Relation of thickening of colon wall to pancreatic-enzyme treatment in cystic fibrosis

Ultra-high-frequency ultrasound (48-70 MHz) is a promising tool for improved gastrointestinal diagnostics in infants

AIM

To investigate the clinical feasibility of ultra-high-frequency abdominal ultrasound (UHFUS) scans of preterm and term infants.

METHODS

Prospectively, 19 healthy term newborn infants were examined with conventional ultrasound (CUS) (Toshiba, Aplio i700, linear probe 14L5) and UHFUS (Visualsonics VevoMD, linear probes UHF48 and UHF70) according to a standardised protocol. Measurements of wall thickness were performed for; stomach, small intestine, colon and peritoneum. Five preterm infants, with or without suspected necrotising enterocolitis (NEC), were also examined with UHF48. Of these, only one was later diagnosed with NEC.

RESULTS

Differences between CUS and UHFUS (UHF48) were found in measurements of thickness; for peritoneum 0.25 versus 0.13 mm (p < 0.001), small intestine 0.76 versus 0.64 mm (p = 0.039) and colon 0.7 versus 0.47 mm (p < 0.001) in healthy term infants. Gaining frequency from 46 to 71 MHz showed a mean reduction in measurements of peritoneum from 0.13 to 0.09 mm (p < 0.001). One preterm infant with NEC showed a fivefold and twofold increase in peritoneal and gastrointestinal wall thickness respectively, compared to healthy preterm infants.

CONCLUSION

UHFUS was a clinically feasible, promising method with potential to improve gastrointestinal diagnostics in infants. Lower peritoneum thickness and gastrointestinal wall thickness were demonstrated with UHFUS compared to CUS, suggesting an overestimation by CUS.

Small Bowel Ultrasound beyond Inflammatory Bowel Disease: An Updated Review of the Recent Literature

The use of bowel ultrasonography (US) for the evaluation of gut diseases has increased in recent years and has been proven to provide a widely available, non-invasive and inexpensive method for the initial work-up and follow-up of different intestinal diseases, limited mostly by technical challenges posed by the patient's anatomy. The present review aims to provide an extensive overview of the main pathologic features at US examination of intestinal diseases other than inflammatory bowel disease, both acute (e.g., acute appendicitis, colonic diverticulitis, infectious diseases and ischemic conditions) and chronic (e.g., celiac disease, cystic fibrosis and other enterocolites). The identification of typical US features may help in the diagnostic process and guide the treatment approach. Therefore, the application of knowledge of the US appearance of gastrointestinal diseases is of relevance in enabling greater diagnostic performance and better patient management.

Bowel ultrasound imaging in patients with cystic fibrosis: Relationship with clinical symptoms and CFTR genotype

BACKGROUND

Ultrasound imaging is used to assess bowel abnormalities in gastrointestinal diseases. We aimed to assess the rate of predefined bowel ultrasound signs and their relationship with gastrointestinal symptoms and the cystic fibrosis transmembrane conductance regulator (CFTR) genotype in cystic fibrosis patients in regular follow-up.

METHODS

Prospective study of 70 consecutive patients with cystic fibrosis and 45 controls who underwent abdominal ultrasound; pertinent findings were related to gastrointestinal symptoms and, in cystic fibrosis patients, to pancreatic status, malabsorption degree, lipase intake, CFTR genotype (classified as severe or mild against functional class of CFTR mutations).

RESULTS

96% patients showed at least one abnormal bowel ultrasound sign. Most frequent signs were lymph node enlargement (64%), bowel loop dilatation (55%), thick corpuscular intraluminal content (49%), bowel wall hypervascularization (26%), thickened bowel wall (22%) and intussusception (17%). Patients with recurrent abdominal pain showed more bowel wall hypervascularization than patients without recurrent pain (47% vs. 19%, respectively; p = 0.02) and intussusception (58% vs. 17%, respectively; p < 0.01). Genotype was not associated to specific bowel ultrasound signs. Patients with bowel loop intussusception showed greater lipase intake than those without intussusception (8.118 ± 2.083 vs. 5.994 ± 4.187, respectively; p < 0.01).

CONCLUSION

Cystic fibrosis patients present a higher rate of bowel ultrasound abnormalities than controls. Bowel ultrasound abnormalities are associated with abdominal symptoms.

