Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 534

Pancreatitis is diagnosed in patients with (i) characteristic abdominal symptoms, (ii) elevated serum amylase and/or lipase, and/or (iii) imaging demonstrating pancreatic inflammation. At least two of those three criteria must be met to render a diagnosis. Serum lipase is more specific than amylase. Lipase levels elevated three times the upper limit of normal, with characteristic abdominal pain, is considered diagnostic of pancreatitis. The serum lipase rises within 4–8 hours, peaks at 24 hours, and returns to normal in 8–14 days; but serum enzyme levels are not helpful in tracking the clinical course of the illness after the initial diagnosis is made, and daily lipase measurements are not helpful in monitoring the clinical course of pancreatitis patients.

Thoughtful use of radiologic imaging is essential in pancreatitis. An abdominal ultrasound is a helpful first step if aetiology is uncertain, to determine if gallstones or biliary dilation is present. A computed tomography (CT) scan is often performed in the early evaluation of pancreatitis, but we suggest that this should often not be necessary if the diagnosis is clear from other clinical parameters. A CT scan is often more valuable if performed on or after day 5 of a severe clinical course, at which point the presence or absence of pancreatic necrosis may be noted and has important prognostic implications. In elderly patients with mild pancreatitis, a CT scan, either at initial presentation or at four‐ to eight‐week follow‐up (once inflammation has completely diminished), can be important to rule out the rare possibility of tumour. In patients with persistent symptoms after weeks, a CT scan may also reveal the presence of a pseudocyst or walled‐off necrosis. The role of magnetic resonance cholangiopancreatography (MRCP) has expanded significantly over the years. MRCP can visualize biliary and pancreatic duct obstructions, occult lesions, microlithiasis, autoimmune pancreatitis, and complications of severe pancreatitis, e.g. peripancreatic fluid collections, necrosis, and pancreatic duct disruption. Due to its non‐invasive nature, it has largely replaced diagnostic endoscopic retrograde cholangiopancreatography (ERCP) for the investigation of suspected bile duct stones or other biliary or pancreatic ductal pathology. ERCP is now recognized as a high‐risk technique that is better suited to therapeutic indications.

In select patients, ERCP is indicated when there is a high pre‐test probability for choledocholithiasis, cholangitis, and biliary obstruction. Endoscopic ultrasound (EUS) is another highly sensitive diagnostic modality to visualize the biliary system, pancreatic duct, and parenchyma; it has had a growing role, in conjunction with MRCP, in ruling out biliary stones or sludge as a cause of pancreatitis.