroenterol Rep (Oxf). 2016;4(1):16-23