Chronic pancreatitis: Clinical sciences

Chronic pancreatitis refers to persistent, chronic inflammation of the pancreas that’s associated with irreversible changes, such as fibrosis, calcifications, and atrophy. This eventually decreases the function of the exocrine pancreas, subsequently causing difficulties with digestion and absorption of nutrients, as well as abdominal pain that’s worse with eating, steatorrhea, and unintentional weight loss. Additionally, the destruction of the endocrine pancreas can lead to difficulties in producing hormones, such as insulin. Now, there’s a variety of conditions that can cause chronic pancreatitis, including toxins like chronic alcohol consumption, and metabolic conditions; genetic and autoimmune conditions; as well as recurrent acute pancreatitis and ductal obstruction. An important thing to remember is that tobacco smoking may not be a direct cause, but it is a strong risk factor.

Now, if you suspect chronic pancreatitis, first perform an ABCDE assessment to determine if your patient is unstable or stable. If unstable, stabilize the patient’s airway, breathing, and circulation. Next, obtain IV access and, if needed, start IV fluids. Finally, put your patient on continuous vital sign monitoring.

Ok, now let’s go back to the ABCDE assessment and take a look at stable individuals. If the patient is stable, obtain a focused history and physical examination. These patients typically report upper abdominal pain that can range from constant and dull, to acute and stabbing. Sometimes, the pain might radiate to the back and can be relieved by leaning forward. Other important history findings include nausea, vomiting, and diarrhea. Also, they might report fatty stools that are difficult to flush, abdominal bloating, and unexplained weight loss.

Moreover, these findings typically occur due to progressive loss of acinar cells that eventually result in decreased production of digestive enzymes and subsequent malabsorption. This condition is called Pancreatic Exocrine Insufficiency, or PEI for short.

On the other hand, physical exam findings typically include tenderness to palpation in the upper abdomen.

At this point, you should suspect chronic pancreatitis. Your next step is to order labs, such as lipase, amylase, fecal elastase-1, trypsinogen, and trypsin. Additionally, don’t forget to order imaging, primarily CT or MRI, but in some cases you may also get an endoscopic ultrasonography or EUS, as well as a secretin-stimulated magnetic resonance cholangiopancreatography or s-MRCP. Rarely, you may want to get a biopsy of the pancreas.

A clinical pearl to keep in mind is that there’s no single diagnostic test for pancreatitis, so your diagnosis must be based on a combination of the right history, clinical presentation, lab results, and imaging findings.

Labs often reveal elevated amylase and lipase, as well as low fecal elastase-1, trypsinogen and trypsin.

Keep in mind that, in acute pancreatitis, amylase and lipase would be elevated more than three times the upper limit of normal; however, in chronic pancreatitis, these enzymes can be only mildly elevated or even normal, especially as the pancreas is replaced by increasing amounts of fibrotic tissue later in the disease process. For this reason, they are a poor indicator of pancreatic inflammation and do not correlate with the severity of clinical presentation in chronic pancreatitis.

That’s why you need imaging! CT and MRI typically reveal the “chain of lakes” sign from dilated and irregular pancreatic ducts, as well as extensive ductal calcifications, which are pathognomonic findings of chronic pancreatitis. Additionally, there might be pancreatic atrophy, which is actually highly specific for end-stage chronic pancreatitis.

If the CT and MRI are inconclusive, proceed with EUS or s-MRCP to get more detailed examination of pancreatic and ductal abnormalities. If additional imaging is still not confirmatory for chronic pancreatitis, but your clinical suspicion remains high, consider a biopsy of the pancreas.

Now, the combination of the clinical presentation with these lab results and imaging findings is highly suggestive of chronic pancreatitis. Once you set the diagnosis, your next step is to determine the underlying cause. A mnemonic that can help you remember the most common causes of chronic pancreatitis is TIGARO, which stands for Toxic and metabolic, Idiopathic, Genetic, Autoimmune, Recurrent acute pancreatitis or RAP, and Obstruction.

First, let’s start with toxic and metabolic causes. For example, if your patient reports excessive alcohol use, you should suspect alcohol-induced pancreatitis and order labs, primarily AST and ALT. If AST and ALT are elevated, usually around 2 times the upper limit of normal, you can confirm the diagnosis of alcohol-induced pancreatitis.