Detection of pancreatic steatorrhea by oral pancreatic function tests

Staging exocrine pancreatic dysfunction

Digestive capacity of the gastrointestinal tract, largely but not wholly, depends on exocrine pancreatic function to achieve near complete digestion and absorption of ingested food. Coefficient of fat absorption (CFA), the proportion of ingested fat absorbed (normal >93%), reflects digestive capacity. Exocrine pancreatic insufficiency (EPI) is the state of insufficient digestive capacity (CFA <93%) caused by severe loss of pancreatic exocrine function despite variable compensation by upregulation of extra-pancreatic lipolysis. Fecal elastase 1 (FE1) level is the most widely used, though imperfect, non-invasive test of pancreatic enzyme output. Decline in pancreas enzyme output, or pancreatic exocrine dysfunction (EPD), has a variable correlation with measurable decline in CFA. EPI results in steatorrhea, weight loss and nutrient deficiency, which are mitigated by pancreatic enzyme replacement therapy (PERT). We propose a staging system for EPD, based on measurement of fecal elastase (FE1) and, if necessary, CFA and serum fat-soluble vitamin levels. In Stage I (Mild) EPD, FE1 is 100-200 mcg/gm; if steatorrhea is present, non-pancreatic causes are likely. In Stage II (Moderate) EPD), FE1 is < 100 mcg/gm without clinical and/or laboratory evidence of steatorrhea. In Stage III, there are marked reductions in FE1 and CFA, but vitamin levels remain normal (Severe EPD or EPI without nutritional deficiency). In Stage IV all parameters are abnormal (Severe EPD or EPI with nutritional deficiency). EPD stages I and II are pancreas sufficient and PERT may not be the best or first approach in management of early-stage disease; it needs further study to determine clinical utility. The term EPI refers strictly to EPD Stages III and IV which should be treated with PERT, with Stage IV requiring micronutrient supplementation as well.

Long-term results of extracorporeal shockwave lithotripsy and endoscopic therapy for pancreatic stones

BACKGROUND & AIMS

The aim of this study was to evaluate the short- and long-term results of extracorporeal shockwave lithotripsy (ESWL) and endoscopic therapy for pancreatic stones.

METHODS

A total of 117 patients with pancreatic stones underwent ESWL and endoscopic treatment in our institute. Seventy patients who were followed-up for over 3 years after treatment were evaluated retrospectively.

RESULTS

Immediate pain relief was achieved in 97% and complete removal of stones was achieved in 56%. During the long-term follow-up evaluation, 49 of 70 patients continued to be asymptomatic. Pain recurred more frequently in patients with incomplete removal than in those with complete removal (P < .05). Twenty-one patients who became symptomatic during the follow-up period underwent additional therapy, and pain relief was attained without surgery in all of them. Both endocrine and exocrine function deteriorated after the long-term follow-up period (P < .05).

CONCLUSIONS

ESWL and endoscopic treatment of pancreatic stones proved to be effective for long-term pain relief, especially in patients in whom stones were removed completely at initial therapy.

Biochemical tests in diseases of the intestinal tract: their contributions to diagnosis, management, and understanding the pathophysiology of specific disease states

Biochemical testing plays a major role in the complete evaluation of patients with suspected or established intestinal disease. We have classified these tests according to the medium in which they are performed: breath tests, including isotopic and nonisotopic tests, fecal tests, urine tests, serum tests, tissue tests, and other tests. The principles of various tests are outlined, and the role of each test in the evaluation of particular gastrointestinal disorders is discussed.

Exocrine pancreatic insufficiency: accuracy and clinical value of the uniformly labelled 13C-Hiolein breath test

BACKGROUND AND AIMS

The 13C-Hiolein breath test (98% [U-13C] labelled long chain triglyceride mixture (highly labelled triolein) was evaluated as a non-invasive, non-radioactive test for exocrine pancreatic insufficiency. Accuracy and clinical validity were examined with reference to both the secretin pancreozymin test and faecal fat analysis.

METHODS

A secretin pancreozymin test and faecal fat analysis were performed in 46 patients, 30 with exocrine pancreatic insufficiency and 16 with normal pancreatic function. In all of these patients and in seven healthy volunteers (controls), a 13C-Hiolein breath test was performed using 2 mg/kg [U-13C] labelled Hiolein with a standard risk snack (1.5 g/kg; 25% fat). 13CO2/12CO2 enrichment in the exhaled breath was measured by isotope ratio mass spectrometry.

RESULTS

In patients with pancreatic steatorrhoea the 13CO2 response was below the 95% confidence interval of 13CO2 exhalation in the controls. These responses were also diminished (p < 0.001) compared with patients with impaired lipase output but normal fat excretion and with disease as well as healthy controls. There was a linear correlation between stimulated lipase output and the ratio of lipase output/13CO2 response (r = 0.95). Among the 40 patients in whom direct pancreatic function testing was clinically indicated, the sensitivity of the 13C-Hiolein test for detecting steatorrhoea was 91.7%, with a specificity of 85.7%.

CONCLUSIONS

In patients with pancreatic disease the 13C-Hiolein breath test reflects impaired lipase output and indicates decompensated lipolysis. The 13C-Hiolein breath test is a convenient alternative to faecal fat analysis.

