The efficiency of endoscopic pancreatic function testing is optimized using duodenal aspirates at 30 and 45 minutes after intravenous secretin

EUS pancreatic function testing and dynamic pancreatic duct evaluation for the diagnosis of exocrine pancreatic insufficiency and chronic pancreatitis

BACKGROUND AND AIMS

EUS and endoscopic pancreatic function tests (ePFTs) may be used to diagnose minimal-change chronic pancreatitis (MCCP). The impact of evaluation for exocrine pancreatic insufficiency (EPI) and real-time assessment of EUS changes after intravenous secretin on the clinical diagnosis of MCCP is unknown.

METHODS

Patients with suspected MCCP underwent baseline EUS assessment of the pancreatic parenchyma and measurement of the main pancreatic duct (B-MPD) in the head, body, and tail. Human secretin 0.2 μg/kg was given intravenously followed 4, 8, and 12 minutes later by repeat MPD (S-MPD) measurements. Duodenal samples at 15, 30, and 45 minutes were aspirated to assess bicarbonate concentration. Endoscopists rated the percentage clinical likelihood of chronic pancreatitis (1) before secretin; (2) after secretin but before aspiration; and (3) after bicarbonate results.

RESULTS

A total of 145 consecutive patients (mean age, 44±13 years; 98 females) were diagnosed with EPI (n = 32; 22%) or normal exocrine pancreatic function (n = 131, 78%). S-MPD/B-MPD ratios in the tail 4 and 8 minutes after secretin were higher in the group with normal exocrine function. Ratios at other times, locations, and duodenal fluid volumes were similar between the 2 groups. A statistically significant change in the median percentage likelihood of chronic pancreatitis was noted after secretin in all groups. The sensitivity and specificity of EPI for the EUS diagnosis of chronic pancreatitis (≥5 criteria) were 23.4% (95% confidence interval, 12.3-38.0) and 78.6% (95% confidence interval, 69.1-86.2), respectively.

CONCLUSION

Real-time EUS findings and ePFTs have a significant impact on the clinical assessment of MCCP. The diagnosis of EPI shows poor correlation with the EUS diagnosis of MCCP. (Clinical trial registration number: NCT01997476.).

Endoscopic Pancreatic Function Testing (ePFT) in Children: A Position Paper From the NASPGHAN Pancreas Committee

Endoscopic pancreatic function testing (ePFT) is one of the few ways to directly diagnose exocrine pancreatic insufficiency, and considerable confusion regarding indications, utility, and interpretation of the test remains. This position paper of the Pancreas Committee of the North American Society of Pediatric Gastroenterology, Hepatology and Nutrition reviews the history and indications for ePFT in children. We compare various methods in current practice and determine their strengths and limitations, and based on data from children and adults we provide guidance on a protocol on how to perform ePFT in children. Lastly, we pose areas in need of further research relating to ePFT in children.

Report on the Short Endoscopic Exocrine Pancreatic Function Test in Children and Young Adults

OBJECTIVES

Endoscopic pancreatic function test (ePFT) has been in use for exocrine function testing since the 1990s. In patients, short ePFT assesses acinar function, unlike the longer version for ductal function in adults. The present study summarizes characteristics of 1913 short ePFTs (S-ePFT) performed at 2 centers since 2001.

METHODS

The main indications in patients presenting at ages infancy to 24.3 years, for the S-ePFT were failure to thrive, weight loss, diarrhea, and abdominal pain with bloating. Secretin was administered as bolus, and 4 aliquots of fluid were collected between 4 and 10 minutes after administration. Amylase, lipase, trypsin, and chymotrypsin activities were measured in the laboratory.

RESULTS

The pH of consecutive samples increased by 0.3 to 0.7. Overall, 36.7% had abnormal S-ePFT with selective amylase deficiency (9.5%) and generalized enzyme deficiency (8.9%) being the most frequent. Retest reproducibility, repeatability, and clinical validity were high. By adding S-ePFT to endoscopy for the suspicion of malabsorption, the abnormal findings increased by 36.9%.

CONCLUSIONS

Short ePFT assesses pancreatic acinar function in a reliable and clinically meaningful way in patients. Diagnostic yield of endoscopy increased substantially albeit with increased sedation time. By S-ePFT ductal function, cytokines and proteomics can also be assessed.

Analysis of lipase activity in duodenal juice. Comparison of an automated spectrophotometric assay to a fluorometric microplate assay, and factors affecting sample stability

BACKGROUND

Direct pancreas function testing (DPFT) has been regarded as gold standard for assessment of exocrine pancreas function. One of the outcomes from DPFT is pancreatic lipase activity in duodenal juice, but no standard assay for measuring pancreas lipase activity in duodenal juice exists.

AIMS

To optimize and evaluate an autoanalyzer assay for measuring lipase activity in duodenal juice.

METHODS

We used samples of duodenal juice from our biobank, collected through a short endoscopic secretin test in patients with suspected exocrine pancreas insufficiency. Samples were analyzed on a Cobas autoanalyzer (Roche Diagnostics), using a colorimetric, kinetic enzyme activity assay. We compared stability of samples diluted in saline to samples diluted in 3-(N-morpholino) propane sulfonic acid (MOPS) buffer added bovine serum albumin (BSA). Results from the Cobas assay were compared to Confluolip method, a fluorometric, kinetic enzyme assay, modified to fit into a microplate setting.

RESULTS

We tested the stability of 54 samples from 21 patients. Diluting samples with MOPS buffer added BSA gave stable results, and was superior to diluting samples in saline. We compared the two assays in 50 samples from 20 patients and found a good correlation between the two assays (r = 0.91, p < .001). There was a significant proportional bias between the two assays, but no significant systematic bias.

CONCLUSION

Pancreatic lipase activity in duodenal juice samples diluted in MOPS buffer added BSA is stable for one hour at room temperature. Quantification of lipase activity in duodenal juice using a standard automated activity assay has comparable accuracy to a manual fluorometric method.

Standard Operating Procedures for Biospecimen Collection, Processing, and Storage: From the Consortium for the Study of Chronic Pancreatitis, Diabetes, and Pancreatic Cancer

High-quality and well-annotated biorepositories are needed to better understand the pathophysiology and biologic mechanisms of chronic pancreatitis (CP) and its consequences. We report a methodology for the development of a robust standard operating procedure (SOP) for a biorepository based on the experience of the clinical centers within the consortium to study Chronic Pancreatitis, Diabetes and Pancreas Cancer Clinical Centers (CPDPC), supported by the National Cancer Institute and the National Institute for Diabetes and Digestive and Kidney Diseases as a unique multidisciplinary model to study CP, diabetes, and pancreatic cancer in both children and adults. Standard operating procedures from the CPDPC centers were evaluated and consolidated. The literature was reviewed for standard biorepository operating procedures that facilitated downstream molecular analysis. The existing literature on biobanking practices was harmonized with the SOPs from the clinical centers to produce a biorepository for pancreatic research. This article reports the methods and basic principles behind the creation of SOPs to develop a biorepository for the CPDPC. These will serve as a guide for investigators developing biorepositories in pancreas research. Rigorous and meticulous adherence to standardized biospecimen collection will facilitate investigations to better understand the pathophysiology and biologic mechanisms of CP, diabetes, and pancreatic cancer.

