Pseudomonas aeruginosa and Burkholderia cepacia infection in cystic fibrosis patients treated in Toronto and Copenhagen

Differences in the course of pulmonary disease in cystic fibrosis (CF) may be altered by different treatment strategies in different CF centers. The Copenhagen clinic uses scheduled, regular and very aggressive treatment of lung infection. The Toronto clinic treats pulmonary infection with oral, inhaled, or intravenous antibiotics, and has emphasized aggressive nutritional therapy. This study compared the clinical status of CF patients treated in the two centers (Toronto, Canada, n=302, and Copenhagen, Denmark, n=214) using a cross-sectional design in terms of Pseudomonas aeruginosa (PA) and Burkholderia cepacia (BC) lung infections, pulmonary function, and levels of PA and BC precipitating antibodies (precipitins). Median ages were similar, but the age distribution was significantly different, with a higher proportion of patients under 10 and > or = 25 years in Toronto, and higher proportion of patients 11-24 years of age in Copenhagen. A higher number of female patients was observed in Copenhagen than in Toronto. Seventy-nine percent of Copenhagen patients, and 52% of Toronto patients were deltaF508 homozygous. Of all the patients, 20.1% of Copenhagen patients and 38% of Toronto patients were deltaF508 heterozygous. Ten percent of Toronto patients had two uncommon mutations. Pulmonary function and nutritional status in both groups were similar despite varying treatment strategies. The prevalence of PA was lower in Danish children and higher in Danish adults than in Canada. These differences are probably due to cohort isolation, which was introduced in Copenhagen in 1981. The prevalence of BC was higher in Toronto than in Copenhagen patients at all ages. In both centers, the number of PA and BC precipitins increased with age in patients chronically infected with PA and BC, respectively, and the number of both PA and BC precipitins rose with declining lung function. This study suggests that the clinic populations had similar pulmonary and nutritional statuses despite differing clinic antibiotic treatment strategies. Microbial colonization seemed to differ, at least in part, because of differences in cohort isolation strategies. Early, aggressive anti-pseudomonal chemotherapy may have reduced pseudomonal colonization among younger patients in Copenhagen. Future studies will be required to assess the impact of this on this cohort's outcome.

Longitudinal analysis of pulmonary function decline in patients with cystic fibrosis

BACKGROUND

Chronic progressive lung disease is the most prominent cause of morbidity and death in patients with cystic fibrosis (CF), but severity of lung disease and rate of lung function decline are widely variable. Accurate estimates of decline have been difficult to define and compare because the timing of measurements and duration of follow-up differ in various patient groups.

PATIENTS

Three hundred sixty-six patients with CF, born from 1960 to 1974, were selected from a CF database birth cohort if they had two or more measurements of pulmonary function, at least one of which was performed before the age of 10 years.

METHODS

Mixed model regression analysis provided estimates of the average rate of decline of spirometry measurements in subgroups on the basis of survival age, sex, pancreatic status, and genotype.

RESULTS

Patients who died before the age of 15 years had significantly poorer pulmonary function when first tested and a more rapid decline in pulmonary function thereafter than patients who survived beyond the age of 15 years. In the latter, functional levels at the age of 5 years were normal, but average rates of decline were significantly related to survival age. Female patients had significantly steeper decline than male patients, and those with pancreatic insufficiency had much steeper decline than those with pancreatic sufficiency. In the subset of 197 who survived to 1990 and were subsequently genotyped, rate of decline was greater in those homozygous for the delta F508 mutation, compared with those who were heterozygous for delta F508 or those, who had two other mutations.

DISCUSSION

All but the most severely affected patients, who died before age 15, appear to have had normal pulmonary function when first tested in early childhood. Pancreatic sufficiency, male gender, and some non-delta F508 mutations are associated with a slower rate of pulmonary function decline. Mixed model analysis is a valuable tool for describing and comparing pulmonary function decline in groups of patients with CF.

Does ketotifen have a steroid-sparing effect in childhood asthma?

In view of the possible systemic side-effects of inhaled corticosteroids (ICS), a study was performed to determine whether ketotifen (versus placebo) can replace or allow a reduction in the dose of ICS required for the maintenance treatment of childhood asthma. Sixty six children (aged 6-13 yrs) with asthma (confirmed by methacholine challenge), who were maintained on ICS, at a dose of < or = 1 mg.day-1, were selected, and 52 subjects completed the trial. Children on long-term oral steroids or cromoglycate were excluded. After a 4 week baseline period, the children were randomized to receive ketotifen, 2 mg.day-1, or placebo for 32 Weeks. Between weeks 13-20 of the study, the daily dose of steroid was tapered by 25% every second week to the minimum dose tolerated by the patients. For the remainder of the study (Weeks 21-32) the patients continued on this dose (if tolerated). Beta 2-agonists were allowed, as necessary, for symptom relief. During the baseline period, the mean daily ICS dosage was 432 micrograms in the ketotifen group versus 408 micrograms in the placebo group (NS). Among the-patients who completed the study, the average ICS dosage during the final phase of the study (Weeks 21-32) was only 18% of baseline in the ketotifen group versus 35% in the placebo group (NS). Lung function, diurnal variability in peak flow rates and methacholine sensitivity (provocative concentration producing a 20% fall in forced expiratory volume in one second (PC20)) remained unchanged in both groups throughout the study. During the last 12 weeks of the study, the ketotifen-treated patients were symptomatically better controlled. In the present study, ketotifen did not have a greater steroid-sparing effect than placebo.

The role of corticosteroids in respiratory diseases of children

Glucocorticosteroids are potent anti-inflammatory agents and have an important role in a variety of respiratory diseases. Although their exact mode of action is unknown, it is thought that they exert their effects by binding to cytoplasmic glucocorticoid receptors. In certain conditions, such as asthma, the value of steroids cannot be questioned, and inhaled steroids have revolutionized management. In other situations, such as interstitial lung disease, the true role of steroids is still to be defined. In the management of diseases such as tuberculosis, the use of steroids is solely based on anecdotal experience.

