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Fecal elastase 1, serum amylase and lipase levels in children with cholestasis
Original Paper Pancreatology 2005;5:432–437 DOI: 10.1159/000086545
Received: March 15, 2004 Accepted after revision: September 13, 2004 Published online: June 28, 2005
Fecal Elastase 1, Serum Amylase and Lipase Levels in Children with Cholestasis Wan-Hsin Wena, e Huey-Ling Chena, b Mei-Hwei Changa Yen-Hsuan Nia Hsiang-Hung Shihd Hong-Shiee Laic Wen-Ming Hsuc Departments of a Pediatrics, b Primary Care Medicine, and c Surgery, National Taiwan University Hospital, Taipei; d Department of Pediatrics, Chai-Yi Chang-Gung Memorial Hospital, Chai-Yi Hsien; and e Department of Pediatrics, Cardinal Tien Hospital, Taipei, Taiwan
Key Words Fecal elastase 1 Amylase Lipase Biliary atresia Progressive familial intrahepatic cholestasis Byler disease Alagille syndrome Choledochal cyst Exocrine pancreatic function
Abstract Background/Aim: The pancreatic functions of children with cholestatic liver diseases were unclear. Due to anatomic vicinity and common ontogenic origin, hepatobiliary disorders of infancy may also affect pancreatic function. The aim of the study was to evaluate the exocrine pancreatic function and common pancreatic function tests in children with cholestatic disorders. Methods: In 40 children with cholestasis, fecal elastase 1 (FE1) concentrations were measured. Serum amylase and lipase values were tested. The diagnoses included 32 patients with extrahepatic cholestasis (biliary atresia (BA) and choledochal cyst), and 8 patients with intrahepatic cholestasis (progressive familial intrahepatic cholestasis and Alagille syndrome). None had renal insufficiency or clinical symptoms/signs of acute pancreatitis. Results: All the patients had normal FE1 (1200 g/g). Nineteen percent (7/37) had elevated serum amylase levels (1100 U/l). Thirty-two percent (12/37) had elevated serum lipase levels above the normal (1120 U/l). Seventy-three
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Accessible online at: www.karger.com/pan
percent (8/11) of BA patients with bilirubin 12 mg/dl had elevated serum lipase levels compared to 18% (3/17) with bilirubin ^2 mg/dl (p = 0.0036). None had detectable pancreatic abnormality on ultrasonography and magnetic resonance images. Conclusions: None of the cholestatic children in this study had exocrine pancreatic insufficiency as detected by FE1. Hyperamylasemia and/or hyperlipasemia were frequently found. In children with BA, those with impaired biliary excretion tended to have elevated serum pancreatic enzymes as compared with those who had no jaundice. A decreased hepatic metabolism may be the cause. Copyright © 2005 S. Karger AG, Basel and IAP
Introduction
The causes of childhood cholestasis are diverse. Some result from pathological processes affecting the bile ducts, such as biliary atresia (BA) and choledochal cyst [1], and some are related to genetic mutations, such as progressive familial intrahepatic cholestasis (PFIC) and Alagille syndrome [2]. Since the pancreas is anatomically adjacent to and probably shares a common ontogenic origin with the hepatobiliary system [3, 4], children with these cholestatic diseases may have exocrine pancreatic insufficiency (EPI).
Dr. Huey-Ling Chen Departments of Pediatrics and Primary Care Medicine National Taiwan University Hospital, No. 7, Chung-Shan South Road Taipei 100 (Taiwan), Tel. +886 2 23123456, ext 5148 Fax +886 2 23938871, E-Mail [email protected]
Table 1. Clinical characteristics of the 40 children with cholestasis
Diagnosis
Extrahepatic disorders BA Choledochal cyst Intrahepatic disorders PFIC FIC1 gene defect BSEP gene defect MDR3 gene defect No known gene defects identified Alagille syndrome
Chronic diarrhea is frequently observed in cholestatic patients. A decreased bile acid excretion with subsequent fat malabsorption is a reasonable explanation [5], but EPI may also lead to chronic diarrhea. However, little was known about the exocrine pancreatic function in children with cholestatic disorders. This is likely caused by the fact that the direct pancreatic function tests, which are performed by duodenal intubation and stimulation with secretin-cholecystokinin or secretin-ceruletide [6], are time consuming, invasive and uncomfortable, especially in young children. Elastase 1 is a pancreatic enzyme and it is not degraded during intestinal passage [7]. Measurement of fecal elastase 1 (FE1) concentration is relatively simple and noninvasive. It has been reported to be a sensitive screening test for severe EPI [8–10]. In addition, the adult reference value for FE1 of greater than 200 g/g feces can be applied to infants older than 2 weeks [11]. The aim of the present study was to investigate the exocrine pancreatic function and common pancreatic function tests in children with different causes of cholestasis by measurements of FE1 and serum amylase and lipase levels.
