Comparison of serum amylase pancreatic isoamylase and lipase in patients with hyperamylasemia

Protective effects of Coenzyme Q10 against acute pancreatitis

Acute pancreatitis (AP) refers to inflammation in the pancreas, which may lead to death in severe cases. Coenzyme Q10 (Q10), generally known to generate energy, plays an important role as an anti-oxidant and anti-inflammatory effector. Here, we showed the effect of Q10 on inflammatory response in murine AP model. For this study, we induced AP by injection of cerulein intraperitoneally or pancreatic duct ligation (PDL) in mice. The level of cytokines and digestive enzymes were measured in pancreas, and blood. All pancreatic tissues were excised for investigation such as histological changes, infiltration of immune cells. Administration of Q10 attenuated the severity of AP and its associated pulmonary complication as shown by reduction of acinar cell death, parenchymal edema, inflammatory cell infiltration and alveolar thickening in both cerulein-induced AP and PDL-induced AP. Moreover, reduction of the cytokines such as interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α were observed in pancreas and pancreatic acinar cells by Q10. Furthermore, Q10 reduced the infiltration of immune cells such as monocytes and neutrophils and augmentation of chemokines such as CC chemokine-2 (CCL2) and C-X-C chemokine-2 (CXCL2) in pancreas of AP mice. In addition, Q10 deactivates the phosphorylation of extracellular signal-regulated kinase (ERK) and c-jun NH₂-terminal kinase (JNK) in pancreas. In conclusion, these observations suggest that Q10 could attenuate the pancreatic damage and its associated pulmonary complications via inhibition of inflammatory cytokines and inflammatory cell infiltration and that the deactivation of ERK and JNK by Q10 might contribute to the attenuation of AP.

Superfluous Amylase/Lipase Testing at a University-Affiliated Teaching Hospital: A Retrospective Review

Background: The combination of amylase and lipase tests for diagnosing acute pancreatitis is not better than a lipase test alone; however, both tests are commonly ordered simultaneously. Further, although no data indicate usefulness of monitoring changes in elevated amylase and lipase levels, the tests are often ordered multiple times during the same clinical encounter. Methods: We retrospectively reviewed all amylase and lipase tests performed at a university-affiliated teaching hospital during a 6-month period. We considered amylase and lipase results diagnostic if they were >3 times the upper limit of normal and borderline if they were ≤3 times the upper limit of normal. During a single clinical encounter, we considered amylase tests superfluous if ordered simultaneously with lipase tests or repeated after diagnostic results, questionably superfluous if repeated alone, and nonsuperfluous otherwise. Lipase tests were considered superfluous if repeated after diagnostic results, questionably superfluous if repeated after nondiagnostic results, and nonsuperfluous otherwise. Results: In this study, 3,502 patients had 8,801 tests (4,926 lipase, 3,875 amylase), 4% of which were diagnostic and 10% borderline. Of the 8,801 tests, 45% were superfluous and 9% were questionably superfluous. Nonsuperfluous testing was less frequent (P<0.0001) in the intensive care/stepdown units (22% of 748 tests) than in the emergency department (54% of 6,000 tests) or other settings (31% of 2,053 tests). Among 3,545 simultaneous amylase/lipase tests with nondiagnostic lipase results, 0.6% amylase results were diagnostic. Of the 190 lipase tests repeated after nondiagnostic lipase results, 12% were diagnostic. Conclusion: Superfluous amylase/lipase testing in one teaching hospital is substantial, suggesting significant potential for reducing healthcare costs without compromising the quality of care when evaluating patients for acute pancreatitis.

Serum amylase and lipase and urinary trypsinogen and amylase for diagnosis of acute pancreatitis

BACKGROUND

The treatment of people with acute abdominal pain differs if they have acute pancreatitis. It is important to know the diagnostic accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis, so that an informed decision can be made as to whether the person with abdominal pain has acute pancreatitis. There is currently no Cochrane review of the diagnostic test accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis.

OBJECTIVES

To compare the diagnostic accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase, either alone or in combination, in the diagnosis of acute pancreatitis in people with acute onset of a persistent, severe epigastric pain or diffuse abdominal pain.

SEARCH METHODS

We searched MEDLINE, Embase, Science Citation Index Expanded, National Institute for Health Research (NIHR HTA and DARE), and other databases until March 2017. We searched the references of the included studies to identify additional studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively. We also performed a 'related search' and 'citing reference' search in MEDLINE and Embase.

SELECTION CRITERIA

We included all studies that evaluated the diagnostic test accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis. We excluded case-control studies because these studies are prone to bias. We accepted any of the following reference standards: biopsy, consensus conference definition, radiological features of acute pancreatitis, diagnosis of acute pancreatitis during laparotomy or autopsy, and organ failure. At least two review authors independently searched and screened the references located by the search to identify relevant studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from the included studies. The thresholds used for the diagnosis of acute pancreatitis varied in the trials, resulting in sparse data for each index test. Because of sparse data, we used -2 log likelihood values to determine which model to use for meta-analysis. We calculated and reported the sensitivity, specificity, post-test probability of a positive and negative index test along with 95% confidence interval (CI) for each cutoff, but have reported only the results of the recommended cutoff of three times normal for serum amylase and serum lipase, and the manufacturer-recommended cutoff of 50 mg/mL for urinary trypsinogen-2 in the abstract.

MAIN RESULTS

Ten studies including 5056 participants met the inclusion criteria for this review and assessed the diagnostic accuracy of the index tests in people presenting to the emergency department with acute abdominal pain. The risk of bias was unclear or high for all of the included studies. The study that contributed approximately two-thirds of the participants included in this review was excluded from the results of the analysis presented below due to major concerns about the participants included in the study. We have presented only the results where at least two studies were included in the analysis.Serum amylase, serum lipase, and urinary trypsinogen-2 at the standard threshold levels of more than three times normal for serum amylase and serum lipase, and a threshold of 50 ng/mL for urinary trypsinogen-2 appear to have similar sensitivities (0.72 (95% CI 0.59 to 0.82); 0.79 (95% CI 0.54 to 0.92); and 0.72 (95% CI 0.56 to 0.84), respectively) and specificities (0.93 (95% CI 0.66 to 0.99); 0.89 (95% CI 0.46 to 0.99); and 0.90 (95% CI 0.85 to 0.93), respectively). At the median prevalence of 22.6% of acute pancreatitis in the studies, out of 100 people with positive test, serum amylase (more than three times normal), serum lipase (more than three times normal), and urinary trypsinogen (more than 50 ng/mL), 74 (95% CI 33 to 94); 68 (95% CI 21 to 94); and 67 (95% CI 57 to 76) people have acute pancreatitis, respectively; out of 100 people with negative test, serum amylase (more than three times normal), serum lipase (more than three times normal), and urinary trypsinogen (more than 50 ng/mL), 8 (95% CI 5 to 12); 7 (95% CI 3 to 15); and 8 (95% CI 5 to 13) people have acute pancreatitis, respectively. We were not able to compare these tests formally because of sparse data.

