Case Files Surgery, (LANGE Case Files) 4th Ed.

SECTION II. Clinical Cases

CASE 31

A 26-year-old man is seen in the emergency department for abdominal pain that began after returning home from a party where he consumed pizza and eight beers. The pain is constant, located in the upper part of his abdomen, and radiates to his back. Approximately 3 to 4 hours after onset of the pain, the patient vomited a large amount of undigested food, but the emesis did not resolve his pain. His past medical history is unremarkable, and he consumes alcohol only during the weekends when he attends parties with his friends. On examination, the patient appears uncomfortable. His temperature is 38.8°C (101.8°F), heart rate 110 beats/min, blood pressure 110/60 mm Hg, and respiratory rate 28 breaths/min. The abdomen is distended and tender to palpation in the epigastric and periumbilical areas. Laboratory studies reveal a WBC count of 18,000/mm3, hemoglobin 17 g/dL, hematocrit 47%, glucose 210 mg/dL, total bilirubin 3.2 mg/dL, aspartate aminotransferase (AST) 380 U/L, alanine aminotransferase (ALT) 435 U/L, lactose dehydrogenase (LDH) 300 U/L, and serum amylase 6800 IU/L. Arterial blood gas studies (room air) reveal pH 7.38, Paco2 33 mm Hg, Pao2 68 mm Hg, and HCO3 21 mEq/L. Chest radiography reveals the presence of a small pleural effusion.

Images What is the most likely diagnosis?

Images What are your next steps?

Images What are the complications associated with this disease process?

ANSWERS TO CASE 31: Pancreatitis (Acute)

Summary: A 26-year-old man presents with acute nausea and vomiting and abdominal pain radiating to the back following binge drinking. The clinical presentation of fever, leukocytosis, hemoconcentration, elevated amylase level, and hypoxemia suggests severe acute pancreatitis.

• Most likely diagnosis: Acute pancreatitis.

• Next steps: Resuscitative measures including administration of supplemental oxygen and intravenous fluids.

• Complications of the disease: Acute pancreatitis can cause local complications, including hemorrhage, necrosis, fluid collection, and infection. Pancreatitis may also lead to systemic complications such as pulmonary, cardiac, and renal dysfunction.

ANALYSIS

Objectives

1. Be familiar with the diagnosis and initial treatment of patients with acute pancreatitis.

2. Recognize the value and limitations of clinical prognosticators and CT scans in evaluating patients with acute pancreatitis.

3. Understand the diagnosis and management of the regional and systemic complications of acute pancreatitis.

Considerations

This patient, with a history of alcohol consumption and the sudden onset of abdominal and back pain, likely has acute alcoholic pancreatitis. This diagnosis is further supported by findings from the patient’s physical examination and the elevated serum amylase level. The amylase level is helpful for diagnosis but does not correlate with the severity of the disease. The patient’s fever, tachypnea, and hyperdynamic state are caused by the systemic inflammation related to acute pancreatitis. The presence of three of the Ranson criteria (WBC, LDH, and AST measurements) and initial chest x-ray findings of pleural effusion indicate a severe process. Based on these initial findings, close monitoring of the patient’s cardiopulmonary status in an ICU and a CT scan of his abdomen to assess the pancreas for evidence of necrosis may be appropriate. During the ICU stay, the patient is monitored for signs of distant organ dysfunction, including respiratory insufficiency (Pao2/Fio2), renal insufficiency (urine output and serum creatinine), cardiac dysfunction (blood pressure, pressor requirement), and neurologic dysfunction (Glasgow Coma Score [GCS]). Patients with severe pancreatitis experience severe catabolism leading to rapid loss of lean body mass; therefore nutritional support should be considered and initiated early to counterbalance this effect. For most patients, intragastric or enteral nutritional support can be initiated as soon as initial resuscitation for shock is completed.

APPROACH TO: Acute Pancreatitis

DEFINITIONS

INFECTED PANCREATIC NECROSIS: An infectious complication with necrotic pancreas and peripancreatic tissue, which is most frequently caused by secondary infection by bowel-derived microorganisms within the first few weeks of onset. Antibiotic prophylaxis may be beneficial in preventing this complication, and operative debridement is indicated in managing this process.

