Chronic Pancreatitis - Disorders of the Pancreas

CHRONIC PANCREATITIS

Chronic pancreatitis is an inflammatory disorder characterized by progressive anatomic and functional destruction of the pancreas. As cells are replaced by fibrous tissue with repeated attacks of pan-creatitis, pressure within the pancreas increases. The end result is mechanical obstruction of the pancreatic and common bile ducts and the duodenum. Additionally, there is atrophy of the epithelium of the ducts, inflammation, and destruction of the secreting cells of the pancreas.

Alcohol consumption in Western societies and malnutrition worldwide are the major causes of chronic pancreatitis. Excessive and prolonged consumption of alcohol accounts for approximately 70% of the cases (Clain & Pearson, 1999). The incidence of pan-creatitis is 50 times greater in alcoholics than in the nondrinking population. Long-term alcohol consumption causes hypersecre-tion of protein in pancreatic secretions, resulting in protein plugs and calculi within the pancreatic ducts. Alcohol also has a direct toxic effect on the cells of the pancreas. Damage to these cells is more likely to occur and to be more severe in patients whose diets are poor in protein content and either very high or very low in fat.

Clinical Manifestations

Chronic pancreatitis is characterized by recurring attacks of se-vere upper abdominal and back pain, accompanied by vomiting. Attacks are often so painful that opioids, even in large doses, do not provide relief. As the disease progresses, recurring attacks of pain are more severe, more frequent, and of longer duration. Some patients experience continuous severe pain; others have a dull, nagging constant pain. The risk of dependence on opioids is increased in pancreatitis because of the chronic nature and severity of the pain.

Weight loss is a major problem in chronic pancreatitis: more than 75% of patients experience significant weight loss, usually caused by decreased dietary intake secondary to anorexia or fear that eating will precipitate another attack. Malabsorption occurs late in the disease, when as little as 10% of pancreatic function re-mains. As a result, digestion, especially of proteins and fats, is im-paired. The stools become frequent, frothy, and foul-smelling because of impaired fat digestion, which results in stools with a high fat content. This is referred to as steatorrhea. As the disease progresses, calcification of the gland may occur, and calcium stones may form within the ducts.

Assessment and Diagnostic Findings

ERCP is the most useful study in the diagnosis of chronic pan-creatitis. It provides detail about the anatomy of the pancreas and the pancreatic and biliary ducts. It is also helpful in obtaining tissue for analysis and differentiating pancreatitis from other conditions, such as carcinoma. Various imaging procedures, in-cluding magnetic resonance imaging, computed tomography, and ultrasound, have been useful in the diagnostic evaluation of patients with suspected pancreatic disorders. Computed tomog-raphy scanning or ultrasound is helpful to detect pancreatic cysts.

A glucose tolerance test evaluates pancreatic islet cell function, information necessary for making decisions about surgical resec-tion of the pancreas. An abnormal glucose tolerance test indica-tive of diabetes may be present. In contrast to the patient with acute pancreatitis, serum amylase levels and the white blood cell count may not be elevated significantly.

Medical Management

The management of chronic pancreatitis depends on its probable cause in each patient. Treatment is directed toward preventing and managing acute attacks, relieving pain and discomfort, and managing exocrine and endocrine insufficiency of pancreatitis.

NONSURGICAL MANAGEMENT

Nonsurgical approaches may be indicated for the patient who re-fuses surgery, who is a poor surgical risk, or whose disease and symptoms do not warrant surgical intervention. Endoscopy to re-move pancreatic duct stones and stent strictures may be effective in selected patients to manage pain and relieve obstruction. How-ever, such therapy is available only in special centers and is suit-able for few patients (Bornman & Beckingham, 2001).

Management of abdominal pain and discomfort is similar to that of acute pancreatitis; however, the focus is usually on the use of nonopioid methods to manage pain. Persistent, unrelieved pain is often the most difficult aspect of management (Bornman Beckingham, 2001). The physician, nurse, and dietitian em-phasize to the patient and family the importance of avoiding al-cohol and other foods that the patient has found tend to produce abdominal pain and discomfort. The fact that no other treatment is likely to relieve pain if the patient continues to consume alco-hol is stressed to the patient.

Diabetes mellitus resulting from dysfunction of the pancreatic islet cells is treated with diet, insulin, or oral antidiabetic agents.

The hazard of severe hypoglycemia with alcohol use is stressed to the patient and family. Pancreatic enzyme replacement is indi-cated in the patient with malabsorption and steatorrhea (Trolli, Conwell & Zuccaro, 2001).

SURGICAL MANAGEMENT

Surgery is generally carried out to relieve abdominal pain and dis-comfort, restore drainage of pancreatic secretions, and reduce the frequency of acute attacks of pancreatitis. The surgery performed depends on the anatomic and functional abnormalities of the pancreas, including the location of disease within the pancreas, diabetes, exocrine insufficiency, biliary stenosis, and pseudocysts of the pancreas. Other factors taken into consideration in deter-mining whether surgery is to be performed and what procedure is indicated include the patient’s continued use of alcohol and the likelihood that the patient will be able to manage the en-docrine or exocrine changes that are expected after surgery.

Pancreaticojejunostomy (also referred to as Roux-en-Y)with a side-to-side anastomosis or joining of the pancreatic duct to the jejunum allows drainage of the pancreatic secretions into the jejunum. Pain relief occurs by 6 months in more than 80% of the patients who undergo this procedure, but pain returns in a substantial number of patients as the disease itself progresses (Tierney et al., 2001).

Other surgical procedures may be performed for different de-grees and types of disease, ranging from revision of the sphincter of the ampulla of Vater, to internal drainage of a pancreatic cyst into the stomach (see Pancreatic Cyst discussion), to insertion of a stent, to wide resection or removal of the pancreas. A Whipple resection (pancreaticoduodenectomy) has been carried out to relieve the pain of chronic pancreatitis.

Autotransplantation or implantation of the patient’s pancreatic islet cells has been attempted to preserve the endocrine function of the pancreas in patients who have undergone total pancreatec-tomy. Testing and refinement of this procedure continue in an ef-fort to improve outcomes.

When chronic pancreatitis develops as a result of gallbladder disease, the obstruction is treated by surgery to explore the com-mon duct and remove the stones; usually, the gallbladder is re-moved at the same time. In addition, an attempt is made to improve the drainage of the common bile duct and the pancre-atic duct by dividing the sphincter of Oddi, a muscle that is lo-cated at the ampulla of Vater (this surgical procedure is known as a sphincterotomy). A T-tube usually is placed in the common bile duct, requiring a drainage system to collect the bile post-operatively. Nursing care after such surgery is similar to that in-dicated after other biliary tract surgery.

Patients who undergo surgery for chronic pancreatitis may ex-perience weight gain and improved nutritional status; this may result from reduction in pain associated with eating rather than from correction of malabsorption. However, morbidity and mor-tality after these surgical procedures are high because of the poor physical condition of the patient before surgery and the con-comitant occurrence of cirrhosis. Even after undergoing these surgical procedures, the patient is likely to continue to have pain and impaired digestion secondary to pancreatitis unless alcohol is avoided completely.