AUTHORS' CONCLUSIONS

As about a quarter of people with acute pancreatitis fail to be diagnosed as having acute pancreatitis with the evaluated tests, one should have a low threshold to admit the patient and treat them for acute pancreatitis if the symptoms are suggestive of acute pancreatitis, even if these tests are normal. About 1 in 10 patients without acute pancreatitis may be wrongly diagnosed as having acute pancreatitis with these tests, therefore it is important to consider other conditions that require urgent surgical intervention, such as perforated viscus, even if these tests are abnormal.The diagnostic performance of these tests decreases even further with the progression of time, and one should have an even lower threshold to perform additional investigations if the symptoms are suggestive of acute pancreatitis.

Misdiagnosis of macroamylasemia in pregnancy as pancreatitis

Background: While elevated serum amylase in the presence of abdominal pain can be indicative of pancreatitis, differential diagnosis of macroamylasemia depends on additional assessment of serum lipase and urinary amylase. The present report concerns misdiagnosis of pancreatitis in a pregnant woman with elevated serum amylase but normal lipase.

Highlights: The patient was a nulligravid woman on her first pregnancy diagnosed with pancreatitis in her 32nd week plus 3 days of gestation, on the basis of elevated serum amylase and abdominal pain, after treatment for premature contractions and antepartum vaginal bleeding with ritodrine HCl and nifedipine. She was started on painful and invasive intravenous hydration; oral intake was stopped. Repeat elevated serum amylase suggested that the patient might in fact have macroamylasemia, not pancreatitis.

Conclusions: Normal serum lipase levels should be considered as a likely indication of an alternative cause of elevated serum amylase to pancreatitis, and urinary amylase should be routinely checked to assist in differential diagnosis to avoid unnecessary and invasive treatment and stress to pregnant women.

Evaluation of miR-216a and miR-217 as potential biomarkers of acute pancreatic injury in rats and mice

Mild injury of the exocrine pancreas is often asymptomatic and can be under- or mis-diagnosed. The pancreas-enriched microRNAs miR-216a and miR-217 were evaluated as potential serum biomarkers of exocrine pancreas injury in rodent models of acute pancreatitis induced by caerulein, l-arginine, and pancreatic duct ligation. Both microRNAs showed time- and dose- relevant responses to pancreatic injury and wider dynamic ranges of response than serum amylase or lipase. Pancreas-selective microRNAs were found to be relatively sensitive serum biomarkers of pancreatic injury in rodents with potentially greater specificity than the current standard assays.

Value of serum amylase and lipase in early diagnosis of acute pancreatitis: A Meta-analysis

AIM: To systematically assess the value of serum amylase and lipase in the early diagnosis of acute pancreatitis (AP) to provide the best evidence for clinical decision-making.

METHODS: Medline, EMBASE, Science Direct, Springer link, CBM, Cnki, Wan fang and VIP database were electronically searched between January 2004 and November 2013 to collect the articles assessing serum amylase and lipase in early diagnosis of AP. Quality assessment was made using the QUADAS scale. The Meta-Disc1.4 software was used to assess the heterogeneity of included articles, plot the SROC curve, and calculate the summary sensitivity and specificity.

RESULTS: A total of 22 articles were included, including 16 Chinese studies, and 6 English articles. The summary sensitivity, summary specificity and the area under the SROC curve of serum amylase in diagnosing AP were 73% (95%CI: 71%-75%), 87% (95%CI: 85%-88%) and 0.8758, respectively. The corresponding values for serum lipase were 89% (95%CI: 87%-90%), 88% (95%CI: 86%-89%) and 0.9430.

CONCLUSION: Serum lipase has higher diagnostic value in early diagnosis of AP than serum amylase. Serum lipase can be used as an early diagnostic marker for AP.

Amylase, pancreatic isoamylase and lipase in serum before and after endoscopic pancreatography

Serum amylase, isoamylase and lipase were determined in 17 patients with pancreatic or biliary diseases before and after endoscopic retrograde pancreatography (ERP). Within 1/2-2 hours after cannulation of the pancreatic duct, serum lipase was increased to approximately 4 times the upper reference level and normalized almost completely at 24 hours. A much smaller increase was found in amylase and isoamylase. The elevation in enzyme activities was less in patients with abnormal than with normal ERP. The results suggest that lipase is a more sensitive indicator of pancreatic injury than amylase and isoamylase.

Serum enzyme half life can be a useful factor for follow-up management of biliary pancreatitis

BACKGROUND AND OBJECTIVE

The purpose of this study was to show that the half lives of serum amylase and lipase activities could be useful factors for follow-up management of biliary pancreatitis.

METHODS

Ten patients with initial biliary pancreatitis (IBP) and six with post-endoscopic pancreatitis (PEP) were selected from those who had undergone endoscopic surgery. Serum amylase and lipase activities were examined and the relaxation patterns were investigated continuously after the endoscopic removal of the pancreatico-biliary obstruction causing this disease.

RESULTS

Pancreatitis in the subjects was confirmed as a biliary type since the serum bilirubin activities decreased exponentially after removal of the obstruction. The average half lives of serum amylase and lipase were both larger in the IBP, while the average peak values were higher in the PEP.

CONCLUSIONS

Half life can be a useful factor for follow-up management of this disease.