Patients and Methods A total of 40 children (17 boys, 23 girls) with cholestatic diseases were enrolled. Informed consents were obtained from their parents. The study has been approved by the Institutional Review Board. The ages of the subjects ranged from 4 months to 11.2 years (median, 2.4 years). The diagnoses included 32 patients with extrahepatic cholestasis: BA in 31 and choledochal cyst in 1; and 8 patients with intrahepatic cholestasis: PFIC in 7 and Alagille syn-
Fecal Elastase 1, Serum Amylase, and Lipase in Cholestasis
Number of cases
Serum total bilirubin (mg/dl) median (range)
total
jaundice failure to thrive
chronic diarrhea
31 1
11 0
5 0
1 0
1.0 (0.3–27.4) 0.3
4 1 1 1 1
3 1 1 1 1
3 1 0 0 0
2 1 0 0 0
3.3 (0.8–11.9) 2.2 3.1 23.6 4.0
drome in 1. The clinical characteristics of these children are listed in table 1. None of the subjects had clinical symptoms of acute pancreatitis, such as nausea, vomiting, or abdominal pain. None of them had renal insufficiency. All had received an abdominal ultrasonographic examination. Some patients, including 18 with BA, 5 with PFIC, and 1 with choledochal cyst, had received an abdominal magnetic resonance image examination. Among the 31 children with BA, 30 had undergone hepatic portoenterostomy at an age ranging from 21 to 98 days, before this study. None had received liver transplantation. Eleven of the 31 with BA had jaundice (total bilirubin 12.0 mg/dl) at the time of the study. Among the 20 jaundice-free children, none had insufficient growth with a body weight below the 3rd percentile and none had chronic diarrhea. Six of the 7 children with PFIC had gene defects described in our previous reports [12, 13]. Among them, 4 had a defective familial intrahepatic cholestasis 1 (FIC1) gene, 1 had a defective bile salt export pump (BSEP) gene, 1 had a defective MDR3 gene, and no known gene defects were identified in the remaining 1 case. Among the 4 with FIC1 gene deficiency, 2 had received orthotonic liver transplantation and 1 had undergone biliary diversion before the study. In the child receiving biliary diversion, jaundice persisted after the operation. In the child with choledochal cyst, the study was performed before surgical resection of the cyst. Samples of feces were collected from each patient and were stored at –40 ° C till analysis. All fecal samples were examined within 1 year after collection. Determination of FE1 was performed with an enzyme-linked immunosorbent assay, based on two monoclonal antibodies against human pancreatic elastase 1 (Schebo Biotech, Giessen, Germany). Samples of serum were also obtained from 37 of the 40 subjects for the detection of amylase and lipase, which were measured by an enzymatic method (Ortho-Clinical Diagnostics Inc., Rochester, N.Y., USA). Three children with BA had no result of serum amylase and lipase. Normal values are 1200 g/g for FE1 [8–11], !100 U/l for serum amylase, and !120 U/l for serum lipase [14].
Pancreatology 2005;5:432–437
433
700
600
FE1 (μg/g)
500
400
300
200
Fig. 1. The individual values of FE1 in chil-
100
dren with different causes of cholestasis. Dotted line: normal reference for FE1 (200 g/g).
Statistical analysis was performed with Stata Statistical Software 7.0 (Stata Cooperation, College Station, Tex., USA). 2 test was used to compare the frequencies of hyperamylasemia/hyperlipasemia in BA patients with or without jaundice. A p value less than 0.05 was considered to be significant.