Effect of tissue optics on wavelength optimization for quantum dot-based surface and subsurface fluorescence imaging

Optimization is an important but relatively unexplored aspect of contrast-enhanced fluorescence imaging, since minimizing contrast agent usage reduces the associated cost and potential toxicity. In a previous study, the authors developed a quantitative experimental approach to optimize quantum dot (QD)-based imaging using homogenized liver as a model tissue. In this follow-up study, the authors further extend and validate the approach using eight different tissues and five QDs emission wavelengths, and introduce quantitative imaging performance metrics, namely the threshold QD concentration and wavelength optimization gain. These metrics allow quantification of the improvements through spectral optimization in terms of reduced QD dose and identify the conditions that make the optimization process worthwhile. The authors show that, for most tissues, the most important parameter to optimize is the emission wavelength, yielding improvements of up to four orders of magnitude, followed by the excitation wavelength (up to 20-fold improvement) and the excitation filter bandwidth (up to 50% improvement). The authors also observe, by means of the optimization gain metric, that tissues exhibiting both high autofluorescence and strong pigmentation are generally better candidates for excitation wavelength optimization. This work contributes to the development of robust and quantitative dosimetry for QD-based fluorescence imaging near to the tissue surface.

Sonographic assessment of splanchnic arteries and the bowel wall

The intestinal wall can be visualized using high resolution transabdominal ultrasound. The normal intestinal wall thickness in the terminal ileum, cecum, and right and left colon is <2mm when examined with graded compression. It is important to appreciate that a contracted intestinal segment can be misinterpreted as a thickened wall. Vascularisation can be mainly displayed in the second hyperechoic layer (submucosal layer) as well as vessels penetrating the muscularis propria. Imaging of the gastrointestinal wall is dependent on the experience of the examiner as well dependent on the equipment used. Acute or chronic inflammation of the intestinal wall is accompanied by increased perfusion of the mesentery, which can be displayed non-quantitatively with colour duplex. In contrast, ischemia is characterised by hypoperfusion of the mesenteric arteries and the bowel wall. The most promising sonographic approach in assessing splanchnic arteries and the bowel wall is combining the analysis of superior and inferior mesenteric inflow by pulsed Doppler scanning (systolic and diastolic velocities, resistance index) with the end-organ vascularity by colour Doppler imaging diminishing the influence of examination technique only displaying bowel wall vascularity. Colour Doppler imaging has been described as helpful in a variety of gastrointestinal disorders, particularly in patients with Crohn's disease, celiac disease, mesenteric artery stenosis and other ischemic gastrointestinal diseases, graft versus host disease and hemorrhagic segmental colitis.

[Digestive complications in adults with cystic fibrosis]

In France the median life expectancy of patients with cystic fibrosis (CF) is 36 years and one third of patients are adults. Respiratory disorders are the main determinants of survival during adulthood, although gastrointestinal complications can also have a major impact on quality of life and nutritional status. We reviewed gastro-intestinal and pancreatic manifestations of CF in adults. Some complications (diabetes, distal intestinal obstruction syndrome and acute pancreatitis) are more frequent in adulthood than in childhood. Clinical and therapeutic aspects of specific conditions (such as distal intestinal obstruction syndrome) or atypical presentations (including appendicular complications) are presented herein.

Enhanced production of Penicillium expansum PED-03 lipase through control of culture conditions and application of the crude enzyme in kinetic resolution of racemic Allethrolone

Alkaline lipase production was performed in submerged fermentation by Penicillium expansum PED-03. It was found that the suitable carbon source and nitrogen source for lipase production were 0.5% starch and 4.0% soybean meal, respectively. The maximal lipase activity (850 U/mL) of production was achieved at initial pH 5.5-6.0, 26 degrees C, 72 h. Tween-80 was an effective enhancer for lipase production. Agitation speed of the fermentor played an important role, and the suitable agitation speed for lipase production was 500 r/min. The lipase was stable within the range of pH 7.0-10.0 and 20-40 degrees C, and the optimum conditions for the enzymatic reaction were 35 degrees C and pH 9.5. The enzymatic resolution of racemic allethrolone (4-hydroxy-3-methyl-2-(2-propenyl)-2- cyclopenten-1-one) was carried out by the lipase from P. expansum PED-03, and the conversion reached 48% with excellent enantioselectivity (E > 100), which showed a good application potential in the production of optically pure allethrolone.

Pancreatic Enzyme Supplementation Therapy

Effective treatment of malabsorption due to severe pancreatic exocrine insufficiency requires delivery of sufficient enzymatic activity into the duodenal lumen simultaneously with meal nutrients. To achieve this, modern therapeutic concepts recommend administration of 25,000 to 40,000 units of lipase per meal using pH-sensitive pancreatin microspheres. In case of treatment failure, dosage should be increased two to three times. If this still is not successful, compliance may be checked by measurement of fecal chymotrypsin, although this is not a standardized procedure. In the compliant patient, diagnosis of pancreatic exocrine insufficiency needs to be reviewed, particularly cases of celiac disease, (concomitant) bacterial overgrowth, and blind loop syndrome, as well as giardiasis, which need to be excluded or otherwise be treated specifically. Finally, additional acid suppression with application of unprotected pancreatin and/or reduced fat intake may help to control malabsorption. Still, in most patients, lipid digestion cannot be completely normalized by current standard therapy. On the one hand, this leads to loss of energy that may only partly be compensated for by increased nutrient intake. On the other hand, increased nutrient exposition of distal intestinal sites may release excessive amounts of mostly inhibitory distal intestinal neurohumoral mediators, and thereby disturb gastrointestinal secretory and motor functions. Consequently, future developments are needed for optimizing treatment.

