EDUCATION CLINICAL REVIEW Acute pancreatitis • Link to this article online 1 2 3 for CPD/CME credits C D Johnson, M G Besselink, R Carter 1University Surgery, University Acute pancreatitis is a common cause of emergency admis- SOURCES AND SELECTION CRITERIA Hospital Southampton sion to hospital. Most hospitals in the United Kingdom We have drawn heavily on three recent evidence based SO16 6YD, UK serving a population of 300 000-400 000 people admit guidelines1‑3 that we helped to write and we reviewed the 2Dutch Pancreatitis Study Group, Academic Medical Center about 100 cases each year. We review up to date evidence Cochrane Library for relevant clinical trials. In December Amsterdam, Netherlands for the assessment, diagnosis, and management of acute 2013 we again reviewed the Cochrane Library to identify any 3West of Scotland Pancreatic Unit, pancreatitis. systematic review or update relevant to acute pancreatitis. Glasgow Royal infirmary, Glasgow, UK Correspondence to: C D Johnson What is acute pancreatitis? How does acute pancreatitis present? [email protected] Acute pancreatitis is inflammation of the pancreas; it Acute pancreatitis presents as an emergency, requiring Cite this as: BMJ 2014;349:g4859 is sometimes associated with a systemic inflammatory acute admission to hospital. Patients almost always mention doi: 10.1136/bmj.g4859 response that can impair the function of other organs or severe constant abdominal pain (resembling peritonitis), systems. The inflammation may settle spontaneously or usually of sudden onset and, in 80% of cases, associated may progress to necrosis of the pancreas or surround- with vomiting. The pain may radiate to the back, usually the ing fatty tissue. The distant organ or system dysfunction lower thoracic area. Most patients present to hospital within may resolve or may progress to organ failure. Thus there 12-24 hours of onset of symptoms. Abdominal examination is a wide spectrum of disease from mild (80%), where shows epigastric tenderness, with guarding. Differential patients recover within a few days, to severe (20%) with diagnoses to consider include perforated peptic ulcer, myo- prolonged hospital stay, the need for critical care sup- cardial infarction, and cholecystitis. port, and a 15-20% risk of death.3 If patients have organ failure during the first week in hospital, it is usually How is the diagnosis confirmed? already present on the first day in hospital.1 This early Biochemical tests organ failure may resolve in response to treatment. The The diagnosis is based on abdominal pain and vomiting, diagnosis of severe acute pancreatitis depends on the associated with increases in serum amylase or lipase lev- presence of persistent organ failure (>48 hours) either els at least more than three times the upper limit of nor- during the first week or at a later stage, and also on the mal.2 3 In the United Kingdom, amylase testing is widely presence of local complications (usually apparent after available, although estimation of lipase is preferred by the first week). some because lipase levels remain increased for longer than amylase levels after the onset of acute pancreatitis. What are the risk factors and potential causes of acute In about 5% of patients, enzyme levels may be normal at pancreatitis? the time of admission to hospital. Acute pancreatitis has many causes, the commonest in most European and North American studies being gall- Imaging stones (50%) and alcohol (25%). Rare causes (<5%) In cases where there is diagnostic doubt, either because include drugs (for example, valproate, steroids, azathio- the biochemical tests are not conclusive (enzyme levels prine), endoscopic retrograde cholangiopancreatography, may decrease during delayed presentation to hospital) hypertriglyceridaemia or lipoprotein lipase deficiency, or because the severity of clinical presentation raises the hypercalcaemia, pancreas divisum, and some viral infec- possibility of other intra-abdominal conditions such as tions (mumps, coxsackie B4). About 10% of patients have perforation of the gastrointestinal tract, contrast enhanced idiopathic pancreatitis, where no cause is found. computed tomography may be needed to make the diagno- sis.2-4 International consensus is that acute pancreatitis is SUMMARY POINTS diagnosed when two of three criteria are present: typical abdominal pain, raised enzyme levels, or appearances of All patients with acute pancreatitis should have liver function tests and abdominal pancreatitis on computer tomography. Computed tomogra- ultrasonography within 24 hours of admission to look for gallstones phy also has a role in the assessment of the severity of acute Severe acute pancreatitis is characterised by persistent (>48 hours) organ failure; these pancreatitis if the