Nutritional status of infants with cystic fibrosis associated with early diagnosis and intervention.

The purpose of this study was to characterize the nutritional status of infants diagnosed with cystic fibrosis (CF) through neonatal screening and to determine if they would achieve normal nutrition when managed with early intervention. In addition, nutrient intake was assessed to determine energy and macronutrient-consumption patterns. Evaluation of growth revealed that normal patterns could be achieved with mean energy intake values at ages 6 and 12 mo of 481 and 426 kJ/kg body wt (115 and 102 kcal/kg body wt), respectively. Biochemical assessment demonstrated low alpha-tocopherol and linoleic acid values at diagnosis in the majority of infants whereas one-third had abnormal indices of protein nutriture. Essential fatty acid deficiency was also demonstrated at diagnosis by abnormal triene-tetraene ratio values in 27% of screened infants. With predigested formula and dietary supplementation, there was improvement in all indices of nutritional status and only a low percentage of patients showed mild biochemical abnormalities at age 12 mo.

Newborn screening for cystic fibrosis is complicated by age-related decline in immunoreactive trypsinogen levels.

Detection of elevated levels of immunoreactive trypsinogen (IRT) in dried neonatal blood spots has been used as a screening test for cystic fibrosis. In other cystic fibrosis newborn-screening studies, a sweat chloride test is generally performed only if an infant has a persistent IRT level above a selected cutoff value on both the initial and subsequent specimens. Neither the timing of the second specimen nor the value of the cutoff point for the second specimen has been comprehensively evaluated. In this randomized, controlled study, 145,024 infants were screened in the neonatal period for cystic fibrosis using the 99.8 percentile (180 ng/mL) as the neonatal cutoff point. A total of 129 infants had elevated neonatal IRT levels and had negative results on sweat tests (false-positive by IRT screening). A total of 54 children with cystic fibrosis were identified in the screened and comparison groups. Excluding patients with meconium ileus, 4 infants with cystic fibrosis had neonatal IRT values less than 180 ng/mL, and an additional 9 infants with cystic fibrosis had values decline to less than 180 ng/mL within the first 2 1/2 months of age. The IRT values of infants with and without cystic fibrosis overlapped considerably beyond 30 days of age. These findings suggest that further refinement of cystic fibrosis screening methodology will be necessary to achieve an acceptable sensitivity and specificity.

Cystic fibrosis newborn screening: impact on reproductive behavior and implications for genetic counseling.

OBJECTIVE: To evaluate the impact of newborn screening for cystic fibrosis (CF) on the reproductive knowledge and behavior of CF families and to determine if heterozygote detection with the immunoreactive trypsinogen (IRT) method in conjunction with DNA analysis (IRT/DNA) influences knowledge and attitudes about reproduction in false-positive families. METHODS: The Wisconsin CF Neonatal Screening Project investigated 650 340 infants from 1985 to 1994 in a comprehensive randomized controlled trial to study both benefits and risks of newborn screening and to determine if early diagnosis would improve the prognosis of children with CF. Assessments of reproductive knowledge, attitudes, and behaviors of 135 families of children diagnosed as having CF in both the early treatment group and control groups were made 3 months after diagnosis using a questionnaire which was completed by 100 families. The same questionnaire was administered 1 year later to evaluate retention of information. It was completed by 71 families. A follow-up assessment tool was also administered in 1994 and responses obtained from 73 families. Knowledge, attitudes, and behavior among false-positive families were also assessed at the time of the sweat test in 206 families who experienced IRT screening and 109 families tested with the IRT/DNA method. Follow-up assessments were completed 1 year later in 106 IRT families and 63 IRT/DNA families. RESULTS: In families with a CF child, 95% initially understood that there was a 1 in 4 risk in subsequent pregnancies, and there was good retention of this information 1 year later. At the 1994 assessment, 52% of families had not yet conceived more children, but 74% of these already had children. In the couples in whom CF was diagnosed in the first child, 70% (95% confidence interval = 54% to 85%) conceived more children. There were 43 subsequent pregnancies in 31 families. Prenatal diagnosis was used by 26% of the families (8/31) for 21% of the pregnancies (9/43). There were 3 pregnancies with CF detected, all of which were carried to term. In the false-positive groups, >95% of families initially understood that their child definitely did not have CF. There was no difference between false-positive IRT and IRT/DNA groups, and the information was retained at 1 year. Follow-up assessment 1 year after negative sweat tests revealed that 7% of the IRT and 10% of the IRT/DNA families still thought about the results often or constantly. When asked whether the experience of screening affected feelings about having more children, an affirmative response was obtained in 4% of IRT families but in 17% of IRT/DNA families. One year later, more than half of the false-positive IRT/DNA families did not understand that they were at increased risk of having a child with CF. CONCLUSIONS: We conclude that CF neonatal screening does not have a significant impact on the reproductive behavior of most families and that prenatal diagnosis is not used by the majority of CF families. IRT/DNA testing experiences seem to affect attitudes about having more children, and some parents are confused about the implications of the results, even with genetic counseling. However, persistent concerns about the sweat test result are limited. Questions raised by this study confirm the need for more research regarding the process of genetic counseling and its impact on reproductive attitudes and behavior in the newborn screening setting.