Dietary intakes of young children with cystic fibrosis: is there a difference?

Caloric intakes of preadolescent and adolescent girls and boys with cystic fibrosis (CF) were compared in order to evaluate the possibility that poor caloric intake contributes to poor nutritional status and high mortality among girls with CF. Fifty-six CF patients (26 girls and 30 boys), 10-15 years old, completed a 3-day food record, answered a short questionnaire, and underwent anthropometric and pulmonary function assessment. The mean ages of the girls and boys were similar, but the height and weight percentiles of the girls were lower than those of the boys (p = 0.02). Mean caloric intakes were no different (116% and 112% of the recommended nutrient intake in the girls and boys, respectively). Nutritional status, as determined by weight as a percentage of ideal weight for height, mean triceps skinfold thickness, and midarm muscle circumference, was normal and similar in both sexes. Most girls and boys with CF in this study had an appropriate perception of their body weight. Pulmonary function tests suggested mild lung disease with no significant difference between girls and boys (forced expiratory volume in 1 s of 82.2% and 79.8% of predicted values, respectively). The similar nutritional and pulmonary status of the girls and boys with CF in this age group is in contrast to previous reports. This finding may be the result of our policy, introduced > 15 years ago, of expecting normal growth, by paying close attention to enzyme therapy and encouraging high energy intake from the time of diagnosis. It remains to be seen whether boys and girls continue to maintain similar nutritional and pulmonary status at a later age and whether both sexes experience a similar mortality rate as they age.

Correlation of sweat chloride concentration with classes of the cystic fibrosis transmembrane conductance regulator gene mutations

OBJECTIVE

To compare differences in epithelial chloride conductance according to class of mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

METHODS

We evaluated the relationship between the functional classes of CFTR mutations and chloride conductance using the first diagnostic sweat chloride concentration in a large cystic fibrosis (CF) population.

RESULTS

There was no difference in sweat chloride value value between classes of CFTR mutations that produce no protein (class I), fail to reach the apical membrane because of defective processing (class II), or produce protein that fails to respond to cyclic adenosine monophosphate (class III). Those mutations that produce a cyclic adenosine monophosphate-responsive channel with reduced conductance (class IV) were associated with a significantly lower, intermediate sweat chloride value. However, patients with the mutations that cause reduced synthesis or partially defective processing of normal CFTR (class V) had sweat chloride concentrations similar to those in classes I to III.

CONCLUSION

Studies of differences in chloride conductance between functional classes of CFTR mutations provide insight into phenotypic expression of the disease.

Comparison of airway reactivity induced by cold air and metacholine challenges in asthmatic children

Bronchial responsiveness to isocapnic hyperventilation with cold air (CAH) and to inhaled methacholine (MCH) was compared in 17 children with bronchial asthma. The response to cold air was expressed as the percent drop in FEV1 from baseline at 4 min. after the challenge (delta % FEV1 CAH), and the response to methacholine as the provocative concentration required to reduce the FEV1 by 20% from baseline (PC20MCH). Both tests were sensitive (94%) for detecting airway hyperreactivity. There was no statistically significant relationship between delta % FEV1 CAH and the log PC20MCH (r = 0.39; P = 0.12). In clinical practice, methacholine test is easier to perform, but in the research field cold air challenge may be preferable because it avoids potential drug effects.

Efficacy of frequent nebulized ipratropium bromide added to frequent high-dose albuterol therapy in severe childhood asthma

OBJECTIVE

The objective of this trial was to determine the efficacy of frequent nebulized ipratropium added to high-dose albuterol therapy in children with severe asthma.

METHODS

One hundred twenty children (5 to 17 years) of age) with severe acute asthma (forced expiratory volume in 1 second (FEV1), < 50% of the predicted value) were enrolled into a randomized double-blind three-arm placebo-controlled trial comparing three groups: group 1, three doses of nebulized ipratropium bromide within 60 minutes (250 micrograms/dose); group 2, one dose of ipratropium; group 3, no ipratropium. All patients were also treated with three doses of nebulized albuterol within 60 minutes (0.15 mg/kg per dose). Pulmonary function and clinical measures were assessed every 20 minutes for up to 120 minutes.

RESULTS

The groups were comparable at baseline. At 120 minutes, the mean percentage of predicted FEV1 improved from 33.4% to 56.7% in group 1, from 34.2% to 52.3% in group 2, and from 35.4% to 48.4% in group 3 (p = 0.0001). The differences between groups were larger in those children with a baseline FEV1 < or = 30% of the predicted value: FEV1 increased from 24.5% to 50.9% in group 1, from 25.0% to 39.8% in group 2, and from 25.9% to 36.5% in group 3 (p = 0.0001). In group 1, 38% of the patients were hospitalized after the study, 44% in group 2, and 46% in group 3 (p value not significant). However, in patients with FEV1 < or = 30%, the hospitalization rates were 27% in group 1, 56% in group 2, and 83% in group 3 (p = 0.027). There were no toxic effects attributable to ipratropium.

CONCLUSION

The addition of repeated doses of nebulized ipratropium to frequent high-dose albuterol therapy in patients with acute severe asthma is both safe and more effective than albuterol alone; its use in patients with very severe asthma may reduce hospitalizations.