Results
All of the 40 children in this study had FE1 levels higher than 200 g/g feces. Figure 1 demonstrates the individual values of FE1. Abdominal ultrasonographic examination assessing the size, shape and echotexture of the pancreas showed no abnormality in all the children. The individual values of serum amylase and lipase are shown in figure 2. Among the 37 children tested, 19% (7/37), including 5 with BA, 1 with PFIC (MDR3 gene deficiency) and 1 with Alagille syndrome, had serum amylase levels above the upper limit of normal (100 U/l) for pediatric subjects. None had serum amylase levels above 2 times normal. Thirty-two percent (12/37), including 11 with BA and 1 with PFIC (no known gene defects identified), had serum lipase levels above the upper limit of normal (120 U/l) for pediatric subjects. Seven children with BA had lipase levels above 2 times normal and 5 of them exceeded 3 times normal. No evidence of pancreatic divisum was found in the children who had magnetic reso-
434
Pancreatology 2005;5:432–437
BA
Choledochal cyst
PFIC
Alagille
Diagnosis
nance image studies, including 3 patients with hyperamylasemia and 9 patients with hyperlipasemia. Except for the 3 children who had no data of serum amylase and lipase, we divided the patients of BA into two groups (17 patients in group 1 with bilirubin ^2 mg/ dl and 11 patients in group 2 with bilirubin 12 mg/dl) to investigate whether hyperamylasemia and hyperlipasemia are associated with the severity of cholestasis. In group 1, 24% (4/17) had hyperamylasemia and 18% (3/17) had hyperlipasemia. In group 2, 9% (1/11) had hyperamylasemia and 73% (8/11) had hyperlipasemia. Group 2 patients had significantly higher percentage of hyperlipasemia than group 1 patients (p = 0.0036), while no differences in the percentage of hyperamylasemia was found (p = 0.33). Totally, 24% (4/17) of patients in group 1 and 73% (8/11) of patients in group 2 had hyperamylasemia and/or hyperlipasemia (p = 0.01).
Discussion
FE1 has been found to be a rapid and convenient test in detecting EPI, since direct measurement of exocrine pancreatic functions were often hampered by the difficulties in duodenal intubation in infants and young children. Previous studies reported a satisfying sensitivity around 100% for severe EPI [8–10, 15]. However, its sensitivity
Wen/Chen/Chang/Ni/Shih/Lai/Hsu
200 180 160
Serum amylase (U/l)
140 120 100 80 60 40 20 0 BA
Choledochal cyst
PFIC
Alagille
Diagnosis 1,200
Serum lipase (U/l)
1,000
800
600
400
200
0
Fig. 2. The individual values of serum am-
ylase and lipase in children with different causes of cholestasis. Dotted lines: normal references for serum amylase (100 U/l) and lipase (120 U/l).
BA
Choledochal cyst
PFIC
Alagille
Diagnosis
in detecting mild forms of EPI was only 22–65% [9, 15, 16]. In this study we have found that all the subjects had normal FE1 levels. Therefore, these cholestatic children were unlikely to have severe EPI, but the possibility of mild EPI could not be excluded due to the limitation of the test. BA is the leading cause of cholestasis in infancy. It is characterized by stenosis or obstruction of extrahepatic bile ducts and the etiology remains elusive [1]. In this
study, none of the children with BA had abnormally low FE1 levels. This finding indicates that the exocrine pancreatic secretion in patients with BA is not impaired as detected by FE1. It is compatible with a previous article in which endoscopic retrograde cholangiopancreaticography performed in 29 infants with BA, detected patent pancreatic ducts in contrast to their atretic or stenotic bile ducts [17].
Fecal Elastase 1, Serum Amylase, and Lipase in Cholestasis
Pancreatology 2005;5:432–437
435
PFIC is a heterogeneous group of cholestatic disorders related to mutations in hepatocellular transporter genes involved in bile formation. Mutations in FIC1 (ATP8B1), BSEP (ABCB11), or MDR3 (ABCB4) are responsible for 3 different types of PFIC [2]. FIC1, the defective gene in PFIC type I (Byler disease), encodes a P-type ATPase, which may function as an aminophospholipid translocase, but how the mutation produces cholestasis is still under study [18, 19]. A number of patients with PFIC type I suffered from severe diarrhea and malabsorption in addition to jaundice and pruritus [18, 20]; so did the cases in our study. Since FIC1 is also expressed in small intestine and pancreas, even more strongly than in the liver [18], malabsorption in these children was thought to be attributed to the defective intestinal and/or exocrine pancreatic functions. However, all the 4 children with PFIC type I in this study had normal FE1 values. It is possible that the consequence of a defective FIC1 gene on exocrine pancreatic function was not severe enough to be detected by FE1 measurement, or the chronic diarrhea in these children was not related to EPI. The case of Alagille syndrome in this study did not have chronic diarrhea and his FE1 level was not low. However, some children with Alagille syndrome, especially those with chronic diarrhea, did have EPI proved by direct measurement of pancreatic secretion in duodenal aspirate [21]. It is of interest to find a high prevalence of hyperamylasemia/hyperlipasemia (19 and 32%, respectively) in children with cholestasis in this study. Elevation of serum pancreatic enzymes has been noted in adult patients with liver diseases but no clinical symptoms or signs of pancreatic diseases were described [22, 23]. A decreased hepatic metabolism of these enzymes was speculated as ev-