Method Performance of Bicarbonate and Electrolytes by Use of Duodenal Fluid for Assessment of Exocrine Pancreatic Function

BACKGROUND

Evaluation of exocrine pancreatic insufficiency is challenging for both clinicians and laboratories. Indirect pancreatic function tests such as serum trypsinogen, fecal elastase, and fecal fat measurements are moderately sensitive for diagnosis of advanced chronic pancreatitis but show reduced sensitivity and specificity for diagnosis of early disease. An alternative is the endoscopic pancreatic function test, which uses duodenal secretions after administration of IV secretin. Samples are collected at various times via the endoscopic tube and then analyzed for bicarbonate, sodium, potassium, and chloride.

METHODS

Precision, linearity, method comparison, and stability studies were performed on the Beckman Coulter AU5822 chemistry analyzer with duodenal fluid. Comparison with the Vitros 4600 dry slide chemistry instrument was used to interrogate differences between methods.

RESULTS

All assays produced a CV <2% without any measurable effects from the endoscopy fluid matrix and showed acceptable imprecision near the limit of detection (CV < 5%). All analytes showed linear dilution across the analytical measuring range. All the calculated error biases from dilutions were within 50% of the CLIA-allowable error for serum for each of the respective analytes. The calculated slopes ranged from 0.841 to 1.274 when compared to the Vitros 4600. Stability studies demonstrated that sodium, potassium, chloride, and bicarbonate remained stable after storage at -20 °C and after multiple freeze-thaw cycles. The percent change for all analytes was <5% mmol/L.

CONCLUSIONS

The AU5800 series demonstrated adequate performance for the analysis of bicarbonate in duodenal fluid and therefore can be used for assessment of exocrine pancreatic function. However, notable discrepancies were observed for sodium, potassium, and chloride between the AU5800 series and the Vitros 4600.

A study of the clinical utility of a 20-minute secretin-stimulated endoscopic pancreas function test and performance according to clinical variables

BACKGROUND AND AIMS

Direct pancreas juice testing of bicarbonate, lipase, or trypsin after stimulation by secretin or cholecystokinin is used to determine exocrine function, a surrogate for diagnosing chronic pancreatitis (CP). Endoscopic pancreas function tests (ePFTs), where a peak bicarbonate concentration (PBC) ≥80 mEq/L in pancreas juice is considered normal, are now used more frequently. In this ePFT, aspirates start 35 minutes after secretin administration because pancreas output peaks 30 minutes after secretagogue administration. The performance of ePFT in a cohort of patients with a presumptive diagnosis of CP referred to a pancreas clinic for consideration of an intervention including total pancreatectomy and islet autotransplantation was studied, compared with EUS, ERCP, histology, and consensus diagnosis. The effect of sedation, narcotic use, aspirate volume, body mass index, age, and proton pump inhibitors (PPIs) on test performance is reported.

METHODS

After a test dose, synthetic human secretin was administered intravenously, and 30 minutes later sedation was achieved with midazolam and fentanyl or propofol. A gastroscope was advanced to the major papilla where 4 continuous aspiration samples were performed at 5-minute intervals in sealed bottles. PBC ≥80 mEq/L was normal.

RESULTS

Eighty-one patients had ePFTs from August 2010 through October 2015. Twenty-seven patients (33%) were diagnosed with CP. Eighteen of the 27 patients with CP and 1 of the 54 patients without CP had an abnormal ePFT, producing a sensitivity of 66% (95% CI, 46.0-83.5), specificity 98% (95% CI, 90.1-99.9), positive predictive value 94.7% (95% CI, 74-99.9), and negative predictive value 85.5% (95% CI, 74.2-93.1). ERCP and PBC concordance was generally poor, but none of the patients without CP had major EUS changes, and only 3 patients with a PBC <80 mEq/L had a normal EUS. The PBC was affected by narcotics and PPI use.

CONCLUSION

A 20-minute ePFT after secretin administration had a marginal sensitivity for diagnosis of CP. The diagnosis of CP should not rely on a single study and certainly not a PFT. The duodenal aspirate volume did not correlate with the PBC, which contrasts with current secretin-enhanced MRCP knowledge; therefore, further studies on this subject are warranted. Neither type of sedation, BMI, nor age affected test performance. Narcotics and PPIs may affect the PBC, so borderline results should be interpreted with caution in these groups.

Comparison of Combined Endoscopic Ultrasonography and Endoscopic Secretin Testing With the Traditional Secretin Pancreatic Function Test in Patients With Suspected Chronic Pancreatitis: A Prospective Crossover Study

OBJECTIVE

We aimed to determine the feasibility and accuracy of a combined endoscopic ultrasonography (EUS) with a shortened pancreatic function testing (sEUS) for structural and functional assessment using a single instrument in patients with suspected chronic pancreatitis (CP).

METHODS

We completed a prospective crossover study, enrolling patients with suspected CP. Patients who underwent both traditional 1-hour secretin pancreatic function test (sPFT) and sEUS were included in the analysis. We compared study results for test concordance and for correlation of peak bicarbonate concentrations.

RESULTS

Eleven (64.7%) of 17 patients had concordant sPFT and sEUS findings when the cutoff for peak bicarbonate was 80 mEq/L. Six patients had discordant findings with a negative sPFT and positive sEUS. This poor concordance suggests that sEUS is an unreliable functional test. Lowering the sEUS cutoff to 70 mEq/L resulted in improved concordance (64.7% vs 70.6%). Finally, there was no significant correlation between peak bicarbonate concentrations (r = 0.47; 95% confidence interval, -0.02 to 0.79) in these 2 functional tests.

CONCLUSIONS

We demonstrate poor concordance between sPFT and sEUS suggesting that a combined shortened functional and structural test using a single instrument may not be a feasible test for diagnosis of suspected CP when a cutoff of 80 mEq/L is used.

Diagnosis of Chronic Pancreatitis Incorporating Endosonographic Features, Demographics, and Behavioral Risk

OBJECTIVES

Diagnosing chronic pancreatitis remains challenging. Endoscopic ultrasound (EUS) is utilized to evaluate pancreatic disease. Abnormal pancreas function test is considered the "nonhistologic" criterion standard for chronic pancreatitis. We derived a prediction model for abnormal endoscopic pancreatic function test (ePFT) by enriching EUS findings with patient demographic and pancreatitis behavioral risk characteristics.

METHODS

Demographics, behavioral risk characteristics, EUS findings, and peak bicarbonate results were collected from patients evaluated for pancreatic disease. Abnormal ePFT was defined as peak bicarbonate of less than 75 mEq/L. We fit a logistic regression model and converted it to a risk score system. The risk score was validated using 1000 bootstrap simulations.

RESULTS

A total of 176 patients were included; 61% were female with median age of 48 years (interquartile range, 38-57 years). Abnormal ePFT rate was 39.2% (69/176). Four variables formulated the risk score: alcohol or smoking status, number of parenchymal abnormalities, number of ductal abnormalities, and calcifications. Abnormal ePFT occurred in 10.7% with scores 4 or less versus 92.0% scoring 20 or greater. The model C-statistic was 0.78 (95% confidence interval, 0.71-0.85).

CONCLUSIONS

Number of EUS pancreatic duct and parenchymal abnormalities, presence of calcification, and smoking/alcohol status were predictive of abnormal ePFT. This simple model has good discrimination for ePFT results.