Clinical laboratory assessment of acute pancreatitis

BACKGROUND

Several biochemical markers in blood and urine have been investigated to establish their clinical application in patients with acute pancreatitis (AP). The relevant studies are reviewed and critically appraised.

METHODS

Medline and the World Wide Web were searched and the relevant literature was classified under the following categories: (1) diagnosis of AP and (2) prediction of: a) disease severity, b) pancreatic necrosis and its secondary infection, c) organ failure and death, and d) disease etiology.

RESULTS AND CONCLUSIONS

Serum lipase is a more reliable diagnostic marker of AP than serum amylase. Urinary strip tests for trypsinogen activation peptide (TAP) and trypsinogen-2 provide a reliable early diagnosis of AP. Useful predictors of severity may include serum procalcitonin and urinary TAP and trypsinogen-2 on admission, serum interleukins-6 and -8 and polymorphonuclear elastase at 24 h, and serum C-reactive protein (CRP) at 48 h. Other markers such as amyloid A and carboxypeptidase B activation peptide (CAPAP) need further investigation. Biochemical prediction of pancreatic necrosis requires 72 h to reach reliability and is impractical. However, the daily monitoring of serum procalcitonin provides a non-invasive detection of infected necrosis; the promising role of phospholipase A(2) in this regard requires further investigation. Early transient hypertransaminasemia reliably predicts biliary etiology, while serum carbohydrate-deficient transferrin and trypsin may predict an alcoholic etiology.

[Hypertriglyceridemic acute pancreatitis. Is its clinical course different from lithiasic acute pancreatitis?]

BACKGROUND AND OBJECTIVE

Although hypertriglyceridemia is an accepted cause of acute pancreatitis, its clinical course is not well defined. What is more, lipemic serum may interfere with an accurate pancreatic enzyme measurement and may hinder the diagnosis of acute pancreatitis. The objective was to analyze the clinical performance of hypertriglyceridemic acute pancreatitis and the diagnosis value of the serum measurement of pancreatic enzymes.

PATIENTS AND METHOD

31 demographic, clinical, analytical and radiological data of 19 hypertriglyceridemic acute pancreatitis were retrospectively analyzed and their results were compared with data of 19 lithiasic acute pancreatitis without hypertriglyceridemia. Diagnosis of acute pancreatitis was based on clinical, radiological and/or laparotomical findings. Serum levels of triglycerides higher than 1,000 mg/dl were considered the cause of acute pancreatitis when other causes were excluded. Acute pancreatitis was considered lithiasic when gallstones were identified by ultrasonography, serum levels of triglycerides were lower than 200 mg/dl and there was no history of alcohol consumption.

RESULTS

Compared with lithiasic acute pancreatitis, hypertriglyceridemic acute pancreatitis showed more personal and family hypertriglyceridemia (9 vs 0), more previous episodes of pancreatitis (13 vs 2), pancreatitis was more severe (13 vs 5) and had more complications (29 vs 5). There was no mortality in either group. The serum levels of amylase and lipase supported the diagnosis in 26% and 58% of patients with hypertriglyceridemic acute pancreatitis compared with 58% and 79% of patients with lithiasic acute pancreatitis, respectively. Hospital stay was longer in hypertriglyceridemic than in lithiasic acute pancreatitis (24 [45] vs 7.6 [3.1] days; p = NS). Demographic and analytical factors which could permit to predict the severity of acute pancreatitis could not be identified.

CONCLUSIONS

Hypertriglyceridemic acute pancreatitis is relapsing and its clinical course is more severe than lithiasic acute pancreatitis. The measurement of amylase and lipase levels is less useful in the diagnosis of hypertriglyceridemic than in lithiasic acute pancreatitis.

[Validity of serum amylase and lipase in the differential diagnosis between acute/acutized chronic pancreatitis and other causes of acute abdominal pain]

BACKGROUND

Raised serum amylase and lipase levels are observed in several abdominal diseases.

AIM

Assessing the validity of serum amylase and lipase for the differential diagnosis between acute pancreatitis/acutized chronic pancreatitis, biliary tract disease, perforated gastroduodenal ulcer and acute appendicitis. PATIENTS E METHODS: Prospective study including 134 individuals: 38 with acute pancreatitis/acutized chronic pancreatitis, 35 with biliary tract disease, 17 with perforated gastroduodenal ulcer and 44 with acute appendicitis, mean age (standard deviation) of 42.4 +/- 17.7, 46.7 +/- 18.3, 47.8 +/- 12 and 33.7 +/- 17.8 years, respectively. Serum amylase and lipase were determined at admission to the emergency department.

RESULTS

For the diagnosis of acute pancreatitis/acutized chronic pancreatitis, when the cutt-off levels of serum amylase were set at the upper normal range level or up to 5-fold as high, the sensitivity decreased from 92% to 74%, the specificity increased from 85% to 99%, the positive predictive value increased from 71% to 97%, and the negative predictive value decreased from 96% to 91%. For serum lipase levels similar figures were obtained for sensitivity and negative predictive value, but the specificity and positive predictive value were lower. When the combination of raised serum amylase or lipase were analyzed, a minor increase was observed in sensitivity and negative predictive value.

CONCLUSIONS

For the diagnosis of acute pancreatitis/acutized chronic pancreatitis: 1) the best cut-off level for both tests was 2-times the upper normal range; 2) the sensitivities of serum amylase and lipase were similar; 3) the specificity and positive predictive value of serum amylase were slightly higher than observed for serum lipase; 4) the sensitivity but not the specificity increased when at least one between amylase or lipase was raised.

Development and validation of a radioimmunoassay for the measurement of canine pancreatic lipase immunoreactivity in serum of dogs

OBJECTIVE

To develop and validate a radioimmunoassay (RIA) for measuring canine pancreatic lipase immunoreactivity (cPLI) in serum obtained from dogs.

SAMPLE POPULATION

Serum samples from 47 healthy dogs.

PROCEDURES

Canine pancreatic lipase (cPL) was purified from pancreatic specimens of dogs. Antibodies against cPL were raised in rabbits and purified by use of affinity chromatography. A tracer was produced by iodination of cPL with 125I. An RIA was established and validated by determination of sensitivity, working range, dilutional parallelism, spiking recovery, and intra- and interassay variability. A reference range for cPLI in serum was established by use of the central 95th percentile for samples obtained from 47 healthy dogs.

