Churg-Strauss syndrome in children: a clinical and pathologic review

Churg-Strauss syndrome is a vasculitis accompanied by asthma and eosinophilia. It is generally considered a disease of adults; occurrence in children has been reported infrequently. Here we report 2 pediatric patients with Churg-Strauss syndrome manifesting with prominent pulmonary involvement. One, a 16-year-old with a previous history of asthma, presented with pleuritic chest pain and a peripheral pulmonary nodule complicated by an eosinophilic pleural effusion. The other patient presented at age 6 with cough, weight loss, and radiographic infiltrates. Lung biopsies revealed elements characteristic of Churg-Strauss syndrome, including eosinophilic microabscesses and vasculitis. Three- and 5-year follow-up showed continued symptoms in both patients despite medical therapy. Both patients illustrate many of the typical features of Churg-Strauss syndrome. We report these cases to expand the scant knowledge about Churg-Strauss syndrome in pediatric patients and to heighten awareness that this serious disease may affect the pediatric population. The relevant literature on Churg-Strauss syndrome, with specific reference to childhood cases, is reviewed.

Membranous obliterative bronchitis: a proposed unifying model

Three adults with cystic fibrosis (one after lung transplantation) presented with fever, chest pain, and acute radiographic changes. The changes included a cavitary lesion of the lung, acute dense infiltrates, and lobar collapse. After failing conventional antibiotic therapy, the patients underwent flexible bronchoscopy. All had bronchial obstruction by a membrane that had completely occluded the bronchial orifice at the bifurcation of the bronchi. Therapeutic interventions ranged from continuing intravenous antibiotics, bronchoscopy-assisted perforation of the membrane by sharp instrumentation, and transthoracic needle-guided perforation of the membrane with subsequent stenting of the orifice. The patients recovered, but the posttransplant patient had recurrent membranous obstructions with multiple interventions. The cause and triggers of the process are unknown. Based on repeated observations of the evolution of the membranes, and histologic material from bronchoscopies, we propose a putative paradigm of the natural history of the process. We suggest that local stimuli generate a richly vascularized granulation polyp, which progresses in a "shutter-like" motion to form partial or completely obstructive membranes. The subsequent course depends on the vascular supply to the membrane. We also propose that similar processes may be the underlying pathologic events in some cases of lung abscess and necrotizing pneumonia.

Relationship between insulin-like growth factor I, dehydroepiandrosterone sulfate and proresorptive cytokines and bone density in cystic fibrosis

INTRODUCTION

Patients with cystic fibrosis (CF) are known to be at risk for early osteoporosis, and the mechanisms that mediate bone loss are still being delineated. The aim of the present investigation was to investigate if a correlation exists in these patients between skeletal measurements by dual-energy x-ray absorptiometry (DXA) and two anabolic factors, dehydroepiandrosterone (DHEA) and insulin-like growth factor I (IGF-I), and proresorptive factors such as the cytokines interleukin-1beta, tumor necrosis factor alpha, and interleukin-6.

METHODS

We studied 32 outpatients (18 females; mean age: 26.2+/-7.9 years) at a tertiary care medical center. The subjects had venous samples obtained, underwent anthropometric and bone mineral density (BMD) measurements, and completed a health survey. Serum IGF-I concentrations were below the age-adjusted mean in 78% of the participants, and DHEA sulfate (DHEAS) concentrations were low in 72%. Serum concentrations of all cytokines were on the low side of normal; nonetheless, there was a modest inverse correlation between IL-1beta and BMD at all sites.

RESULTS

In univariate analyses, IGF-I and DHEAS were significant correlates of BMD or bone mineral content. In final multivariate models controlling for anthropometric and other variables of relevance to bone density, only IGF-I was identified as a significant independent skeletal predictor. While alterations in DHEAS, IGF-I, and specific cytokines may contribute to skeletal deficits in patients with CF, of these factors a low IGF-I concentration appears to be most strongly correlated with BMD.

CONCLUSIONS

These findings may have therapeutic implications for enhancing bone density in these patients.

Head circumference and chronic positive pressure ventilation in children: a pilot study

METHODS

We reviewed the cases of 11 children <12 years of age with complex medical conditions and respiratory failure requiring chronic positive pressure ventilation (CPPV). We conducted a within-group comparison of average head circumference (HC) percentiles with each child's age-expected 50th percentile value and a between-groups comparison with children with no history of ventilation. We examined the relationship between HC, peak levels of positive inspiratory pressure (PIP), and length of time on CPPV.

RESULTS

We found that children on CPPV had an average HC value at the 71st percentile, significantly greater (p=0.009) than the age-expected 50th percentile; that children on CPPV had a greater (p=0.003) average HC percentile compared with children with complex medical conditions not on CPPV; and that peak levels of PIP had a moderately strong correlation to HC (r=0.689, p=0.019).

CONCLUSION

We conclude that children on CPPV have larger than expected HC and HC appears related to the peak level of PIP. Research to further investigate the relationship between HC and CPPV in children appears to be warranted.

Congenital absence of the right upper lobe bronchus with double segmental tracheal bronchi

A multidisciplinary approach revealed an absent right upper lobe bronchus and atretic bronchioles in a child with recurrent pulmonary infections. Use of a multidimensional computed tomographic scan and bronchoscopy clearly delineated the anatomical aberration. The child underwent an uncomplicated right upper anterior segmentectomy with an expedient recovery.

Dornase alpha and exhaled NO in cystic fibrosis

Nitric oxide (NO) that is produced within the airways can be measured in the exhaled air. Concentrations of exhaled NO (FENO) are decreased in cystic fibrosis (CF) and, in cross sectional studies, have been shown to be even lower in patients with more advanced pulmonary disease. This may result from retention and metabolisation of NO within viscous airway secretions. Treatment with recombinant human DNase I (dornase alpha) modifies the rheological properties of airway secretions and thereby improves pulmonary function even in young and apparently healthy patients with CF. We studied FENO and pulmonary function in children with CF with little clinical evidence of lung morbidity in a two-year randomized double-blind placebo-controlled study with nebulized dornase alpha. Mean age at enrollment was 8 years (range 6 to 11 years), mean forced vital capacity (FVC) was 112% (range 86 to 133%), and mean forced expiratory volume in one second (FEV1)was 109% (range 88 to 128%) of predicted values. In five of six (83%) of the dornase alpha treated patients, FENO changed in parallel to changes in pulmonary function tests while no such correlation was observed in any of the eight patients receiving placebo. This difference between treatment groups was statistically significant for both FVC (P = 0.026, Wilcoxon-test) and FEV1 (P = 0.042). These data suggest that FENO may serve as a surrogate measure for evaluating the effectiveness of interventions that affect airway clearance in CF.

