Acute pancreatitis: Clinical sciences

Acute pancreatitis is an inflammation of the pancreas, most commonly caused by biliary stones, followed by alcohol use and hypertriglyceridemia, but can also be idiopathic. There are many other causes of acute pancreatitis, including trauma, iatrogenic post-endoscopic retrograde cholangiopancreatography or ERCP, autoimmune disorders, genetic diseases, infections, malignancies, toxic exposure, and medications like thiazides, antiretrovirals, and valproic acid. Depending on the severity of the disease, pancreatitis can range from mild to moderate or even severe, life-threatening pancreatitis.

The first step in assessing a patient with signs and symptoms suggestive of acute pancreatitis is to perform the ABCDE assessment to determine if the patient is stable or unstable. If the patient is unstable, start acute management and stabilize the airway, breathing, and circulation. Next, obtain IV access and initiate IV fluids for aggressive resuscitation. Make sure the patient is NPO, and provide supportive care including pain management and antiemetic medication.

Alright, now let's talk about stable patients. Start by taking a focused history and physical examination. Usually, patients with acute pancreatitis present with persistent, unremitting epigastric abdominal pain that radiates to the back, worsens after meals, and improves when leaning forward. The pain is often associated with nausea and vomiting, while some patients might report a fever as well. It is also possible for patients to present with jaundice as a sign of biliary obstruction. Additionally, some patients might develop tetany, or involuntary muscle spasms, as a result of hypocalcemia. Finally, don’t forget to ask about a history of similar previous episodes, cholelithiasis, or alcohol use.

Physical exam typically reveals epigastric abdominal tenderness, distention, or guarding. Some patients' physical examinations may show ecchymosis due to associated intra-abdominal or retroperitoneal bleeding. Examples include the Cullen sign, or periumbilical ecchymosis; the Grey-Turner sign, or flank ecchymosis; the Fox sign, or inguinal ecchymosis; and the Bryant sign, or scrotal ecchymosis. Lastly, in some cases, you might find signs of fluid sequestration like ascites or pleural effusion.

These findings should make you suspect acute pancreatitis.The next step is to get labs. The obvious labs you should think of are lipase and amylase to confirm the diagnosis; but be sure to also check CBC, total and direct bilirubin, LFTs, LDH, glucose, calcium, and triglycerides, which will help determine the cause and severity. First of all, if labs show that lipase and amylase levels are normal, then consider an alternative diagnosis.

On the other hand, if lipase levels are elevated, with or without elevated amylase levels, you should suspect acute pancreatitis. Other labs can help you identify the cause; for instance, elevated total and direct bilirubin with elevated LFTs typically indicates gallstone pancreatitis; while sometimes elevated LFTs may indicate liver disease from excessive alcohol use, hinting at alcohol-induced hepatitis; and elevated triglycerides may indicate hypertriglyceridemia-induced pancreatitis. The remaining labs will be used later to help determine the severity of the disease.

Next, you should also consider imaging to help confirm your diagnosis and look for possible causes. For example, you will usually want to start with an abdominal x-ray and CT of the abdomen and pelvis with IV contrast. In certain cases, you can also consider an ultrasound and MRI with magnetic resonance cholangiopancreatography, or MRI/MRCP, because they are ideal for detecting gallstones.

Okay, let's take a look at the imaging findings. X-ray may often be normal or show non-specific findings, while CT may show peripancreatic free fluid, fat stranding, and pancreatic edema. Additionally, you may or may not find an enlarged pancreatic duct. If the patient has gallstones, then an ultrasound may show stones or biliary sludge in the gallbladder, as well as stones in the biliary tree, and possibly a dilated biliary tree.

Finally, an MRI/MRCP might show an enlarged, edematous pancreas with or without peripancreatic free fluid. You may also see common bile duct or CBD obstruction. If you have these findings, you can diagnose acute pancreatitis.

Here’s a clinical pearl to simplify things! In general, acute pancreatitis is diagnosed by meeting two out of three criteria: clinical presentation of epigastric abdominal pain, labs showing elevated serum lipase or amylase 3 times above the normal upper limit, and radiologic evidence of pancreatitis.

Alright, now that we have a diagnosis, let’s talk about next steps. It is important to assess the severity of the disease as it can range from mild to fatal, which will of course determine the management.