Analysis of amylase in duodenal juice - Automated kinetic spectrophotometric analysis versus manual colorimetric endpoint assay

OBJECTIVE

The measurement of duodenal amylase by a colorimetric end-point assay has been the most used method for amylase activity analyses. The method is manual, time consuming and dependent on specialized equipment. In this study, we compare an automated kinetic spectrophotometric method for pancreatic amylase measurement in duodenal juice with a standardized colorimetric end-point assay.

METHODS

We used specimen of duodenal juice at random from a biobank obtained by short endoscopic secretin test in patients with suspected exocrine pancreatic failure of different reasons. Duodenal juice was tested for amylase activity with a conservative manual colorimetric endpoint assay (Phadebas Amylase test, Magle AB) and an automated enzymatic kinetic spectrophotometric method using standard reagents for pancreatic amylase activity for Cobas c111 (Roche Diagnostics).

RESULTS

52 samples for assay of amylase were analyzed in pairs. Correlation between measurements with the two methods was r = 0.99 (p < 0.001), linear regression 0.99 (p < 0.001).

CONCLUSION

Quantification of duodenal amylase activity with automated spectrophotometry has excellent correlation to measurements made by the manual method. This allows for standardized, center independent analyses of duodenal amylase for the assessment of acinar pancreatic function.

Utility of Direct Pancreatic Function Testing in Children

OBJECTIVES

Exocrine pancreatic insufficiency (EPI) can have a significant impact on a child's growth and nutrition. Our aim was to evaluate the utility of direct endoscopic pancreatic function testing (ePFT) in pediatrics.

METHODS

A single-center retrospective chart review was performed of children who underwent ePFT from December 2007 through February 2015. Endoscopic pancreatic function testings were performed by 1 of 2 methods: (1) intravenous cholecystokinin, followed by the collection of a single duodenal aspirate at 10 minutes, or (2) intravenous cholecystokinin or secretin, followed by the collection of 3 duodenal aspirates at a 5, 10, and 15 minutes. Samples were tested for pH and enzyme activities.

RESULTS

A total of 508 ePFTs were performed (481 single-sample tests, 27 multiple-sample tests). Based on the multiple-sample group, enzyme levels for chymotrypsin, amylase, and lipase peaked at 5 minutes, followed by a decrease in activity over time. Exocrine pancreatic sufficiency was identified in 373 (73.4%) and EPI in 93 (18.3%). Exocrine pancreatic sufficiency analysis found all pancreatic enzyme activities significantly increase with age: trypsin, chymotrypsin, amylase, and lipase, (P < 0.05).

CONCLUSIONS

Endoscopic pancreatic function testing can be used in the evaluation of EPI in children. Normative data suggest that pancreatic enzyme activities mature with age.

Automated spectrophotometric bicarbonate analysis in duodenal juice compared to the back titration method

OBJECTIVES

We have recently evaluated a short endoscopic secretin test for exocrine pancreatic function. Bicarbonate concentration in duodenal juice is an important parameter in this test. Measurement of bicarbonate by back titration as the gold standard method is time consuming, expensive and technically difficult, thus a simplified method is warranted. We aimed to evaluate an automated spectrophotometric method in samples spanning the effective range of bicarbonate concentrations in duodenal juice. We also evaluated if freezing of samples before analyses would affect its results.

METHODS

Patients routinely examined with short endoscopic secretin test suspected to have decreased pancreatic function of various reasons were included. Bicarbonate in duodenal juice was quantified by back titration and automatic spectrophotometry. Both fresh and thawed samples were analysed spectrophotometrically.

RESULTS

177 samples from 71 patients were analysed. Correlation coefficient of all measurements was r = 0.98 (p < 0.001). Correlation coefficient of fresh versus frozen samples conducted with automatic spectrophotometry (n = 25): r = 0.96 (p < 0.001) CONCLUSIONS: The measurement of bicarbonate in fresh and thawed samples by automatic spectrophotometrical analysis correlates excellent with the back titration gold standard. This is a major simplification of direct pancreas function testing, and allows a wider distribution of bicarbonate testing in duodenal juice. Extreme values for Bicarbonate concentration achieved by the autoanalyser method have to be interpreted with caution.

Diagnostic Accuracy of a Short Endoscopic Secretin Test in Patients With Cystic Fibrosis

OBJECTIVE

Short endoscopic secretin tests for exocrine pancreatic function are not properly evaluated in cystic fibrosis (CF).

METHODS

Patients with CF and healthy controls (HCs) underwent endoscopic collection of duodenal juice between 30 and 45 minutes after secretin stimulation. Duodenal juice was analyzed for HCO3 concentration and pancreatic enzyme activities. Stool was analyzed for fecal elastase.

RESULTS

Thirty-one patients with CF and 25 HCs were tested. Patients were classified as exocrine pancreatic sufficient (n = 13) or insufficient (n = 18). Both bicarbonate concentrations and enzyme activities in duodenal juice differentiated patients with CFI from patients with CFS and HC (P < 0.001). The population displays strong correlation between severe CF genotype in both alleles and pancreatic insufficient phenotype (P < 0.001).

CONCLUSIONS

Pancreatic exocrine insufficient CF patients could be differentiated from exocrine sufficient patients and HCs using short endoscopic secretin test.

Evaluation of Qualitative Magnetic Resonance Imaging Features for Diagnosis of Chronic Pancreatitis

OBJECTIVES

The purpose of this study was to determine qualitative pancreatic magnetic resonance imaging (MRI) features that must be present to predict abnormal pancreatic secretory function in patients evaluated for chronic pancreatitis (CP).

METHODS

The MRIs of study subjects were reviewed by 2 abdominal radiologists; qualitative parenchyma and ductal features were recorded. Endoscopic pancreatic function test (ePFT) results (reference standard) were classified as normal (peak pancreatic fluid bicarbonate [HCO3-] ≥75 meq/L) or abnormal (<75). Abnormal ePFT was further classified as mild/moderate (74-65) and marked deficiency (<65). Statistical analysis was performed to assess the association between MRI features and abnormal ePFT.

RESULTS

The study cohort was composed of 93 subjects, mean age 49 years (range, 18-78 years), 65% females. Univariate analysis identified 9 qualitative MRI features significantly (P < 0.05) associated with abnormal pancreatic secretory function. Number of MRI features increases as peak pancreatic fluid [HCO3-] decreases (Pearson r = -0.629; P = 0.001). Receiver operating characteristic curve analysis determined that a threshold of 6 or more associated MRI features 64% sensitive and 94% specific for marked bicarbonate deficiency.

CONCLUSIONS

Qualitative MRI parenchymal and ductal features are associated with CP. Presence of 6 or more features results in a higher specificity for the diagnosis of CP in advanced disease.

Diagnosis of Exocrine Pancreatic Insufficiency

OPINION STATEMENT

The accurate diagnosis of exocrine pancreatic insufficiency (EPI) helps identify those in need of pancreatic enzyme replacement therapy. Conversely, ruling out EPI identifies those in which additional evaluation should be pursued to explain their symptoms. There are many available tests that can be used to diagnose EPI; however, the tests must be tailored to each clinical scenario. Tests that are convenient but less accurate (e.g., fecal elastase-1, qualitative fecal fat determination) are best suited for patients with a high pretest probability of EPI. In contrast, tests that are highly accurate but more cumbersome (e.g., endoscopic pancreatic function testing, 72-h fecal fat collection) are favored in patients suspected to have mild EPI or an early stage of chronic pancreatitis. Additional research is needed to identify a more convenient means of accurately diagnosing at all stages of EPI.