Treatment with tobramycin solution for inhalation reduces hospitalizations in young CF subjects with mild lung disease

Our objective was to study the effect of tobramycin solution for inhalation (TSI; TOBI, Chiron Corp.) on lung function decline rate in 400 young persons with cystic fibrosis (CF) and mild lung disease. Effects on hospitalization, antibiotic use, school days missed, and nutritional status also were determined. This was an open-label, randomized (stratified by sex and age group, i.e., 6-10 and 11-15 years), parallel-group, multicenter study. Routine subject management (control group) was compared to routine management plus 28 days of twice-daily TSI inhalation, followed by 28 days off the drug (TSI group) for 56 weeks. Primary efficacy endpoints included rate of lung function decline (as measured by forced expiratory volume in 1 sec; FEV(1)), hospitalization, and concomitant antibiotic use. Safety was assessed by analysis of treatment-emergent adverse events. Only 184 of 400 planned subjects were recruited and randomized (93 to the TSI group, and 91 to the control group). Enrollment was ended after 2 years because of difficult recruitment. An interim safety review showed a 2.42-fold risk of respiratory hospitalization for control group subjects (P = 0.020), and the study was terminated. Sixty-three subjects (34.2%) completed the entire study (30 in the TSI group, or 32.3%; and 33 in the control group, or 36.3%). Significantly fewer TSI subjects were hospitalized for worsening of respiratory symptoms (11.0% vs. 25.6%; P = 0.011), and fewer TSI subjects were hospitalized overall (16.5% vs. 27.8%; P = 0.065). Fewer TSI subjects received antibiotics other than the study drug (78.0% vs. 95.6%), and significantly fewer received oral antibiotics (76.9% vs. 91.1%; P = 0.009). No other safety or adverse event differences were observed. In conclusion, significant reductions in respiratory hospitalizations, concomitant antibiotic use, and a trend towards improvement in percent predicted forced expiratory flow (FEF(25-75)) provide evidence of a clinical benefit of TSI use in young persons with CF and mild lung disease. An effect on lung function decline rate could not be evaluated as planned, due to inadequate enrollment and early study termination.

CF: an X-ray database to assess effect of aerosolized tobramycin

This paper assesses the effectiveness of aerosolized tobramycin (TOBI) on cystic fibrosis (CF) lung disease, using a radiologic tool. The published tool, the age-based severity curve (ABS), is derived from Brasfield scoring of chest X-rays (CXR). This study evaluates both the usefulness of the ABS as an assessment tool and the effectiveness of TOBI. Thirty-eight patients were treated with TOBI. Twenty-four treated with dornase alfa were excluded. Fourteen patients, aged 2 months to 22 years (mean, 17 months of TOBI treatment), comprised the study group. Radiographs were obtained over a mean of 7.8 years (SD = 6.5 years; range, 9 months-18 years). Two hundred and eighty-two CXR of TOBI patients were analyzed following the ABS protocol. Rate of decline in radiologic status of the TOBI group and ABS were compared. Also, TOBI was assessed by comparing rate of decline before and after initiation of treatment. The TOBI group's radiologic assessment was compared to its rate of decline in pulmonary function studies and published population data. Rate of decline in ABS was 0.175 Brasfield points/year vs. 0.150 points/year in the TOBI group (P < 0.001). Before treatment, the TOBI group's rate of decline was 0.169 Brasfield points/year; after treatment, it was 0.150 points/year (P = 0.02). Forced vital capacity revealed a statistically significant slowing in rate of decline on TOBI. Although not statistically significant, rate of decline in forced expiratory volume at 1 sec showed a similar trend. The degree of slowing in decline is similar to that previously reported for pulmonary function studies.

Pulmonary exacerbations in cystic fibrosis

The clinical characteristics most relevant to the decision to treat for a pulmonary exacerbation with antibiotics in cystic fibrosis patients were determined. Variables including age, increased cough frequency and sputum production, new crackles and wheezing, asthma, symptomatic sinusitis, hemoptysis, decreased lung function, weight loss, and new acquisition of Pseudomonas aeruginosa were collected in a large prospective multicenter database (Epidemiologic Study of Cystic Fibrosis). During a 12-month baseline period, data from 11692 patients were compared with data collected during the subsequent 6-month study period. Because pulmonary function assessments were unavailable for patients <6 years of age, separate analyses were done for those <6 and >or=6 years of age. The outcome of interest was any antibiotic treatment in the 6-month study period reported as indicated for an exacerbation. Characteristics with the most discriminatory power were determined using stepwise multiple logistic regression. For patients <6 years of age, the strongest independent associations with treatment for a pulmonary exacerbation were new crackles, increased cough frequency, decline in weight, and increased sputum production. For those patients >or=6 years of age, the strongest independent associations were a relative decrease in percent predicted forced expired volume in 1 sec, increased cough frequency, new crackles, and hemoptysis. The presence of three or more of these key characteristics was strongly associated with the occurrence of a treated exacerbation. The reproducibility of the model over time was confirmed by application to a subsequent set of data. This model has potential for use as an outcome measure in clinical trials, and to assist in treatment decisions for individual patients.

Maximal expiratory flow at FRC (V'maxFRC): Methods of selection and differences in reported values

We compared three methods of reporting maximal expiratory flow (V'maxFRC) measured in partial expiratory flow-volume curves (PEFVCs) at the point of functional residual capacity (FRC). PEFVCs were obtained with the rapid thoracoabdominal compression technique (RTC) on a total of 446 occasions in 281 HIV-negative, asymptomatic infants (4.8-28.1 months old). Three different expressions of V'maxFRC were recorded: 1) the highest measured flow (maxV'FRC), 2) the mean of the three highest flows (mean3V'FRC), and 3) the flow at FRC in a composite curve (compV'FRC) consisting of PEFVCs, obtained at different jacket pressures and superimposed at their distal limb. The numerical value of maxV'FRC was 7.4% (+/-5.6%) higher than the mean3V'FRC, and 11.9% (+/-17.7%) higher than the compV'FRC; the mean3V'FRC was 5% (+/-18.3%) higher than the compV'FRC. Bland-Altman analysis was used to evaluate the agreement between the three indices. The mean difference and 95% limits of agreement were: maxV'FRC -mean3V'FRC, 14 +/- 18 ml/sec; maxV'FRC - compV'(FRC), 23 +/- 58 ml/sec; and mean3V'(FRC) - compV'(FRC), 10 +/- 52 ml/sec. The differences between the slopes of the three indices (regressed against height) were statistically significant, although clinically unimportant. We conclude that despite their high correlation, the mean3V'FRC and maxV'FRC should not be used interchangeably, and that the composite analysis, although useful, does not improve the reproducibility of V'maxFRC, and thus it cannot be recommended for routine use in its current form.

Perspectives of patients with cystic fibrosis on preventive counseling and transition to adult care

The purpose of this study was to investigate how adolescents and adults with cystic fibrosis (CF) view preventive counseling and their transition to adult-centered care within a children's hospital. Thirty-two patients >/=16 years old diagnosed with CF were recruited from a pediatric tertiary care setting. During face-to-face interviews, patients were asked 27 structured questions and completed a 30-item self-administered questionnaire on preventive counseling by healthcare providers and on transition issues. The median age of patients was 25.5 years (range, 16-43 years); 69% of patients identified a pulmonologist as their "main doctor," even though 78% had a primary care provider. Participants felt that 13-16 years of age was the best time for them to begin spending time alone with their main doctor. Less than half of the participants recalled receiving preventive counseling during the previous 12 months, and more patients wanted to discuss issues than actually did. Qualitative data emphasized the importance of independence in making decisions in healthcare and establishing relationships with providers, and many patients did not desire to transfer care to an adult hospital. Participants identified adult-focused services such as inpatient rooms, discussion groups, work options, and social service support that would enhance care. In conclusion, the majority of adolescent/young adult patients with CF receiving care in a pediatric institution reported satisfaction with their healthcare. However, patients identified preventive issues that they desired to be more regularly addressed, starting in early adolescence, and changes in the delivery of services to enhance transition to adult-oriented care. This study underscored the understanding of the integration of transition planning into the facilitation of healthcare decision-making by the adolescent in issues of self-care, sexuality, education, and finances. Future initiatives to enhance the care of patients with CF should provide training of pulmonologists in preventive care and increased attention to helping patients utilize appropriate primary-care services during the adult years. In addition, prospective studies are needed to compare outcomes of CF patients who have transitioned and transferred to adult hospitals and those transitioning to adult-oriented services in a pediatric institution.