Suspected respiratory tract infection in the tracheostomized child: the pediatric pulmonologist's approach.

STUDY OBJECTIVES: It is difficult to determine, in the child with a long-term tracheostomy, when bacterial airway colonization has progressed to a respiratory infection requiring antibiotic treatment. Our aim was to investigate whether there is a consensus regarding this and related chronic care issues among clinicians treating these patients. DESIGN AND SETTING: A questionnaire asking about practices regarding use of tracheal aspirate cultures and antibiotics was distributed to 47 pediatric pulmonary centers. PARTICIPANTS: Individuals representing 34 centers (72%), caring for 10 to 400 patients, responded. INTERVENTIONS: None. RESULTS: At 65% of centers, management is variable, dependent on the patient's underlying condition. The most common indications to obtain a culture were change in secretions (91%) or fever without an obvious source (21 centers). Indications to treat with antibiotics included many leukocytes in secretions (21 centers) or a respiratory illness (18 centers). When treating, 97% prescribe antibiotics empirically, most often enterally; nine centers use inhaled antibiotics. In most centers (79%), management is often done by telephone. CONCLUSIONS: Although pediatric pulmonologists tend to have similar approaches to assessment and management of suspected respiratory tract infections in tracheostomized children, no clear consensus exists, and much of current practice is empirical. To optimize care of these patients, studies should be conducted to develop criteria to objectively differentiate bacterial airway "colonization" from "infection."

Evaluation of vitamin E deficiency in children with lung disease.

The clinical assessment of vitamin E status has traditionally depended upon measurement of tocopherol concentrations in plasma or serum, with 0.5 mg/dl being used as the lower limit of normal. This approach can be supplemented by measurement of tocopherol in erythrocytes or by evaluating their susceptibility to hemolysis in the presence of hydrogen peroxide. Data obtained during the last decade indicate that tocopherol concentrations in blood samples may be misleading, and that tocopherol-lipid ratios are more reliable indicators of vitamin E status. In our studies, small populations of healthy children have been evaluated, along with infants and children with a variety of chronic diseases. Of interest is the observation that premature infants susceptible to lung disease, who often require high levels of inspired oxygen, and children with cystic fibrosis who have chronic obstructive pulmonary disease are almost invariably below 0.5 mg tocopherol per deciliter plasma. A substantial number, however, show no abnormality in peroxide-induced erythrocyte hemolysis. Expression of the tocopherol data per gram of total lipid indicates that many children with "low" tocopherol concentrations per unit volume of plasma are not deficient in vitamin E, but rather are above 0.8 mg/g, the ratio of tocopherol to lipid previously reported as the lower limit of normal.

Immunoreactive trypsinogen screening for cystic fibrosis: characterization of infants with a false-positive screening test.