Diagnostic accuracy of secretin-stimulated ultrasonography of the pancreas assessing exocrine pancreatic failure in cystic fibrosis and chronic pancreatitis

OBJECTIVE

Volume output failure is a feature of decreasing exocrine pancreatic function. This parameter is assessed by secretin-stimulated MRI in several studies. Our purpose was to evaluate ultrasonography of the fluid in the descending duodenum and Wirsung duct (WD) after secretin stimulation as a measure of pancreatic fluid flow in patients expected to have severe output failure.

MATERIAL AND METHODS

We included subjects with chronic pancreatitis (CP), cystic fibrosis (CF) and a group of healthy controls in a prospective observation study. Transabdominal ultrasonography was performed before and during 15 min after secretin i.v. duodenal juice was collected by endoscopic short test (EST), and bicarbonate concentration measured. Patient groups were classified according to exocrine pancreatic function.

RESULTS

Pancreatic insufficient CF (CFI) patients and CP insufficient (CPI) patients showed less duodenal fluid filling compared to other groups (p < 0.001). Measures of the WD diameter could only identify the most severe failure in the CFI group (p < 0.001).

CONCLUSION

Secretin-stimulated ultrasonography can be used to assess pancreatic fluid flow and may be combined with EST in the evaluation of exocrine pancreatic function. Fluid filling in the descending part of duodenum was the most accurate predictor of pancreatic insufficiency in both patient groups. The test demonstrated better diagnostic accuracy diagnosing exocrine pancreatic failure in the CF patients than in CP patients.

Approach to patients with suspected chronic pancreatitis: a comprehensive review

Chronic pancreatitis (CP) represents a significant health care burden in the United States. Diagnosing it early and accurately is important for the efficient management of these patients. However, the early diagnosis of CP, when structural and functional pancreatic changes are subtle, remains difficult. Complicating this is the large cohort of patients with nonspecific abdominal pain who are often suspected of having early CP and who utilize significant health care resources in attempts at diagnosis and management. We present a review of the current diagnostic tests available for making an early diagnosis of CP. We further report our approach to patients suspected of having CP based on the available literature.

13C-mixed triglyceride breath test for evaluation of pancreatic exocrine function in diabetes mellitus

OBJECTIVE

The clinical relevance of pancreatic exocrine insufficiency (PEI) in diabetic patients is unclear mostly because established function tests are invasive and expensive or lack sensitivity and specificity. A modified version of the noninvasive 13C-mixed triglyceride breath test (13C-MTGT) has recently been shown to detect moderate PEI reliably in patients with chronic pancreatitis. Its sensitivity and specificity in other patient groups are unknown. We therefore aimed to clarify the significance of this test for patients with diabetes mellitus (DM).

METHODS

A secretin cerulein test and a modified 13C-MTGT were performed in 14 patients with DM (10 patients with type 1 DM) and 10 healthy volunteers.

RESULTS

Secretin cerulein test showed significantly lower outputs of amylase, trypsin, and lipase in DM compared with healthy volunteers (P < 0.05). Likewise, 13C-MTGT showed significantly lower maximal and cumulative 13C-exhalation in DM (P < 0.005). Stimulated lipase output correlated with cumulative 13C-exhalation (P < 0.05). However, when compared with normal values, only 2 patients with diabetes had abnormally low lipase output, whereas cumulative 13C-exhalation was pathologically decreased in 8 patients, including those with decreased lipase output.

CONCLUSIONS

The noninvasive 13C-MTGT can detect mild to moderate PEI in DM. However, the specificity of the 13C-MTGT is low in these patients probably because nonpancreatic mechanisms contribute to decreased intestinal lipolysis.

An overview of the diagnosis and management of nutrition in chronic pancreatitis

Chronic pancreatitis is characterized by long-standing inflammation of the pancreas, which results in fibrosis and the gradual loss of pancreatic function. The loss of islets and acinar cells results in diabetes and exocrine insufficiency, respectively. Exocrine insufficiency can result in maldigestion of fat, protein, and carbohydrate as well as vitamins and minerals. Patients may present with variable severity of disease, from mild to severe. The diagnosis of chronic pancreatitis can be challenging, especially in patients with early or mild disease who have few to no morphologic abnormalities on standard abdominal imaging studies. A number of imaging modalities and tests have evolved to aid in the diagnosis of chronic pancreatitis based on changes in structure or function. Clinicians typically focus on treating pain in chronic pancreatitis as opposed to exocrine insufficiency, despite the fact that maldigestion and malabsorption can result in nutrition deficiencies. The aims of this review are to describe the various modalities used to diagnose chronic pancreatitis, to illustrate the nutrition deficiencies associated with exocrine insufficiency, and to provide an overview of nutrition assessment and treatment in these patients.

Current options for the diagnosis of chronic pancreatitis

The diagnostic options for chronic pancreatitis have evolved over recent years. The previous gold standard references for structural imaging and exocrine pancreatic function testing have both been supplanted and redesigned. Endoscopic retrograde pancreatography has now been overtaken by endoscopic ultrasound and magnetic resonance cholangiopancreatography, whilst the old technique for Dreiling tube pancreatic function testing has now been replaced by the endoscopic pancreatic function test. New advances in endoscopic ultrasound elastography have also extended the options for evaluating pancreatic masses to differentiate mass-forming chronic pancreatitis from malignancy. Genetic contribution to chronic pancreatitis is also now more widely recognized than ever before.

Carboxyl-ester lipase maturity-onset diabetes of the young is associated with development of pancreatic cysts and upregulated MAPK signaling in secretin-stimulated duodenal fluid

Carboxyl-ester lipase (CEL) maturity-onset diabetes of the young (MODY) is a monogenic form of diabetes and pancreatic exocrine dysfunction due to mutations in the CEL gene encoding CEL. The pathogenic mechanism for diabetes development is unknown. Since CEL is expressed mainly in pancreatic acinar cells, we asked whether we could find structural pancreatic changes in CEL-MODY subjects during the course of diabetes development. Furthermore, we hypothesized that the diseased pancreas releases proteins that are detectable in pancreatic fluid and potentially reflect activation or inactivation of disease-specific pathways. We therefore investigated nondiabetic and diabetic CEL-mutation carriers by pancreatic imaging studies and secretin-stimulated duodenal juice sampling. The secretin-stimulated duodenal juice was studied using cytokine assays, mass spectrometry (MS) proteomics, and multiplexed MS-based measurement of kinase activities. We identified multiple pancreatic cysts in all eight diabetic mutation carriers but not in any of the four nondiabetic mutation carriers or the six healthy controls. Furthermore, we identified upregulated mitogen-activated protein kinase (MAPK) target proteins and MAPK-driven cytokines and increased MAPK activity in the secretin-stimulated duodenal juice. These findings show that subjects with CEL-MODY develop multiple pancreatic cysts by the time they develop diabetes and that upregulated MAPK signaling in the pancreatic secretome may reflect the pathophysiological development of pancreatic cysts and diabetes.

Severe pancreatic dysfunction but compensated nutritional status in monogenic pancreatic disease caused by carboxyl-ester lipase mutations

OBJECTIVES

The impact of pancreatic dysfunction in several diseases of the pancreas, including chronic pancreatitis and cystic fibrosis, is obscured by concomitant extra-pancreatic disease. Carboxyl-ester lipase-maturity-onset diabetes in the young (CEL-MODY) is a monogenic, highly penetrant and progressive pancreatic disease with no known primary extrapancreatic manifestations. It is characterized by low fecal elastase, steatorrhea, and development of diabetes mellitus. We sought to determine the nature of the exocrine dysfunction in CEL-MODY and relate the findings to clinical parameters of malnutrition.