Sonographic evaluation of bowel wall thickness in patients with cystic fibrosis

GOALS AND BACKGROUND

Fibrosing colonopathy causing severe thickening of the colon wall was recently described in cystic fibrosis (CF). Since it has been suspected that subclinical colon-wall thickening is a common feature in CF patients, bowel-wall thickness was measured in a series of patients and compared with controls. Additionally, possible clinical factors influencing wall thickness were investigated.

STUDY

In 83 CF patients and 31 controls transabdominal ultrasound was performed in the terminal ileum, cecum, ascending and descending colon. The relation of the measured wall thickness to age, sex, pancreatic enzyme intake, and intestinal diseases was analyzed.

RESULTS

In controls, mean wall thickness depending on gut region was 1.1 to 1.3 mm (SD 0.19-0.23). In CF patients, no evidence of severe thickening or stricture was found, but wall thickness was significantly higher than in controls in all measured regions (1.5-1.6 mm; SD 0.31-0.41). Patients with meconium ileus and distal intestinal obstruction syndrome had significantly increased thickness of the terminal ileum compared with patients without these complications. Neither the intake of high-strength enzymes nor enzyme dosage, age or sex were associated with wall thickness.

CONCLUSIONS

We found no evidence that a subclinical stage of fibrosing colonopathy is prevalent among the CF patients. Slightly thickened gut walls in CF can be interpreted as an expression of glandular dysfunction in the CF intestine.

Lipase supplementation therapy: standards, alternatives, and perspectives

Treatment of steatorrhea by lipase supplementation therapy has become more successful in the last decade due to better understanding of the physiology and pathophysiology of the digestive process. Porcine lipase has been the therapeutic standard for several decades and will continue to be the treatment of choice in pancreatic exocrine insufficiency. Modern therapeutic concepts recommend administration of 25,000-40,000 units of porcine lipase per meal using pH-sensitive pancreatin microspheres. In case of treatment failure, the dose should be increased, compliance should be checked, and other reasons for malabsorption should be excluded. Still, in most patients, lipid digestion cannot be completely normalized by current standard therapy, and future developments are needed for optimizing treatment. In this article, pathophysiologic characteristics of pancreatic exocrine insufficiency, prerequisites for use of alternative lipase sources as well as currently available lipases of nonporcine origin, and new developments are discussed. Current literature suggests that bovine lipase products present a theoretical alternative but play no major role in the western world. Fungal lipase has inferior properties compared with conventional products. Bacterial lipase products show promising potential and offer future therapeutic alternatives. Moreover, human pancreatic lipase gene transfer and application of bioengineered human gastric lipase appear on the horizon.

Oral bleeding associated with pancreatic enzyme supplementation in three dogs with exocrine pancreatic insufficiency

Three dogs with exocrine pancreatic insufficiency developed oral bleeding during treatment with pancreatic enzyme supplements. According to the owners of the dogs, bleeding from the oral cavity developed during or shortly after consumption of meals containing the pancreatic enzyme supplement. Oral bleeding stopped in all dogs when owners reduced the dose of the pancreatic enzyme supplement. In 2 dogs, the decrease in the dose of the pancreatic enzyme supplement did not affect fecal consistency. However, in the third dog, the decrease in dose led to a recurrence of clinical signs. Findings in these dogs suggest that high doses of pancreatic enzyme supplements can cause oral bleeding in dogs with pancreatic insufficiency, but that oral bleeding can be successfully managed by dose reduction in most dogs.

Ranitidine and omeprazole as adjuvant therapy to pancrelipase to improve fat absorption in patients with cystic fibrosis

BACKGROUND

Inadequate treatment of pancreatic insufficiency in patients with cystic fibrosis (CF) causes malabsorption of nutrients with significant sequelae. The objective of this study was to measure the effect of acid suppressant therapy on fat absorption in patients with CF who received a pH-sensitive, enteric-coated microtablet enzyme product.