idenced by high prevalence of hyperamylasemia (35%) and hyperlipasemia (21%) without associated pancreatic abnormalities on ultrasonography in patients with chronic viral liver diseases, especially cirrhosis [24]. From our study, an association between jaundice and elevation of serum lipase level was also demonstrated in children with BA, supporting the mechanism of decreased liver metabolism leading to accumulation of these enzymes in blood. Children with choledochal cyst are prone to develop pancreatitis, many due to anomalous pancreatobiliary junction [25, 26]. The only case of choledochal cyst in this study had normal amylase and lipase levels. Pancreatic divisum is another congenital anomaly that is associated with recurrent pancreatitis [27]. Most of the children who had elevated pancreatic enzymes in this study were cases of BA without coexisting choledochal cysts. In children who had received magnetic resonance image exams in this study, none had evidences of pancreatic anomalies. To our knowledge, there has been no report of coexistence of BA and pancreatic divisum. In conclusion, our results indicate that in cholestatic children without associated pancreatic anomalies, EPI is not evident as measured by FE1 tests, although elevated amylase and lipase levels are frequently found. Other pancreatic function tests with a higher sensitivity may be needed to detect possible minor EPI. A decreased hepatic metabolism may contribute to hyperamylasemia and/ or hyperlipasemia in cholestatic children without clinical symptoms of pancreatitis or evidences of pancreatic anomalies. Physicians should carefully seek any evidence of pancreatitis and/or pancreatic insufficiency as well as anatomic anomalies in cholestatic patients with chronic diarrhea and poor weight growth.
References 1 Witzleben CL, Piccoli DA: Extrahepatic bile ducts; in Walker WA, Durie PR, Hamilton JR, Walker-Smith JA, Watkins JB (eds): Pediatric Gastrointestinal Disease: Pathophysiology, Diagnosis, Management. ed 3. Hamilton, B.C. Decker Inc., 2000, pp 915–927. 2 Bull LN: Hereditary forms of intrahepatic cholestasis. Curr Opin Genet Dev 2002; 12: 336– 342. 3 Terada T, Nakanuma Y: Expression of pancreatic enzymes (-amylase, trypsinogen, and lipase) during human liver development and maturation. Gastroenterology 1995; 108: 1236–1245.
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4 O’Rahilly R, Müller F: Human Embryology & Teratology. ed 3. New York, Wiley-Liss Inc., 2000, pp 269–272. 5 Dellert SF, Balistreri WF: Neonatal cholestasis; in Walker WA, Durie PR, Hamilton JR, Walker-Smith JA, Watkins JB (eds): Pediatric Gastrointestinal Disease: Pathophysiology, Diagnosis, Management. ed 3. Hamilton, B.C. Decker Inc., 2000, pp 880–894. 6 Glasbrenner B, Kahl S, Malfertheiner P: Modern diagnostics of chronic pancreatitis. Eur J Gastroenterol Hepatol 2002;14:935–941.
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7 Sziegoleit A, Krause E, Klör HU, Kanacher L, Linder D: Elastase 1 and chymotrypsin B in pancreatic juice and feces. Clin Biochem 1989; 22:85–89. 8 Domínguez-Muñoz JE, Hieronymus C, Sauerbruch T, Malfertheiner P: Fecal elastase test: Evaluation of a new noninvasive pancreatic function test. Am J Gastroenterol 1995; 90: 1834–1837. 9 Löser C, Möllgaard A, Fölsch UR: Fecal elastase 1: A novel, highly sensitive, and specific tubeless pancreatic function test. Gut 1996;39: 580–586.
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10 Soldan W, Henker J, Sprössig C: Sensitivity and specificity of quantitative determination of pancreatic elastase 1 in feces of children. J Pediatr Gastroenterol Nutr 1997;24:53–55. 11 Nissler K, Von Katte I, Huebner A, Henker J: Pancreatic elstase 1 in feces of preterm and term infants. J Pediatr Gastroenterol Nutr 2001;33:28–31. 12 Chen HL, Chang PS, Hsu HC, Lee JH, Ni YH, Hsu HY, Jeng YM, Chang MH: Progressive familial intrahepatic cholestasis with high glutamyltranspeptidase levels in Taiwanese infants: Role of MDR3 gene defect? Pediatr Res 2001;50:50–55. 13 Chen HL, Chang PS, Hsu HC, Ni YH, Hsu HY, Lee JH, Jeng YM, Shau WY, Chang MH: FIC1 and BSEP defects in Taiwanese patients with chronic intrahepatic cholestasis with low -glutamyltranspeptidase levels. J Pediatr 2002;140:119–124. 14 Lockitch G, Halstead AC, Albersheim S, MacCullum C, Quigley G: Age- and sex-specific pediatric reference intervals for biochemistry analytes as measured with the Ektachem-700 analyzer. Clin Chem 1988;34:1622–1625. 15 Lüth S, Teyssen S, Forssmann K, Kölbel C, Krummenauer F, Singer MV: Fecal elastase-1 determination: ‘Gold standard’ of indirect pancreatic function test? Scand J Gastroenterol 2001;36:1092–1099.