Blood immunoreactive trypsinogen (IRT) is elevated in newborns with cystic fibrosis (CF) and has been used as a neonatal screening test. However, not only is the benefit of early diagnosis unknown, but also the sensitivity, specificity, and time related decline of IRT values have yet to be comprehensively evaluated. This report describes the characteristics of infants with a false-positive IRT in our experience with CF screening of 87,000 infants. The IRT value was elevated in 92 newborns; 13 had a confirmed diagnosis of CF by quantitative pilocarpine iontophoresis sweat testing, and 79 infants did not have CF and were therefore classified as false positives by IRT screening. In order to test the hypothesis that perinatal stress factors are associated with high neonatal IRT values, we evaluated Apgar scores at 1 and 5 minutes. We found that the scores of false-positive infants were significantly lower (P = 0.0004 and P = 0.0102 at 1 and 5 minutes, respectively), compared with infants in the general population. While perinatal asphyxia as reflected by low Apgar scores is an associated factor accounting for an elevated IRT value, the majority of non-CF newborns with an elevated IRT have normal Apgar scores.

Predigested formula for infants with cystic fibrosis.

The object of this study was to assess the growth rates of patients with cystic fibrosis fed various diets and test the hypothesis that the weight of infants could be normalized by 1 year of age if they were placed on predigested formula before age 6 months. A group of 19 newly diagnosed patients placed on Pregestimil were compared with a group who were fed standard formula. At 1 year of age, the Pregestimil group showed significantly greater length and weight and a twofold higher average weight percentile. Growth velocity determined for the period between diagnosis and 12 months of age was better (p less than .001) for babies raised on Pregestimil (556 compared with 423 gm/month). Using weight percentile as the major growth index and values less than the fifth percentile as abnormal at age 12 months, we found that all 19 babies were normal in the group fed Pregestimil, whereas nine were below the fifth percentile in the group fed regular formula (p = .0006).

Oral supplementation with a high-fat, high-energy product improves nutritional status and alters serum lipids in patients with cystic fibrosis.

OBJECTIVE: To assess the tolerance and acceptability of a nutrition supplement in patients with cystic fibrosis (CF), to monitor changes in dietary intake, and to evaluate nutritional status. DESIGN: Subjects were their own controls for this 3-month, prospective, open study. Acceptability and tolerance questionnaires and 3-day food records were completed at baseline and monthly intervals. Compliance and nutritional status were also assessed. SETTING: This study was conducted at the University of Wisconsin Hospital and Clinics Cystic Fibrosis Center, Madison. SUBJECTS: Patients with CF older than 4 years of age were recruited during clinic or hospital visits if they met specific weight or growth criteria (n = 19). INTERVENTION: Subjects were asked to consume the supplement at a maximum of 30% their estimated daily energy requirements. MAIN OUTCOME MEASURES: Responses to acceptability ratings of and tolerance questions about the supplement were obtained along with anthropometric data and biochemical measurements of serum albumin, plasma retinol, alpha-tocopherol, and fatty acid levels. STATISTICAL ANALYSES PERFORMED: Data were analyzed using Minitab and Statistical Analysis Software. Paired and unpaired t tests and nonparametric sign tests were used, as well as regression and Pearson correlations. A significance level of .05 was used for all tests. RESULTS: All subjects tolerated the supplement, although 12 reported mild symptoms of fullness, nausea, and/or bloating, which were resolved when intake was distributed throughout the day. Mean compliance was 69% of recommended intake. Weight gain in children was strongly correlated with compliance (r = .98). Linoleic acid intake increased significantly (P = .0003) as did plasma linoleic acid in the phospholipid fraction (P = .03). CONCLUSION: The supplement studied would be a beneficial addition to the supplementation choices available to patients with CF.

Parents' knowledge of neonatal screening and response to false-positive cystic fibrosis testing.

Neonatal screening for cystic fibrosis (CF) has become feasible through analyzing dried blood specimens for immunoreactive trypsinogen (IRT), but the benefits and risks of such a screening program remain to be delineated. This study, a survey of the parents of 104 Wisconsin infants with false-positive IRT tests, showed parents had knowledge deficits about neonatal screening in general, misconceptions about test results, and high levels of anxiety. Parenting behaviors were reportedly unchanged during the usual 3-day waiting period between the news of the abnormal screening test and the diagnostic sweat test. Most, but not all, parents were relieved by negative sweat test results subsequent to the abnormal IRT test. Factors associated with continued parental concern included having less than a high school education and/or having an infant with low Apgar scores. Additionally, those contacted by telephone were more likely to have misinformation and lingering concerns about the presence of CF in their child.