METHODS

We examined CEL-MODY patients and control subjects by rapid, endoscopic secretin test and dynamic magnetic resonance imaging of the pancreas. The findings were related to the subjects' clinical status.

RESULTS

The CEL-MODY patients displayed severely reduced acinar function and moderately reduced ductal function of the pancreas compared with control subjects. Surprisingly, CEL-MODY patients did not have clinical or biochemical signs of malnutrition, except for subnormal levels of vitamin E. Vitamin E levels seemed to be directly related to pancreatic acinar function.

CONCLUSIONS

Pancreatic exocrine dysfunction in CEL-MODY is associated with severely reduced acinar and moderately reduced ductal dysfunction. Despite severely reduced exocrine pancreatic function, CEL-MODY patients revealed only minor signs of malnutrition.

Quantification of pancreatic function using a clinically feasible short endoscopic secretin test

OBJECTIVES

Clinical and morphological criteria are not precise enough to diagnose early chronic pancreatitis (CP). We investigated if short endoscopic pancreas function testing as a part of routine upper endoscopy could improve clinical diagnostics.

METHODS

Patients with suspected CP underwent modified secretin-stimulated upper endoscopy (short endoscopic secretin test, or EST). Duodenal juice was collected during 15 minutes starting 30 minutes after stimulation. A modified scoring system for CP after Layer with bicarbonate and fecal elastase 1 (FE1) was used. We tested with receiver operating characteristic curves the diagnostic accuracy of bicarbonate and FE1 and with analysis of variance how precise the 2 parameters can discriminate the groups.

RESULTS

Fifty-two patients aged 19 to 67 years and 25 healthy controls aged 19 to 64 years were included. Twenty-four patients fulfilled the modified Layer Score for CP or non-CP. The overall accuracy of the EST versus FE1 test was 85%/71%, with positive and negative predictive values of 100%/79% and 80%/69%, respectively.

CONCLUSIONS

Short EST is rapid and easy to perform and can be incorporated in daily routines. We demonstrate that EST is superior to FE1 in the assessment of pancreatic insufficiency and may prove to be useful in diagnosing early or mild CP.

Defining the accuracy of secretin pancreatic function testing in patients with suspected early chronic pancreatitis

OBJECTIVES

The diagnosis of chronic pancreatitis in patients with characteristic symptoms but normal pancreatic imaging is challenging. Assessment of pancreatic function through secretin pancreatic function testing (SPFT) has been advocated in this setting, but its diagnostic accuracy is not fully known.

METHODS

This was a retrospective review of patients who received SPFT at our tertiary care institution between January 1995 and December 2008 for suspected chronic pancreatitis. For all patients, medical records were reviewed for evidence of subsequent development of chronic pancreatitis by imaging and/or pathology. Patients were then categorized as "true positive" or "true negative" for chronic pancreatitis based on follow-up imaging or histologic evidence.

RESULTS

In all, 116 patients underwent SPFT. Of the 27 patients who tested positive, 7 were lost to follow-up. Of the remaining 20 SPFT-positive patients, 9 (45%) developed radiologic or histologic evidence of chronic pancreatitis after a median of 4 years (1-11 years). Of the 89 patients who had negative SPFT testing, 19 were lost to follow-up. Of the remaining 70 patients, 2 were eventually diagnosed with chronic pancreatitis based on subsequent imaging/histology after a median follow-up period of 7 years (3-11 years). The sensitivity of the SPFT in diagnosing chronic pancreatitis was 82% with a specificity of 86%. The positive predictive value (PPV) of chronic pancreatitis was 45% with a negative predictive value (NPV) of 97%.

CONCLUSIONS

In patients with suspected early chronic pancreatitis and normal pancreatic imaging, SPFT is highly accurate at ruling out early chronic pancreatitis with a NPV of 97%.

Exocrine pancreatic function in hepatocyte nuclear factor 1β-maturity-onset diabetes of the young (HNF1B-MODY) is only moderately reduced: compensatory hypersecretion from a hypoplastic pancreas

OBJECTIVES

To examine the exocrine pancreatic function in carriers of the hepatocyte nuclear factor 1β gene (HNF1B) mutation by direct testing.

METHODS

Patients with HNF1B mutations and control subjects were assessed using rapid endoscopic secretin tests and secretin-stimulated magnetic resonance imaging. Seven patients and 25 controls underwent endoscopy, while eight patients and 20 controls had magnetic resonance imaging. Ductal function was assessed according to peak bicarbonate concentrations and acinar function was assessed according to peak digestive enzyme activities in secretin-stimulated duodenal juice. The association of pancreatic exocrine function and diabetes status with pancreatic gland volume was examined.

RESULTS

The mean increase in secretin-stimulated duodenal fluid was smaller in patients than controls (4.0 vs 6.4 ml/min; P = 0.003). We found lower ductal function in patients than controls (median peak bicarbonate concentration: 73 vs 116 mEq/L; P < 0.001) and lower acinar function (median peak lipase activity: 6.4 vs 33.5 kU/ml; P = 0.01; median peak elastase activity: 0.056 vs 0.130 U/ml; P = 0.01). Pancreatic fluid volume outputs correlated significantly with pancreatic gland volumes (r² = 0.71, P = 0.008) in patients. The total fluid output to pancreatic gland volume ratios were higher in patients than controls (4.5 vs 1.3 ml/cm³; P = 0.03), suggesting compensatory hypersecretion in the remaining gland.

CONCLUSION

Carriers of the HNF1B mutation have lower exocrine pancreatic function involving both ductal and acinar cells. Compensatory hypersecretion suggests that the small pancreas of HNF1B mutation carriers is attributable to hypoplasia, not atrophy.

Cigarette smoking impairs pancreatic duct cell bicarbonate secretion

OBJECTIVE

To compare pancreatic duct cell function in smokers (current and past) and never smokers by measurement of secretin-stimulated peak bicarbonate concentration ([HCO3-]) in endoscopic collected pancreatic fluid (PF).

METHODS

This retrospective study was cross-sectional in design, recording demographic information (age, gender, etc.), smoking status (former, current, never), alcohol intake, clinical data (imaging, endoscopy), and laboratory results (peak PF [HCO3-]) from subjects evaluated for pancreatic disease at a tertiary pancreas center. Univariate and multivariate statistical analysis (SAS Version 9.2, Cary, NC, USA) was performed to assess the relationship between cigarette smoking and secretin-stimulated pancreatic fluid bicarbonate concentration.