PANCREATIC ABSCESS: Secondary infection of the pancreas and peripancreatic fluid collection. This condition is usually encountered at 3 to 6 weeks after the onset of severe pancreatitis and is recognized by the accumulation of thick, purulent fluid and infected debris. Surgical drainage is generally indicated in treating this condition.

INFECTED PANCREATIC PSEUDOCYST: Usually a late process that occurs several weeks or months after the onset of severe pancreatitis. This process usually occurs ≥6 weeks following the onset of severe pancreatitis and can be adequately treated by percutaneous drainage.

PERIPANCREATIC LOCAL DISEASE PROGRESSION: Severe pancreatitis may produce pancreas necrosis during the first few days after disease onset. This process may or may not be associated with peripancreatic fluid collections, which are different from pseudocysts because during early pancreatitis, the fluid is walled off by surrounding structures rather than contained by a fibrinous pseudocapsule. As the severe pancreatitis improves, areas of pancreas necrosis undergo liquefaction and produce a combination of solid and liquid structures, which is referred to as a pancreatic phlegmon. With continued improvement of the pancreatitis, the solid tissue debris are further broken down by the host, and at the same time the local inflammation produces a fibrinous response around the fluid collections, which form pseudocysts.

CLINICAL APPROACH

In North America and Europe, the most common etiologies of acute pancreatitis are gallstones and alcohol consumption. Acute pancreatitis should be diagnosed early because it may alter the management of the disease. The diagnosis is based on the history and typical clinical presentation of severe epigastric pain that radiates to the back, nausea, vomiting, and fever. Serum amylase and lipase levels confirm the diagnosis in patients with the symptoms just listed, but by themselves they are not diagnostic because they can be elevated in other pathologic conditions.

The severity of acute pancreatitis ranges from mild and self-limited (85% of cases) to severe and complicated (15% of cases). Mild pancreatitis is characterized by edema of the pancreas and rarely proceeds to necrosis or infection. Severe pancreatitis is characterized by necrosis of the pancreas and may be complicated by infection in approximately 50% of cases. Furthermore, severe pancreatitis is associated with increased microvascular permeability, leading to large-volume losses of intravascular fluid into the tissues, thereby decreasing perfusion of the lungs, kidneys, and other organs. The most important element in preventing multiple-organ failure is fluid resuscitation and intensive monitoring. Much current investigation has focused on the systemic inflammatory response syndrome and multiple-organ failure during pancreatitis.

Prognostic Criteria

Several prognostic systems have been developed to differentiate between mild and severe pancreatitis. One of the oldest and most widely used system is the Ranson criteria (Table 31–1), which include five parameters determined at the time of admission and six parameters determined during the subsequent 48 hours. The Ranson criteria attempt to reflect the severity of the retroperitoneal inflammatory process, and the original purpose was to help predict patient outcome. Patients with three or more Ranson criteria have more severe disease and an increased risk of complications and death; however, with current improvements in patient care, the high-mortality rates identified by the investigators are no longer applicable. Although helpful in the diagnosis, serum amylase and lipase levels do not correlate with the severity of pancreatitis. Other prognostic systems such as APACHE II (Acute Physiology and Chronic Health Evaluation II) and C-reactive protein levels have similar sensitivity and specificity when compared to the Ranson criteria.

Table 31–1 • RANSON CRITERIA

Images

Computed Tomography Imaging of the Abdomen

Contrast-enhanced CT imaging of the pancreas should be performed when the diagnosis of pancreatitis is in question. In addition, patients who do not improve clinically in 3 to 5 days or who have severe pancreatitis based on the Ranson score should undergo contrast-enhanced CT scanning of the pancreas to determine the presence of necrosis. Two or more extrapancreatic fluid collections or necrosis (nonenhancement) of more than 50% of the pancreas indicate severe disease and an increased risk of complications. Necrotizing pancreatitis is complicated by infection approximately 50% of the time, and prophylactic antibiotics should be prescribed when necrosis is confirmed by a CT scan, because appropriate prophylactic antibiotics have been shown to significantly reduce the occurrence of peripancreatic infections. Severe pancreatitis can lead to other complications such as hemorrhage and splenic vein thrombosis. Pancreatic abscesses and pseudo-cyst formation are other possible complications of acute pancreatitis.

