Clinical Signs and Characteristics of Pancreatitis July/August 2012 issue of Radiologic Technology. Directed Readings In the Classroom

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Objectives Describe the underlying physiologic alterations that lead to acute and chronic pancreatitis. Summarize the clinical presentation of acute and chronic pancreatitis. Explain the etiology, diagnosis, and medical management of pancreatitis. Identify and distinguish the imaging characteristics of pancreatitis as seen on computed tomography and sonography.

Pancreas The pancreas is a hard-working, 6- to 8-inch long, tadpole-shaped glandular organ with complex structures that perform vital functions. The pancreas is most often found within the midline of the upper abdomen in the epigastric region

Acute Pancreatitis The rapid onset of pancreatic inflammation is referred to as acute pancreatitis, a common disease with the potential for substantial morbidity and mortality. It comprises a wide range of diseases that vary from focal or diffuse pancreatic edema to severe necrosis of the gland.

Pathogenesis of Acute Pancreatitis The pathogenesis of acute pancreatitis includes: The edema or obstruction of the ampulla of Vater by a biliary stone. The reflux of bile into the pancreatic duct from a faulty sphincter of Oddi, subsequently leading to edema of the pancreas. A predisposing factor, such as genetic causes, that allows for the premature activation of pancreatic enzymes. Regardless of the origin, the chief mechanism for the destruction of the gland is autodigestion of the pancreatic tissue by inappropriately activated pancreatic digestive enzymes.  

Acute Pancreatitis: Clinical Assessment Pancreatitis has a wide spectrum of clinical manifestations. Acute abdominal pain is the hallmark of acute pancreatitis, however abdominal pain may be mild to severe, making the clinical manifestations unpredictable and somewhat vague.   Other clinical assessments include: Laboratory findings consistent with the diagnosis of acute pancreatitis include an elevation in serum amylase and lipase (Amylase levels rise first, typically within the first 24 hours from the disease onset, while lipase levels increase within the first 72 to 96 hours. Physicians often use clinical scoring systems, such as the Ranson score to assess the severity of the disease. A Ranson score takes into account the patient’s age and many vital laboratory findings

Acute Pancreatitis: Imaging Assessment When patients present with acute abdominal pain, concerns multiply. Imaging often confirms a diagnosis when pancreatitis is suspected clinically. Although radiography and MR are valuable, contrast-enhanced CT and sonography are the most practical imaging modalities used for diagnosing acute pancreatitis.

Computed Tomography CT is used to assess the pancreas when pancreatic abnormalities are suspected CT is superior to other imaging modalities because of the speed and accuracy at which it can provide high-resolution, diagnostic information.

Ultrasonography Ultrasonography often is used in screening the acute abdomen. Patients who present with clinical symptoms of pancreatic or biliary disease may be offered a sonographic evaluation of the pancreas before scheduling more expensive and invasive procedures such as CT or ERCP.

Chronic Pancreatitis Chronic pancreatitis can be a severely debilitating disease. It is characterized by progressive destruction, cellular infiltration, and irreversible fibrosis of the gland , with the latter being the hallmark feature. Pathologically, chronic pancreatitis is apparent by the loss of the exocrine pancreatic function.   Chronic pancreatitis causes the organ to undergo considerable structural changes, including: Atrophy. Dilation or stricture of pancreatic duct segments. Calcification development within the parenchyma of the gland. Peripancreatic fluid collections. Alterations of peripancreatic fat.

Pathogenesis of Chronic Pancreatitis Acute pancreatitis and chronic pancreatitis are established as distinct diseases because not all patients with acute pancreatitis develop the chronic form of the disease. There appear to be 2 contradictory theories as to how fibrosis occurs within the organ. Despite the debate, chronic pancreatitis is routinely depicted as having either alcoholic- or nonalcoholic-related causes

Chronic Pancreatitis: Clinical Assessment Diagnosing chronic pancreatitis requires a clinical and imaging approach. The diagnosis can be difficult, and clinical features may be identical to acute pancreatitis. Patients may present with recurrent abdominal, back, or epigastric pain, with other clinical features such as flatulence, weight loss, anorexia, nausea, vomiting, and constipation. Laboratory findings for chronic pancreatitis include an elevation of amylase and lipase during attacks of acute pancreatitis.

Chronic Pancreatitis: Imaging Assessment As with acute pancreatitis, imaging is important in the diagnosis and follow-up care of patients with chronic pancreatitis. ERCP often serves a dual purpose for chronic pancreatitis because it is an outstanding imaging tool and interventional instrument. ERCP is considered the gold standard for diagnosing chronic pancreatitis.   

Conclusions Although much clinical research exists, additional research is needed to understand the intricacies of acute and chronic pancreatitis. We know that the pathogenesis of pancreatitis ultimately begins with the activation of pancreatic enzymes, although how these enzymes become active is unknown. Ultimately, the autodigestion of the organ from these destructive enzymes devastates normal pancreatic tissue and the surrounding tissues of the abdomen, potentially leading to irreparable distortions of anatomic structures, necrosis, and fibrosis.

Discussion Questions Thinking about the different options used to image acute pancreatitis, what are the pros and cons of each option? What is the chief mechanism that causes the destruction of the pancreas? Two theories are present for the cause of chronic pancreatitis, discuss the similarities and difference for these two theories.

Additional Resources Visit www.asrt.org/students to find information and resources that will be valuable in your radiologic technology education.