RESULTS

Sensitivity and upper limit of the working range were 0.88 and 863 microg/L, respectively. Observed-to-expected ratios for serial dilutions ranged from 84.9 to 116.5% for 4 samples. Observed-to-expected ratios for spiking recovery ranged from 82.8 to 128.6% for 4 samples. Coefficients of variation for intra-assay variability for 4 serum samples were 18.3, 4.2, 3.5, and 8.9%, whereas interassay coefficients of variation were 29.2, 6.2, 3.9, and 4.4%, respectively. The reference range was 4.4 to 276.1 microg/L.

CONCLUSIONS AND CLINICAL RELEVANCE

We conclude that the RIA described is sensitive, linear, accurate, precise, and reproducible, with limited accuracy in the high end of the working range and limited precision and reproducibility in the low end of the working range. Additional studies are needed to evaluate whether this degree of accuracy, precision, and reproducibility will negatively impact clinical use of this assay.

Alcohol-induced pancreatic injury

Alcoholic pancreatitis is a major complication of alcohol abuse. Until recently, it was generally accepted that alcoholic pancreatitis was a chronic disease from the outset. However, evidence is now emerging in support of the 'necrosis-fibrosis' hypothesis that alcoholic pancreatitis begins as an acute process and that repeated episodes of acute injury lead to the changes of chronic pancreatitis (acinar atrophy and fibrosis) resulting in exocrine and endocrine dysfunction. The treatment of acute pancreatitis follows the regimen of bed rest, nasogastric suction, analgesia and intravenous support. The role of additional therapeutic measures such as prophylactic antibiotics, antioxidants and enteral nutrition in severe cases has not yet been precisely defined. The treatment of chronic pancreatitis involves attention to its three cardinal features: pain, maldigestion and diabetes. With respect to the pathogenesis of alcoholic pancreatitis, the focus of research over the past 30 years has shifted from the sphincter of Oddi and ductular abnormalities to the acinar cell itself. It has now been established that the acinar cell is capable of metabolizing alcohol and that direct toxic effects of alcohol and/or its metabolites on acinar cells may predispose the gland to injury in the presence of an appropriate trigger factor. A significant recent development relates to the characterization of pancreatic stellate cells, increasingly implicated in alcoholic pancreatic fibrosis. This chapter summarizes the natural history, clinical features, current trends in treatment as well as recent advances in our understanding of the pathogenesis of alcoholic pancreatitis.

[Acute pancreatitis]

While interstitial acute pancreatitis usually takes a benign course, necrotizing acute pancreatitis takes a severe course, mainly because of severe local and systemic complications. After a quick diagnosis it is necessary to rapidly assess a degree of severity of the disease and thus the prognosis. The clinical picture and the result of imaging procedures do not always correspond. The management basically includes to treat pain as well as to administer fluid, electrolyte, protein and calories. In addition, systemic treatment of complications such as shock or respiratory and renal insufficiency--if occurring--is necessary. In case of pancreatic necrosis, prophylactic administration of pancreas-penetrable antibiotics is recommended to avoid infection. In the severely ill with infected pancreatic necrosis, surgery is the treatment of choice. In approximately 10% of all patients with alcohol-induced pancreatitis, there is a gradual transition to chronic pancreatitis.

A critical evaluation of laboratory tests in acute pancreatitis

An ideal laboratory test in the evaluation of a patient with acute pancreatitis (AP) should, in addition to accurately establishing the diagnosis of AP, provide early assessment of its severity and identify the etiology. None of the tests available today meet all these criteria, and presently there is no biochemical test that can be considered the "gold standard" for the diagnosis and assessment of severity of AP. In the diagnosis of AP, serum amylase and lipase remain important tests. Advantages of amylase estimation are its technical simplicity, easy availability, and high sensitivity. However, its greatest disadvantage is its low specificity. A normal amylase would usually exclude the diagnosis of AP, with the exception of AP secondary to hyperlipidemia, acute exacerbation of chronic pancreatitis, and when the estimation of amylase is delayed in the course of the disease. The major advantage of lipase is an increased sensitivity in acute alcoholic pancreatitis and in patients who initially present to the emergency room days after the onset of the disease, as lipase remains elevated longer than amylase. Although once considered to be specific for AP, nonspecific elevations of lipase have been reported in almost as many disorders as amylase, thus decreasing its specificity. Simultaneous estimation of amylase and lipase does not improve the accuracy. Other enzymes for the diagnosis of AP--pancreatic isoamylase, immunoreactive trypsin, and elastase--are more cumbersome and expensive and have no clear role in the diagnosis of AP. No enzyme assay has a predictive role in determining the severity or etiology of AP. Once the diagnosis of AP is established, daily measurements of enzymes have no value in assessing the clinical progress of the patient or ultimate prognosis and should be discouraged. A host of new serological and urinary markers have been investigated in the last few years. Their main use is in predicting the severity of AP. At present, serum C-reactive protein at 48 h is the best available laboratory marker of severity. Urinary trypsinogen activation peptides within 12-24 h of onset of AP are able to predict the severity but are not widely available. Serum interleukins 6 and 8 seem promising but remain experimental.

New laboratory tests in acute pancreatitis

Acute pancreatitis (AP) is a common disease with wide variation of severity. The diagnosis of AP is usually based on high serum amylase or lipase values but the accuracy of these methods is considered unsatisfactory. One in five of the patients develops a severe disease and carries a considerable risk of development of organ failure and high mortality. Early detection of patients with severe AP and especially those with increased risk of organ failure is importance since such patients seem to benefit from treatment in an intensive care unit started as soon as possible after presentation. In addition to enzymological methods, increasing interest has been focused on laboratory markers reflecting the level of inflammatory response in AP. At present, in routine clinical work the most commonly used severity marker is serum C-reactive protein, the concentration of which rises too slowly to be used for early prediction of severity. New therapies aiming at modifying the course of systemic inflammation in AP are being developed and therefore monitoring the patient's immune inflammatory status is needed. In this review article we present the current knowledge of laboratory tests, which has been evaluated for diagnostic and prognostic purposes in AP.