Iatrogenic pleuropulmonary charcoal instillation in a teenager

Activated charcoal given through a nasogastric tube is a standard intervention for many types of toxic ingestions in the emergency department. This case study describes a teenage girl whose multidrug overdose was complicated by accidental charcoal instillation into her left lung and pleural space through a misplaced nasogastric tube. The ensuing empyema did not respond to antibiotic therapy alone, probably due to the inherent properties of charcoal, and required a chest tube placement with continuous irrigation. Unlike previously reported cases, this patient did well clinically, without long-term morbidity.

Outcomes of primary image-guided drainage of parapneumonic effusions in children

OBJECTIVE

To assess the outcome of image-guided needle aspiration when compared with image-guided percutaneous catheter drainage in the management of parapneumonic effusions in children.

METHODS

A retrospective chart review was conducted of the medical records, microbiology, and radiology reports of 67 children who presented with parapneumonic effusions and underwent primary image-guided drainage between April 1, 1995, and April 1, 2000.

RESULTS

Thirty-four patients had aspiration only, and 33 patients had pigtail catheters placed. The 2 drainage methods had similar median length of stay and complication rates. The reintervention rate in this study was 27% (18 patients). Children who underwent primary aspiration without catheter placement had significantly higher rates of reintervention. Method of drainage, pH lower than 7.2, and loculation of the fluid collection were independent predictors of reintervention. A low glucose level was an additive predictor of reintervention when the pH was low.

CONCLUSIONS

Aspiration and catheter drainage of parapneumonic effusions had similar complication rates and lengths of stay, but children who underwent primary aspiration had significantly higher reintervention rates, particularly when pH and glucose levels were low. Therefore, primary catheter placement for parapneumonic effusions should be considered in children who undergo diagnostic thoracentesis. The decision regarding tube placement could be facilitated by the on-site availability of a pH meter and a glucometer.

Levalbuterol hydrochloride

Racemic albuterol, a commonly used bronchodilator, is an exact 50:50 mixture of two enantiomers, R- and S-albuterol. Concern regarding increased mortality associated with the use of this beta-2 (beta 2) agonist triggered the study of both of these enantiomers separately. In vitro studies suggest that the two enantiomers have different binding affinities for beta-adrenoreceptors, may exert opposing effects on inflammation, demonstrate different effects on mucocilary transport, and display differing pharmacokinetics. Clinical studies comparing both enantiomers are few, of short duration, and often in small patient populations, and their results vary. R-albuterol has greater bronchodilatory effects than the racemate and may have anti-inflammatory properties. S-albuterol has markedly less affinity for the beta-adrenoreceptor. It was found to cause bronchoconstriction in animal models, but neither bronchoconstrictive nor pro-inflammatory effects have been conclusively demonstrated in human studies. The data available at present, while suggestive, are insufficient to conclusively recommend R-albuterol over the racemate. Further basic research and investigations in humans comparing both enantiomers at increasing doses over longer time periods are required to clarify the precise roles of R- and S-albuterol.

Respiratory diseases in the first year of life in children born to HIV-1-infected women

Our objective was to describe the respiratory complications, clinical findings, and chest radiographic changes in the first year of life in infected and uninfected children born to HIV-1-infected women. We prospectively followed a cohort of 600 infants born to HIV-1-infected women from birth to 12 months in a multicenter study. Of these, 93 infants (15.5%) were HIV-1-infected, 463 were uninfected, and 44 were of unknown status prior to death or loss to follow-up. The cumulative incidence ( +/- SE) of an initial pneumonia episode at 12 months was 24.1 +/- 4.7% in HIV-1-infected children compared to 1.4 +/- 0.6% in HIV-1-uninfected children (P < 0.001). The rate of Pneumocystis carinii pneumonia (PCP) was 9.5 per 100 child-years. The HIV-1 RNA load was not higher in the group that developed pneumonia in the first year vs. those who did not. Children who developed lower respiratory tract infections or PCP had increased rates of decline of CD4 cell counts during the first 6 months of life. Lower maternal CD4 cell counts were associated with higher rates of pneumonia, and upper and lower respiratory tract infections. The rates of upper respiratory tract infection and bronchiolitis/reactive airway disease in infected children were not significantly different than in uninfected children. At 12 months, significantly more HIV-1-infected than uninfected children had tachypnea and chest radiographs with nodular and reticular densities. There was no relationship between cytomegalovirus infection in the first year of life and radiographic changes or occurrences of pneumonia. In conclusion, despite a low incidence of PCP, rates of pneumonia remain high in HIV-infected children in the first year of life. The incidence of pneumonia in uninfected infants born to HIV-1-infected mothers is low. Chest X-ray abnormalities and tachypnea suggest that subacute disease is present in infected infants. Further follow-up is warranted to determine its nature.

Forced expiratory flow in uninfected infants and children born to HIV-infected mothers

The Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted HIV (P(2)C(2) HIV) Study is a multicenter study examining pulmonary and cardiac outcomes in offspring of HIV-infected mothers. This portion of the P(2)C(2) study tests the hypothesis that infants exposed to, but uninfected by, maternal HIV have normal maximal expiratory flow at functional residual capacity (V'max,(FRC)). We obtained 500 measurements of V'max,(FRC) by rapid thoracic compression in 285 children ages 6-30 mo in five U.S. centers. The data were compared with those from a healthy cohort of children described elsewhere. V'max,(FRC) rose with height in a linear relationship. The slope of the regression line in the exposed infants did not differ statistically from the slope in the comparison group, but the intercept was about 20% lower (p < 0.001). Height and weight were comparable in the two cohorts, and the differences between intercepts persisted after adjusting for birth weight and gestational age. However, maternal HIV infection cannot be assumed to be the cause as the cohorts may have differed in other variables, such as socioeconomic status and frequency of maternal smoking and drug use. Also, measurements varied substantially within and between our five centers, probably in part because of different racial and ethnic distributions. In summary, maternal HIV infection probably has only a modest effect, if any, on maximal expiratory flow at functional residual capacity in uninfected infants.

Human immunodeficiency virus-related mortality in infants and children: data from the pediatric pulmonary and cardiovascular complications of vertically transmitted HIV (P(2)C(2)) Study

OBJECTIVES

To identify the causes of mortality in children with vertically transmitted human immunodeficiency virus (HIV) infection and to study age-related mortality trends.

METHODS

In the multicenter P(2)C(2) HIV Study, 816 children born to HIV-infected mothers were followed for a median of 3.6 years. Two hundred five study participants with HIV infection were enrolled at a median age of 23 months; 611 were enrolled either prenatally or in the neonatal period before their HIV infection status was known. There were 121 deaths in study patients. The cause of death for all patients, its relationship to HIV infection, and pulmonary or cardiac involvement were determined. Age trends in disease-specific mortality were summarized for the HIV-related deaths.

RESULTS

Ninety-three children died of HIV-related conditions. Infection was the most prevalent cause of death for children under 6 years of age with 32.3% caused by pulmonary infection and another 16.9% caused by nonpulmonary infection. The frequency of pulmonary disease as the underlying cause of death decreased significantly with increasing age: 5/9 (55.6%) by age 1, 1/12 (8.3%) after age 10 years. The frequency of chronic cardiac disease as the underlying cause increased with age-0% by age 1 year, 3/12 (25.0%) after age 10 years, as did the frequency of wasting syndrome with disseminated Mycobacterium avium complex-0% by age 1 year, 6/12 (50.0%) after age 10 years.