RESULTS

A total of 131 subjects underwent pancreatic fluid collection (endoscopic pancreatic function test, ePFT) for bicarbonate analysis: 25.2% (33 out of 131) past smokers, 31.3% (41 out of 131) current smokers, and 43.5% (57 out of 131) were never smokers. Measures of Association: The mean peak PF [HCO3-] in never smokers (81.3 ± 18.5 mEq/L) was statistically higher (indicating better duct cell function) when compared to past smokers (66.8 ± 24.7 mEq/L, P=0.005) and current smokers (70.0 ± 20.2 mEq/L, P=0.005). However, the mean peak [HCO3-] in past smokers was not statistically different from that in current smokers (P=0.575), and therefore, the two smoking groups were combined to form a single "smokers cohort". When compared to the never smokers, the smokers cohort was older (P=0.037) and had a greater proportion of subjects with definite chronic pancreatitis imaging (P=0.010), alcohol consumption ≥20 g/day (P=0.012), and abnormal peak PF [HCO3-] (P<0.001). Risk-Based Estimates: Cigarette smoking (risk ratio, RR: 2.2, 95% CI: 1.3-3.5; P<0.001), diagnosis of definite chronic pancreatitis imaging (RR: 2.2, 95% CI: 1.6-3.2; P<0.001) and alcohol consumption ≥20 g/day (RR: 1.6, 95% CI: 1.1-2.4; P=0.033) were all associated with low mean peak PF [HCO3-] (indicating duct cell secretory dysfunction). Multivariate Analysis: Smoking (odds ratio, OR: 3.8, 95% CI: 1.6-9.1; P=0.003) and definite chronic pancreatitis imaging (OR: 5.7, 95% CI: 2.2-14.8; P<0.001) were determined to be independent predictors of low peak PF [HCO3-], controlling for age, gender, and alcohol intake. Furthermore there was no interaction between smoking status and alcohol intake in predicting duct cell dysfunction (P=0.571).

CONCLUSION

Measurement of pancreatic fluid bicarbonate in smokers reveals that cigarette smoking (past and current) is an independent risk factor for pancreatic duct cell secretory dysfunction (low PF [HCO3-]). Furthermore, the risk of duct cell dysfunction in subjects who smoked was approximately twice the risk (RR: 2.2) in never smokers. Further in depth, translational research approaches to pancreatic fluid analysis may help unravel mechanisms of cigarette smoking induced pancreatic duct cell injury.

Endoscopic pancreatic function test using combined secretin and cholecystokinin stimulation for the evaluation of chronic pancreatitis

BACKGROUND

Current endoscopic pancreatic function test (ePFT) methods use either secretin or cholecystokinin (CCK) to measure pancreatic function.

OBJECTIVE

To evaluate a novel ePFT protocol that includes both secretin and CCK stimulation and to assess which fluid parameters best discriminate patients with chronic pancreatitis (CP).

DESIGN

Prospective, cross-sectional diagnostic study.

SETTING

Single, tertiary-care institution.

PATIENTS

Healthy volunteers and patients evaluated for CP were included.

INTERVENTIONS

All patients underwent a combined secretin-CCK ePFT. Patients evaluated for CP also underwent EUS during the same endoscopic session.

MAIN OUTCOME MEASUREMENTS

Duodenal fluid bicarbonate, lipase, and amylase concentrations were measured after CCK and secretin stimulation. Results were compared based on the presence of CP detected by EUS (≥5 features).

RESULTS

Twenty healthy volunteers and 69 patients evaluated for CP completed the secretin and CCK ePFT. Patients with an EUS score of 5 or higher had significantly decreased peak bicarbonate concentrations (72 mmol) compared with patients with an EUS score lower than 5 (90 mmol) and healthy subjects (108 mmol) (P < .001). Peak concentrations of amylase and lipase and total fluid volume were not significantly different between patients with CP and controls. Receiver-operating characteristic analysis revealed that peak bicarbonate concentration had superior discrimination for CP (area under the curve [AUC] 0.738) compared with peak amylase (AUC 0.677) and peak lipase (AUC 0.627). The addition of enzyme concentration measurement did not improve discrimination compared with peak bicarbonate alone.

LIMITATIONS

Secretin and cholecystokinin endoscopic pancreatic function test (SC ePFT) results were not compared with those of single hormone ePFTs.

CONCLUSIONS

The addition of CCK infusion and enzyme concentration measurement to a standard secretin ePFT does not enhance the diagnosis of CP.

Abnormal duodenal [HCO3-] following secretin stimulation develops sooner than endocrine insufficiency in minimal change chronic pancreatitis

OBJECTIVES

Direct pancreatic function tests (PFTs) are often used to diagnose chronic pancreatitis (CP). We aimed to determine the temporal relationship between an abnormal PFT result, cross-sectional imaging, and clinical symptoms.

METHODS

All patients referred for endoscopic ultrasound (EUS) and PFT for suspected CP at our medical center from 2008 to 2010 were included. Each subject underwent EUS and PFT on the same day using secretin stimulation.

RESULTS

Seventeen patients had duodenal HCO3 values of less than 80 mEq/L and were labeled as abnormal; the 25 other patients had at least 1 duodenal HCO3 values of 80 mEq/L or greater. Patients with abnormal PFTs had more parenchymal (2.0 vs 0.92, P = 0.012), ductal (1.18 vs 0.6, P = 0.036), and total features (3.18 vs 1.52, P = 0.009) than those with normal PFTs on EUS examination. There was no difference in regard to the frequency of abnormal CT scans (25% vs 15%, P = 0.139), diarrhea (67% vs 60%, P = 0.463), fat-soluble vitamin deficiency (33% vs 26%, P = 0.315), or diabetes (10% vs 4%, P = 0.066).

CONCLUSIONS

Patients with equivocal imaging and abnormally low duodenal HCO3 have more EUS features of CP than do patients with normal duodenal HCO3 values, suggesting that low duodenal HCO3 values are among the first measurable abnormalities in CP.

A modified ¹³C-mixed triglyceride breath test detects moderate pancreatic exocrine insufficiency

OBJECTIVES

The noninvasive ¹³C-mixed triglyceride breath test (¹³C-MTG-T) has been shown to diagnose severe pancreatic exocrine insufficiency reliably. We hypothesized that sensitivity of the test could be increased by strict limitation of physical activity, correction for gastric emptying velocity, and/or increased lipid dose.

METHODS

In 10 healthy volunteers and 9 patients with suspected pancreatic disease, a secretin test, a modified ¹³C-MTG-T (250 mg ¹³C-MTG, 26 g fat, breath samples over 8 hours), and a ¹³C-octanoic acid gastric emptying test were performed. Subjects remained strictly seated during breath testing.

RESULTS

Intravenously administered secretin 1 U/kg·h stimulated outputs of all enzymes significantly. Mean basal and stimulated enzyme outputs were similar in patients and healthy controls; however, compared with normal values, 5 patients and 1 control had moderately decreased lipase output. Cumulative 4-, 6-, and 8-hour ¹³C exhalation was significantly lower in patients than in controls. Sensitivity of ¹³C-MTG-T (6-h cumulative ¹³C exhalation <27% of dose) for detection of decreased lipase output was 100%; specificity was 92%. Gastric emptying parameters were similar in patients and controls, and correction for these did not improve accuracy of ¹³C-MTG-T.

CONCLUSIONS

The modified ¹³C-MTG-T detects moderate pancreatic exocrine insufficiency.