Amylase and lipase in the emergency department evaluation of acute pancreatitis

Serum amylase and lipase levels are commonly obtained in the emergency department for the diagnosis of acute pancreatitis. The role of these enzymes has frequently been the subject of confusion and controversy. This article comprehensively reviews the history, biochemistry, clinical, and laboratory literature on both enzymes as used in the evaluation of pancreatitis. Specific guidelines are presented to assist the Emergency Physician in the appropriate use and interpretation of these clinical laboratory tests.

The clinical significance of hyperamylasemia in organophosphate poisoning

OBJECTIVE

Hyperamylasemia with a presumptive diagnosis of acute pancreatitis has been reported following organophosphate poisoning but there are no large-scale studies incorporating more specific diagnostic criteria.

METHODS

Retrospective review of the medical records of 159 patients with a diagnosis of organophosphate poisoning over 3 years. Serum amylase, pancreatic amylase, salivary amylase, lipase and cholinesterase levels, and the clinical manifestations were analyzed.

RESULTS

Serum amylase data was available for 121 of the 159 study patients. Hyperamylasemia (amylase > or = 360 U/L) was found in 44 patients (36%). Lipase was measured in 28 patients with hyperamylasemia; 9 of 28 had hyperlipasemia (lipase > or = 380 U/L). The finding of hyperamylasemia was closely related to clinical severity and presence of shock. A presumptive diagnosis of painless acute pancreatitis was diagnosed by hyperlipasemia associated with hyperamylasemia, clinical severity, serum LDH, and leukocyte counts. Two patients with presumptive pancreatitis died. Shock, coma, and hypoalbuminemia were the factors predicting fatality.

CONCLUSIONS

Hyperamylasemia is frequent in severe organophosphate poisoning. However, hyperamylasemia is not synonymous with acute pancreatitis and pancreatic amylase is not a reliable parameter in the diagnosis of organophosphate-induced pancreatitis due to its low sensitivity and specificity. Lipase assay is indicated in patients with hyperamylasemia for early diagnosis of pancreatitis. Proper image studies and even pathological examination are also needed to confirm the extent of pancreatic injury. With prompt diagnosis and appropriate treatment, a complete recovery can be anticipated unless the patient has otherwise unrelated complications.

Alcohol and the pancreas

Alcoholic pancreatitis is a major, often lethal complication of alcohol abuse. Until recently it was generally accepted that alcoholic pancreatitis was a chronic disease from the outset. However, there is now emerging evidence in favour of the necrosis-fibrosis hypothesis that alcoholic pancreatitis begins as an acute process and that repeated acute attacks lead to chronic pancreatitis, resulting in exocrine and endocrine failure. Over the past 10-15 years, the focus of research into the pathogenesis of alcoholic pancreatitis has shifted from possible sphincteric and ductular abnormalities to the acinar cell itself which has increasingly been implicated as the initial site of injury. Recent studies have shown that the acinar cell can metabolize alcohol at rates comparable to those observed in hepatocytes. In addition, it has been demonstrated that alcohol and its metabolites exert direct effects on the pancreatic acinar cell which may promote premature digestive enzyme activation and oxidant stress. The challenge remains to identify predisposing and triggering factors in this disease.

What is the best biochemical test to diagnose acute pancreatitis? A prospective clinical study

OBJECTIVE

To determine which biochemical test is best to distinguish acute pancreatitis from other pancreatic and nonpancreatic diseases associated with hyperamylasemia.

DESIGN

We conducted a prospective clinical study of 836 consecutive patients who had a total serum amylase test requested by a physician during a 7-month period.

MATERIAL AND METHODS

Radioimmunoassay and enzymatic activity methods were used to measure pancreas-specific proteins of varied size, charge, and stability. In addition, scoring systems were used for the diagnosis of pancreatitis, and statistical analyses were done to determine sensitivity and specificity.

RESULTS

We found minor differences in sensitivity and specificity for diagnosis of acute pancreatitis among pancreatic isoamylase, phospholipase A2, colipase, lipase, and carboxylester lipase. Of these tests, the combination of isoamylase and phospholipase A2 had a small but statistically significant increased sensitivity (90%; 95% confidence interval [CI] = 74 to 98%) and specificity (93%; 95% CI = 91 to 95%) over isoamylase (90% and 92%, respectively; 95% CI = 90 to 94%) and phospholipase A2 (90% and 75%, respectively; 95% CI = 72 to 78%) alone for the diagnosis of acute pancreatitis.

CONCLUSION

Pancreas-specific proteins are satisfactory for diagnosing acute pancreatitis if the test is validated by the laboratory. Clinically, the slight advantage of using both isoamylase and phospholipase A2 does not outweigh the expense of performing two assays; we recommend using isoamylase to diagnose acute pancreatitis.

Cholelithiasis, cholecystitis, and pancreatitis

Cholelithiasis, cholecystitis, and pancreatitis are common conditions in the adult patient population that may be challenging to recognize because of their variable clinical presentations and broad differential diagnoses. This article discusses the pathophysiology of each condition and its common complications. The clinical presentation and evaluation of patients is reviewed with emphasis on current diagnostic tests used to identify severity of illness and the presence of complications. Treatment options are presented for straightforward as well as complicated initial management and disposition.

Rapid measurement of serum pancreatic amylase

A simple, rapid assay for the pancreatic isoenzyme of human serum amylase was developed. The assay utilized an immunoabsorbent prepared by coating latex beads with a monoclonal antibody specific for pancreatic amylase. Treatment of patient serum with immunoabsorbent removed pancreatic amylase, and measurement of residual amylase activity with standard total amylase methodology allowed estimation of the pancreatic amylase content. Extraction efficiency of pancreatic amylase was consistent at amylase concentrations up to 1,000 U/L (y = 0.97 x +16.7 U/L; r = 0.9995). The assay was standardized with purified pancreatic amylase added to neonatal serum (low endogenous activity). A comparison of patient specimen results with the results of a standard technique (cellulose acetate electrophoresis) yielded an excellent correlation (immunoabsorption result = 0.96 electrophoresis result + 1.2 U/L; r = 0.987). Salivary amylase did not interfere with the assay until levels exceeded 1,000 U/L. Daily analysis of a frozen serum pool yielded a coefficient of variation of 9.2% at mean pancreatic amylase value of 54 U/L (+/- 5 U/L). A normal range study found a strong influence of age, with pancreatic amylase levels increasing dramatically in the first 3 years of life, to stabilize at a range of 0-66 U/L thereafter.