CONCLUSIONS

Children with HIV who survive longer are less likely to die of pulmonary disease or infection and more likely to die of cardiac causes or with wasting syndrome.pediatric acquired immunodeficiency syndrome, mortality, human immunodeficiency virus.

Reproductive and sexual health in males with cystic fibrosis: a case for health professional education and training

PURPOSE

To survey the attitudes and clinical practice of health professionals to identify current practice and possible barriers to discussion of sexual and reproductive health issues in adolescent males with cystic fibrosis (CF).

METHODS

An interview schedule was developed to seek information about attitudes to reproductive and sexual health in males with CF and to elicit details of reported professional practice of health care providers from four CF centers in Massachusetts.

RESULTS

Of 32 health professionals interviewed, 66% informed parents about male infertility soon after diagnosis in infancy; 22% of those not informing parents at this time waited until later childhood or adolescence; and 12% reported they did not discuss these issues with parents during childhood or adolescence. All respondents reported they discuss infertility with male adolescents. The mean age thought most appropriate to discuss infertility was 13.8 (+/-2.2) years, although most do so at 15.2 (+/-2.8) years (p <.05). Fifty percent report routinely discussing that sexual performance is not affected by CF; 38% discuss the importance of condom use; 50% discuss normal sexual performance; 13% offer semen analysis to adolescents; and 3% inform males about small-volume ejaculates. Reproductive options are discussed with adolescents by 19% of clinicians. The themes of embarrassment, insufficient time, the difficulty of finding the "right" time, and insufficient training were identified as barriers to these discussions.

CONCLUSIONS

Greater training for health professionals in the reproductive and sexual health issues of CF is a step to more complete, timely, and comfortable discussion of this area of health care.

Passive respiratory mechanics: the occlusion techniques

The aim of this position paper is to define quality control and acceptance criteria for measuring passive respiratory mechanics in infants using the occlusion techniques to ensure that valid results are obtained. These guidelines cover numerous aspects including: 1) terminology and definitions; 2) equipment; 3) data acquisition; 4) data handling and analysis; 5) reporting of results. Adherence to these guidelines should ensure that measurement of passive respiratory mechanics in infants in different lung function laboratories could be performed with an acceptable degree of safety, precision, and reproducibility. This will facilitate multi-centre collection of data and performance of clinical investigations.

Thoracoabdominal compression and respiratory system compliance in HIV-infected infants

The thoracoabdominal compression technique (TAC) is used to measure expiratory flow in infants. We investigated whether TAC caused a change in total thoracic compliance (Crs), resistance (Rrs), and respiratory system time constant (Trs). We studied 41 infants (mean age, 12.4 mo; SD, 7.5) from five centers studying longitudinal lung and cardiovascular function of infants from HIV-infected mothers. We measured Crs, Rrs, and Trs before and after TAC. Changes in Crs, Rrs, and Trs after TAC were not dependent on the length of time since TAC. Crs and Trs were reduced after TAC, p = 0.013 and p = 0.003, respectively, whereas Rrs did not change. When compared with uninfected infants, HIV-infected infants had a larger post-pre TAC percent decline in Crs (p = 0.003) and a post-pre TAC rise in mean Rrs (p = 0.03). These differences remained significant after adjusting for sex and age. When performing infant pulmonary function testing, TAC itself produces a temporary decrease in Crs and Trs that is more significant in infants at risk for abnormal lung volume or compliance. Therefore, the sequence of performing the infant lung function parameters should be the same each time the testing is repeated with TAC as the last parameter tested at each testing session.

Mycobacterium abscessus infection in cystic fibrosis. Colonization or infection?

We present a case of a patient with cystic fibrosis who was thought to be colonized with Mycobacterium abscessus for 13 yr prior to developing clinically apparent mycobacterial infection. However, histologic evidence indicated that invasive mycobacterial disease was present from the onset. While accepting that chronic endobronchial colonization with atypical mycobacteria may occur in patients with cystic fibrosis, the repeated isolation of mycobacteria from the sputum of these patients should alert the clinician to the possibility of indolent disease. Early consideration of treatment for this infection should occur in any patient with cystic fibrosis in whom there is an unexplained deterioration in lung function. The recent introduction of high dose ibuprofen raises concerns about its possible contribution to the progression of the infection.

Epidemiologic study of cystic fibrosis: design and implementation of a prospective, multicenter, observational study of patients with cystic fibrosis in the U.S. and Canada

Cystic fibrosis (CF) is a complex illness characterized by chronic lung infection leading to deterioration in function and respiratory failure in over 85% of patients. An understanding of the risk factors for that progression and the interaction of these factors with current therapeutic strategies should materially improve the prevention of this progressive lung disease. The Epidemiologic Study of Cystic Fibrosis (ESCF) was therefore designed as a multicenter, longitudinal, observational study to prospectively collect detailed clinical, therapeutic, microbiologic, and lung function data from a large number of CF treatment sites in the U.S. and Canada. The ESCF also serves an important role as a phase-IV study of dornase alfa. To be eligible for enrollment, subjects must have the diagnosis of CF and receive the majority of their care at an ESCF site. In this paper, the authors present the ESCF study design in detail. Further, enrollment data collected at 194 study sites in 18,411 subjects enrolled from December 1, 1993 to December 31, 1995 are presented in summary form. This comprehensive study is unique in the detail of clinical data collected regarding patient monitoring and therapeutic practices in CF care. Two companion articles present data regarding practice patterns in cystic fibrosis care, including data on resource utilization and prescribing practices.

Thoracoabdominal asynchrony and ratio of time to peak tidal expiratory flow over total expiratory time in adolescents with cystic fibrosis

Thoracoabdominal asynchrony (TAA) and the ratio of time to peak tidal expiratory flow over total expiratory time (TME/TE) have been used to assess airway obstruction in infants and adults. We obtained these measurements using calibrated respiratory inductance plethysmography (RIP) on 15 adolescents and young adults with cystic fibrosis (CF) and varying disease severity. The measurements were then compared to 15 normal age-matched controls. TAA was expressed as a phase angle (phi) calculated from the abdominal (AB) and ribcage (RC) signals acquired from scalar strip chart recordings. Using CODAS (DATAQ Instruments, Akron, OH) software, the analog signals were digitized, and the differentiated sum (AB + RC) signal was used to calculate TME/TE. Forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1) were obtained using RIP in all subjects. Subjects with CF had a significantly higher mean phi than the control subjects (15 degrees vs. 8 degrees, respectively, P = 0.01). In the CF patients the specificity of a high phi as an indicator of abnormality was 80%, while the sensitivity was 65%. There was no correlation in the magnitude of phi and disease severity as assessed by FVC or FEV1. There was no significant difference in TME/TE between the groups. We conclude that RIP-acquired phi, but not TME/TE, is a simple and useful method to detect the presence of airway obstructive disease. We speculate that the sensitivity of this method will increase in younger patients with more compliant chest walls and less air trapping. Longitudinal studies of phi in infants and young children with lung disease could help in assessing disease severity and progression in this population, in whom repeated measures are few and complex.

Allergic bronchopulmonary aspergillosis in cystic fibrosis: reported prevalence, regional distribution, and patient characteristics. Scientific Advisory Group, Investigators, and Coordinators of the Epidemiologic Study of Cystic Fibrosis

OBJECTIVES

Using the large database from the Epidemiologic Study of Cystic Fibrosis (ESCF), the objectives of this study were to (1) estimate the reported prevalence of allergic bronchopulmonary aspergillosis (ABPA) in patients with cystic fibrosis (CF); (2) compare reported prevalence rates across geographic regions; (3) compare reported prevalence rates between patient subgroups based on demographic and disease characteristics; and (4) describe the ABPA group with regard to their sex, age, and disease severity.