METHODS

A double-blind, placebo-controlled crossover study of 12 children and 10 adults with pancreatic insufficient CF was performed. All subjects were receiving pancrelipase therapy (Pancrease MT10 and MT16; Ortho-McNeil, Springhouse, PA, U.S.A.) and for the study also received either placebo or ranitidine (Zantac; Glaxo-Wellcome, Research Triangle Park, NC U.S.A.) 5 mg/kg or 10 mg/kg daily. The adult subjects also received omeprazole therapy (Prilosec; AstraZeneca/Merck, Wilmington, DE, U.S.A.), 20 mg daily, as adjuvant therapy to pancreatic enzymes. Serial 3-day fat-balance studies were performed in the Clinical Research Center. The data were analyzed using individual paired t tests that compared each treatment with placebo and two repeated-measures, general linear model F tests.

RESULTS

The linear model for all subjects showed no overall adjuvant drug effect on fat absorption, P = 0.32. A second linear model F test analysis of adult subjects, comparing all four drug treatments (placebo, ranitidine 5 and 10 mg/kg daily and omeprazole), also showed no difference in fat absorption, P = 0.15. Paired t test subgroup analysis of the adults showed an improvement of 4.97% (P = 0.003) in mean fat absorption comparing low-dose ranitidine to placebo. All other t test analyses showed no significant change in fat absorption between placebo and acid suppressant treatment. There was marked intersubject and intrasubject variability in fat absorption.

CONCLUSIONS

No overall significant improvement in fat absorption could be demonstrated with adjuvant therapy. Fat absorption measured by 3-day fat-balance studies varied greatly even when comparing the same subject for placebo and baseline treatments, despite identical dietary fat and enzyme intakes. The large variability limited our ability to test for a difference in fat absorption and has significant implication for the use of this test, considered the gold standard, for determining enzyme dosage adequacy.

The role of MRI in the intestinal complications in cystic fibrosis

Fibrosing colonopathy is a complication recently detected in children with cystic fibrosis (CF), and is thought to be associated with the use of high-strength pancreatic enzymes. The goal of this study was to evaluate the effectiveness of magnetic resonance (MR) in detecting possible pathologic gut findings in patients with CF under pancreatic enzyme treatment. Twenty-five patients with CF and pancreatic insufficiency, all under treatment with high-dose pancreatic enzymes, were studied by MR. MR was performed on a 1.5-T magnet by T1-weighted, 2D-FLASH fat-suppression, breath-hold sequences before and after intravenous administration of gadolinium, and by T2-weighted Turbo Spin-Echo (TSE) and Half-Fourier Acquisition Single-Shot Turbo Spin Echo (HASTE) fat-suppression, breath-hold sequences. A superparamagnetic negative oral contrast agent was given 1.5 h before the examination. MR showed a wall thickening of the terminal ileum and the ascending colon (>4-12 mm) in 22 patients; nine of them (wall thickness >4-6 mm) showed both a moderate hyperintensity of the bowel wall on T2-weighted sequences and an enhancement after intravenous gadolinium on T1-weighted sequences; 13 patients (wall thickness >6-12 mm) showed both a great wall enhancement after intravenous gadolinium and an increased signal intensity of the bowel wall on T2-weighted sequences. Fecal impaction without bowel wall involvement was detected in three patients. MR proved to be a useful, noninvasive, diagnostic tool for the evaluation of patients with CF and fibrosing colonopathy. The signal hyperintensity on T2-weighted sequences and the great wall enhancement after intravenous gadolinium administration indicating an acute edematous condition, provide the clinicians useful information for the therapeutic adjustment.

Pancreatic enzyme replacement therapy

Malabsorption due to severe pancreatic exocrine insufficiency is one of the most important late features of chronic pancreatitis. Generally, steatorrhea is more severe and occurs several years prior to malabsorption of other nutrients because synthesis and secretion of lipase are impaired more rapidly, its intraluminal survival is shorter, and the lack of pancreatic lipase activity is not compensated for by nonpancreatic mechanisms. Patients suffer not only from nutritional deficiencies but also from increased nutrient delivery to distal intestinal sites, causing symptoms by profound alteration of upper gastrointestinal secretory and motor functions. Adequate nutrient absorption requires delivery of sufficient enzymatic activity into the duodenal lumen simultaneously with meal nutrients. The following recommendations are based on modern therapeutic concepts: 25,000 to 40,000 units of lipase per meal using pH-sensitive pancreatin microspheres, with dosage increases, compliance checks, and differential diagnosis in case of treatment failure. Still, in most patients, lipid digestion cannot be completely normalized by current standard therapy, and future developments are needed to optimize treatment.