Update on endoscopic pancreatic function testing

Hormone-stimulated pancreatic function tests (PFTs) are considered the gold standard for measuring pancreatic exocrine function. PFTs involve the administration of intravenous secretin or cholecystokinin, followed by collection and analysis of pancreatic secretions. Because exocrine function may decline in the earliest phase of pancreatic fibrosis, PFTs are considered accurate for diagnosing chronic pancreatitis. Unfortunately, these potentially valuable tests are infrequently performed except at specialized centers, because they are time consuming and complicated. To overcome these limitations, endoscopic PFT methods have been developed which include aspiration of pancreatic secretions through the suction channel of the endoscope. The secretin endoscopic pancreatic function test (ePFT) involves collection of duodenal aspirates at 15, 30, 45 and 60 min after secretin stimulation. A bicarbonate concentration greater than 80 mmol/L in any of the samples is considered a normal result. The secretin ePFT has demonstrated good sensitivity and specificity compared with various reference standards, including the "Dreiling tube" secretin PFT, endoscopic ultrasound, and surgical histology. Furthermore, a standard autoanalyzer can be used for bicarbonate analysis, which allows the secretin ePFT to be performed at any hospital. The secretin ePFT may complement imaging tests like endoscopic ultrasound (EUS) in the diagnosis of early chronic pancreatitis. This paper will review the literature validating the use of ePFT in the diagnosis of exocrine insufficiency and chronic pancreatitis. Newer developments will also be discussed, including the feasibility of combined EUS/ePFT, the use of cholecystokinin alone or in combination with secretin, and the discovery of new protein and lipid pancreatic juice biomarkers which may complement traditional fluid analysis.

An automated analyzer provides clinically concordant results to manual back titration for quantitation of bicarbonate in pancreatic juice

OBJECTIVES

Secretin pancreatic function tests play an important role in the diagnosis of chronic pancreatitis. Back titration is the standard method for measurement of bicarbonate in pancreatic juice but is time consuming and manually performed. Use of an autoanalyzer for this purpose is not validated.

METHODS

Bicarbonate concentrations in secretin-stimulated pancreatic juice specimens were quantitated by manual back titration, a clinical chemistry autoanalyzer (automated bicarbonate, Roche Cobas c501, Roche Diagnostics, Indianapolis, Ind), and a blood gas analyzer (calculated bicarbonate, GEM 3000, Instrumentation Laboratories, Bedford, Mass). Kappa statistic analysis, Bland-Altman analysis, and Lin concordance correlation coefficients were calculated.

RESULTS

Ninety specimens from 31 subjects were included. Using a bicarbonate concentration of 80 mEq/L as a cutoff value, there was poor agreement between back titration and calculated bicarbonate (κ = 0.188); however, only 1 specimen showed discrepancy between back titration and automated bicarbonate (κ = 0.977). The limit of agreement between the back titration and automated bicarbonate was -9.0 to + 8.3 mEq/L. The Lin concordance correlation coefficient between the 2 methods was 0.931 (P < 0.001).

CONCLUSIONS

There is strong concordance between manual back titration and chemistry autoanalyzer methods for measurement of bicarbonate concentrations in pancreatic juice. Autoanalyzers may replace back titration for this purpose. Blood gas analyzers are unsuitable.

Magnetic resonance cholangiopancreatography reports in the evaluation of chronic pancreatitis: a need for quality improvement

BACKGROUND

Numerous publications from academic centers suggest that magnetic resonance cholangiopancreatography (MRCP) can diagnose early chronic pancreatitis (CP) and assess pancreatic secretory reserve/function. However, the rigorous composite interpretation methods and quantitative secretory dynamics reported in these studies are not routinely measured in clinical practice. Therefore, the utility of routine MRCP reports in the clinical setting is unknown.

STUDY DESIGN

Cross-sectional study of patients referred to a tertiary center who underwent both MRCP and endoscopic pancreas function testing (ePFT) for assessment of chronic pancreatitis and abdominal pain.

AIMS

To compare MRCP and sMRCP reports to a reference standard pancreas function test for diagnosis of chronic pancreatitis.

METHODS

Source population: patients seen within a pancreas clinic at a tertiary referral center. MRCP and sMRCP reports were reviewed to record pancreas duct (dilation, side-branch changes), parenchyma enhancement (T(1), T(2) signal) and physiologic response (duodenal filling, pancreas duct response) to secretin. ePFT was categorized based on previously published data (normal peak bicarbonate >80 mEq/l). Referent values were calculated for MRCP and sMRCP using secretin ePFT as gold standard.

RESULTS

A total of 69 patients were identified (mean age 43.5 +/- 12; 65.2% female). 28 (40.6%) patients had abnormal ePFT based on their peak bicarbonate level. The mean bicarbonate values in the abnormal PFT and normal PFT groups were 59 +/- 13.9 and 95.3 +/- 12.6 mEq/l, respectively. Peak bicarbonate decreased with severity of chronic pancreatitis on MRCP (p = 0.0016). There was fair agreement of MRCP and ePFT (kappa 0.335 [0.113, 0.557]). The pre-stimulation pancreas duct changes reported were found to be the only predictor of abnormal pancreas function (p = 0.002). The post-stimulation findings of duodenal filling (p = 0.47), T(2)enhancement (p = 0.21) or change in pancreas duct caliber (p = 0.3) reported did not improve MRCP agreement with ePFT. Overall diagnostic accuracy, sensitivity and specificity were 70, 85 and 46%, respectively, for MRCP reports using ePFT as the gold standard.

CONCLUSIONS

Pancreas ductal features described on routine MRCP reports correlate with abnormal pancreas function. Current MRCP reports should be standardized to include all radiologic information available in hopes of predicting early chronic pancreatitis.

Evaluation of duct-cell and acinar-cell function and endosonographic abnormalities in patients with suspected chronic pancreatitis

BACKGROUND & AIMS

Endoscopic ultrasound (EUS) detects mild and severe structural abnormalities of the pancreas that correlate with fibrosis. Direct pancreatic function tests (PFTs) detect mild exocrine insufficiency associated with early fibrosis. The primary aim of this study was to compare EUS structural criteria with duct-cell and acinar-cell function.

METHODS

Fifty patients evaluated for chronic pancreatitis underwent combined EUS and secretin endoscopic PFTs (ePFT) on day 1 and CCK ePFT on day 2. EUS images were videotaped and interpreted by consensus of 3 blinded expert reviewers.

RESULTS

There were inverse correlations of EUS consensus score with both duct-cell bicarbonate secretion (R = -0.71, P < .001) and acinar-cell lipase secretion (R = -0.52, P < .001). With secretin ePFT as reference standard, EUS (>or=4 criteria) showed a sensitivity of 71% (95% confidence interval [CI], 53%-89%) and specificity of 92% (95% CI, 75%-99%). With CCK ePFT as reference standard, EUS had a sensitivity of 63% (95% CI, 43%-82%) and specificity of 85% (95% CI, 71%-98%). Main duct dilation, irregularity, calcifications, and visible side-branches were most predictive of exocrine insufficiency (positive predictive value >80% for both acinar- and duct-cell insufficiency).

CONCLUSIONS

Acinar- and duct-cell function decreases as EUS structural abnormalities increase. EUS has fair sensitivity and very good specificity compared with secretin and CCK functional reference standards.

Pancreatic function testing is best determined by the extended endoscopic collection technique

OBJECTIVE

To evaluate whether the extended secretin-stimulated direct endoscopic pancreatic function test (ePFT) technique is superior to the rapid 15 minute secretin-stimulated ePFT in determining pancreatic exocrine function.

METHODS

We conducted a retrospective study of 53 patients with chronic abdominal pain and normal pancreatic imaging. These patients had ePFT testing with the following modified endoscopic collection system. Porcine synthetic or human secretin was intravenously administered 15 minutes before endoscopic duodenal aspiration. The first 10-minute collection was performed in the third portion of the duodenum. A Liguory drainage tube was placed in the third portion of the duodenum. Two additional 10-minute-period collections were obtained via the drainage tube at 30 and 45 minutes after intravenous administration of secretin. All fluid collections were analyzed for bicarbonate (HCO3) concentration.