illness fails to resolve within one week. patients have a >30% mortality rate If symptoms persist for more than seven days computed tomography is required to assess What other diagnostic tests are required? pancreatic and peripancreatic necrosis Once acute pancreatitis has been diagnosed, the cause Initial management includes adequate fluid resuscitation and supplemental oxygen needs to be sought. In most cases this will be determined If gallstones are found, definitive treatment (by cholecystectomy or sphincterotomy) should from a combination of careful clinical evaluation and be given within two weeks of resolution of symptoms initial investigations. When taking a history, it is impor- Necrotising pancreatitis should be managed by a specialist team including surgeons, tant to ask about alcohol consumption, drug use, symp- endoscopists, interventional radiologists, and intensivists toms of viral illness, and a family or personal history of genetic disease. Blood tests may reveal hypercalcaemia 26 16 August 2014 | the bmj EDUCATION CLINICAL REVIEW and hypertriglyceridaemia. Abdominal ultrasonography thebmj.com Box 2 | Features of systemic inflammatory response Previous articles in this may identify gallstones. No evident cause will be found syndrome (SIRS)* in 10-20% of patients3; these people may require further series • Core body temperature >38°C or <36°C investigation, especially if they have experienced more • The management of • Heart rate >90 bmp than one acute attack. spasticity in adults • Respiratory rate >20/min (or arterial carbon dioxide (BMJ 2014;349:g4737) pressure <32 mm Hg) Ultrasonography 9 9 • Non-alcoholic fatty • White cell count >12×10 /L or <4×10 /L Gallstones are found in about half of patients with acute *If SIRS is present for >48 hours the patient is likely to have severe pancreatitis liver disease pancreatitis, so in every case abdominal ultrasonogra- (BMJ 2014;349:g4596) phy should be performed within 24 hours of admission cholangiopancreatography are usually requested only • Diagnosis and to look for gallstones in the gallbladder.3 5 Early detec- after patients have recovered from the acute phase and management of heritable tion helps plan the definitive management of gallstones after a detailed history and repeat ultrasonography have thrombophilias (usually by cholecystectomy) to prevent further attacks failed to identify a cause. (BMJ 2014;348:g4387) of pancreatitis. • HIV testing and How is the severity of acute pancreatitis assessed? management of newly Liver function tests Eighty per cent of patients with acute pancreatitis diagnosed HIV In addition to ultrasonography, increased liver enzymes respond to initial support with intravenous fluid, oxygen (BMJ 2014;349:g4275) levels provide supportive evidence for gallstones as the supplements, and analgesia, and they can be discharged • Allergic rhinitis in cause of the acute pancreatitis. Two large observational home within a week or so. About 20% of patients, how- studies with 139 and 464 patients of whom 101 and 84 ever, do not recover during the first few days and may children had gallstones found that an alanine transaminase (ALT) need transfer to a specialist unit.8 (BMJ 2014;348:g4153) level >150 U/L has a positive predictive value of 85% for The Atlanta classification is a useful framework for gallstones.4-6 These tests should be done in all patients assessing the severity of acute pancreatitis.9 The current within 24 hours of admission. classification recognises three levels of severity: mild, where patients recover with good supportive care within a Endoscopic ultrasonography week without complication; moderately severe, in which A systematic review of five studies in patients with appar- there is transient organ failure that resolves within 48 ently idiopathic pancreatitis after initial assessment hours, or a local complication (that is, peripancreatic reported a diagnostic yield of up to 88% with endoscopic fluid collections) without organ failure; and severe acute ultrasonography, with detection of biliary sludge, com- pancreatitis, in which there is persistent organ failure mon bile duct stones, or chronic pancreatitis.7 for more than 48 hours. This classification enables non- specialist clinicians to identify those patients who require Magnetic resonance cholangiopancreatography treatment by, or in consultation with, a specialist centre Expert opinion also recommends magnetic resonance chol- (box 1). Persistent organ failure during the first week is angiopancreatography to elucidate rare anatomical causes associated with a 1 in 3 risk of mortality.10 11 of acute pancreatitis.2 The sensitivity of this investigation is Patients who have local complications and organ failure improved by the addition of secretin stimulation.