Maximal expiratory flows generated by rapid chest compression following end-inspiratory occlusion or expiratory clamping in young children

Partial forced expiratory flow-volume curves obtained by the rapid chest compression technique are being widely used to assess pulmonary function in infants and young children. The aim of this study is to assess whether in this age group flow limitation is achieved with the partial forced expiratory flow-volume curve with rapid chest compression. In eight infants and young children sedated with chloral hydrate, flow-volume curves were obtained by regular rapid chest compression technique, end-inspiratory airway occlusion prior to rapid chest compression, and expiratory clamping prior to rapid chest compression. In each technique, beginning with a cuff pressure of 20 cmH2O, the cuff pressure was increased by 10 cmH2O increments until the compression pressure reached 90 cmH2O. Maximal flow-volume curves were generated by each technique. End-inspiratory occlusion prior to rapid chest compression caused higher flows over the entire phase of expiration than the regular rapid chest compression. This increase could be observed over the entire phase of expiration. Forced expiratory flow at 50% and at 75% of vital capacity (V50 and V75) with regular rapid chest compression were 207 +/- 44 ml.s-1 (mean +/- SD) and 138 +/- 59 ml.sec-1, respectively. When end-inspiratory occlusion preceded rapid chest compression, V50 and V75 increased to 283 +/- 114 and 206 +/- 61 ml.sec-1 respectively, with a mean increase in V50 of 34% and in V75 of 31%. When expiratory clamping preceded the compression, even higher expiratory flows resulted.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma carnitine levels in cystic fibrosis

Plasma carnitine concentrations were measured in 43 children and adults with cystic fibrosis (CF), and values were compared with those from normal controls. Clinically significant abnormalities of plasma carnitine concentration were not found in CF patients. The concentration of free carnitine was slightly but significantly elevated in CF patients, and the acylcarnitine concentration and acylcarnitine/free-carnitine ratio were slightly but significantly lower. Total carnitine concentrations were similar to those of controls. The CF patients did not have abnormal urinary acylcarnitines. Altered concentrations of free and esterified carnitine were not associated with nutritional status or with liver or pulmonary function.

Passive smoking and lung function in cystic fibrosis

The relationship between passive exposure to cigarette smoking and objective measures of health was examined in 340 patients with cystic fibrosis attending a large hospital-based clinic. Patients who came from households with smokers did not differ from those living in smoke-free households in terms of nutritional status, clinical scores, spirometry, or colonization with Pseudomonas. The number of cigarettes smoked in the household was not significantly related to nutritional status, clinical score, spirometry, or hospitalization. Similar results were found when children 6 to 11 yr of age were analyzed separately, except that height percentile was negatively related to the number of cigarettes smoked in the household. The effects of household exposure to cigarette smoke were further evaluated by analyzing changes in nutritional status, clinical score, and spirometry over a 15-yr period among patients whose families never, always, stopped, or started smoking during this time. Height percentile increased slightly during this interval among those whose households never smoked, whereas no change occurred among patients whose households always smoked, and a decline was seen among patients whose households quit. These differences were statistically significant. Patients whose households never smoked had consistently higher pulmonary function measurements than did patients whose families always smoked, although the differences were not statistically significant. The rates of decline were similar in these two groups. Patients whose households stopped smoking had significantly lower pulmonary functions at the end of the study than did subjects whose households never smoked.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of albuterol administered by nebulizer versus spacer device in children with acute asthma

The aim of this study was to compare the response to inhaled albuterol after administration by nebulizer with the response after administration by a metered-dose inhaler and spacer device (MDI-spacer) to children with acute asthma. In a double-blind fashion, 33 children (6 to 14 years of age) with forced expiratory volume in 1 second (FEV1) between 20% and 70% of predicted values, and who were seen in the emergency department with acute asthma, were studied. They were treated with aerosolized albuterol or placebo by MDI-spacer, followed immediately by albuterol or placebo administered by nebulizer with oxygen. The dose ratio for albuterol by MDI-spacer versus nebulizer was 1:5. Outcome measures included a clinical score, respiratory rate, arterial oxygen saturation, and FEV1, measured before and 10, 20, and 40 minutes after treatment. With the exception of heart rate (which increased in the nebulizer group and decreased in the MDI-spacer group (p < 0.05), no difference in the rate of improvement of clinical score, respiratory rate, arterial oxygen saturation, or FEV1 was noted during the 40-minute study period between children who received albuterol by nebulizer and those who received it by MDI-spacer. We conclude that spacers and nebulizers are equally effective means of delivering beta 2-agonists to children with acute asthma.

Efficacy of adding nebulized ipratropium bromide to nebulized albuterol therapy in acute bronchiolitis

Nebulized ipratropium bromide is though to be synergistic with albuterol in therapy for acute childhood asthma. Because the efficacy of ipratropium in bronchiolitis is uncertain and some infants with bronchiolitis do not respond to nebulized albuterol alone, the following study was undertaken. In this double-blind, placebo-controlled trial, 69 infants between 6 weeks and 24 months of age who exhibited the first episode of acute bronchiolitis were randomly assigned to receive either nebulized albuterol (0.15 mg/kg per dose) and ipratropium bromide (250 micrograms per dose) (group A, n = 36) or nebulized albuterol and normal saline (placebo) (group B, n = 33) for two doses, 1 hour apart. The two groups were comparable at baseline. Both therapies resulted in clinically significant improvement. However, the addition of ipratropium resulted in no additional benefit with respect to decrease in the respiratory rate (mean decreases 10.6/min vs decreases 8.6/min, P = .86), accessory muscle score (range 0 through 3) (decreases 0.92 vs decreases 0.82, z = -0.44), wheeze score (range 0 through 3) (decreases 0.94 vs 0.85, z = -0.20), oxygen saturation (increases 0.25% vs increases -0.33%, P = .86), or hospitalization rate (17 vs 10). The number of "nonresponders" and "clear responders" was also very similar in both groups. No toxicity was noted. The increase in heart rate was mild and similar in both groups (increases 6.7 vs increases 11.1). The power of the study to detect a difference between the two treatment groups in the respiratory rate change > or = 8/min is greater than 90%.(ABSTRACT TRUNCATED AT 250 WORDS)

Wheezing in infants with cystic fibrosis: clinical course, pulmonary function, and survival analysis