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16 Gullo L, Ventrucci M, Tomassetti P, Migliori M, Pezzilli R: Fecal elastase 1 determination in chronic pancreatitis. Dig Dis Sci 1999; 44: 210–213. 17 Iinuma Y, Narisawa R, Iwafuchi M, Uchiyama M, Naito M, Yagi M, Kanada S, Otaki M, Yamazaki S, Honma T, Motoyama H, Baba Y: The role of endoscopic retrograde cholangiopancreatography in infants with cholestasis. J Pediatr Surg 2000;35:545–549. 18 Bull LN, van Eijk MJT, Pawlikowska L, De Yong JA, Jujin JA, Liao M, Klomp LW, Lomri N, Berger R, Scharschmidt BF, Knisely AS, Houwen RH, Freimer NB: A gene encoding a P-type ATPase mutated in two forms of hereditary cholestasis. Nat Genet 1998; 18: 219– 224. 19 Ujhazy P, Ortiz D, Misra S, Li S, Moseley J, Jones H, Arias IM: Familial intrahepatic cholestasis 1: Studies of localization and function. Hepatology 2001;34:768–775. 20 Schneider BL: Disorders of biliary transport; in Walker WA, Durie PR, Hamilton JR, Walker-Smith JA, Watkins JB (eds): Pediatric Gastrointestinal Disease: Pathophysiology, Diagnosis, Management. ed 3. Hamilton, B.C. Decker Inc., 2000, pp 928–938.
21 Chong SKF, Lindridge J, Moniz C, Mowat AP: Exocrine pancreatic insufficiency in syndromic paucity of interlobular bile ducts. J Pediatr Gastroenterol Nutr 1989;9:445–449. 22 Tsianos EB, Jalali MT, Gowenlock AH, Braganza JM: Serum isoamylases in liver diseases. Hepatogastroenterology 1986;33:247–249. 23 Ede RJ, Moore KP, Marshall WJ, Williams R: Frequency of pancreatitis in fulminant hepatic failure using isoenzyme markers. Gut 1988;29: 778–781. 24 Pezzilli R, Andreone P, Morselli-Labate AM, Sama C, Billi P, Cursaro C, Barakat B, Granenzi A, Fiocchi M, Miglio F, Bernardi M: Serum pancreatic enzyme concentrations in chronic viral liver diseases. Dig Dis Sci 1999;44:350– 355. 25 Choi BH, Lim YJ, Yoon CH, Kim EA, Park YS, Kim KM: Acute pancreatitis associated with biliary disease in children. J Gastroenterol Hepatol 2003;18:915–921. 26 Okada A, Higaki J, Nakamura T, Fukui Y, Kamata S: Pancreatitis associated with choledochal cyst and other anomalies in childhood. Br J Surg 1995;82:829–832. 27 Varshney S, Johnson CD: Pancreatic divisum. Int J Pancreatol 1999;25:135–141.
