"Acute Pancreatitis Home"
Acute pancreatitis Mohammad Hossein Somi professor of gastroenterology Liver and Gastrointestinal Disease Research Center Tabriz University of Medical Sciences 1 INCIDENCE AND MORTALITY The incidence of acute pancreatitis in England, Denmark, and the United States varies from 4.8 to 24.2 per 100,000 In a retrospective study from the Netherlands, the observed incidence of acute pancreatitis increased by 28% between 1985 and 1995, but the mortality remained stable due to a decrease in the case-fatality rate 2 INCIDENCE AND MORTALITY The mortality in the first two week period is usually due to systemic inflammatory response syndrome and organ failure, while after two weeks it is usually due to sepsis and its complications The frequency of early (<two weeks after onset) death has been to reported vary from 0 to 50 percent of all deaths due to acute pancreatitis 3 INCIDENCE AND MORTALITY Advances in diagnostic and therapeutic interventions have lead to a decrease in mortality from acute pancreatitis, especially in those with severe, often necrotizing pancreatitis While the overall mortality in all hospitalized patients with acute pancreatitis is approximately 10% (range 2 to 22 percent), the mortality in the subset with severe acute pancreatitis may be as high as 30 percent 4 5 6 7 8 9 MEDICAL TREATMENT OF ACUTE PANCREATITIS 10 Acute pancreatitis can be divided into two broad categories Edematous or mild acute pancreatitis Necrotizing or severe acute pancreatitis – A subgroup of patients has early severe acute pancreatitis characterized by extended pancreatic necrosis with organ failure at admission 11 GENERAL PRINCIPLES OF THERAPY Treatment of acute pancreatitis is aimed at : Correcting any underlying predisposing factors : – Early ERCP in patients with gallstone pancreatitis who have obstructive jaundice or biliary sepsis – Reversal of hypercalcemia – Cessation of possible causative drugs – The administration of insulin to the poorly controlled diabetic with marked hypertriglyceridemia. The pancreatic inflammation itself 12 Mild pancreatitis is treated for several days with supportive care including: – Pain control – Intravenous fluids – NPO The majority of patients require no further therapy, and recover and eat within three to seven days 13 Supportive treatment In severe pancreatitis, ICU monitoring and support of pulmonary, renal, circulatory, and hepatobiliary function may minimize systemic sequelae These patients need monitoring of vital signs and urine output every few hours in the first 24 to 48 hours Patients with severe pancreatitis will need ongoing monitoring for other complications that might arise 14 Fluid resuscitation Fluid resuscitation is particularly important because patients with necrotizing pancreatitis accumulate vast amounts of fluid in the injured pancreatic bed Inadequate hydration can lead to hypotension and acute tubular necrosis Fluid depletion damages pancreatic microcirculation and results in pancreatic necrosis 15 Fluid resuscitation Approximately 250 to 300 cc of intravenous fluids per hour are typically required for 48 hours if the cardiac status permits Adequate fluid replacement can be assessed by improvement in vital signs and urine output and reduction in hematocrit over 24 hours, particularly if it was high at the onset In some patients, a low urine output may already reflect the development of ATN rather than persistent volume depletion 16 supplemental oxygen Oxygen saturation needs to be assessed routinely and supplemental oxygen administered to maintain arterial oxygen saturation of greater than 95 percent – Blood gas analysis should be done if SaO2 is less than 95 percent or if clinical situation demands. Prophylaxis against DVT should be considered in bedridden patients – Intermittent pneumatic compression may be the preferred method because of the theoretical risk of precipitating pancreatic hemorrhage with anticoagulation 17 Pain management Abdominal pain is often the dominant symptom Adequate pain control requires the use of intravenous opiates, usually in the form of a patient controlled analgesia (PCA) pump Meperidine has traditionally been favored over morphine for analgesia in pancreatitis, probably because human studies showed that morphine caused an increase in sphincter of Oddi pressure Despite these data there is no clinical evidence to suggest that morphine can aggravate or cause pancreatitis or cholecystitis 18 Pain management Repeated doses of meperidine can lead to accumulation of the metabolite normeperidine that causes neuromuscular irritation and, rarely, seizures An alternative is intravenous fentanyl, which use in patients who require large doses of meperidine As with other opiates, fentanyl can depress respiratory function – Concurrent use of a calcium channel blocker and a beta-adrenergic blocker with fentanyl has resulted in severe hypotension. 