Introduction

Chronic pancreatitis (CP) is an inflammatory process in which the pancreatic parenchyma is altered and replaced by fibrous tissue. This permanently changes the pancreatic duct and parenchyma leading to endocrine and exocrine dysfunctions. ^1,2 In most patients, the main clinical characteristic is pain. Other clinical characteristics depend on the degree of pancreatic endocrine and exocrine dysfunction. ³

This review will focus on diagnostic methods and therapeutic modalities for this entity. Improving each patient’s quality of life depends on understanding the disease as a whole and comprehensive management on a case by case basis.

DIAGNOSIS

Advanced CP is more easily diagnosed than are mild or moderate cases whose diagnosis can be challenging. Diagnosis requires evaluation of a patient’s clinical symptoms, pancreatic function tests and imaging such as magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS). Diagnostic tests can be classified into functional and structural. The latter evaluates the parenchyma and/or duct anatomy. Functional tests can be direct or indirect. The latter has better diagnostic capacity when the disease is in more advanced stages but has lower sensitivity for detecting early and moderate disease. ^2,4

Pancreatic function tests

Pancreatic structure test

Diagnostic imaging is used for structural study of CP, but plain abdominal radiography has a very low sensitivity because the pancreatic calcifications characteristic CP can only be seen when the disease is already well advanced. In the past, endoscopic retrograde cholangiopancreatography (ERCP) using the Cambridge criteria for diagnosis of CP was considered to be the definitive method for evaluating changes in the pancreatic duct. This invasive method, which has had associated complications, has recently been displaced. ⁴

Abdominal computed tomography (CT) is the first line in the diagnostic algorithm for patients suspected of having CP. It is available and non-invasive nature but has low diagnostic yield in cases of mild to moderate CP. When CT scans are inconclusive, Magnetic resonance cholangiopancreatography (MRCP) is indicated. It is superior to CT scans for detecting incipient parenchymal and ductal changes and has better diagnostic sensitivity for early CP. ¹⁰

The use of secretin increases the diagnostic potential of MRCP since it improves evaluation of ducts and of pancreatic secretion into the duodenum. Imaging techniques including abdominal ultrasound allow us to evaluate ductal changes, pancreatic enlargement, calcifications, and peripancreatic collections. ¹¹

Today, endoscopic ultrasound (EUS) is the most sensitive diagnostic method. It can be used to evaluate both the pancreatic parenchyma and the ductal system and has the ability to detect early and late changes in CP. ^12-15 The purpose of EUS is to evaluate alterations of the parenchyma and pancreatic duct and to make early diagnoses.

The literature lacks data to support any particular method of criteria based classification and diagnosis of chronic pancreatitis. There are many classifications and criteria which evaluate issues including duct dilation, irregularity, and enhancement, visualization of secondary ducts and calculi as well hyperechoic foci, bands, lobularity and cysts in the parenchyma. The classification systems include the Lees-Wiersema, Milwaukee, Japanese and Rosemont systems which classify findings as definitive or consistent, suggestive, indeterminate or inconclusive (normal) for CP. ^13-16

Recently, the important concept of minimal endosonographic changes which do not meet criteria for diagnosing pancreatitis has appeared. An article by Sheel explains the issue very well. It describes the diagnostic value of the Japanese and Rosemont criteria in patients with undetermined, suggestive, possible or early chronic pancreatitis and shows that criteria that explain a patient’s symptoms are not always found. ¹⁶ A great majority of patients have pain and typical signs but have normal images even though discrete changes can be seen by EUS. It is important to assess the histories of these patients for social issues, alcohol intake, cigarette smoking, and family histories of disease. If possible, genetic studies and endosonographic follow-up for at least 30 months should be conducted to observe which patients have true chronic pancreatitis, which patients heal, and which patients show improvement of EUS changes. Similarly, patients who have had acute pancreatitis should be followed up to determine who will develop CP. ¹⁶

It is important to determine which EUS criteria help diagnosis the most. In 1993, Wiersema et al. described a scale of the following nine diagnostic criteria. ¹⁷

They gave all of these criteria equal diagnostic values. No optimal cut-off point has been found, but it has been said that the presence of four or more confirms the diagnosis. ¹⁷ Given the poor sensitivity of this classification, in the Rosemont International Consensus was proposed in 2007. It includes the following two major parenchymal criteria. ^14,18

In addition, it includes the following four minor parenchymal criteria.

It includes one major ductal criterion:

It includes four minor ductal criteria:

A diagnosis is made with one major parenchymal and three minor criteria or with two major parenchymal or ductal criteria or with two major parenchymal criteria. A diagnosis of chronic pancreatitis is suggested by three minor criteria or with only one ductal or pancreatic parenchyma criterion. ^14,18

In 2010, the Japanese criteria for chronic pancreatitis were issues. They include the following criteria. ¹⁹

Although this Japanese classification is more sensitive and specific, it is difficult to use because it combines multiple variables. The use of endosonography with the Rosemont criteria is easier. Here is a summary list of some findings that can be observed:

Figure 1 Calculi in the parenchyma of the pancreas and branches seen by Fujinon’s linear endosonography (image edited by the Union of Surgeons SAS, Lázaro Arango). 