Nutritional assessment of infants with cystic fibrosis diagnosed through screening.

Presymptomatic infants diagnosed through neonatal screening for cystic fibrosis can have biochemical evidence of malnutrition. With aggressive dietary management and treatment with pancreatic enzymes, normal biochemical indices of nutrition can be achieved at 12 months of life in most cases. Males with cystic fibrosis appear to be more at risk than females for abnormal growth and biochemical indices of nutrition in the first year of life. This may be related to the observed decrease in fat intake when compared to females. Males, especially, should be carefully observed for development of nutritional abnormalities based on this data. Careful attention should be paid to vitamin E and essential fatty acid status in all CF infants. The numbers in this study are small and the long-term consequences of early nutritional intervention await the conclusion of the randomized, controlled study on-going in Wisconsin.

Current issues in neonatal screening for cystic fibrosis and implications of the CF gene discovery.

Many questions remain regarding the efficacy, toxicity, and costs of CF neonatal screening. It would be premature, in our opinion, to implement mass population screening of newborns for CF until the benefits and risks have been fully defined, and an adequate and logistically feasible testing system developed and/or highly effective therapy for CF lung disease becomes available. In addition, the ethical issues described herein need to be resolved. This pertains not only to the CF patient but also the heterozygote carrier. These reservations notwithstanding, the discovery of the CF gene should have a favorable impact both directly and indirectly on neonatal screening for the disease. Mutation analysis coupled to IRT testing seems most attractive at this time, at least on a research basis, but primary molecular diagnostic procedures might supervene in the future, particularly if they are financially feasible.

Newborn screening for cystic fibrosis. The Cystic Fibrosis Neonatal Screening Study Group.

Many questions remain regarding the efficacy, risks, and costs of CF neonatal screening. The major gap in knowledge that must be closed before CF neonatal screening can be recommended generally in the United States concerns the potential long-term medical benefits of initiating treatment in early infancy. It would be premature, in our opinion, to implement mass population screening of newborns for CF until the benefits and risks have been fully defined, and an adequate and logistically feasible testing system developed and/or highly effective therapy for CF lung disease becomes available. It is for this reason we designed a randomized, controlled investigation of CF neonatal screening and implemented this project in Wisconsin during 1985. The fact that 5 years of randomized screening and systematic evaluation of outcome measures have not yet revealed any pulmonary benefits underscores the importance of rigorous investigation to resolve the efficacy issue. In addition to the medical uncertainties, we believe that the ethical issues described herein need to be resolved; this concern pertains not only to the CF patient but also the heterozygote carrier. On the other hand, financial factors and uncertainty about the cost effectiveness of CF neonatal screening do not appear to be dominant issues according to our assessment of current data. Despite the reservations related to the benefit/risk relationship, we expect that the discovery of the CF gene should have a favorable impact on neonatal screening for the disease, as well as for management.

Demineralization in cystic fibrosis detected by direct photon absorptiometry.

Bone mineral content, bone width, and their ratio were measured in patients with cystic fibrosis (CF) using monoenergetic photon absorptiometry. Serial measurements of the radius and ulna were made in 27 patients with CF and were compared with 968 age-matched controls. Demineralization was found in 37% of the boys and 63% of the girls. Patients under age 10 years had normal bone mineral content and nine of 15 patients aged 13 or older were demineralized (P less than .01). Demineralization correlated with the extent of weight reduction in patients (P less than .001). Patients most likely to be demineralized were adolescent girls. To our knowledge, this is the first report of bone mineral status of children with CF, and the results indicate that a sizable proportion of these patients may be demineralized without overt rickets.

Analysis of granulocyte beta-adrenergic response in cystic fibrosis: correlation of decreased responsiveness with disease severity.