STUDY DESIGN

All patients > or = 5 years of age enrolled in ESCF between December 1993 and May 1996 were eligible. Criteria for the diagnosis of ABPA were defined by the ESCF guidelines. Prevalence rates for ABPA were calculated, and potential risk factors for the diagnosis of ABPA were analyzed, including sex, age, pulmonary function, diagnosis of asthma, presence of wheeze, and positive respiratory culture for Pseudomonas.

RESULTS

There were 14,210 eligible patients enrolled in ESCF during this period, and ABPA was diagnosed in 281 patients (2%). Regional prevalence varied from 0.9% in the Southwest to 4.0% in the West. Increased prevalence rates occurred in female patients, the adolescent age group, and subjects with lower lung function, wheeze, asthma, and positive Pseudomonas cultures. Although most ABPA patients had evidence of airway obstruction, 10% had an FEV1 of > 100% of predicted. The rates of wheeze (17%) and asthma (30%) were lower than expected in the ABPA group.

CONCLUSIONS

This observational study found a reported prevalence rate of ABPA of 2% of CF patients in a large database. This rate was lower than the 5 to 15% rate reported in smaller studies, suggesting that ABPA is underdiagnosed in the CF population. There was wide regional variation in reported prevalence rates, which is unexplained at this time. The characteristics of the patients with ABPA and the epidemiologic risk factors for diagnosis of ABPA were described. Simplified diagnostic criteria were adapted for ESCF with the intent of increasing awareness of ABPA among the participants in this study.

Unexpected non-HIV causes of death in children born to HIV-infected mothers. Pediatric Pulmonary and Cardiac Complications of Vertically Transmitted HIV Infection Study Group

INTRODUCTION

A high incidence of sudden, unexplained deaths in infants born to HIV-infected mothers has been noted in several epidemiologic studies. During the course of a prospective study of heart and lung disease in children born to HIV-infected mothers, we noted that of 5 unexpected non-HIV-related deaths, 4 were attributed to traumatic events.

METHODS

The Pediatric Pulmonary and Cardiac Complications of Vertically Transmitted HIV Infection (P2C2) study is a multicenter, prospective investigation of the incidence of heart and lung disease in HIV-infected children. A total of 805 children were enrolled and followed for 5 to 7 years with serial immunologic, pulmonary and cardiac function studies. During the study, a multidisciplinary committee was formed to review the cause of death for those patients who died. The committee used results of pulmonary, cardiac, and laboratory tests, hospital summaries, as well as autopsy and coroners' reports. The committee formed a consensus about the underlying and contributing causes of death for each subject using the definitions from the 1989 US Standard Certificate of Death.

RESULTS

A total of 121 deaths occurred during the course of the P2C2 study. Of the 121 deaths, 5 were traumatic or sudden and unexpected and judged by the Mortality Review Committee to be unrelated to HIV infection. The median age at the time of death was 1.3 months and ranged from 1.2 to 37.8 months. Two infants died of trauma: a skull fracture and subdural hematoma in 1 infant and multiple skeletal fractures consistent with battered child syndrome in the other infant. The third infant died of accidental suffocation at home at 1.2 months of age. The fourth infant died suddenly and unexpectedly at home at 1.3 months of age. The autopsy showed no sign of HIV or other infection and was consistent with sudden unexpected death or SIDS. One non-HIV-related death occurred when a 38-month-old child died together with the mother in an unwitnessed drowning. The cumulative mortality rate attributable to trauma and sudden death at 4 months of age was 0.95% (95% CI: 0.02-1. 87%) and the infant mortality rate was 9.5/1000 live births. Three children were born prematurely at 30, 33, and 36 weeks' gestational age, respectively, and 3 mothers admitted using recreational drugs before or during pregnancy.

DISCUSSION

These traumatic and sudden non-HIV-related deaths accounted for 4.1% (5/121) of the deaths during the entire P2C2 study period and for 20% (4/20) of the deaths in the first year of life. Four deaths were attributable to accidental and nonaccidental trauma rather than to other common causes of infant death. One death was a sudden unexpected death, similar to SIDS, a leading cause of infant death in the United States. The majority of previously reported non-HIV-related deaths in infants born to HIV-infected mothers have been attributed to SIDS or to unexplained sudden death. In contrast with other reports, 4 of the 5 children in our series died of accidental or nonaccidental trauma and only 1 was a sudden unexplained death. It is unlikely that HIV exposure is related directly to the deaths described in this report; however, maternal HIV infection may be a marker for factors that place the child at risk for sudden or traumatic death.

SUMMARY

This report suggests that children born to HIV-infected mothers may be at increased risk for traumatic or sudden, unexplained, non-HIV-related death. These children seem to be at risk regardless of their own HIV infection status. Furthermore, 4 of the deaths in our study occurred within the first few months of life, suggesting that this is a period of increased vulnerability. Studies to identify associated risk factors for non-HIV-related deaths are needed to identify these high-risk infants. Children born to HIV-infected mothers may be more vulnerable than was recognized previously and may be in need of increased social services, especially in early infancy.

Lung abscess versus necrotizing pneumonia: implications for interventional therapy

OBJECTIVE

To assess and contrast the role of interventional therapy for two types of cavitating pneumonias: lung abscess and necrotizing pneumonia.

MATERIALS AND METHODS

We retrospectively reviewed the imaging, interventional therapy, and outcome of 14 children seen between February 1987 and January 1996 with lung abscess and 9 with necrotizing pneumonia. All children were treated with antibiotics prior to intervention. Pulmonary parenchymal fluid was percutaneously aspirated from ten lung abscesses and three necrotizing pneumonias. Percutaneous catheters drained five lung abscesses. Pleural drainage was performed for three lung abscesses and eight necrotizing pneumonias.

RESULTS

All 14 children with lung abscesses had positive Gram stains of the pulmonary fluid; 13 cultures were positive. All 14 defervesced within 48 h of intervention. None developed a bronchopleural fistula. All nine necrotizing pneumonias were presumed to be sequelae of prior pneumonia. Streptococcus pneumoniae was the only organism as documented by pleural fluid latex fixation in three patients, gram stain in two, and culture in only one. Seven of these children developed pneumatoceles, five developed bronchopleural fistulae, and three required long-term chest tubes for persistent pneumothoraces.

CONCLUSION

Aggressive interventional therapy can be diagnostic and therapeutic in the infected lung abscess. Interventional therapy can be harmful in postinfectious necrotizing pneumonia.

Cystic fibrosis: predictors of accelerated decline and distribution of disease in 230 patients

OBJECTIVE

The purpose of this study was to determine predictors of accelerated deterioration in radiographic manifestations of cystic fibrosis. The incidence and distribution of focally accentuated disease were also studied.

MATERIALS AND METHODS

From 230 patients, 3038 chest radiographs were scored using the Brasfield system. Scores were plotted against age, and a single age-based severity curve was created. Specific observations (at least one episode in the first 5 years of life of air trapping, linear markings, nodular cystic lesions, or large lesions) were assessed to determine predictors of accelerated decline in scores compared with the aggregate scores plotted in the age-based severity curve. Specific observations were noted as present or absent and graded as to severity. A specific observation was counted as present if seen on at least one occasion. (The number of occasions on which the observation was made did not affect statistical analysis.) We also evaluated the distribution of lung disease by assessing the severity and nature of disease through specific lobar distribution.