Figure 2 Dilation of the Wirsung duct and calculi within it, seen with Fujinon’s linear endosonography (image courtesy of the Union of Surgeons SAS, Lázaro Arango). 

Figure 3 Echogenic bands in Olympus linear endosonography (image courtesy of the Union of Surgeons SAS, Lázaro Arango). 

Figure 4 Fujinon’s linear EUS. Wirsung duct dilation in the body of the pancreas and enhancement of its walls (image courtesy of the Union of Surgeons SAS, Lázaro Arango). 

Figure 5 Linear EUS of the pancreas with Fujinon instrument. Wirsung duct dilation, secondary branch dilation, and lobularity of the gland (image courtesy of the Union of Surgeons SAS, Lázaro Arango). 

Figure 6 Lobularity, fibrous bands, and dilation of secondary branches (image courtesy of the Union of Surgeons SAS, Lázaro Arango). 

EUS also integrates the use of elastography to measure the degree of pancreatic fibrosis and its relationship to the probability of exocrine pancreatic insufficiency. ²⁰

Treatment of chronic pancreatitis

Treatment of CP consists of relieving pain, preventing recurrent attacks, correcting the consequences of endocrine and exocrine insufficiency such as diabetes and malnutrition, and treating any complications that may arise. It begins with medical management. Endoscopic and/or surgical treatment should be used only when medical treatment fails to relieve pain or for management of complications. ²¹

Endoscopic Treatment

Endoscopic treatment for CP is indicated in cases with stones that obstruct the pancreatic duct, benign biliary stenosis, pancreatic stenosis, pancreatic pseudocyst drainage, and celiac plexus block. ²⁸

Primary pancreatic duct stones smaller than 5 mm are managed with standard ERCP maneuvers for stone removal (Figures 7, 8, 9, 10). Stones larger than 5 mm require the use electrohydraulic, extracorporeal, or Spyglass-guided electrohydraulic lithotripsy. In the latter case, the duct can be entered for use of a laser to fragment stones. ²⁹ We have been gaining experience with the use of a cholangioscope which has been very useful for non-surgical management of patients with pancreatic stones. Figures 11, 12 and 13 show the Spyglass inside the Wirsung duct performing laser lithotripsy on a large stone. After the procedure, a pancreas stent is always placed.

Figure 7 Cannulation of the Wirsung duct. Cloudy material is seen due to chronic pancreatitis (image courtesy of the Union of Surgeons SAS, Lázaro Arango). 

Figure 8 Opening cut of the pancreatic duct (image courtesy of the Union of Surgeons SAS, Lázaro Arango). 

Figure 9 Exploration of the Wirsung duct with Dormia basket (image courtesy of the Union of Surgeons SAS, Lázaro Arango). 

Figure 10 Stone extraction from the Wirsung duct (image courtesy of the Union of Surgeons SAS, Lázaro Arango). 

Figure 11 Calculi within the Wirsung duct seen by cholangioscopy (image courtesy of Unión de Cirujanos SAS, Manizales, Colombia). 

Figure 12 Calculus fragments fractured by laser and ready to be extracted (image courtesy of Unión de Cirujanos SAS, Manizales, Colombia). 

Figure 13 Stones to be removed with lithotripsy are shown in the upper left. The upper right is the same image as in Figure 12. Below left is the guide used to introduce the extraction balloon to sweep or clean the remnants of stones. Below right, the pancreatic stent placed at the end of the procedure is shown. 

ERCP plus sphincterotomy, balloon dilation, and plastic, metal, or biodegradable stents are used to manage biliary strictures and the main pancreatic duct. ³⁰ A pseudocyst should be treated when it becomes symptomatic and can be done by either a transpapillary or transmural (transgastric or transduodenal) route. The ERCP-guided approach is indicated for lesions measuring less than 5 mm which disrupt the main pancreatic duct. For large pseudocysts, EUS-guided transmural drainage is indicated. ^28,30

A celiac plexus block is used to manage pain, especially in patients who require high doses of narcotics. It relieves pain and reduces the need to administer analgesics, but its effect is temporary. ²¹ The procedure consists of a guided injection (preferably by EUS) of a steroid and a local anesthetic into the celiac plexus to cut the afferent nociception pathways. ¹

Conclusion

CP significantly alters patients’ quality of life. Management should initially focus on pain management, but should also work to prevent and manage complications. The approach must be comprehensive and multidisciplinary with the judicious use of replacement therapy and early intervention, using endoscopic and surgical therapy only for selected patients.