Human Genome Project and cystic fibrosis--a symbiotic relationship

When Watson and Crick determined the structure of DNA in 1953, a biological revolution began. One result of this revolution is the Human Genome Project. The primary goal of this international project is to obtain the complete nucleotide sequence of the human genome by the year 2005. Although molecular biologists and geneticists are most enthusiastic about the Human Genome Project, all areas of clinical medicine and fields of biology will be affected. Cystic fibrosis is the most common, inherited, lethal disease of white persons. In 1989, researchers located the cystic fibrosis gene on the long arm of chromosome 7 by a technique known as positional cloning. The most common mutation (a 3-base pair deletion) of the cystic fibrosis gene occurs in 70% of patients with cystic fibrosis. The knowledge gained from genetic research on cystic fibrosis will help researchers develop new therapies (e.g., gene) and improve standard therapies (e.g., pharmacologic) so that a patient's life span is increased and quality of life is improved. The purpose of this review is twofold. First, the article provides an overview of the Human Genome Project and its clinical significance in advancing interdisciplinary care for patients with cystic fibrosis. Second, the article includes a discussion of the genetic basis, pathophysiology, and management of cystic fibrosis.

Cystic fibrosis colonopathy

An epidemic of fibrosing colonopathy, a new disease caused by the prolonged administration of excessive doses of pancreatic enzymes, was first reported in 1994. More than 60 cases were known to occur worldwide before dosage guidelines were enforced. Predisposing factors were young age, previous intestinal surgery, meconium ileus equivalent, and use of H2 blockers, corticosteroids, and DNase. Abnormal features included foreshortened colon, strictures, marked submucosal fibrosis, ascites, and nodular hyperplasia of the liver. Histologic examination showed eosinophilia, mild cryptitis, epithelial regeneration, and widespread interruption of the muscularis mucosa. These findings are distinct from, but share many of the features of, those of Crohn's's disease and ischemic bowel disease. The pathogenic mechanisms remain unknown.

Findings on routine abdominal ultrasonography in cystic fibrosis patients

BACKGROUND

Right lower quadrant abdominal pain may pose a diagnostic problem in patients with cystic fibrosis. Abdominal ultrasound examination, used commonly in the diagnostic work-up, may reveal abnormalities of the appendix. However, interpretation of such findings is problematic, because the appearance of the gastrointestinal system during routine examination has not been documented in patients with cystic fibrosis. The purpose of this study was to investigate the findings during routine abdominal ultrasound scans in our cohort of patients with cystic fibrosis and in control subjects.

METHODS

Abdominal ultrasound scans were performed prospectively during routine clinic visits in a cohort of patients with cystic fibrosis.

RESULTS

Fifty patients aged 10+/-6 years, (range, 0.5-28 years) were examined; 45 had pancreatic insufficiency. Four patients (3 with pancreatic insufficiency) reported right lower quadrant pain at the time of the scan. According to standard ultrasound criteria, the appearance of the appendix was abnormal in 8 patients (16%), 6 had a mucoid appendix, and 2 had a pathologically thickened appendiceal wall. Only 1 of these 8 patients mentioned abdominal pain at the time of the study. Other incidental findings included gallstones (3 patients), intussusception (2 patients), and pancreatic cyst (1 patient).

CONCLUSIONS

Abnormalities can be observed during routine abdominal ultrasonographic studies in cystic fibrosis. These findings may not be associated with abdominal pain; their clinical relevance needs further investigation.

Pancreatic enzymes: secretion and luminal nutrient digestion in health and disease

Severe pancreatic exocrine insufficiency leading to malabsorption of nutrients is one of the most important late features of chronic pancreatitis. In contrast to other key enzymes, pancreatic synthesis and secretion of lipase is impaired more rapidly, its intraluminal survival is shorter due to its higher susceptibility against acidic and proteolytic denaturation, and its luminal digestive action is hardly compensated by nonpancreatic mechanisms. As a consequence, steatorrhea is in general more severe and occurs several years before clinical malabsorption of protein or starch. Apart from the detrimental effects of nutrient deficiency, profound alterations of upper gastrointestinal secretory and motor functions may be an additional and hitherto underestimated consequence of increased nutrient delivery to distal intestinal sites. Effective reduction of nutrient malabsorption in pancreatic insufficiency requires delivery of sufficient enzymatic activity into the duodenal lumen simultaneously with meal nutrients. Modern enteric-coated pancreatin microsphere preparations attempt to achieve this by optimizing the size of individual microspheres and chemical properties of the coating. However, lipid digestion cannot be completely normalized in most patients by current standard therapy. In the future, acid and protease stable bacterial and fungal lipases with additional pH optima in the acidic milieu or animal or bioengineered human gastric lipase preparations may offer superior therapeutic alternatives. This review first summarizes current knowledge about secretion and luminal fate of pancreatic enzymes and their effects on nutrient digestion in health and chronic pancreatitis. Second, rationale, current standards, options, and future aspects of enzyme replacement therapy are discussed.

Fat malabsorption in cystic fibrosis patients receiving enzyme replacement therapy is due to impaired intestinal uptake of long-chain fatty acids

BACKGROUND

Pancreatic enzyme replacement therapy frequently fails to correct intestinal fat malabsorption completely in cystic fibrosis (CF) patients. The reason for this failure is unknown.