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Received: March 15, 2004 Accepted after revision: September 13, 2004 Published online: June 28, 2005
Fecal Elastase 1, Serum Amylase and Lipase Levels in Children with Cholestasis Wan-Hsin Wena, e Huey-Ling Chena, b Mei-Hwei Changa Yen-Hsuan Nia Hsiang-Hung Shihd Hong-Shiee Laic Wen-Ming Hsuc Departments of a Pediatrics, b Primary Care Medicine, and c Surgery, National Taiwan University Hospital, Taipei; d Department of Pediatrics, Chai-Yi Chang-Gung Memorial Hospital, Chai-Yi Hsien; and e Department of Pediatrics, Cardinal Tien Hospital, Taipei, Taiwan
Key Words Fecal elastase 1 Amylase Lipase Biliary atresia Progressive familial intrahepatic cholestasis Byler disease Alagille syndrome Choledochal cyst Exocrine pancreatic function
Abstract Background/Aim: The pancreatic functions of children with cholestatic liver diseases were unclear. Due to anatomic vicinity and common ontogenic origin, hepatobiliary disorders of infancy may also affect pancreatic function. The aim of the study was to evaluate the exocrine pancreatic function and common pancreatic function tests in children with cholestatic disorders. Methods: In 40 children with cholestasis, fecal elastase 1 (FE1) concentrations were measured. Serum amylase and lipase values were tested. The diagnoses included 32 patients with extrahepatic cholestasis (biliary atresia (BA) and choledochal cyst), and 8 patients with intrahepatic cholestasis (progressive familial intrahepatic cholestasis and Alagille syndrome). None had renal insufficiency or clinical symptoms/signs of acute pancreatitis. Results: All the patients had normal FE1 (1200 g/g). Nineteen percent (7/37) had elevated serum amylase levels (1100 U/l). Thirty-two percent (12/37) had elevated serum lipase levels above the normal (1120 U/l). Seventy-three
© 2005 S. Karger AG, Basel and IAP 1424–3903/05/0055–0432$22.00/0 Fax +41 61 306 12 34 E-Mail [email protected] www.karger.com
Accessible online at: www.karger.com/pan
percent (8/11) of BA patients with bilirubin 12 mg/dl had elevated serum lipase levels compared to 18% (3/17) with bilirubin ^2 mg/dl (p = 0.0036). None had detectable pancreatic abnormality on ultrasonography and magnetic resonance images. Conclusions: None of the cholestatic children in this study had exocrine pancreatic insufficiency as detected by FE1. Hyperamylasemia and/or hyperlipasemia were frequently found. In children with BA, those with impaired biliary excretion tended to have elevated serum pancreatic enzymes as compared with those who had no jaundice. A decreased hepatic metabolism may be the cause. Copyright © 2005 S. Karger AG, Basel and IAP
Introduction
The causes of childhood cholestasis are diverse. Some result from pathological processes affecting the bile ducts, such as biliary atresia (BA) and choledochal cyst [1], and some are related to genetic mutations, such as progressive familial intrahepatic cholestasis (PFIC) and Alagille syndrome [2]. Since the pancreas is anatomically adjacent to and probably shares a common ontogenic origin with the hepatobiliary system [3, 4], children with these cholestatic diseases may have exocrine pancreatic insufficiency (EPI).
Dr. Huey-Ling Chen Departments of Pediatrics and Primary Care Medicine National Taiwan University Hospital, No. 7, Chung-Shan South Road Taipei 100 (Taiwan), Tel. +886 2 23123456, ext 5148 Fax +886 2 23938871, E-Mail [email protected]
Table 1. Clinical characteristics of the 40 children with cholestasis
Diagnosis
Extrahepatic disorders BA Choledochal cyst Intrahepatic disorders PFIC FIC1 gene defect BSEP gene defect MDR3 gene defect No known gene defects identified Alagille syndrome
Chronic diarrhea is frequently observed in cholestatic patients. A decreased bile acid excretion with subsequent fat malabsorption is a reasonable explanation [5], but EPI may also lead to chronic diarrhea. However, little was known about the exocrine pancreatic function in children with cholestatic disorders. This is likely caused by the fact that the direct pancreatic function tests, which are performed by duodenal intubation and stimulation with secretin-cholecystokinin or secretin-ceruletide [6], are time consuming, invasive and uncomfortable, especially in young children. Elastase 1 is a pancreatic enzyme and it is not degraded during intestinal passage [7]. Measurement of fecal elastase 1 (FE1) concentration is relatively simple and noninvasive. It has been reported to be a sensitive screening test for severe EPI [8–10]. In addition, the adult reference value for FE1 of greater than 200 g/g feces can be applied to infants older than 2 weeks [11]. The aim of the present study was to investigate the exocrine pancreatic function and common pancreatic function tests in children with different causes of cholestasis by measurements of FE1 and serum amylase and lipase levels.