The diagnosis of acute pancreatitis is initially a presumptive one. Patients presenting with acute abdominal symptoms require careful clinical, biochemical, and radiologic evaluations to exclude other intra-abdominal processes such as bowel obstruction, perforated viscus, and mesenteric ischemia. It is also important to determine the severity of the disease. The presence or absence of gallstones should be determined as early as possible, usually with ultrasonography. Patients with gallstone pancreatitis require cholecystectomy once the pancreatitis has resolved.

Treatment

The initial treatment of acute pancreatitis is nonoperative and focuses on fluid resuscitation, pain management, ventilatory support, adequate oxygenation, and renal perfusion. Patients with severe pancreatitis should be monitored in an ICU. Gastric decompression is indicated for patients with nausea and vomiting. Approximately 85% of patients improve with these supportive measures. In the 15% of patients who do not improve within 3 to 5 days, a contrast-enhanced CT scan of the pancreas should be obtained to determine the presence of pancreatic necrosis. Broad-spectrum antibiotics against enteric pathogens are indicated in patients with necrotizing pancreatitis in reducing peripancreatic infections. One very effective antibiotic in penetrating the pancreatic tissue is imipenem–cilastatin. The role of prophylactic antibiotics for patients with pancreatic necrosis is unclear. The controversies are that there have been published studies to suggest that antibiotics may reduce infectious complications in patients with severe forms of pancreas necrosis; however, antibiotic prophylaxis has also been demonstrated to cause increased risk of infections by resistance bacteria and fungal species. Aggressive nutritional support and proper electrolyte replacement are also important in the successful management of patients with severe pancreatitis.

Percutaneous needle aspiration of fluid collections or necrotic areas found on CT imaging can be performed to identify the presence of infection and guide therapeutic decisions about the need for drainage. When infected pancreatic necrosis or infected fluid is present, operative debridement or percutaneous drainage is indicated. Patients with sterile necrosis generally improve with nonoperative therapy, including antibiotics and intensive support; however, surgical exploration may be indicated in patients showing clinical deterioration despite appropriate nonoperative therapy. Over the past decade, most surgeons have adapted a more conservative approach toward patients with severe pancreatitis and pancreas necrosis. It is generally accepted that delaying operative interventions until later in the disease process (>14 days after onset) produces lower complication rates, shorter hospitalizations, and lower mortality.

Patients with gallstone pancreatitis (confirmed by ultrasound) may require endoscopic retrograde cholangiopancreatography (ERCP) if evidence of biliary obstruction persists. The patient described in this case should undergo abdominal ultrasonography on admission, and daily serum liver function test values should be measured. If the total bilirubin level does not decrease, the patient should undergo ERCP to clear the duct of stones and to prevent biliary complications. Patients with gallstone pancreatitis usually undergo cholecystectomy before discharge to prevent recurrent attacks, which occur in up to a third of patients who do not undergo cholecystectomy.

The initial nutritional support for patients with acute pancreatitis has been extensively studied. The traditional concept of acute pancreatitis was that pancreatic injury and destruction associated with the process were secondary to overstimulated acinar cell functions; therefore, resting of the pancreas was considered the mainstay of therapy. Recent evidences have shown that acinar cell stimulation does not appear to exacerbate the injury associated with pancreatitis, and that the pain that some patients with pancreatitis experience with food ingestion is not associated with worsening of the pancreatitis. Based on these recent evidences, it is appropriate to attempt oral feeding in patients with acute pancreatitis, and, if the patient should develop pain, an alternative route of nutritional support (eg, postpyloric tube feeding) can be attempted.