Normal amylase levels in the presentation of acute pancreatitis

Recent literature suggests that serum amylase levels are not an appropriate screen for the diagnosis of acute pancreatitis because specificity and sensitivity are poor. Evidence from several studies supports the use of lipase determinations to diagnose acute pancreatitis, and recent improvements in this assay have made it more readily available to the emergency physician. This retrospective review compares the use of serum amylase to lipase levels in the diagnosis of acute pancreatitis in 52 patients who presented to the emergency department, with the hospital discharge diagnosis serving as the gold standard to which the assays were compared. Serum lipase was found to be more sensitive than serum amylase (95% vs 79%); serum amylase levels decreased to normal significantly faster than lipase levels.

Acute pancreatitis

Acute pancreatitis is an inflammatory disease of variable clinical severity. The pathologic conditions that correlate with clinical severity and with local systemic complications range from mild edema to pancreatic an peripancreatic necrosis. This article discusses diagnosis, etiology, laboratory evaluation, and imaging studies with respect to acute pancreatitis. Assessing the prognosis, detecting complications, and therapy are discussed also.

Glycerol interference in serum lipase assay falsely indicates pancreas injury

The measurement of serum lipase activity has been shown to be a very sensitive and specific marker for the diagnosis of pancreatic injury. Two case reports are presented showing that glycerol ingested coincidentally in the formulation of several medications taken therapeutically and given in the emergency room causes a falsely elevated serum lipase activity when measured on the Kodak Ektachem 700 clinical analyzer (Eastman Kodak Co., Rochester, NY). The transient but falsely elevated serum lipase activity could potentially affect the differential diagnosis of patients by the admitting physician.

Plasma disappearance of homologous and heterologous pancreatic enzymes in dogs

Homologous and heterologous (human) pure pancreatic juice was infused into dogs to compare the behaviour of pancreatic enzymes in the circulation. This was achieved by estimating the magnitude of elevation and speed of disappearance of pancreatic enzymes in plasma. The half-lives of the plasma enzymes did not differ significantly between dogs and humans. However the half-lives of other enzymes (longest for amylase and shortest for trypsinogen) did differ. The magnitude of elevation expressed as a ratio of peak (5 min) to basal level was greatest for trypsinogen (28 times) and least for amylase (1.4 times). However, 289% and 410% of the initial lipase enzyme activity was recovered 5 min after infusion of dog and human pure pancreatic juice, respectively (44% when measured by immunoreactive human lipase activity). The excess recovery requires re-evaluation of diagnostic value of turbidimetric activity of plasma pancreatic lipase.

Relation of diagnostic serum amylase levels to aetiology and severity of acute pancreatitis

The sensitivity of diagnostic serum amylase (greater than 1000 iu/l) was assessed in 417 patients with acute pancreatitis as a result of gall stones (258), alcohol (104), or miscellaneous causes (55), of whom 111 (27%) had a clinically severe attack (including 34 deaths). On hospital admission, an amylase value diagnostic of pancreatitis was found in 96.1% of all mild cases and in 87.4% of severe cases (p less than 0.001); at 48 hours these values were 33.3% and 48.2% respectively (p = 0.026). Diagnostic amylase levels for alcoholic patients were found in 86% of mild cases on admission and in 76% of severe cases (p less than 0.001, compared with other groups). The diagnostic levels were also significantly lower at 24 hours for both the alcoholic and miscellaneous groups compared with the gall stone group (p less than 0.001). Eight of 27 (30%) patients with a serum amylase activity less than 1000 iu/l had pancreatic necrosis compared with 12 of the remaining 390 (3.1%) patients (p less than 0.001); the mortality was also significantly different (44% v 5.6% respectively, p less than 0.001). These data support the view that more sensitive tests for acute pancreatitis are needed for routine use especially in those whose disease has an alcoholic aetiology.

Risk factors for pancreatic cellular injury after cardiopulmonary bypass

BACKGROUND

Pancreatitis is a known complication of cardiac surgery with cardiopulmonary bypass. Although ischemia is believed to be a factor, the cause of pancreatitis after cardiopulmonary bypass remains unknown.

METHODS

We prospectively studied 300 consecutive patients undergoing cardiac surgery with cardiopulmonary bypass. Serum amylase, pancreatic isoamylase, and serum lipase were measured on postoperative days 1,2,3,7, and 10. Pancreatic cellular injury was defined as the presence of hyperamylasemia (greater than 123 U per liter) with an increase in either the serum level of lipase (greater than 24 U per liter) or the peak level of pancreatic isoamylase. Trypsinogen-activation peptides, which indicate intrapancreatic enzyme activation, were measured in the urine of the last 101 patients studied.

RESULTS

Evidence of pancreatic cellular injury was detected in 80 patients (27 percent), of whom 23 had associated abdominal signs or symptoms and 3 had severe pancreatitis (2 with pancreatic abscess and 1 with necrotizing hemorrhagic pancreatitis). Two of 19 postoperative deaths were secondary to pancreatitis. In multivariate analyses, the development of pancreatic cellular injury was significantly associated with preoperative renal insufficiency, valve surgery, postoperative hypotension, and perioperative administration of calcium chloride. The administration of more than 800 mg of calcium chloride per square meter of body-surface area was an independent predictor of pancreatic cellular injury, and the increase in risk was dose-related. No differences were found in the level of trypsinogen-activation peptides between patients who had pancreatic cellular injury and those who did not.

CONCLUSIONS

Pancreatic cellular injury, as indicated by hyperamylasemia of pancreatic origin, is common after cardiac surgery. The administration of large doses of calcium chloride is an independent predictor of pancreatic cellular injury and may be a cause of it.