RESULTS

Males showed a slightly greater rate of radiologic decline. Early development of air trapping or bronchiectasis was associated with an accelerated rate of decline over time. Lobe-dominant disease occurred in one third of all images and in two thirds of the patients. It varied with age in its incidence, location, and etiology.

CONCLUSION

Hyperinflation or bronchiectasis that occurs before age 5 is associated with accelerated radiographic deterioration. The incidence and location of lobe-dominant disease varied with age in these patients.

Cystic fibrosis: a system for assessing and predicting progression

OBJECTIVE

This study presents a radiography-based database scoring changes over time in a large population of patients with cystic fibrosis. The purpose of this database is to provide comparison for groups of patients undergoing experimental treatment to assess effect of the treatment. The data may also be used to compare individuals with their age-matched cohorts with cystic fibrosis.

MATERIALS AND METHODS

From 230 patients, 3038 chest radiographs were scored using the Brasfield system. The scores from radiographs from all the patients were individually plotted for age, and a single age-based severity curve was created. The age-based severity curve was compared with similar curves derived from pulmonary function studies of a subset of the same patient population.

RESULTS

We found high inter- and intraobserver reliability. The difference between the observers averaged 1.3 Brasfield points, the scale of which ranges up to 25 points. The age-based severity curve was presented as mean Brasfield scores versus age (birth to > 30 years) plotted with 95% confidence limits; the curve was also plotted in percentiles. The rate of decline of this curve was similar to the decline of pulmonary function studies in this patient population.

CONCLUSION

The age-based curve, a structural anatomic parameter, differs from pulmonary function studies, which are functional. Thus the age-based severity curve provides an additional, independent basis for comparison between groups and individuals. It may be used for the initial assessment of lung disease and for gauging and predicting the rate of decline. The curve may be used as a long-range outcome criterion to evaluate new treatments in groups of patients with cystic fibrosis.

Reproductive health in males with cystic fibrosis: knowledge, attitudes, and experiences of patients and parents

Males with cystic fibrosis (CF) are generally infertile as a result of aberrant development of Wolffian duct derivitives. The personal significance of this and related reproductive and sexual health (RSH) issues is unknown. We set out to describe the knowledge, attitudes, and experiences regarding RSH in a group of adolescent and adult males with CF, as well as the knowledge and attitudes of parents. This descriptive study was based on a semi-structured interview utilizing in-depth interview techniques. Questions included aspects of knowledge, attitudes, and experiences. Adolescent (aged 14-17 years) and adult (at least 18 years) males attending the Children's Hospital Cystic Fibrosis Clinic, Boston, MA, USA, or hospitalized at the Children's Hospital over that period were eligible; the accompanying parent of the adolescent was also interviewed. Consecutive eligible males were interviewed over a 3 month period. Summary data are presented, attitudinal data are analyzed qualitatively, and a selection of representative transcript data are reported to describe the range of opinions. Fifty males (10 adolescents, 40 adults) participated; this constituted a consecutive sample of 44% of the eligible clinic population. Ninety percent of adults, 60% of adolescents, and 50% of parents knew of male infertility. The mean age (+/-SD) at which adults recalled first hearing this was 16.0 +/- 4.7 years and 13.9 +/- 1.6 years for those adolescents who knew of infertility. Nineteen (48%) of adults and 5 (83%) of adolescents first heard about infertility from their health care providers. Ninety percent reported no major distress upon first hearing about infertility during adolescence. Increasing significance of infertility with maturity was reported by 12 men (30%); only 4 adults (10%) reported that infertility was not a significant aspect of CF. Forty percent knew that males with CF have a small volume ejaculate, but none had been told this by a health care provider. Thirty percent of men had semen analysis performed and all were azoospermic. We conclude that the majority of males with CF know of likely infertility. The significance of this knowledge changes with time. Poor knowledge and confusion surround a range of RSH issues in males with CF.

Use of a rapid HPLC assay for determination of pharmacokinetic parameters of ibuprofen in patients with cystic fibrosis

High doses of ibuprofen have been shown to delay the progression of lung disease without serious adverse effects in patients with cystic fibrosis. To be effective, peak ibuprofen concentration of 50 to 100 mg/L has to be achieved. We developed an HPLC assay to rapidly determine plasma ibuprofen concentration. We used this assay to determine the pharmacokinetics of ibuprofen in patients with cystic fibrosis. The assay possessed linearity up to 500 mg/L, sensitivity to 1 mg/L, average recovery of 98%, and run-to-run precision (n = 23) of 3%. Furthermore, the assay proved to be free of interference from 51 medications. Observed time to peak concentration varied significantly between those receiving ibuprofen tablets (mean + SD, 94 +/- 29 min, n = 16) and syrup (30 +/- 0 min, n = 4) (P < 0.0001). We conclude that the method described here is ideal for therapeutic monitoring of ibuprofen.

Use of a rapid HPLC assay for determination of pharmacokinetic parameters of ibuprofen in patients with cystic fibrosis

High doses of ibuprofen have been shown to delay the progression of lung disease without serious adverse effects in patients with cystic fibrosis. To be effective, peak ibuprofen concentration of 50 to 100 mg/L has to be achieved. We developed an HPLC assay to rapidly determine plasma ibuprofen concentration. We used this assay to determine the pharmacokinetics of ibuprofen in patients with cystic fibrosis. The assay possessed linearity up to 500 mg/L, sensitivity to 1 mg/L, average recovery of 98%, and run-to-run precision (n = 23) of 3%. Furthermore, the assay proved to be free of interference from 51 medications. Observed time to peak concentration varied significantly between those receiving ibuprofen tablets (mean + SD, 94 +/- 29 min, n = 16) and syrup (30 +/- 0 min, n = 4) (P &lt; 0.0001). We conclude that the method described here is ideal for therapeutic monitoring of ibuprofen.

Vitamin A status in acute exacerbations of cystic fibrosis

Vitamin A is an essential nutrient for epithelial cell maintenance and repair, and it is known that infectious stresses may depress plasma vitamin A concentrations. Patients with cystic fibrosis are at risk for vitamin A deficiency because of fat malabsorption as well as for the inflammatory stresses of pulmonary exacerbations of their underlying disease. We therefore hypothesized that acute pulmonary exacerbations of CF would depress plasma retinol concentrations, and that these concentrations would return to baseline values when clinical symptoms improved. We prospectively studied 35 CF patients (mean age: 24.2 y) consecutively admitted with pulmonary exacerbations. Plasma retinol, vitamin E, retinol binding protein (RBP), and C-reactive protein (CRP) concentrations were measured on hospital admission and discharge. Dietary intake was measured by using a semiquantitative food-frequency questionnaire. Regression analysis was used to identify significant clinical and laboratory correlates of retinol concentrations. On admission, mean (+/- SD) concentrations of plasma retinol were 1.14 +/- 0.5 mumol/L compared with 1.70 +/- 0.6 mumol/L on discharge (P = 0.0001). Of 35 subjects, 8 (22.9%) had plasma retinol concentrations considered to be in the deficient range (< 0.70 mumol/L). Concurrently, mean concentrations of plasma RBP increased during hospital admission (from 1.46 to 2.24 mumol/L, P = 0.003), and the mean CRP concentration declined (from 25.7 to 9.8 mg/L, P = 0.002). Significant positive correlations were found between plasma retinol concentrations at admission and age, weight, body mass index, triceps-skinfold-thickness percentile, midupper arm circumference percentile, plasma vitamin E, and RBP concentration, thus suggesting that better-nourished patients had more optimal vitamin A status. At admission, plasma retinol concentrations were negatively correlated with maximum body temperature and CRP concentrations, which indicated that the body's acute-phase response was associated with the depression in retinol concentrations. We conclude that plasma retinol concentrations are depressed in acute pulmonary exacerbations of cystic fibrosis, and that concentrations considered to be in the deficient range are common. Vitamin A metabolism during acute inflammatory stress deserves further study.