Patients and Methods A total of 40 children (17 boys, 23 girls) with cholestatic diseases were enrolled. Informed consents were obtained from their parents. The study has been approved by the Institutional Review Board. The ages of the subjects ranged from 4 months to 11.2 years (median, 2.4 years). The diagnoses included 32 patients with extrahepatic cholestasis: BA in 31 and choledochal cyst in 1; and 8 patients with intrahepatic cholestasis: PFIC in 7 and Alagille syn-
Fecal Elastase 1, Serum Amylase, and Lipase in Cholestasis
Number of cases
Serum total bilirubin (mg/dl) median (range)
total
jaundice failure to thrive
chronic diarrhea
31 1
11 0
5 0
1 0
1.0 (0.3–27.4) 0.3
4 1 1 1 1
3 1 1 1 1
3 1 0 0 0
2 1 0 0 0
3.3 (0.8–11.9) 2.2 3.1 23.6 4.0
drome in 1. The clinical characteristics of these children are listed in table 1. None of the subjects had clinical symptoms of acute pancreatitis, such as nausea, vomiting, or abdominal pain. None of them had renal insufficiency. All had received an abdominal ultrasonographic examination. Some patients, including 18 with BA, 5 with PFIC, and 1 with choledochal cyst, had received an abdominal magnetic resonance image examination. Among the 31 children with BA, 30 had undergone hepatic portoenterostomy at an age ranging from 21 to 98 days, before this study. None had received liver transplantation. Eleven of the 31 with BA had jaundice (total bilirubin 12.0 mg/dl) at the time of the study. Among the 20 jaundice-free children, none had insufficient growth with a body weight below the 3rd percentile and none had chronic diarrhea. Six of the 7 children with PFIC had gene defects described in our previous reports [12, 13]. Among them, 4 had a defective familial intrahepatic cholestasis 1 (FIC1) gene, 1 had a defective bile salt export pump (BSEP) gene, 1 had a defective MDR3 gene, and no known gene defects were identified in the remaining 1 case. Among the 4 with FIC1 gene deficiency, 2 had received orthotonic liver transplantation and 1 had undergone biliary diversion before the study. In the child receiving biliary diversion, jaundice persisted after the operation. In the child with choledochal cyst, the study was performed before surgical resection of the cyst. Samples of feces were collected from each patient and were stored at –40 ° C till analysis. All fecal samples were examined within 1 year after collection. Determination of FE1 was performed with an enzyme-linked immunosorbent assay, based on two monoclonal antibodies against human pancreatic elastase 1 (Schebo Biotech, Giessen, Germany). Samples of serum were also obtained from 37 of the 40 subjects for the detection of amylase and lipase, which were measured by an enzymatic method (Ortho-Clinical Diagnostics Inc., Rochester, N.Y., USA). Three children with BA had no result of serum amylase and lipase. Normal values are 1200 g/g for FE1 [8–11], !100 U/l for serum amylase, and !120 U/l for serum lipase [14].
Pancreatology 2005;5:432–437
433
700
600
FE1 (μg/g)
500
400
300
200
Fig. 1. The individual values of FE1 in chil-
100
dren with different causes of cholestasis. Dotted line: normal reference for FE1 (200 g/g).
Statistical analysis was performed with Stata Statistical Software 7.0 (Stata Cooperation, College Station, Tex., USA). 2 test was used to compare the frequencies of hyperamylasemia/hyperlipasemia in BA patients with or without jaundice. A p value less than 0.05 was considered to be significant.
Results
All of the 40 children in this study had FE1 levels higher than 200 g/g feces. Figure 1 demonstrates the individual values of FE1. Abdominal ultrasonographic examination assessing the size, shape and echotexture of the pancreas showed no abnormality in all the children. The individual values of serum amylase and lipase are shown in figure 2. Among the 37 children tested, 19% (7/37), including 5 with BA, 1 with PFIC (MDR3 gene deficiency) and 1 with Alagille syndrome, had serum amylase levels above the upper limit of normal (100 U/l) for pediatric subjects. None had serum amylase levels above 2 times normal. Thirty-two percent (12/37), including 11 with BA and 1 with PFIC (no known gene defects identified), had serum lipase levels above the upper limit of normal (120 U/l) for pediatric subjects. Seven children with BA had lipase levels above 2 times normal and 5 of them exceeded 3 times normal. No evidence of pancreatic divisum was found in the children who had magnetic reso-
434
Pancreatology 2005;5:432–437
BA
Choledochal cyst
PFIC
Alagille
Diagnosis
nance image studies, including 3 patients with hyperamylasemia and 9 patients with hyperlipasemia. Except for the 3 children who had no data of serum amylase and lipase, we divided the patients of BA into two groups (17 patients in group 1 with bilirubin ^2 mg/ dl and 11 patients in group 2 with bilirubin 12 mg/dl) to investigate whether hyperamylasemia and hyperlipasemia are associated with the severity of cholestasis. In group 1, 24% (4/17) had hyperamylasemia and 18% (3/17) had hyperlipasemia. In group 2, 9% (1/11) had hyperamylasemia and 73% (8/11) had hyperlipasemia. Group 2 patients had significantly higher percentage of hyperlipasemia than group 1 patients (p = 0.0036), while no differences in the percentage of hyperamylasemia was found (p = 0.33). Totally, 24% (4/17) of patients in group 1 and 73% (8/11) of patients in group 2 had hyperamylasemia and/or hyperlipasemia (p = 0.01).