COMPREHENSION QUESTIONS

31.1 A 28-year-old man with a 5-day history of progressively worsening abdominal pain and nausea and vomiting is diagnosed with acute pancreatitis. Which of the following is the best treatment for this patient?

A. Observation and monitoring

B. Restriction of fluids to 80 mL/h

C. Intravenous antibiotic therapy to prevent pancreatic abscess formation

D. Hypertonic glucose solution to prevent hypoglycemia

E. Exploratory laparoscopy to look for peripancreatic complications

31.2 A 42-year-old man with alcoholism has chronic pancreatitis and presents with a palpable abdominal mass. He is noted to have a slightly elevated serum amylase level. Which of the following is the most likely diagnosis?

A. Pancreatic cancer

B. Pancreas necrosis

C. Pancreatic abscess

D. Hepatic hemangioma

E. Pancreatic pseudocyst

31.3 A 65-year-old woman is hospitalized with gallstone pancreatitis and noted to have significant abdominal pain, emesis, tachycardia, and tachypnea. Her amylase level is 3100 IU/L, glucose is 120 mg/dL, and calcium level is 13 mg/dL. Which of the following is most likely to correlate with poor prognosis in disease severity?

A. The patient’s age

B. The high amylase level

C. A glucose level less than 140 mg/dL

D. Hypercalcemia

E. Body mass index of 22

31.4 A 43-year-old woman has been hospitalized for 15 days due to worsening pancreatitis associated with multiple-organ dysfunction syndrome. She now has developed fever and leukocytosis and is diagnosed with extensive infected necrotic pancreatitis. Which of the following is the most appropriate treatment option for this patient?

A. Antibiotic therapy

B. Percutaneous drainage

C. Surgical pancreatic debridement and drainage

D. Endoscopic drainage

E. Antifungal therapy

ANSWERS

31.1 A. Observation and monitoring to determine the severity of pancreatitis, identification and treatment of local and systemic complications, fluid hydration, and parenteral analgesia are the mainstay of therapy. Antibiotic therapy does not decrease the incidence of pancreatic complications unless significant pancreas necrosis is present. Strict gycemic control is important for patients with pancreatitis to help prevent infectious complications.

31.2 E. Pancreatic pseudocysts are collections of fluid and necrotic tissue around the pancreas and usually resolve over several weeks to months, but they occasionally persist and cause symptoms, necessitating surgery.

31.3 A. The level of the amylase or lipase does not correlate with disease severity. Hypoxemia, hypocalcemia, and age more than 55 years are some of the poor prognostic factors based on Ranson criteria. High body mass index has been reported to be associated with worse prognosis related to acute pancreatitis.

31.4 C. Surgical debridement and drainage are indicated in the treatment of infected pancreatic necrosis, especially in the setting of worsening disease and multiple-organ dysfunction syndrome. In addition to surgical debridement, antimicrobial therapy, enteral nutritional support, and glycemic control are important adjuncts for the treatment of patients with infected pancreas necrosis. Percutaneous drainage is best reserved for the management of infected pseudo-cysts and some pancreatic abscesses.

CLINICAL PEARLS

Images The most important element in preventing multiple-organ failure is fluid resuscitation with intensive monitoring.

Images Serum amylase and lipase levels are useful in diagnosing acute pancreatitis, but these values correlate poorly with disease severity.

Images The primary indications for surgery in chronic pancreatitis include intractable pain, bowel or biliary obstruction, and persistent symptomatic pseudocysts.

REFERENCES

Eatcock FC, Chong P, Mendez N, et al. A randomized study of early nasogastric versus nasojejunal feeding in severe acute pancreatitis. Am J Gastroenterol. 2005;100:432-439.

Pezzilli R, Zerbi A, Di Carlo V, Bassi C, Delle Fave GF. Practical guidelines for acute pancreatitis. Pancreatology. 2010;10:523-535.

Schneider L, Buchler MW, Werner J. Acute pancreatitis with an emphasis on infection. Infect Dis Clin North Am. 2010;24:921-941.