OBJECTIVE

We investigated whether fat malabsorption in CF patients treated with pancreatic enzymes is caused by insufficient lipolysis of triacylglycerols or by defective intestinal uptake of long-chain fatty acids.

DESIGN

Lipolysis was determined on the basis of breath 13CO2 recovery in 10 CF patients receiving pancreatic enzyme replacement therapy after they ingested 1.3-distearoyl,2[1-13C]octanoyl glycerol ([13C]MTG). Intestinal uptake of long-chain fatty acids was determined by analyzing plasma [13C]linoleic acid ([13C]LA) concentrations after patients ingested [13C]LA. For 3 d, dietary intakes were recorded and feces were collected.

RESULTS

Fecal fat excretion ranged from 5.1 to 27.8 g/d (mean+/-SD: 11.1+/-7.0 g/d) and fat absorption ranged from 79% to 93% (89+/-5%). There was no relation between breath 13CO2 recovery and dietary fat absorption (r = 0.04) after ingestion of [13C]MTG. In contrast, there was a strong relation between 8-h plasma [13C]LA concentrations and dietary fat absorption (r = 0.88, P < 0.001).

CONCLUSION

Our results suggest that continuing fat malabsorption in CF patients receiving enzyme replacement therapy is not likely due to insufficient lipolytic enzyme activity, but rather to incomplete intraluminal solubilization of long-chain fatty acids, reduced mucosal uptake of long-chain fatty acids, or both.

Colonic wall thickness, pancreatic enzyme dose and type of preparation in cystic fibrosis

Increased colonic wall thickness has been reported in patients exposed to large doses of high strength pancreatic enzyme preparations who did not develop fibrosing colonopathy. This has been interpreted as evidence for a spectrum of subclinical disease. The relation between sonographically measured colonic wall thickness and pancreatic enzyme preparation and dose was studied in 86 children with cystic fibrosis (CF). Colonic wall thickness of a control group was also measured. The average thickness in all colonic regions was higher in the CF group (overall average range 0.7-2.5 mm v 0.6-1.4 mm in the control group). There was no significant relation between colonic wall thickness and age, sex, total dose of lipase, or copolymer. Apart from one patient with an early colonic stricture, none of those exposed to high doses of lipase, or the methacrylic acid copolymer Eudragit L30 D55, showed evidence of subclinical damage to the colon. The reproducibility of the sonographic measurements was poor.

Cystic fibrosis with fibrosing colonopathy in the absence of pancreatic enzymes

Fibrosing colonopathy, characterized by dense submucosal fibrosis in the large bowel, is a disorder associated with bowel dysfunction in patients with cystic fibrosis who receive pancreatic enzyme supplementation. Most commonly, patients present with a distended abdomen and abdominal pain. Radiographs frequently demonstrate colonic wall thickening and luminal narrowing. Here I describe a neonate with cystic fibrosis who presented with both clinical and histological features of fibrosing colonopathy who had not received pancreatic enzymes. This report expands our understanding of the pathogenesis of fibrosing colonopathy.

Ultrasound studies of the intestinal wall in patients with cystic fibrosis

BACKGROUND

In 1994, first published reports described cystic fibrosis patients who experienced a then unknown complication-ileocecal and colonic stenoses with submucosal proliferation requiring surgical intervention. To investigate a suspected correlation between increased intestinal wall diameter and high doses of pancreatic enzymes, we carried out a prospective study in our CF-outpatient clinic.

METHODS

By ultrasound analysis we measured the intestinal wall diameter in 201 patients. One hundred ninety-three patients treated with pancreatic enzymes had pancreatic insufficiency. Eight patients showed normal pancreatic function, seven of them had never been treated with pancreatic enzymes. The control group included 12 healthy children. Measuring points were the distal ileum, cecum, ascending, and descending colon. Measurements were made by the longitudinal and cross sectional cut. The following aspects of the patients' history were recorded (a) current type of pancreatic enzyme medication; (b) total dosage per day (with reference to lipase units); (c) duration of therapy with standard-strength pancreatic enzyme (SSPE) preparations (< or = 10,000 lipase units per capsule) and HSPE preparations (> or = 20,000 lipase units per capsule); (d) gastrointestinal complication (distal intestinal obstruction syndrome, meconium ileus, abdominal surgery, intussusception), diabetes mellitus, and hepatobiliary complications.

RESULTS

The intestinal wall diameter in patients receiving HSPE therapy was greater (with prominent submucosal layer) than that in patients receiving SSPE therapy or in patients with pancreatic sufficiency. Healthy subjects had the smallest intestinal wall diameter. There was no correlation between patient history and increased intestinal wall thickness.