Correlation of pancreatic enzyme levels with the patient's recovery from acute edematous pancreatitis

Levels of total amylase, pancreatic isoamylase, lipase and immunoreactive trypsin were measured in 27 consecutive patients with noncomplicated (methemalbumin negative, no pseudocysts on ultrasound) acute pancreatitis during the acute, subacute, and recovery phases. At the beginning of the recovery phase (no pain, start of oral food intake), amylase and pancreatic isoamylase were below normal, whereas lipase (12% of the patients) and especially trypsin (52% of the patients) were still three times above the upper limit of normal. None of the patients showed a relapse of pain at the time of oral food intake. The conclusion is that amylase and pancreatic isoamylase reflect more accurately the patient's recovery pattern in acute pancreatitis than the other enzymes. Trypsin, however, may be significant in cases of delayed diagnosis. Thus, the decision to start oral food intake should be based on the patient's clinical state rather than on pancreatic enzyme levels.

Comparative evaluation of the diagnosis of acute pancreatitis based on serum and urine enzyme assays

We compared the diagnostic sensitivities of serum amylase, lipase (assayed enzymatically and immunologically), trypsinogen and elastase-1, the 2-h-timed urine amylase excretion and the ratio of amylase and creatinine clearances in the recognition of acute pancreatitis. Serial serum and urine findings from 39 patients with acute pancreatitis, and from 42 patients with non-pancreatic causes of abdominal pain (controls), as well as findings from 24 healthy subjects (normals) were studied. Decision thresholds were established for each parameter using either the control or the normal population, and the resulting diagnostic sensitivities determined. On hospital admission, all serum assays were equally sensitive, but on subsequent days lipase, trypsinogen and elastase-1 assays all significantly surpassed the sensitivity of the serum amylase assay. On the second and subsequent hospitalization days, determination of timed urine amylase excretion offered no advantage over the serum amylase, and the ratio of amylase and creatinine clearances lacked discrimination altogether.

Serum enzymes and other laboratory tests in acute pancreatitis

This review evaluates selective enzymes and blood tests available for the diagnosis and prognosis of acute pancreatitis. It is concluded that serum amylase and lipase measurements represent the best available diagnostic methods. Newer alternative assays still require careful evaluation.

Enzyme immunoassay for serum pancreatic lipase in the diagnosis of pancreatic diseases

To evaluate the diagnostic utility of serum immunoreactive lipase (IRL), serum lipase was determined using an enzyme immunoassay and a turbidimetric method along with total serum amylase in 41 healthy controls, 76 patients with pancreatic disease and 60 with nonpancreatic disease. Serum IRL was elevated in 12 of 13 patients with acute pancreatitis, 12 of 44 with chronic pancreatitis and in 12 of 19 with pancreatic cancer. The IRL was low in 9 of the 44 patients with chronic pancreatitis, which coincided with advanced exocrine pancreatic insufficiency. Overall sensitivities in pancreatic diseases were 59% for serum IRL, 38% for turbidimetric lipase and 51% for amylase, specificities in healthy controls and nonpancreatic diseases were 80% for serum IRL, 86% for turbidimetric lipase and 88% for serum amylase. Serum IRL determination is useful for diagnosis in pancreatic diseases when compared with the conventional determination of serum lipase.

Comparison of some recent methods for the differentiation of elevated serum amylase and the detection of macroamylasaemia

A pancreatic isoamylase method (Pancreatic Alpha-Amylase EPS, Boehringer) that uses monoclonal antibodies showed almost complete immunoinhibition of salivary (S) amylase activity with only a minor decrease of pancreatic (P) amylase activity. The method displayed good sensitivity and linearity. The correlations of P-amylase activities determined by this technique with a wheat-germ inhibition method and with agarose electrophoresis followed by densitometric scanning were excellent. However, both the wheat-germ and monoclonal inhibition methods failed to detect macroamylasaemia. To recognise macroamylases we used the PEG precipitation method and confirmed the results with agarose electrophoresis. Of 161 serum samples with elevated amylase activities, only four out of five with macroamylasaemia were detected by the PEG precipitation method. No false positives were demonstrated. After PEG precipitation of 28 samples, P-amylase determinations were performed on the supernatants. Again, four out of five with macroamylasaemia were recognised. We consider P-amylase measurement and, when macroamylasaemia is suspected, the combined use of the PEG precipitation method and P-amylase or total amylase determination to be the most practical way to differentiate between elevated serum amylase levels.

Pancreatitis following liver transplantation

Since 1981, when the liver transplantation program was initiated at the University of Pittsburgh, we have been impressed with the prevalence of pancreatitis occurring following liver transplantation in patients transplanted for hepatitis B-related liver disease. To either confirm this clinical impression or refute it, the records of the 27 HbsAg+ patients and those of an additional 24 HbsAg- but HbcAb and/or HbsAb+ patients who underwent orthotopic liver transplantation were reviewed to determine the prevalence of clinical pancreatitis and hyperamylasemia (biochemical pancreatitis) following liver transplantation (OLTx). Post-OLTx hyperamylasemia occurred significantly more frequently in HbsAg+ patients (6/27) than it did in the HbsAg- patients (0/24) (P less than 0.05). More importantly, clinical pancreatitis occurred in 14% (4/27) of the HbsAg+ patients and 0% (0/24) of the HbsAg- patients. Interestingly, in each case, the pancreatitis was associated with the occurrence of acute hepatitis B infection of the allograft. Based upon these data, we conclude that pancreatitis occurring after liver transplantation is more common in patients transplanted for active viral liver disease caused by hepatitis B than in those with inactive viral liver disease. These observations suggest that pancreatitis occurring in, at least some cases following liver transplantation for viral liver disease, may result from hepatitis B virus infection of the pancreas.

Serum elastase 1 in inflammatory pancreatic and gastrointestinal diseases and in renal insufficiency. A comparison with other serum pancreatic enzymes

Serum elastase 1 has been evaluated in 115 patients with pancreatic and nonpancreatic gastrointestinal diseases and in 36 healthy controls. Increased serum elastase 1 values were found in all 27 patients with acute pancreatitis. If the diagnostic cutoff was established as the 2-fold increase above the upper normal range, sensitivity of elastase 1 (100%) was superior to pancreatic lipase (90%), immunoreactive trypsin (87%) and pancreatic amylase (78%). Specificity was 96% for elastase 1 at this cutoff. No distinction was possible between edematous and necrotizing acute pancreatitis on the basis of peak serum elastase 1 concentrations. Among 32 patients with chronic pancreatitis increased serum elastase 1 values were found in 22% and decreased values in 16% of patients, showing a striking parallelism to serum values of pancreatic lipase and immunoreactive trypsin. Specificity, established in controls and 49 patients with different gastrointestinal diseases, was 77% for elastase 1, 76% for immunoreactive trypsin, 83% for pancreatic lipase and 91% for pancreatic amylase. In addition, we investigated 21 patients with severe chronic renal diseases. In patients with renal insufficiency elastase was increased in 33%, comparable to the frequency of increased amylase and pancreatic amylase serum levels, whereas immunoreactive trypsin was increased in 95%. Immunoreactive trypsin showed a significant correlation to creatinin serum concentration, whereas the other enzymes did not.