Granulocytes from 21 nonasthmatic cystic fibrosis (CF) patients were isolated and the effects of isoproterenol, histamine, and prostaglandin E1 upon zymosan-induced beta-glucuronidase release was measured. Granulocytes from CF patients contained significantly less total beta-glucuronidase activity compared with those from control subjects, but response to zymosan stimulation was normal. Compared with those from control subjects, the granulocytes from CF patients with severe airway disease (% predicted FEV1 less than 60) had significantly reduced responsiveness to isoproterenol, which correlated with both the % predicted FEV1 values and the NIH clinical score. In this same population of CF patients, granulocyte responsiveness to PGE1 was also decreased compared with that of the control subjects, but the degree of impairment was not as severe as that observed with isoproterenol nor did it correlate with disease severity. Histamine responsiveness, however, was normal. Our findings suggest that abnormal beta-adrenergic responses may reflect the severity of airway disease and clinical score.

Comparison of effectiveness of pancreatic enzyme preparations in cystic fibrosis.

To evaluate claims that enteric-coated pancreatic enzyme preparations are more effective than conventional digestants in managing malabsorption in cystic fibrosis (CF), we conducted a trial comparing the efficacy of pancrealipase (enzyme supplement containing lipase, amylase, and protease) in the form of pH-sensitive microspheres (Pancrease) with that in the form of encapsulated enzyme powder (Cotazym). Ten boys with CF received equivalent dosages in a controlled, double-blind fashion using a random sequence of capsule administration with crossover and "washout" periods. Patients experienced significantly enhanced nitrogen and fat absorption while receiving either enzyme when compared with placebo. The enteric-coated product promoted significantly improved fat absorption as compared with the conventional enzyme capsule. Both enzyme preparations caused significantly improved protein absorption as compared with placebo, but there as no significant difference between the two products in the degree of effect on azotorrhea.

Fatty acid abnormalities in cystic fibrosis.

Fatty acids were measured by gas chromatography in lipid extracts of plasma and tissues obtained from three categories of 46 patients with cystic fibrosis. Low levels of the major essential fatty acid linoleate were found in plasma total lipids of patients who had malabsorption but not in those without evidence of steatorrhea. Circulating arachidonic acid was only slightly decreased, and the unusual triene reflecting pathologically altered fatty acid metabolism (20:3 omega 9) was generally not detected, nor was the triene/tetraene ratio abnormal except for in two patients. There was no correlation between plasma linoleate and age, clinical severity score, or vitamin E status. Decreased linoleate did correlate with two indices of malabsorption, namely plasma carotene (r = 0.64) and fecal fat excretion (r = 0.76). Our data therefore indicate that the abnormality in linoleate is associated with (secondary to) malabsorption of dietary fat despite pancreatic enzyme replacement therapy and consumption of a regular diet. The frequency of this alteration was determined to be quite high in 40 patients with steatorrhea, 85% of whom showed values below the lower limit of normal for plasma linoleate. It was of interest to find markedly decreased levels of linoleate in adipose tissue, cardiac muscle, and lung and lesser reductions in liver and psoas muscle taken at autopsies. Tissue arachidonic acid percentage was normal, however, and 20:3 omega 9 was rarely present. Thus, the physiological significance of this common abnormality in CF patients with malabsorption remains to be determined.

Appendiceal abscess in cystic fibrosis. A diagnostic challenge.

A patient with cystic fibrosis who developed appendicitis, rupture, and a periappendiceal abscess is presented. A retrospective chart review revealed 5 other cases that demonstrate a spectrum of clinical presentation of periappendiceal abscess in patients with cystic fibrosis. Three patients were symptomatic for less than 5 days, but the remaining 3 patients were symptomatic for 8, 12, and 30 days before diagnosis. There were two deaths due to respiratory failure. Other complications included a perirectal fistula and 2 cases of recurrent abscess. This demonstrates the difficulty with which this diagnosis is reached in this patient population and the relatively high incidence of abscess formation compared with normal populations. A retrospective autopsy review of 51 cystic fibrosis patients showed that in 49 of 51 instances, the mucosa of the appendix was hyperplastic, and the mucosal glands were distended with eosinophilic secretions. In 12 cases (24%), the appendix itself was grossly firm, dilated, and distended, although the mucosal wall was free of inflammation. This lends credence to the suggestion that these inspissated secretions may be protective against the occurrence of appendicitis, the incidence of which may be as low as 1%-2% among cystic fibrosis patients.