Wheezing is a common finding in infants with cystic fibrosis (CF). This study was undertaken to determine the prevalence of wheezing in infants with CF and to compare the clinical outcome of those who wheezed in infancy with that of those who did not. The study cohort included 229 CF patients born between 1965 and 1979 with CF diagnosed before 2 years of age. Fifty-seven (25%) had physician-documented wheezing during the first 2 years of life. Wheezing had resolved by the age of 2 years in 50% of the patients and by the age of 4 years in 75%. Although wheezing seemed to be linked to a family history of allergy and asthma, the frequency of the delta F508 mutation was similar to that of the non-wheezers. There was no significant difference in survival at the age of 13 years between the two groups. At the age of 7 years, patients who had wheezed had significantly lower forced expiratory flow rate at mid-expiratory phase (85 +/- 34% predicted) compared with those with no wheezing history (101 +/- 34% predicted). At the age of 13 years, forced expiratory volume in 1 second values was lower in the wheezing group (69 +/- 24% predicted vs 78 +/- 21% predicted), as was forced expiratory flow rate at mid-expiratory phase (56 +/- 33% predicted vs 69 +/- 30% predicted). In conclusion, although wheezing in infants with CF seems to have diminished with age, pulmonary function abnormalities were more evident at 7 and 13 years of age in the group that wheezed than in the group that did not.

Meconium ileus in the absence of cystic fibrosis

Although meconium ileus in the absence of cystic fibrosis is considered a rare event, it was found that eight of 37 (21.6%) newborn infants with meconium ileus had no laboratory or clinical evidence of cystic fibrosis.

Cystic fibrosis patients bearing both the common missense mutation Gly----Asp at codon 551 and the delta F508 mutation are clinically indistinguishable from delta F508 homozygotes, except for decreased risk of meconium ileus

The glycine-to-aspartic acid missense mutation at codon 551 (G551D), which is within the first nucleotide-binding fold of the cystic fibrosis transmembrane conductance regulator (CFTR), is the third most common cystic fibrosis (CF) mutation, with a worldwide frequency of 3.1% among CF chromosomes. Regions with a high frequency correspond to areas with large populations of Celtic descent. To determine whether G551D confers a different phenotype than does delta F508, the most common CF mutation, we studied 79 compound heterozygotes for G551D/delta F508, from nine centers in Europe and North America. Each subject was matched, by age and sex, with a delta F508 homozygote from the same center. A retrospective cohort analysis was performed on the following outcome parameters: age at diagnosis, sweat chloride, meconium ileus at birth, height, weight, weight for height, FVC, FEV1, chest X-ray score, pseudomonas colonization, pancreatic sufficiency, and Shwachman clinical score. There was less meconium ileus among the G551D/delta F508 compound heterozygotes (relative risk 0.33; 95% confidence interval .13-.86), as well as a trend toward later age at diagnosis of pancreatic insufficiency. No statistically significant difference was found between the groups for any other parameter. These results suggest that the CF genotype can be a predictor of pancreatic and intestinal phenotype. Prenatal counseling for the two genotype groups should differ only with respect to probability of meconium ileus. Clinical outcome (after survival of meconium ileus) for G551D/delta F508 compound heterozygotes and delta F508 homozygotes is indistinguishable; therefore, prognostic counseling should not differ.

Prediction of mortality in patients with cystic fibrosis

BACKGROUND

The majority of patients with cystic fibrosis die in early adulthood of lung disease. Lung transplantation is a treatment option for patients with advanced pulmonary disease, although the waiting period for organs may be as long as two years. Our purpose was to determine whether the risk of death due to respiratory failure could be predicted one or two years in advance on the basis of pulmonary function, blood gas levels, and nutritional status.

METHODS

The study cohort consisted of 673 patients followed between 1977 and 1989. In each patient, pulmonary function, blood gas levels, nutritional status, and vital status were assessed between 1977 and 1987. Cox proportional-hazards regression analysis was used to compute the relative risk of death within one or two years after particular measurements. The effects of age and sex on mortality were also included in the analysis.

RESULTS

One hundred ninety patients (28 percent) died during the study period. Overall, patients with a forced expiratory volume in one second (FEV1) less than 30 percent of the predicted value, a partial pressure of arterial oxygen below 55 mm Hg, or a partial pressure of arterial carbon dioxide above 50 mm Hg had two-year mortality rates above 50 percent. Among the laboratory measurements, the FEV1 was the most significant predictor of mortality, but age and sex were also significant in predicting risk. After adjustment for age and sex, the relative risk of death within two years was 2.0 (95 percent confidence interval, 1.9 to 2.2) for each decrement in the FEV1 of 10 percent below the predicted value. Among patients with the same FEV1, the relative risk of death was 2.0 (95 percent confidence interval, 1.5 to 2.6) in patients 10 years younger than other patients, and 2.2 (1.6 to 3.1) in female patients as compared with male patients.

CONCLUSIONS

Patients with cystic fibrosis should be considered candidates for lung transplantation when the FEV1 falls below 30 percent of the predicted value. Female patients and younger patients may need to be considered for transplantation at an earlier stage.

Controlled trial of nebulized albuterol in children younger than 2 years of age with acute asthma

To determine the response to nebulized beta 2 agonist, 28 children younger than 2 years of age who visited the emergency department during an episode of acute asthma were studied. Each subject had a previous history of recurrent wheezing episodes. They were randomly assigned to receive two administrations of either nebulized albuterol (0.15 mg/kg per dose) or placebo (normal saline) with oxygen, 1 hour apart. After two nebulizations, the albuterol-treated patients had a greater improvement in clinical status (respiratory rate, degree of wheezing and accessory muscle use, total clinical score, and arterial oxygen saturation) than the placebo group. None of the patients in the albuterol group experienced a decrease of arterial oxygen saturation of greater than or equal to 2%. It is concluded that a trial of nebulized beta 2 agonists is warranted in the treatment of acute asthma in infants and young children.