Discussion
FE1 has been found to be a rapid and convenient test in detecting EPI, since direct measurement of exocrine pancreatic functions were often hampered by the difficulties in duodenal intubation in infants and young children. Previous studies reported a satisfying sensitivity around 100% for severe EPI [8–10, 15]. However, its sensitivity
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200 180 160
Serum amylase (U/l)
140 120 100 80 60 40 20 0 BA
Choledochal cyst
PFIC
Alagille
Diagnosis 1,200
Serum lipase (U/l)
1,000
800
600
400
200
0
Fig. 2. The individual values of serum am-
ylase and lipase in children with different causes of cholestasis. Dotted lines: normal references for serum amylase (100 U/l) and lipase (120 U/l).
BA
Choledochal cyst
PFIC
Alagille
Diagnosis
in detecting mild forms of EPI was only 22–65% [9, 15, 16]. In this study we have found that all the subjects had normal FE1 levels. Therefore, these cholestatic children were unlikely to have severe EPI, but the possibility of mild EPI could not be excluded due to the limitation of the test. BA is the leading cause of cholestasis in infancy. It is characterized by stenosis or obstruction of extrahepatic bile ducts and the etiology remains elusive [1]. In this
study, none of the children with BA had abnormally low FE1 levels. This finding indicates that the exocrine pancreatic secretion in patients with BA is not impaired as detected by FE1. It is compatible with a previous article in which endoscopic retrograde cholangiopancreaticography performed in 29 infants with BA, detected patent pancreatic ducts in contrast to their atretic or stenotic bile ducts [17].
Fecal Elastase 1, Serum Amylase, and Lipase in Cholestasis
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PFIC is a heterogeneous group of cholestatic disorders related to mutations in hepatocellular transporter genes involved in bile formation. Mutations in FIC1 (ATP8B1), BSEP (ABCB11), or MDR3 (ABCB4) are responsible for 3 different types of PFIC [2]. FIC1, the defective gene in PFIC type I (Byler disease), encodes a P-type ATPase, which may function as an aminophospholipid translocase, but how the mutation produces cholestasis is still under study [18, 19]. A number of patients with PFIC type I suffered from severe diarrhea and malabsorption in addition to jaundice and pruritus [18, 20]; so did the cases in our study. Since FIC1 is also expressed in small intestine and pancreas, even more strongly than in the liver [18], malabsorption in these children was thought to be attributed to the defective intestinal and/or exocrine pancreatic functions. However, all the 4 children with PFIC type I in this study had normal FE1 values. It is possible that the consequence of a defective FIC1 gene on exocrine pancreatic function was not severe enough to be detected by FE1 measurement, or the chronic diarrhea in these children was not related to EPI. The case of Alagille syndrome in this study did not have chronic diarrhea and his FE1 level was not low. However, some children with Alagille syndrome, especially those with chronic diarrhea, did have EPI proved by direct measurement of pancreatic secretion in duodenal aspirate [21]. It is of interest to find a high prevalence of hyperamylasemia/hyperlipasemia (19 and 32%, respectively) in children with cholestasis in this study. Elevation of serum pancreatic enzymes has been noted in adult patients with liver diseases but no clinical symptoms or signs of pancreatic diseases were described [22, 23]. A decreased hepatic metabolism of these enzymes was speculated as ev-
idenced by high prevalence of hyperamylasemia (35%) and hyperlipasemia (21%) without associated pancreatic abnormalities on ultrasonography in patients with chronic viral liver diseases, especially cirrhosis [24]. From our study, an association between jaundice and elevation of serum lipase level was also demonstrated in children with BA, supporting the mechanism of decreased liver metabolism leading to accumulation of these enzymes in blood. Children with choledochal cyst are prone to develop pancreatitis, many due to anomalous pancreatobiliary junction [25, 26]. The only case of choledochal cyst in this study had normal amylase and lipase levels. Pancreatic divisum is another congenital anomaly that is associated with recurrent pancreatitis [27]. Most of the children who had elevated pancreatic enzymes in this study were cases of BA without coexisting choledochal cysts. In children who had received magnetic resonance image exams in this study, none had evidences of pancreatic anomalies. To our knowledge, there has been no report of coexistence of BA and pancreatic divisum. In conclusion, our results indicate that in cholestatic children without associated pancreatic anomalies, EPI is not evident as measured by FE1 tests, although elevated amylase and lipase levels are frequently found. Other pancreatic function tests with a higher sensitivity may be needed to detect possible minor EPI. A decreased hepatic metabolism may contribute to hyperamylasemia and/ or hyperlipasemia in cholestatic children without clinical symptoms of pancreatitis or evidences of pancreatic anomalies. Physicians should carefully seek any evidence of pancreatitis and/or pancreatic insufficiency as well as anatomic anomalies in cholestatic patients with chronic diarrhea and poor weight growth.
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