Pulmonary function and clinical observations in men with congenital bilateral absence of the vas deferens

Congenital bilateral absence of the vas deferens (CBAVD) was once thought to be a distinct clinical entity, but genetic similarities in men with cystic fibrosis (CF) and CBAVD are described increasingly. We evaluated the clinical status, growth and nutritional state, and respiratory function of 18 men with CBAVD to determine whether these men with different CF transmembrane regulator (CFTR) genotypes may have clinical evidence of mild CF. Following a thorough history and examination, pulmonary function tests, sweat test, and renal ultrasound were performed. Genetic evaluation for 50 known CF mutations, screening for private mutations (single-strand conformational polymorphism and direct sequencing), and assay of the length of the polypyrimidine tract in the splice site acceptor of intron 8 was performed. A history of pulmonary disease was present in three, and an additional man had some features suggestive of malabsorption. Results of general physical examination and anthropomorphic measurements were unremarkable in all patients, with a mean (SD) body mass index of 26 (3). Pulmonary function tests of large and small airway function as well as lung volumes were normal in all except one whose results were consistent with moderate asthma. Five men were compound heterozygotes for CFTR mutations, four of whom had positive sweat tests (sweat chloride > 60 mEq/L). Twelve men were heterozygotes for CFTR mutations while no mutations were identified in one man. Although putative etiologic factors may suggest that men with CBAVD and CFTR mutations could be considered within the spectrum of clinical CF, the authors suggest that in men with CBAVD without any other clinical features of CF, the diagnosis of CF may not be made.

Aerosolized recombinant human DNase in hospitalized cystic fibrosis patients with acute pulmonary exacerbations

The goal of this study was to evaluate the safety and efficacy of recombinant human DNase (rhDNase) in hospitalized patients with cystic fibrosis (CF) experiencing acute pulmonary exacerbations. Eighty patients with documented CF were enrolled at 11 CF centers when admitted for antibiotic therapy. Patients were at least 5 yr old with a forced vital capacity (FVC) > or = 35% of predicted and an oxygen saturation > or = 90% on a fraction of inspired oxygen (FIO2) < 0.5. Patients were randomized to receive rhDNase 2.5 mg in 2.5 ml excipient twice a day (n = 43) or 2.5 ml excipient alone twice daily (n = 37) along with conventional treatment for exacerbations. Administration of rhDNase was not associated with acute adverse events or deaths, and no patients experienced allergic or anaphylactic reactions. Although forced expiratory volume in one second (FEV1) and FVC improved in both treatment groups during the double-blind period, there were no statistically significant differences in the mean change from baseline in FEV1 or FVC between the two groups. rhDNase therapy is safe and well tolerated in CF patients with acute exacerbations requiring hospitalization, but the study did not demonstrate a statistically significant therapeutic effect of rhDNase when added to a regimen of antibiotics and chest physical therapy.

Recombinant human DNase I in cystic fibrosis patients with severe pulmonary disease: a short-term, double-blind study followed by six months open-label treatment

Chronic pulmonary infection is the major cause of morbidity and mortality in cystic fibrosis (CF). Recombinant human deoxyribonuclease (rhDNase) in vitro has been shown to dramatically reduce the viscoelasticity of the sputum from CF patients. Phase II and III clinical trials have shown the drug to be safe, and that patients with a forced vital capacity (FVC) of > 40% predicted show an improvement in pulmonary function when receiving rhDNase. The current study evaluates the safety and efficacy of rhDNase in the most severly ill CF patients (FVC < 40% predicted). A double-blind, randomized, placebo-controlled trial in which patients received either 2.5 mg rhDNase twice daily or placebo for a period of 14 days followed by a 6 month open extension period (OEP) is reported. Seventy patients were recruited for the double-blind study, and 64 entered the OEP of whom 38 completed. During the OEP, all patients received 2.5 mg rhDNase twice daily. In both the double-blind period and the OEP the drug appeared to be safe. During the double-blind study, forced expiratory volume in one second (FEV1) and FVC improved in both groups but there was no statistically significant difference between the groups. In the OEP, there was mean improvement in percentage predicted FEV1 and FVC, 9 and 18%, respectively, for all patients participating. In conclusion, DNase is safe when administered in conjunction with a rigorous regimen of chest physiotherapy to severely ill patients (FVC < 40% predicted) with CF. The double-blind, 14 day study showed no significant improvement in pulmonary function but some patients may have improved after longer administration of rhDNase.

Recombinant human DNase I in cystic fibrosis patients with severe pulmonary disease: a short-term, double-blind study followed by six months open-label treatment

Chronic pulmonary infection is the major cause of morbidity and mortality in cystic fibrosis (CF). Recombinant human deoxyribonuclease (rhDNase) in vitro has been shown to dramatically reduce the viscoelasticity of the sputum from CF patients. Phase II and III clinical trials have shown the drug to be safe, and that patients with a forced vital capacity (FVC) of > 40% predicted show an improvement in pulmonary function when receiving rhDNase. The current study evaluates the safety and efficacy of rhDNase in the most severly ill CF patients (FVC < 40% predicted). A double-blind, randomized, placebo-controlled trial in which patients received either 2.5 mg rhDNase twice daily or placebo for a period of 14 days followed by a 6 month open extension period (OEP) is reported. Seventy patients were recruited for the double-blind study, and 64 entered the OEP of whom 38 completed. During the OEP, all patients received 2.5 mg rhDNase twice daily. In both the double-blind period and the OEP the drug appeared to be safe. During the double-blind study, forced expiratory volume in one second (FEV1) and FVC improved in both groups but there was no statistically significant difference between the groups. In the OEP, there was mean improvement in percentage predicted FEV1 and FVC, 9 and 18%, respectively, for all patients participating. In conclusion, DNase is safe when administered in conjunction with a rigorous regimen of chest physiotherapy to severely ill patients (FVC < 40% predicted) with CF. The double-blind, 14 day study showed no significant improvement in pulmonary function but some patients may have improved after longer administration of rhDNase.

Efficacy and safety of short-term administration of aerosolized recombinant human deoxyribonuclease in patients with cystic fibrosis

Chronic endobronchial bacterial infection evokes purulent airway secretions in patients with CF. The viscoelastic properties of these secretions is primarily due to the presence of polymerized DNA from degenerating leukocytes. Recombinant human DNase I (rhDNase) reduces the viscosity of CF sputum in vitro. To test the hypothesis that rhDNase would improve pulmonary function in children and adults with CF, we compared the efficacy and safety of 10-day administration of three doses of aerosolized rhDNase (0.6, 2.5, or 10.0 mg twice daily) in 181 outpatients using a randomized, placebo-controlled parallel design. Forced vital capacity (FVC) improved 10 to 12% (p < 0.05 to 0.001), and forced expiratory volume in one second (FEV1) improved 10 to 15% (p < 0.001) across all doses of rhDNase compared with placebo. The magnitude of effect was dose dependent for both FVC and FEV1 through study Day 21 (p < 0.001). rhDNase was associated with a decreased perception of dyspnea and an improved perception of well-being. No patients developed detectable anti-rhDNase antibodies or bronchial reactivity to rhDNase. Some patients experienced mild upper airway irritation, but no major adverse events were reported. Administration for 10 days of aerosolized rhDNase to pediatric and adult outpatients with CF improves lung function and is well tolerated. Although all three doses were efficacious, the greatest improvement in FEV1 and FEV1/FVC ratio was demonstrated in the 2.5 and 10.0 mg rhDNase treatment groups.