The cystic fibrosis gene and resting energy expenditure

To determine whether the increase in resting energy expenditure in cystic fibrosis is associated with the primary genetic defect (delta F508) or with declining pulmonary function, or both, we tested resting every energy expenditure prospectively in 32 male subjects (aged 7 to 39 years) who were normally nourished and had good pulmonary function. They were categorized into three genotype groups on the basis of the presence or absence of delta F508 and pancreatic function. Mean resting energy expenditure was 104% of the predicted value and was not associated with genotype. When 29 subjects with normal nutritional status but variable lung function were added to the group, there was a strong correlation between declining pulmonary function and increased resting energy expenditure. We conclude that increased resting energy expenditure in normally nourished boys and men with cystic fibrosis appears to be more closely associated with declining pulmonary function than with genotype.

Diffuse pulmonary angiomatosis

A six year old girl with diffuse pulmonary angiomatosis presented with haemoptysis and diffuse interstitial changes with bilateral pleural effusions on the chest radiograph. The lung lesion as seen on biopsy specimens (and confirmed at necropsy) consisted of bloodless, thin walled, endothelium lined channels, affecting the interstitial septae, pleura, bronchi, and adventitia of large vessels. There was no response to oral corticosteroids or a trial of cyclosphamide. This lesion may be an example of an angiogenic disease.

Pregnancy and cystic fibrosis

Despite reduced fertility, pregnancy is likely to occur with increasing frequency in cystic fibrosis in proportion to the number of patients reaching childbearing age. Thirty-eight pregnancies in 25 patients with cystic fibrosis are presented. Twelve of the 25 mothers were pancreatic-sufficient. Despite previous reports of the hazards of pregnancy in cystic fibrosis, we found that pregnancy was well tolerated by the vast majority of our patients and had little effect on their pulmonary and nutritional status. Therapeutic abortion for medical indications was required in two pregnancies. The incidence of prematurity and the neonatal mortality rate were low, and no congenital abnormalities occurred. We conclude that pregnancy can be tolerated by the majority of cystic fibrosis patients, particularly those who are pancreatic-sufficient.

Lymphocytic pneumonitis following bone marrow transplantation in severe combined immunodeficiency

Lung disease in patients with severe combined immune deficiency (SCID) undergoing bone marrow transplantation (BMT) is most commonly caused by infection. Noninfectious episodes of pulmonary disease following BMT are more frequently encountered in patients with hematologic disorders or malignancy and are probably related to ablation therapy or graft-versus-host disease (GVHD). In contrast, patients with SCID do not receive chemotherapy before an HLA-identical allogeneic BMT and they do not suffer significant GVHD. We report a patient who developed severe lung disease during the period of rapid engraftment following an HLA-identical allogeneic bone marrow transplantation. Lung biopsy showed dense lymphocytic infiltrates in the alveolar septae and no evidence of infection. Following the idea that the acute recruitment of engrafted lymphocytes may have contributed to or caused the pulmonary disease, we have attempted to suppress cellular immunity by administering high-dose methylprednisolone. The patient's lung disease rapidly improved and eventually completely resolved.

Spontaneous pneumothorax in cystic adenomatoid malformation. Unusual clinical and histologic features

Pneumothorax is a rare presentation of congenital cystic adenomatoid malformation (CCAM) in the newborn period and is presumed to be due to resuscitative measures. A previously well three-week-old baby presented with spontaneous tension pneumothorax due to CCAM. In the lung resection specimen, a malformation was seen, which in addition to the histologic changes of CCAM, showed diffuse vascular proliferation in the interstitium and lining of air space by type 2 pneumocytes. We propose that this is a new variant of CCAM rather than one of the classic three types. The unusual clinical manifestation may be related to the unusual histologic features.

Clinical-physiologic correlations in acute asthma of childhood

Seventy-one patients who presented to the emergency room with acute asthma were evaluated to determine the relationship between common clinical signs and spirometric and transcutaneous arterial oxygen saturation (SaO2) measurements. Prior to treatment, a physical examination was performed, a clinical score assigned, and pulmonary function and SaO2 were measured. Although forced expiratory volume in 1 second (FEV1) and SaO2 had strong correlation with the overall clinical score (r2 = .47, .49 respectively), many patients with low clinical scores and apparent mild clinical disease had low FEV1 values (as low as 20% predicted). Of the individual components of the clinical score (ie, heart rate, respiratory rate, pulsus paradoxus, accessory muscle use, dyspnea, and wheezing), the degree of accessory muscle use correlated most closely with lung function followed by the degree of dyspnea and wheezing. Similarly, the degree of accessory muscle use correlated most closely with SaO2 followed by dyspnea and respiratory rate. Significant correlation (r2 = .59) was found between SaO2 and FEV1, although the range of SaO2 value for a given FEV1 was wide and some patients with low FEV1 values had normal SaO2 values. These results show that although clinically apparent severe disease and hypoxemia were always associated with low FEV1, their absence does not exclude the presence of airflow obstruction. It is concluded that for the optimal evaluation of acute asthma in children in the emergency room, clinical evaluation should be used in conjunction with objective laboratory measurements.

Appendicitis in cystic fibrosis

Appendicitis is said to be uncommon and difficult to diagnose in cystic fibrosis. The clinical and radiological features in nine patients with cystic fibrosis who had appendicitis were studied. All but one of the patients had an appendiceal abscess at surgery. Four patients had a delay in diagnosis of greater than three days before the correct diagnosis was made. This delay may have been due to a more indolent presentation or because these patients were initially considered to have distal intestinal obstruction syndrome. Appendicitis should be considered in the differential diagnosis if a contrast enema demonstrates extrinsic compression of the caecum. Ultrasound, computed tomography, and gallium scans were found to be of limited help in our series.