RESULTS

Peak HCO3 concentrations at 15 minutes occurred in 62%, at 30 to 40 minutes in 23%, and at 45 to 55 minutes in 15%. Normal concentrations of HCO3 (> or =80 mEq/L) were seen in 70%, abnormal concentration in 7%, and equivocal concentrations (60-79 mEq/L) in 23% even after 55 minutes of duodenal collections.

CONCLUSION

Collections beyond 15 minutes are necessary to improve accuracy of the ePFT in determining pancreatic exocrine function.

A rapid, endoscopic exocrine pancreatic function test and the Lundh test: a comparative study

BACKGROUND/AIMS

The diagnosis of chronic pancreatitis is often difficult in the early stages of the disease. Morphological tests may be normal, and reliable methods for the evaluation of the exocrine pancreatic function are time-consuming and troublesome. A new test for exocrine pancreatic function, using endoscopic aspiration of secretin-stimulated pancreatic juice, has been developed. We evaluated the test using the Lundh meal test as reference.

METHODS

The endoscopic secretin stimulation test (ESST) was performed in a consecutive row of 24 patients referred for pancreatic function testing because of clinical suspicion of chronic pancreatitis and in 23 healthy volunteers. The participants fasted overnight and secretin was given intravenously (1 CU/kg) as a bolus the following morning. Thirty minutes after administration of secretin, the tip of the duodenoscope was placed close to the ampulla of Vater and duodenal aspirate was drawn for 10 min. Intraduodenal concentrations of lipase, bicarbonate, elastase and zinc were measured. The concentration of lipase during the Lundh test (4 x 20 min aspiration) was used as reference test in the patients.

RESULTS

Judged from the Lundh test, the exocrine pancreatic function was nearly abolished in 5 patients (<10% of lower normal limit), reduced in 6 patients and normal in 13 patients. ESST failed in 1 patient (no aspirate). Lipase concentrations (KU/l) were significantly lower in the patients with nearly abolished function compared to patients with reduced or normal exocrine pancreatic function (NEPF; Mann-Whitney U test: p < 0.01), but an overlap was found between patients with reduced exocrine pancreatic function [100.1 (median); 60.0-225.0 (range)] patients with NEPF (145.7; 44.6-268.0) and healthy controls (175.0; 84.8-381.0). Bicarbonate concentrations (mEq/l) were significantly lower in patients with reduced exocrine pancreatic function (51.2; 32.5-69.6) compared to patients with NEPF (80.0; 48.1-101.8; Mann-Whitney U test: p < 0.05). Pancreatic elastase concentration was significantly lower in the group with nearly abolished exocrine function compared to patients with NEPF (Mann-Whitney U test: p < 0.05), but there was no difference between elastase concentrations among the other groups. We found significant correlation between lipase and bicarbonate concentrations during ESST and lipase concentrations during the Lundh test in all 23 patients (Spearman's Rank test: rho = 0.597 and 0.683, respectively, p < 0.01). By using receiver operating characteristic curves, best cut-off point for bicarbonate was estimated. Lipase and bicarbonate results in the healthy volunteers were not statistically different from results in patients with NEPF. No side effects were observed except for worsening of nausea and abdominal pain in 2 of the patients.

CONCLUSION

The ESST is safe, and by combining the estimation of lipase and bicarbonate concentrations this test is a rapid, easy and useful diagnostic test for exocrine pancreatic function.

Chronic pancreatitis

PURPOSE OF REVIEW

As in previous reviews in this journal, this review is focused on the most important new observations in chronic pancreatitis made in the last year.

RECENT FINDINGS

Important observations included the search for biomarkers and alternative methods for the detection of early chronic pancreatitis; stellate cell activation and their role in fibrogenesis; the natural history of chronic pancreatitis; reports outlining the complexity in diagnosis of autoimmune pancreatitis; emerging roles of endoscopic ultrasound and magnetic resonance cholangiopancreatography in chronic pancreatitis diagnosis; a better understanding of neurobiology of chronic pancreatitis pain; and the potential role of surgery as first-line therapy in advanced chronic pancreatitis.

SUMMARY

In 2007, major advances were made in our understanding of central processing in chronic pancreatitis pain. New techniques are being utilized in search of a better means to diagnose early chronic pancreatitis. Important prospective studies are emerging, which compare endoscopic and surgical interventions. Furthermore, the complexities of diagnosing autoimmune pancreatitis are being recognized. Overall, the future is promising as advances in genomic and proteomic techniques are applied to improve our understanding of chronic pancreatitis.

Pancreatic function testing: here to stay for the 21st century

The diagnosis of Chronic Pancreatitis (CP) is based on the detection of abnormal structure or function of the diseased pancreas. The pancreatic function tests more accurately determine the presence of CP than tests of structure, especially for early stage disease. The function tests can be divided into two categories: non-invasive and invasive. The invasive "tube" tests can reliably detect mild, early CP, but are only available at a few referral centers and tend to be poorly tolerated by patients. The non-invasive tests are easy to obtain, but tend to perform poorly in patients with early, mild disease. Therefore, no one test is useful in all clinical situations, and a detailed understanding of the rational, pathophysiologic basis, strengths, and limitations of various tests is needed. This review highlights the role of various pancreatic function tests in the diagnosis of CP including fecal fat analysis, fecal elastase, fecal chymotrypsin, serum trypsin, the secretin stimulation test, the cholecystokinin (CCK) stimulation test, the combined secretin-CCK stimulation test, the intraductal and endoscopic secretin stimulation tests, and the functional magnetic resonance imaging of the pancreas after secretin stimulation.

A prospective crossover study comparing secretin-stimulated endoscopic and Dreiling tube pancreatic function testing in patients evaluated for chronic pancreatitis

BACKGROUND

Direct pancreatic function tests (PFT) are conventionally performed with use of double-lumen "Dreiling" collection tubes. We have developed an endoscopic collection method (ePFT) that eases the performance of these tests.

OBJECTIVE

Our aim was to compare the bicarbonate results obtained from the secretin ePFT and Dreiling PFT methods in patients evaluated for chronic pancreatitis.

DESIGN

A prospective crossover design was used to compare the PFT methods.

SETTING

Tertiary care referral center.

PATIENTS AND INTERVENTIONS

Twenty-four patients undergoing an evaluation for chronic pancreatitis underwent the secretin-stimulated ePFT and Dreiling PFT methods on separate days.

MAIN OUTCOME MEASUREMENTS

Duodenal fluid bicarbonate concentrations and estimated bicarbonate outputs were compared.

RESULTS

The mean difference in peak bicarbonate concentration (Dreiling PFT minus ePFT) was 7 mEq/L (SD 20) and not statistically significant (P = .11). A good correlation in peak bicarbonate concentrations (r = 0.74, 95% CI, 0.48-0.88) and estimated bicarbonate output (r = 0.78, 95% CI, 0.54-0.90) was observed between the two PFT methods.

LIMITATION

The sensitivities and specificities of the secretin ePFT and Dreiling PFT could not be compared because of the lack of a histologic gold standard.

CONCLUSION

The secretin ePFT yields results similar to those of the Dreiling PFT in patients evaluated for chronic pancreatitis.