Comparison of unbound and total serum theophylline concentrations with those of stimulated and unstimulated saliva in asthmatic children

Unstimulated saliva, citric acid stimulated saliva, and serum were collected from 31 asthmatic children taking theophylline. Salivary theophylline concentrations, and total and unbound serum theophylline concentrations were measured. The correlation coefficients between both types of saliva, and total and unbound serum theophylline were all statistically significant (p less than 0.001). The highest correlation coefficients were obtained with stimulated saliva and total serum concentrations (r = 0.98), and stimulated saliva and unbound serum (r = 0.96). The coefficients when unstimulated saliva was compared to either total or unbound serum concentrations were 0.90 and 0.89, respectively. Serum binding of theophylline averaged 58.1%. Unstimulated saliva had a higher mean theophylline concentration than stimulated saliva. The results suggest that salivary monitoring using stimulated saliva may be used to predict serum concentrations with a high degree of confidence when the saliva levels are substantially lower than, higher than, or in the middle of the therapeutic range, but there is a considerable degree of uncertainty when the salivary values are near the lower or upper end of the therapeutic range.

Changes in the contribution of the rib cage to tidal breathing during infancy

As the shape, compliance, and deformability of the rib cage (RC) change during infancy, RC participation in quiet breathing may increase. We used respiratory inductive plethysmography (RIP) to determine the relative contributions of the RC and abdomen (AB) to tidal volume (VT) in 20 studies in 14 healthy infants 1 to 26 months of age during quiet natural sleep. RIP was calibrated with simultaneous flow measurements (anesthesia mask and pneumotachograph) by the least squares method of statistical analysis. We analyzed segments of breathing with and without flow measurement for RIP-derived VT, change in RC volume (Vrc) and AB volume (Vab) with each breath and the RC contribution to tidal breathing (%RC = Vrc/Vrc + Vab). The %RC increased with age: %RC = 1.4 age (months) + 33 (r = 0.69, p less than 0.01). After 9 months of age, %RC resembled that found in quietly sleeping adolescents. Mask placement increased VT in all but one subject (mean increase, 29 +/- 23% of baseline +/- SD; p less than 0.001, paired t test). In infants younger than 10 months of age, mask placement also increased %RC (without mask, 40 +/- 9%; with mask, 46 +/- 10% p less than 0.02). We conclude that by 1 yr of age, the RC contribution to tidal breathing during quiet sleep is similar to that of the adolescent, suggesting that major developmental changes in RC shape, compliance, and deformability take place during infancy.

Water, electrolyte, and endocrine homeostasis in infants with bronchiolitis

Twenty-two of 23 consecutive infants with bronchiolitis, 5.5 +/- 3.5 mo of age, showed a 1.9 +/- 1.4% increase in body weight, increased urinary osmolality of 737 +/- 193 mmol/L with low plasma osmolality of 275 +/- 4 mmol/L, and markedly elevated plasma antidiuretic hormone (ADH) levels of 114 +/- 225 pg/mL. Increased ADH, which usually suppresses plasma renin activity, was associated with increased plasma renin activity of 11-55 ng angiotensin 1/mL/h (normal for age less than 10 ng angiotensin 1/mL/h). Hyperaldosteronism was evident from the low fractional excretion of sodium of 0.27 +/- 0.2% and high fractional excretion of potassium of 21 +/- 15%. Serum sodium concentrations were normal. All of the pathologic findings returned to normal when the bronchiolitis subsided. A control group of 10 infants with nonrespiratory febrile illness did not show any of the above abnormalities. Thus, bronchiolitis of infancy is characterized by both increased ADH secretion and hyperreninemia with secondary hyperaldosteronism, which induce water retention but counterbalance each other with respect to serum sodium. Increased ADH secretion as well as increased plasma renin activity are not "inappropriate," but rather suggest a response to the perception of hypovolemia by intrathoracic receptors. We therefore conclude that the clinical management of bronchiolitis requires close monitoring of body wt and plasma osmolality-urinary osmolality relationship; serum sodium levels may be misleading.

Transition from dynamically maintained to relaxed end-expiratory volume in human infants

Newborn infants, in contrast to adults, dynamically maintain end-expiratory lung volume (EEV) above relaxation volume. The purpose of this study was to determine at what age children develop a breathing strategy that is relaxed, i.e., determined by the mechanical characteristics of the lung and chest wall. Forty studies were performed in 27 healthy infants and children aged 1 mo to 8 yr during natural sleep. Volume changes were recorded with the use of respiratory inductance plethysmography (RIP). The volume signal was differentiated to yield flow. Flow-volume representations were generated for a random sample of the recorded breaths to determine the predominant breathing strategy utilized, i.e., relaxed, interrupted, or indeterminate. The respiratory pattern was predominantly interrupted below 6 mo of age and predominantly relaxed over 1 yr of age. Mixed patterns were observed in children 6-12 mo of age. The number of breaths that could not be classified (indeterminate) decreased with age. Respiratory frequency measured from the sample of breaths decreased with age and was accompanied by an increase in expiratory time. We conclude that a relaxed EEV develops at the end of the first year of life and may be related to changes in the mechanical properties of the chest wall associated with growth as well as changes in respiratory timing.

Changes of time constants during infancy and early childhood

We used respiratory inductance plethysmography to record tidal respiration in 27 healthy unsedated infants and children 1 mo to 8 yr of age during sleep. Rib cage and abdominal outputs were present at approximately equal gains and summed to obtain an estimate of volume. Flow-volume curves were generated from the uncalibrated volume signal and its flow derivative. Expiratory time constants (tau) were obtained by visually drawing a line through the linear portion of the expiratory flow-volume relationship. tau increased significantly during the first 10 mo of life. After 10 mo, the estimated rate of increase of tau for older children was less than 5% of the estimated initial rate and not significantly different from zero. Prolongation of tau was paralleled by an increase in expiratory time (Te), and no changes in Te/tau were observed in the first 2 yr of life. These changes in tau likely reflect the increase in lung compliance induced by rapid alveolar growth during infancy. After the first year, expiratory time constants appear to remain relatively constant and may be consistent with balanced changes in compliance and resistance beyond infancy.

The ameliorating effect of lumbar puncture in viral meningitis

To test the hypothesis that lumbar puncture in viral meningitis results in symptomatic improvement, a group of 48 children was studied. Twenty-six patients had proved aseptic meningitis, and 22 had infections outside the central nervous system. Before and after lumbar puncture each subject was repeatedly scored for symptoms independently by the attending pediatrician and a parent. Marked symptomatic improvement in children with meningitis was demonstrated following lumbar puncture, while no significant change was demonstrated in the control group. The mechanism underlying this improvement is not clear; however, we consider a number of possible explanations.

Environmental overheating as a cause of transient respiratory chemoreceptor dysfunction in an infant

A central hypoventilatory state developed in a 6-month-old boy with environmentally induced hyperthermia. The condition subsided within 24 hours of mechanical ventilation. Hypoxic and hypercapneic challenges performed 2 weeks later showed complete resolution of the respiratory chemoreceptor dysfunction. The damage to the CNS caused by accidental hyperthermia in general, and more specifically to the respiratory center, and its possible etiologic role in the pathophysiology of sudden infant death syndrome are discussed.