Predicting the need for hospitalization in children with acute asthma

In an attempt to identify factors which influence the decision of physicians to admit patients with acute asthma to the hospital, we studied prospectively 200 children (age 5.6 +/- 3.1 years, mean +/- SD) presenting to our emergency room with acute asthma. The children were assessed on arrival, and on disposition from the Emergency Room by one of the investigators. After obtaining historic data, a clinical score was assigned, and oxygen saturation and pulmonary function were measured. Of the 134 (67 percent) children who were discharged home from the Emergency Room, five returned within seven days and one was subsequently admitted. The clinical score on disposition was the sole variable found to best predict the decision for hospitalization (sensitivity 73 percent, specificity 95 percent). Of the variables obtained at presentation, the resulting decision tree found the clinical score to predict the decision for hospitalization (sensitivity 79 percent, specificity 75 percent). When the individual components of the clinical score were analyzed, the degree of dyspnea, as assessed by the investigator, was chosen as the rule to predict the hospitalization decision (sensitivity 88 percent, specificity 71 percent). We conclude that the decision with respect to the need for hospitalization in acute childhood asthma, is in practice based mainly on careful clinical evaluation. Pulmonary function and SaO2 measurements, although helpful adjuncts in the assessment of acute asthma, do not appear to contribute to the identification of patients who need hospital admission.

The progressive nature of childhood asthma

Asthma is the most common chronic disease in childhood. It has been repeatedly stated that childhood asthma is a self-limiting disorder, but this is a misleading and often inaccurate generalization. Prospective studies have demonstrated that many patients who had seemingly outgrown their disease experienced symptoms again as they grew older. In addition, recent evidence suggests that, despite the lack of clinical manifestation of asthma, there is a persistence of bronchial hyperreactivity for several years. A number of epidemiologic studies have identified factors that seem to be associated with the persistence of asthma into later childhood or adult life. Information about the effects of treatment of asthma on the natural history of the disease is vital. While treatment greatly reduces the morbidity from asthma, it is not known whether early recognition and aggressive treatment of the disease have any influence on the outcome of the disease later in life.

The relation between genotype and phenotype in cystic fibrosis--analysis of the most common mutation (delta F508)

BACKGROUND AND METHODS

Both the clinical manifestations of cystic fibrosis and the genotypes of patients are heterogeneous, but the associations between the two are not known. We therefore studied blood samples from 293 patients with cystic fibrosis for the presence of the most common disease-causing mutation (delta F508) on chromosome 7 and compared the results with the clinical manifestations of the disease.

RESULTS

The prevalence of the delta F508 allele in the cohort was 71 percent; 52 percent of the patients were homozygous for the mutation, 40 percent were heterozygous, and 8 percent had other, undefined mutations. The patients who were homozygous for the mutation had received a diagnosis of cystic fibrosis at an earlier age and had a greater frequency of pancreatic insufficiency; pancreatic insufficiency was present in 99 percent of the homozygous patients, but in 72 percent of the heterozygous patients and only 36 percent of the patients with other genotypes. The patients with pancreatic insufficiency in all three genotype groups had similar clinical characteristics, reflected by an early age at diagnosis, similar sweat chloride values at diagnosis, similar severity of pulmonary disease, and similar percentiles for weight. In contrast, the patients in the heterozygous-genotype and other-genotype groups who did not have pancreatic insufficiency were older and had milder disease. They had lower sweat chloride values at diagnosis, normal nutritional status, and better pulmonary function after adjustment for age.

CONCLUSIONS

The variable clinical course in patients with cystic fibrosis can be attributed at least in part to specific genotypes at the locus of the cystic fibrosis gene.

Nebulized albuterol in acute bronchiolitis

In a double-blind, placebo-controlled trial, 40 infants between 6 weeks and 24 months of age who had a first episode of wheezing and other signs and symptoms of bronchiolitis were randomly assigned to receive either nebulized albuterol (0.15 mg/kg/dose) or placebo (saline solution) for two administrations 1 hour apart. The albuterol therapy resulted in a significantly greater improvement in the accessory muscle score (decreases 0.70 vs decreases 0.30; p = 0.03), oxygen saturation (increases 0.71% vs decreases 0.47%; p = 0.01) after one dose, and in the accessory muscle score (decreases 0.86 vs decreases 0.37; p = 0.02), respiratory rate (decreases 19.6% vs decreases 8.0%; p = 0.016), and oxygen saturation (increases 0.76% vs decreases 0.79%; p = 0.015) after two doses of the drug. The response to therapy was similar in infants younger and those older than 6 months of age. The heart rate rose slightly more in the albuterol group (increases 7.76 from baseline) versus the placebo group (decreases 6.79). There were no other side effects of the treatment. Of the 34 children from whom nasal specimens were obtained by swab for viral identification, 24 had positive test results (21 for respiratory syncytial virus, 1 for parainfluenza, 1 for paramyxovirus, and 1 for influenza A). We conclude that nebulized albuterol constitutes a safe and effective treatment of infants with bronchiolitis.

Nebulized albuterol in acute childhood asthma: comparison of two doses

Thirty-three children and adolescents from 5 to 17 years of age with moderate to severe acute asthma were given nebulized albuterol therapy in either a high (0.30 mg/kg body weight) or standard (0.15 mg/kg) dose administered at three hourly intervals in a randomized double-blind study. The high-dose hourly regimen resulted in significantly greater improvement in the forced expiratory volume in 1 second (FEV1). Furthermore, patients receiving the high dose showed a steady improvement in the FEV1 from the start to the end of the study, whereas FEV1 plateaued after the second dose in the standard-dose group. Although a rise in heart rate and a fall in serum potassium level occurred, neither of these changes nor other side effects were different in the two groups. The high-dose therapy resulted in much higher serum albuterol levels than the standard dose. There was no correlation between the drug levels and side effects or initial and subsequent FEV1. It is concluded that occasional hourly high-dose albuterol therapy should be considered for some pediatric patients with acute asthma of moderate severity, especially those who relapse between doses.