19 Preventing infection in severe acute pancreatitis The occurrence of pancreatic infection is a leading cause of morbidity and mortality in acute necrotizing pancreatitis Approximately one-third of patients with pancreatic necrosis develop infected necrosis Patients who develop infection tend to have more extensive necrosis compared to those in whom the necrotic tissue remains sterile 20 Preventing infection in severe acute pancreatitis Although infection can occur early in the course of necrotizing pancreatitis, it is more often seen late in the clinical course (after 10 days). In one report, for example, necrotic material obtained at surgery was cultured in 114 patients with necrotizing pancreatitis but no abscess formation Bacterial contamination was present in 24 percent of patients operated on within the first seven days and rose to 71 percent in patients operated on in the third week Identical results were noted in another series in which infection (as determined from fluid obtained by CT-guided drainage) developed in 71 percent of patients with pancreatic necrosis 21 Preventing infection in severe acute pancreatitis The important organisms causing infection in necrotizing pancreatitis are predominantly gut-derived, including Escherichia coli, Pseudomonas, Klebsiella, and Enterococcus spp. The majority of infections (about 75 percent) are monomicrobial Fungal infection and infection with gram-positive organisms are uncommon but occur more frequently in the setting of prophylactic antibiotic use for severe acute pancreatitis, especially when used for more than 10 to 14 days Fungal infections occur in approximately 9 percent of necrotizing pancreatitis and it is not clear if they are associated with higher mortality 22 Preventing infection in severe acute pancreatitis Three approaches have been taken to decrease bacterial infections in acute necrotizing pancreatitis: – Enteral feeding to Avoid central line related infections Maintain gut barrier integrity Decrease bacterial translocations – Selective decontamination of the gut with nonabsorbable antibiotics – Prophylactic systemic antibiotics 23 Selective decontamination of the gut Tthe source of bacterial infections in acute necrotizing pancreatitis is the gut Thus, reduction of intestinal bacteria through the use of oral- nonabsorbable antibiotics could theoretically reduce the risk of infection This hypothesis was supported in a controlled trial involving 102 patients with severe acute pancreatitis who were randomly assigned to standard treatment or gut decontamination (using a combination of oral norfloxacin, colistin, and amphotericin) Overall mortality was significantly lower in patients assigned to gut decontamination (22 versus 35 percent). 24 Systemic antibiotics The role of prophylactic systemic antibiotics in acute pancreatitis is unsettled since studies evaluating its benefits and harms have produced disparate results Initial studies done in the mid-1970s failed to show a benefit, possibly because they included patients with mild disease who were at low risk for infection and used antibiotics that had poor penetration into the pancreas (such as ampicillin). In contrast, some more recent studies demonstrated improved outcomes associated with the use of prophylactic antibiotics in patients with severe necrotizing pancreatitis, 25 Complication of AB prophilaxis Because of the risk of fungal infections – Some authorities advocate the use of prophylactic antifungal therapy, an approach that remains to be validated – Others recommend that prophylactic antibiotics should not be used for longer than 7 to 10 days to prevent superinfection with gram-positive and fungal organisms 26 Recommended approach After assessment of the patient, a contrast-enhanced CT scan is indicated only in patients who are deteriorating or have severe pancreatitis determined clinically and by APACHE II score. A CT scan is not required on the first day unless there are other possible diagnoses It takes time for pancreatic necrosis to develop, and treatment is unlikely to be altered on the basis of CT findings on day one 27 If there is necrotizing pancreatitis (involving more than approximately 30 percent of the pancreas), initiate antimicrobial therapy with imipenem/meropenem and continue it for at least one week Do not routinely recommend prophylactic antifungal therapy with fluconazole Patients without severe necrotizing pancreatitis are managed conservatively with the supportive care If at any time the patient becomes unstable from pulmonary, cardiovascular, or renal complications, we perform a minimally invasive necrosectomy, (endoscopic, or percutaneous radiologic) if possible , to remove necrotic debris and pus 28 If there has been no improvement after one week of antibiotics, perform a percutaneous CT-guided aspiration If there is bacterial infection, consider performing a necrosectomy and change the antibiotics according to the culture and sensitivity results If, on the other hand, the aspirated material is sterile, continue conservative treatment for four to six weeks since most such patients do well with medical therapy However, if clinical suspicion for infection is high, a repeat aspiration may be indicated since a negative FNA does not confidently exclude infection 29 Miscellaneous treatments A variety of other