Radioimmunoassay for human pancreatic lipase in acute pancreatitis

We examined the utility of serum pancreatic lipase by radioimmunoassay as a diagnostic test for acute pancreatitis and its correlation with serum total amylase, pancreatic isoamylase, and lipase activity. Data were analyzed on 11 patients with documented acute pancreatitis, three groups of patients (N = 104) with nongastrointestinal, gastrointestinal, and renal diseases, and 30 healthy controls. Patients with acute pancreatitis had significantly (P less than 0.01) higher mean serum lipase by radioimmunoassay than all other groups. Using a serum lipase of 112 ng/ml as a cutoff point in all patients, the test was 91% sensitive and 96% specific for the diagnosis of acute pancreatitis. The correlation coefficients of serum lipase by radioimmunoassay with respect to total amylase, pancreatic isoamylase, and lipase activity were 0.86, 0.98, and 0.79, respectively.

Diagnostic and prognostic value of serum elastase 1 in acute pancreatitis

Serum elastase 1 was determined in the serum of 38 patients with acute pancreatitis, using specific radioimmunoassay technique. Serving as controls were 36 healthy people, 33 patients with chronic pancreatitis, 49 patients with various GI-tract diseases, and 6 patients with pancreatic carcinoma. Sensitivity of elastase 1 for the diagnosis "acute pancreatitis" was 97% after admission to the hospital and 100% within 48 h after onset of acute pancreatitis. The determination of elastase 1 is clearly superior to that of trypsin, pancreatic lipase, or pancreatic amylase, if diagnosis has to be made more than 48 h after the onset of the disease. The specificity is restricted, because there are some cases with chronic pancreatitis and GI-diseases with raised values. There is no possibility to estimate the severity of acute pancreatitis by measuring serum elastase 1.

Problems of pancreatitis

Pancreatitis is not one disease but several and perhaps many. Diagnosis is imperfect in all forms and the usual lack of histologic material has hampered attempts to understand the pathogenesis and possible interrelationships of the different forms of pancreatic inflammation. Acute pancreatitis does not as a rule evolve into chronic pancreatitis, even after multiple recurrences. Recurrent acute attacks can be ended by identifying and treating the factor causing the disease, including recently recognized entities such as accessory papilla stenosis associated with pancreas divisum. Attempts to improve the treatment of severe acute pancreatitis are focussing upon preventing injury to pancreatic cell structures, enhancing endogenous mechanisms for capture and disposal of activated enzymes, and upon early detection and debridement of damaged pancreatic and peripancreatic tissues. Pancreatic duct stricture or obstruction as a consequence of scarring from necrotizing pancreatitis may produce recurrent symptoms, now designated as obstructive pancreatitis. Obstructive pancreatitis has its own unique histologic characteristics and is appropriately treated by resection of the blocked segment of pancreas when the point of obstruction is distal to the papilla. Chronic pancreatitis differs from acute or obstructive pancreatitis in that it is difficult or impossible to halt its progression. The role of intraductal protein precipitates, whether of enzymes or perhaps of other unique pancreatic secretory proteins, in the pathogenesis of the disease is being evaluated. The goal of surgical treatment is not to cure, but to reduce pain, overcome associated obstruction of the bile duct or duodenum, and to treat pancreatic duct disruptions including pseudocysts and internal pancreatic fistulas. Because continuing deterioration of pancreatic function is to be expected in chronic pancreatitis, maximum conservation of pancreatic tissue by avoiding resectional procedures is advisable.

The role of serum isoamylase and lipase determinations in clinical practice

To determine the clinical utility of routine determination of serum isoamylase (pancreatic/salivary) and/or lipase activity, sera were tested from 109 consecutive patients with elevated total serum amylase. Without knowledge of the isoamylase and lipase results, an assessment was made of the confidence with which the attending medical staff had made or excluded a diagnosis of acute pancreatitis. The attending staff had considered acute pancreatitis to be probable in 78, possible in 12 and unlikely in 19 patients. The confidence of the clinical diagnosis of acute pancreatitis was directly related to the degree of elevation of the serum total amylase: (mean IU/l +/- s.e.m.) probable pancreatitis 1807 +/- 313, possible pancreatitis 680 +/- 74, pancreatitis unlikely 493 +/- 50. Pancreatic isoamylase was elevated in 97% of patients with probable pancreatitis, 92% with possible pancreatitis and 68% in whom pancreatitis had been considered unlikely. Lipase elevations generally parallelled these results. Although gall-stones were usually sought among patients with probable pancreatitis, they were rarely sought in patients in the other categories. In conclusion, amylase isoenzyme or lipase determinations add little information in cases of clinically suspected acute pancreatitis with marked hyperamylasemia. The tests may have a role in the evaluation of patients with clinically unexplained hyperamylasemia by defining more precisely the origin of the amylase.

Acute pancreatitis and its complications. Diagnostic and therapeutic strategies

The most common causes of acute pancreatitis are biliary tract disease and alcoholism, but other causes account for about 10% of cases. Acute pancreatitis can be divided clinically into mild and severe (necrotic) disease. Risk of complications and death varies with the etiology, severity, and number of episodes and is highest in severe cases and biliary tract-related disease. Amylase determination is the best diagnostic serum screening test. Ultrasonography, computed tomography, and endoscopic retrograde pancreatography are also extremely useful in diagnosis. Treatment of acute pancreatitis usually consists of supportive measures; the roles of peritoneal lavage and surgery remain controversial. Pseudocysts occur in about 25% of patients but can be treated successfully with appropriate therapy.