Diabetes mellitus in patients with cystic fibrosis: effect on survival

Patient data obtained from the cystic fibrosis clinic of the Hospital for Sick Children (Toronto, Canada) over the period 1977 to 1988 were analyzed to compare the diabetic and nondiabetic cystic fibrosis patients. The pulmonary function, nutritional status, and survival data for 713 patients who attended the clinic over the 11-year period are reported. Insulin-dependent diabetes was found to exist in 37 (5.2%) of 713 patients. The patient age at time of diabetes diagnosis ranged from 2 to 34 years, with a mean +/- SD of 20.0 +/- 7.4 years. Patients who died in both the diabetic and nondiabetic groups had worse pulmonary and nutritional status than the surviving patients, but there were no significant differences between the diabetic and nondiabetic groups in those who died or in those who remained alive. Survival analysis showed a similar prognosis in the diabetic and nondiabetic groups. It is concluded that cystic fibrosis patients with diabetes are, for their age, not different from patients without diabetes with respect to pulmonary function, nutritional status, and survival.

Response of acute asthma to a beta 2 agonist in children less than two years of age

The management of the young asthmatic child is still controversial and it has been questioned whether the infant and very young child with asthma respond to beta 2 agonists. We studied the response to nebulized beta 2 agonists in 43 children under the age of 2 years who presented to the emergency room with acute asthma. Clinical score and oxygen saturation were determined on admission to the emergency room and at least 30 minutes after each inhalation. The clinical score was defined as the sum of five variables (heart rate, respiratory rate, dyspnea, accessory muscle use, and wheezing), each graded as 0 or 1. The mean clinical score improved significantly after nebulized albuterol (mean +/- SD, 3.75 +/- 1.2 versus 2.80 +/- 1.65, P less than .01). Mean oxygen saturation did not change significantly (mean +/- SD, 94.8% +/- 2.85 versus 95.2% +/- 2.54). Only three patients had a decrease in arterial oxygen saturation of greater than 2% (3% in each one of them) following bronchodilator therapy. Our results suggest beta 2 inhalation to be beneficial to the majority of asthmatic children younger than 2 years of age and safe to administer. The combination of clinical score and oxygen saturation provides a simple noninvasive method of monitoring the response to therapy in young children with acute asthma.

Risk factors for Pseudomonas aeruginosa colonization in cystic fibrosis patients

In an attempt to study the association between Pseudomonas aeruginosa colonization and clinical factors present before colonization, we studied 502 patients who attended our cystic fibrosis (CF) clinic between 1975 and 1988 and who were not colonized with P. aeruginosa before the study period. Twelve percent of the patients became colonized with P. aeruginosa before the age of 1 year and 44% by the age of 7 years. In a birth cohort followed from diagnosis during the study period, 23% were colonized with P. aeruginosa before age 1 year and 67% before age 7 years. Early P. aeruginosa colonization was associated with early diagnosis of CF. Presence of meconium ileus, gastrointestinal symptoms and pancreatic insufficiency at the time of diagnosis was also associated with early colonization. There was no association between the presence of respiratory symptoms at the time of diagnosis and age at first P. aeruginosa colonization. In families in which more than one sibling had CF, the age of P. aeruginosa acquisition was similar in the first colonized and the subsequently colonized siblings. In the year before the colonization patients with P. aeruginosa who were older than 1 year had higher rates of hospitalization and spent more days in hospital compared with patients without P. aeruginosa. In conclusion most P. aeruginosa colonization occurs at a younger age than previously reported. Early age at diagnosis and presence of CF-associated gastrointestinal abnormalities increase the likelihood of earlier colonization of P. aeruginosa.

Chronic illness in infancy and parenting stress: a comparison of three groups of parents

Compared responses of parents of infants with cystic fibrosis, those with congenital heart disease, and those with healthy babies on the Parenting Stress Index. Diagnostic group differences were found mainly in the Child Domain with parents of ill infants reporting greater stress. Differences between mothers and fathers were found mainly in the Parent Domain. The groups did not differ in reports of stress arising from life events other than the target child's illness.

Pulmonary function and clinical course in patients with cystic fibrosis after pulmonary colonization with Pseudomonas aeruginosa

To evaluate the relationship between Pseudomonas aeruginosa colonization and the development of lung disease, we studied 895 patients who attended our cystic fibrosis clinic between 1975 and 1988. The prevalence of P. aeruginosa colonization was 82%. Patients who acquired P. aeruginosa in the first year of life had a similar 10-year survival rate (85%) to that in patients who were colonized between the ages of 1 and 7 years (87%), and to that in patients colonized after the age of 7 years (78%). One year before colonization, mean age, forced expiratory volume in 1 second (FEV1), forced vital capacity, and forced expiratory flow in the mid-expiratory phase were similar to those in a group of patients who remained free of P. aeruginosa. No significant change in pulmonary function variables could be demonstrated 1 year and 2 years after the colonization. The rate and duration of hospitalization did not increase in the years after P. aeruginosa colonization compared with the years before colonization. By the age of 7 years, the mean percentage of predicted FEV1 was lower by 10% in patients who were already colonized by P. aeruginosa compared with those who were not colonized (p less than 0.01). A similar reduction in FEV1 was observed at all ages from 7 to 35 years, but no precipitate rate of decline in FEV1 could be associated with P. aeruginosa colonization. We conclude that although P. aeruginosa colonization is associated with 10% lower lung function, it does not cause an immediate and rapid reduction, as has been previously reported. The clinical course and the pulmonary deterioration in cystic fibrosis after P. aeruginosa colonization is a gradual and variable process.