CONCLUSIONS

Ultrasound detects characteristic ileocecal wall lesions in the majority of cystic fibrosis patients on pancreatic enzymes. These lesions may lead to significantly increased ileocecal wall thickness, which is correlated but not restricted to HSPE.

High-dose pancreatic-enzyme supplements and fibrosing colonopathy in children with cystic fibrosis

BACKGROUND

Fibrosing colonopathy has been reported in young children with cystic fibrosis, the majority of whom take high-strength pancreatic-enzyme supplements to control intestinal malabsorption. We conducted a case-control study in the United States to investigate the relation between dose and type of pancreatic-enzyme supplement and fibrosing colonopathy.

METHODS

Children with histopathologically confirmed cases of fibrosing colonopathy who required colectomy for colonic strictures from January 1, 1990, through December 31, 1994, were identified. Each of these patients was matched according to age at the time of surgery and medical center with up to four controls with cystic fibrosis who did not have fibrosing colonopathy.

RESULTS

We studied 29 patients (mean age, 5.0 years) with fibrosing colonopathy (case patients) and 105 controls (mean age, 5.2 years). The mean dose of pancreatic-enzyme supplement was 50,046 units of lipase per kilogram of body weight per day for the case patients and 18,985 units per kilogram per day for the controls. A history of gastrointestinal complications attributed to cystic fibrosis and the use of histamine H2-receptor blockers, corticosteroids, or recombinant human DNase (dornase alfa) were associated with a higher incidence of fibrosing colonopathy. After adjustment for a history of such complications and the use of these medicines, the relative risk of fibrosing colonopathy that was associated with a dose of 24,001 to 50,000 units of lipase per kilogram per day, as compared with a dose of 0 to 24,000 units per kilogram per day, was 10.9 (95 percent confidence interval, 1.6 to 71.8), and that associated with a dose of more than 50,000 units per kilogram per day was 199.5 (95 percent confidence interval, 9.9 to 4026.0). The strength, coating, and manufacturer of the products used were not associated with the risk of fibrosing colonopathy.

CONCLUSIONS

In young children with cystic fibrosis, we found a strong relation between high daily doses of pancreatic-enzyme supplements and the development of fibrosing colonopathy. Our findings support recommendations that the daily dose of pancreatic enzymes for most patients should remain below 10,000 units of lipase per kilogram.

The pathology of fibrosing colonopathy of cystic fibrosis: a study of 12 cases and review of the literature

The authors studied eight colectomy and eight biopsy specimens from 12 patients with cystic fibrosis who had developed fibrosing colonopathy, a complication observed in patients receiving high-strength enzyme replacement. The colectomies originated from five male and three female patients ranging in age from 18 months to 6 years. Five individuals had localized strictures of the right colon and three had stenosing fibrosis of the entire colon. The affected colon had a cobblestone appearance, submucosal fibrosis, thickening of the muscularis propria and chronic mucosal inflammation in all patients, with active cryptitis in four. Moderate to severe infiltration by eosinophils, with increase in the number of mast cells, and widespread interruption of the muscularis mucosa were present in every case. Four colectomies were preceded by endoscopic biopsies; four patients who have not undergone surgery also underwent biopsy. All the biopsies showed evidence of active or chronic inflammation, and all had increased mucosal eosinophils. Prolonged colonic mucosal contact with either the enzymes and/or the enteric coating itself may lead to mucosal colonic ulceration and inflammation. Topical allergy may then promote the stenosing fibroplasia.

Fibrosing colonopathy in children with cystic fibrosis

PURPOSE

Fibrosing colonopathy is a newly described entity seen in children with cystic fibrosis. The radiological hallmarks are foreshortening of the right colon with varying degrees of stricture formation. High-dose enzyme therapy has been implicated as the cause of this process. The purpose of this study is to review the author's experience with evaluation and treatment of these patients.

METHODS

There are currently 380 patients being treated at our CF center. Fifty-five of these patients have been treated with high-dose enzyme therapy (> 5,000 units of lipase/kg). The medical records of these patients, who are at risk for developing fibrosing colonopathy, were reviewed for the presence of recurrent abdominal complaints, and the work-up and treatment of these symptoms.