Application of DNA analysis in a population-screening program for neonatal diagnosis of cystic fibrosis (CF): comparison of screening protocols.

We compare two protocols for newborn screening for cystic fibrosis (CF). The first uses the immunoreactive trypsinogen (IRT) assay with a cutoff of > or = 180 ng/ml and a sweat test to identify CF patients. The second uses the IRT assay with a 100 ng/ml cutoff in conjunction with direct analysis for the delta F508 CF transmembrane conductance regulator (CFTR) mutation in a two-tiered (i.e., IRT/DNA) protocol, followed by a sweat test. We screened 220,865 newborns from Wisconsin for CF, using the IRT protocol identifying 369 infants with an elevated IRT, of whom 46 were found to have CF. Another 7 CF patients were identified who had a false-negative IRT level. The CF incidence in the white population was 1 in 3,431 (carrier incidence of 1 in 30). The IRT protocol had a sensitivity of 87% and a positive predictive value of 12.5%. We subsequently used the IRT/DNA protocol to screen 21,258 infants. Of 518 infants with an IRT level > or = 100 ng/ml, 24 carried at least one copy of the delta F508 CFTR mutation, and 4 of these infants were found to have CF, yielding a positive predictive value for this protocol of 16.7%. Direct comparison of the positive predictive value of the two protocols is not valid, because of the different populations screened. However, had the IRT protocol been used on the IRT/DNA cohort, 50 infants, including the 4 with CF, would have received sweat tests, yielding a positive predictive value of 8%. Because of the small sample size, this positive predictive value is not significantly different from that obtained for the IRT/DNA test. However, from a practical point of view the IRT/DNA approach does decrease considerably the number of sweat tests that must be undertaken. The number of false positives for the IRT protocol (46 in 21,258) is increased significantly compared with that for the IRT/DNA approach (20 in 21,258; P < .001). The incidence of delta F508 carriers detected in cohorts with an elevated IRT level was increased compared with the incidence in the general population. The direct costs for the IRT/DNA approach (100 ng/ml) were $11,374 per CF patient detected, compared with $10,187 per CF patient detected for the IRT protocol. Therefore, we conclude that the IRT/DNA approach to CF newborn screening decreases the number of false-positive subjects contacted, without a significant increase in cost.

Correction of linoleic acid deficiency in cystic fibrosis.

To identify evidence of essential fatty acid deficiency, we screened 64 patients with cystic fibrosis by analyzing total lipid extracts from plasma. Forty-three had an abnormal linoleate (18:2) level (less than 26%). Thirteen deficient patients (aged 10-24 yr) ingested for 1 yr 7% of their total calories as linoleate derived from a daily supplement of Microlipid. Five deficient patients (aged 10-37 yr) served as controls. Plasma and erythrocyte fatty acid composition were monitored by gas chromatography of total lipid extracts seven times during the twelve month period. Prostaglandins E2 and F2 alpha and their 15 keto 13, 14 dihydrometabolite, 6-keto F1 alpha, and thromboxane B2 were measured by radioimmunoassay. Sweat tests, oxygen saturation, growth indices, clinical severity scores, compliance, and possible side effects from taking Microlipid were followed. Results showed that oral supplementation with Microlipid can significantly increase plasma and erythrocytes % 18:2. One compliant patient died during the study and had normal tissue 18:2 levels. Nine of 13 patients gained more weight while taking Microlipid than in the previous year. No significant changes in sweat electrolytes, clinical scores, or oxygen saturation were found during the study year. Prostaglandin metabolites prostaglandin E2 showed an upward trend in supplemented patients, compared to controls. Prostaglandin F2 alpha remained unchanged over 1 yr but showed a trend significantly downward over the final 6 months in supplemented patients. We conclude that linoleate deficiency can be corrected with daily Microlipid supplements and that correction may alter prostaglandin metabolism.