Standards for the diagnosis of chronic pancreatitis and for the evaluation of treatment

The diagnosis of chronic pancreatitis should be based on the characteristic case history and a combination of exocrine pancreatic function tests and morphological examinations. For diagnostic purposes, an indirect pancreatic function test may be sufficient when direct tests are not available. Otherwise, and especially for scientific evaluation of chronic pancreatitis, a direct pancreatic function test is necessary. In each patient, an ultrasound examination of the pancreas should be performed and, if inconclusive, also computed tomography. In a symptomatic patient, that is, a patient suffering from relapsing pain attacks, an ERCP examination is indicated. A score for the severity of chronic pancreatitis using symptoms, results of function tests, and morphological examinations should be developed for a world-wide comparison of studies. Treatment results should be reported not earlier than 2 yr after the initiation of conservative treatment or surgery. The evaluation of treatment should be based on a score (also to be developed) making use of symptoms.

Biochemical tests in the diagnosis of chronic pancreatitis and in the evaluation of pancreatic insufficiency

Chronic pancreatitis (adults) and cystic fibrosis (children) are the most common diseases leading to exocrine pancreatic insufficiency that, when reduced to < 5% of normal function, is characterised by steatorrhoea. The pathogenesis of the former condition is outlined, and recent concepts are emphasized. Biochemical tests to detect pancreatic insufficiency and to identify pancreatic disease as the cause of steatorrhoea include: serum enzyme tests (lipase, amylase, trypsin); stool chymotrypsin; isotopic tests based upon the assimilation of [14C] lipids and starch or excretion of the isotope as breath CO2, as well as the dual-labelled Schilling test; oral function tests utilising substrates hydrolysed by pancreatic enzymes such as benzoyl tyrosyl-p-aminobenzoic acid and fluorescein dilaurate; and duodenal intubation studies following meal-induced or hormonal stimulation of the pancreas. The rationale for these tests and the cumulative clinical experience of their utility are reviewed. A recommended diagnostic strategy is briefly presented. The role of various biochemical procedures to evaluate the efficacy of pancreatic enzyme replacement therapy is also described.

Function tests in the diagnosis of chronic pancreatitis. Critical evaluation

Direct pancreatic function tests, such as the secretin-pancreozymin test and the Lundh test, are--by direct measurement of the contents of duodenal secretion following exogenous (hormonal) or endogenous (test meal) stimulation--the best way to assess exocrine pancreatic function. However, these tests are time-consuming, invasive, and expensive, and therefore their use is limited to specialized centers only. Several studies have shown that indirect pancreatic function tests are a practicable alternative to direct pancreatic function tests for diagnosing exocrine pancreatic insufficiency. They allow staging of the disease and thereby facilitate comparison of different studies. They are also useful in some cases for determining whether pancreatic enzyme replacement therapy is necessary or not. In contrast to morphological procedures, they involve neither side effects, risks for the patient, nor complications for patients, investigators, and laboratory staff alike. The procedures being standardized, the test results depend to a lesser extent on the experience of the investigator, and more on the selection of and the instructions to the patient, and to some extent, on the severity of the exocrine pancreatic insufficiency. Like all pancreatic function tests, the indirect tests do not give a clue to etiology nor help investigators to differentiate between pancreatic insufficiency owing to chronic pancreatitis and that owing to pancreatic cancer. The role of pancreatic function tests in diagnosing early chronic pancreatitis in comparison to morphological examinations remains to be established.

Pancreatic exocrine and endocrine function after operations for chronic pancreatitis

Exocrine and endocrine function of the pancreas was assessed in the early postoperative period (< or = 2 months) and subsequently (mean, 25 months; range, 3 to 120) in 103 patients (69 men, 34 women; mean age, 42.4 +/- 11.6 years) undergoing operation for chronic pancreatitis. Alcohol was the main causative agent (69%) and pain the most frequent indication (87%) for operation. Drainage procedures (n = 23) did not alter pancreatic function either initially or on long-term follow-up. In the early postoperative period, distal pancreatectomy (n = 42) often impaired endocrine function without affecting exocrine function; seven patients (17%) became diabetic, and results of oral glucose tolerance test showed deterioration in 23 of 28 patients (82%, p < 0.05). On subsequent follow-up, 11 patients developed exocrine failure (p < 0.01) and 10 patients endocrine (p < 0.01) failure. Proximal pancreatectomy (n = 38) precipitated clinical exocrine failure in 14 patients (37%, p < 0.01), yet pancreolauryl tests in 18 patients showed little objective change in exocrine status (0.50 > p > 0.10). Endocrine function was initially spared after proximal pancreatectomy, but six additional patients (16%, p < 0.05) required treatment for diabetes at a mean of 19 months (range, 3 to 34). Deterioration in pancreatic function is thus not an invariable immediate consequence of pancreatic drainage procedures or partial pancreatectomy for chronic pancreatitis. Progression of disease must account, in part, for failure of both exocrine and endocrine function on long-term follow-up. Drainage operations appear to delay this progressive decline in pancreatic function.

Advances in the enzyme diagnosis of pancreatic diseases

This paper reviews recent developments of analytical methods for the determination of alpha-amylase, of its isoenzymes, and of lipase. The evaluation of severity and etiology of acute pancreatitis by enzyme assays, e.g., pancreatic elastase 1, phospholipase A2, and routine enzymes are discussed. The limited significance of enzyme determinations as compared to imaging and endoscopic procedures for the diagnosis of chronic pancreatitis is demonstrated. Indirect "tubeless" tests for the evaluation of pancreatic exocrine insufficiency with respect to the secretion of chymotrypsin (chymotrypsin in stool and NBT-PABA test) and cholesterol esterase (pancreolauryl test) are reviewed. Finally, the superiority of morphologic investigations over biochemical tests for the timely detection of pancreatic carcinoma is shown.