RESULTS

Chronic complaints of abdominal pain, distension, change in bowel habits, or failure to thrive were present in 24 of the 55 patients treated with high-dose enzymes. So far, 18 of these 24 patients have been evaluated by contrast enema. Thirteen of eighteen have been found to have fibrosing colonopathy characterized by foreshortening and strictures of the colon. Additional findings included focal strictures of the right colon (7 of 13), long segment strictures (5 of 13), and total colonic involvement (1 of 13). Nine patients with the most severe symptoms have undergone colon resection, including five segmental right colectomies, three extended colectomies (ileo-sigmoid anastomosis), and one subtotal colectomy with end-ileostomy. Pathological evaluation has shown submucosal fibrosis, destruction of the muscularis mucosa, and eosinophilia. No postoperative complications or deaths occurred. All nine postoperative patients have noted marked symptomatic improvement. Contrast enema follow-up results are available for six patients, and have documented no recurrent strictures to date. Three of four nonoperative patients have less severe symptoms and are currently being treated conservatively. The other family has refused surgery and the patient is being treated symptomatically.

CONCLUSION

High-dose lipase replacement has been implicated as the etiology for FC and was present in all of our patients. Our cystic fibrosis center now routinely limits lipase to 2,500 U/kg per dose. We recommend the use of the contrast enemas to evaluate at-risk patients who have chronic abdominal complaints or who present with recurrent bowel obstruction. Colon resection should be performed in those with clinically and radiographically significant strictures with the expectation of a good outcome.

Neuropathy and vasculopathy in colonic strictures from children with cystic fibrosis

Colonic strictures are rare in patients who have cystic fibrosis, but recently have developed in those who have been treated with delayed-release high-dose pancreatic enzyme supplements. Colonic strictures from eight such pediatric patients showed neural abnormalities consisting of ganglion cell hyperplasia and ectopia, and intermyenteric plexus hyperplasia. Cholinergic and adrenergic stains of mucosal nerve fibers were more prominent in histological sections of the cystic fibrosis strictures than in sections from colons of children without cystic fibrosis. The mean grade of staining with acetylcholinesterase in the lamina propria of the strictured cystic fibrosis colons was 2.38 +/- 1.25, compared with .93 +/- .93 (P < .055) in bowels from children without cystic fibrosis. The mean grade for tyrosine hydroxylase staining in the lamina propria was 2 +/- .97 in the strictures and was .79 +/- .81 (P < .05) in the bowels of children who did not have cystic fibrosis. Vasoactive intestinal peptide staining in bowels from children with cystic fibrosis with and without stricture did not differ significantly from that of children without cystic fibrosis. Vasculopathy consisting of fibrointimal hyperplasia in submucosal veins and mesenteric arteries was found only in colonic strictures owing to cystic fibrosis. Colonic strictures in patients with cystic fibrosis who received high-dose pancreatic enzyme supplements contain ganglion cell abnormalities, and mucosal cholinergic and adrenergic activity may be increased in these strictures. The stricture vasculopathy may be drug-related and/or related to increased catecholamine activity.

Fibrosing colonopathy in cystic fibrosis

The introduction of enteric coated pancreatic enzyme supplements in the early 1980s was undoubtedly one of the major advances in the care of children with cystic fibrosis. Further refinements in the presentation of these preparations inevitably followed, to improve patient acceptability and compliance. The emergence of fibrosing colonopathy took clinicians dealing with cystic fibrosis completely by surprise, and in the last two years there has been a gradual appreciation that as far as pancreatic enzyme products are concerned 'More is not necessarily better'. However, it is encouraging that, in the UK, there have been no histologically confirmed cases in children receiving high strength pancreatic enzyme preparations since July 1994. Hopefully this trend will continue and the causal factors will be defined, ensuring that this serious complication can be effectively prevented in the future.

Fibrosing colonopathy in cystic fibrosis: results of a case-control study

Fibrosing colonopathy was first described in cystic fibrosis (CF) children in 1994. We have done a nested case-control study to identify possible associations with this condition. A case ascertainment within the UK CF population to identify any cases that occurred between January, 1984, and April, 1994, found 14 cases, all under 14 years and confirmed by independent histopathological review. All had presented since April, 1993; 12 were boys and six had received some or all of their care in Liverpool. Each case was matched, by date of birth, with four controls from the UK CF Registry. Information was obtained about cases and controls from their case records and by a structured interview with the families. In the 12 months before surgery, there was an association between the occurrence of fibrosing colonopathy and use of high-strength pancreatic enzyme preparations. This association was dose related. Odds ratio per extra 1000 high-strength capsules was 1.45 (95% CI 1.14-1.84). For use of protease, the odds ratio per million extra units per kg was 1.55 (1.19-2.03). For usage of individual high-strength products at any time during the 12 months before surgery some differences were observed; for Creon 25000 the odds ratio was 0.38 (0.10-1.42), for Nutrizym 22 43.4 (2.51-751), and for Pancrease HL 8.4 (1.95-36.1). These last two confidence intervals are extremely wide and compatible with these two products having the same odds ratios. Laxative use was independently predictive (odds ratio 2.42 [1.20-4.94]). We conclude that there is a dose-related association between high-strength pancreatic enzyme preparations and fibrosing colonopathy.