therapies have been evaluated in the treatment of acute pancreatitis. Plasma exchange dramatically reduced triglyceride levels and improved the outcome in two patients with necrotizing pancreatitis due to hypertriglyceridemia Intravenous infusion of heparin reduced triglyceride levels and improved the outcome in a pregnant patient with severe acute pancreatitis due to hypertriglyceridemia and may be an option in such cases Hypocalcemia (seen in severe cases) can be treated like any other case of low calcium with no special recommendation because of acute pancreatitis 30 Nutrition Patients with mild pancreatitis can often be managed with intravenous hydration alone since recovery often occurs rapidly In contrast, nutritional support is required in patients with severe pancreatitis Such patients typically have been fed parenterally because they often have an ileus and abdominal pain, and because of the potential for stimulating the pancreas with enteral feeding 31 Nutrition Enteral feeding appears safe and feasible in many patients with acute severe pancreatitis Whenever possible, radiologic or endoscopic placement of a jejunal feeding tube beyond the ligament of Treitz and enteral feeding should be attempted Usually, it is possible to do this within three to five days by which time it is possible to make a diagnosis of severe pancreatitis and assess for ileus use high protein, low fat preparations such as Peptamen. Parenteral nutrition should be initiated in patients who do not tolerate enteral feeding or in whom nutritional goals cannot be reached within two days. 32 Initiation of oral feedings When to begin oral feedings? what to feed? How often to feed are questions that arise in every patient with acute pancreatitis? There have been only a few prospective studies: 33 Initiation of oral feedings In mild pancreatitis, oral intake is encouraged early and advanced from clear liquid diet to solid food as tolerated Recovery generally occurs quickly, making it generally unnecessary to initiate supplemental nutrition Begin oral feedings by giving 100 to 300 mL of clear liquids every four hours for the first 24 hours If this diet is tolerated, feedings are advanced gradually over three to four days to soft and finally to solid foods 34 Initiation of oral feedings All feedings contain greater than 50 percent carbohydrate and the total caloric content is gradually increased from 160 to 640 Kcal per meal Oral feeding is frequently not tolerated due to postprandial pain, nausea, or vomiting probably related to gastroduodenal inflammation and/or extrinsic compression from fluid collections leading to GOO Such patients can generally tolerate feeding through a jejunal tube, which can be placed endoscopically or radiologically 35 Initiation of oral feedings If the target rate is not achieved within 48 to 72 hours, supplemental parenteral nutrition should be provided. Jejunal feeding permits earlier discharge from the hospital and avoidance of TPN A few weeks of jejunal feeding allows for the inflammation to subside or the fluid collection to mature and be drained, leading to resolution of gastric outlet obstruction and resumption of oral feeding 36 ACG GUIDELINE Risk factors for disease severity that should be noted on admission – Older age (>55 years), Obesity (BMI>30 kg/m2), Organ failure at admission, and pleural effusion and/or pulmonary infiltrates Such patients may require treatment in a highly supervised area The two tests that are most helpful at admission in distinguishing mild from severe acute pancreatitis are the APACHE-II score and the hematocrit. The APACHE-II score should be generated during the first three days of hospitalization and repeated as needed. The hematocrit should be measured on admission, 12 hours after admission, and 24 hours after admission to help assess the adequacy of fluid resuscitation 37 ACG GUIDELINE Pancreatic necrosis and organ failure are the two most important markers of severity in acute pancreatitis The distinction between interstitial and necrotizing pancreatitis can be established after two to three days of hospitalization by contrast-enhanced CT scan. Supportive care is critical with emphasis on the prevention of hypoxemia and the adequacy of fluid resuscitation 38 ACG GUIDELINE Prompt transfer to an intensive care unit is warranted in patients with sustained organ failure Transfer to an intensive care unit or possibly a step-down care unit should also be considered if there are signs that suggest that the pancreatitis is severe or is likely to be severe. Whenever possible, enteral feeding rather than total parenteral nutrition is suggested for patients with acute pancreatitis who require nutritional support 39 ACG GUIDELINE The use of prophylactic antibiotics to prevent pancreatic infection is not recommended. CT-guided percutaneous aspiration with Gram's stain and culture is recommended when infected pancreatic necrosis is suspected The preferred treatment of this problem is surgical debridement, but minimally invasive approaches may be used in selected cases 40 Managment algorithm for severe acute pancreatitis 41