Childhood asthma: a rational approach to treatment

Asthma is a common, but frequently underdiagnosed and undertreated, condition in childhood. In most children, the diagnosis of asthma can be made on the basis of history, physical examination, and simple investigations. Successful management of asthma is contingent upon both patient and parents having a clear understanding of the condition, the goals, and specific details of treatment. The majority of children with asthma can be managed by avoidance of provoking factors, and suppression of symptoms with drug therapy. Drug therapy should follow a logical scheme such that a child with mild, infrequent asthma attacks would receive intermittent bronchodilator therapy, whereas a child with severe chronic asthma would ultimately be treated with maintenance steroids. Response to therapy should be assessed by serial measurement of pulmonary function. Certain features peculiar to infantile asthma demand a modified approach to the management of asthma in this age group.

Renal calcium handling in cystic fibrosis: lack of evidence for a primary renal defect

Because cystic fibrosis (CF) epithelia have ion transport abnormalities that may in part be regulated by intracellular calcium metabolism, and the kidney is actively involved in both ion transport and calcium homeostasis, we have investigated renal calcium handling in CF. Twenty-four-hour urine collections were analyzed in 34 CF patients (age 5 to 35 years) and kidney ultrasound studies were performed in 17 CF patients (age 6 months to 23 years). Renal histologic findings at postmortem examination of 14 CF patients (age 4 months to 23 years) were compared with those of 12 patients (age 11 months to 17 years) with other chronic illnesses (6 congenital heart disease, 6 malignancy). In 30 of the 34 CF patients urinary calcium excretion was normal (less than 4 mg (0.1 mmol)/kg/24 hr). Four CF patients had hypercalciuria (calcium excretion 4.4 to 8.8 mg (0.11 to 0.22 mmol)/kg/24 hr). However, these patients had other possible explanations for hypercalciuria, such as immobilization (n = 2), increased dietary sodium load (n = 1), and glucocorticoid therapy (n = 1). None of the 17 patients examined by renal ultrasonography had nephrocalcinosis. Five CF patients had histologic evidence of sparse nephrocalcinosis at autopsy. However, 6 of 12 autopsy kidney specimens from patients with other chronic illnesses and similar preterminal events also showed nephrocalcinosis. The hypercalciuria and nephrocalcinosis in CF and other chronic debilitating diseases may be explained by factors known to affect calcium handling. Our evidence does not support a primary renal defect as the basis of hypercalciuria and nephrocalcinosis in CF.

Sequential pulmonary function measurements during treatment of infantile chronic interstitial pneumonitis

Three infants with histologically confirmed chronic interstitial pneumonitis were treated with monthly intravenously administered high doses of methylprednisolone with or without daily hydroxychloroquine therapy. We applied the multiple occlusion technique to measure the static respiratory system compliance, and the end-inspiratory occlusion technique to measure passive respiratory system compliance, resistance, and time constant. When assessed by clinical criteria and pulmonary function measurements, all three patients showed improvement with this treatment. Clinical improvement was associated with an increase in respiratory system compliance as measured by both techniques (60% to 100% increase in all patients). The passive respiratory resistance and the time constant did not closely reflect the clinical course. We conclude (1) that high doses (pulses) of methylprednisolone and daily oral doses of hydroxychloroquine are effective in the treatment of infantile chronic interstitial pneumonitis and (2) that the respiratory system compliance, measured by both pulmonary function techniques, correlates well with the response to treatment and change in clinical status.

Management of asthma: a consensus statement

In developing these international guidelines there were several unifying themes in the diagnosis and simple management of childhood asthma. For the purposes of the meeting, asthma was operationally defined as 'episodic wheeze and/or cough in a clinical setting where asthma is likely and other rarer conditions have been excluded'. In making a diagnosis of asthma, a full history is a prerequisite. Additional tests are only used to support clinical impression and to provide objective evidence for therapeutic recommendations. General features of a multidisciplinary approach include an appreciation of the importance of psychosocial factors, counselling, and education. Drugs should be prescribed in a rational sequence: beta 2-stimulants for mild episodic wheeze; sodium cromoglycate for mild to moderate asthma; inhaled steroids for moderate to severe asthma; with xanthines, ipratropium bromide, and oral steroids having their place in more persistent and severe cases. Children and their parents should be reassured that if asthma is properly controlled there is no reason why the child should not lead a normal and physically active life. The management of asthma is rewarding and return to 'normal' lifestyle is nearly always possible with active participation in sporting activities.

Severe acute asthma in a pediatric intensive care unit: six years' experience

The management of children with severe acute asthma who required admission to the intensive care (ICU) of this hospital during 1982 to 1988 was reviewed retrospectively. A total of 89 children were admitted to the ICU on 125 occasions. During the study period, 24% of the patients were admitted to the ICU on more than one occasion. Prior to admission to this hospital, patients had been symptomatic for a mean of 48 hours. Although all patients had received bronchodilators before admission to hospital, only 23% of patients had received oral corticosteroids. According to initial arterial blood gas values determined in the ICU, 77% of the patients had hypercapnia (PaCO2 greater than 45 mm Hg). The pharmacologic agents used in the ICU included nebulized beta 2-agonists (100% of admissions), theophylline (99%), steroids (94%), nebulized ipratropium bromide (10%), IV albuterol (38%), and IV isoproterenol (10%). Mechanical ventilation was necessary in 33% of admissions; the mean duration of ventilation was 32 hours. Ten patients had pneumothorax; in six cases, these were related to mechanical ventilation. Three of the patients who received mechanical ventilation died, representing a mortality of 7.5%. In each of these patients, sudden, severe asthma episodes had developed at home, resulting in respiratory arrest. They had evidence of hypoxic encephalopathy at the time of admission to the ICU and eventually were declared brain dead. It was concluded that delay in seeking medical care and underuse of oral corticosteroids at home may have contributed to the need for ICU admission.(ABSTRACT TRUNCATED AT 250 WORDS)