Mild asthma: an expert review on epidemiology, clinical characteristics and treatment recommendations

This review is the synthesis of a working group on mild asthma. Mild asthma includes intermittent and persistent mild asthma according to the Global Initiative for Asthma (GINA) classification, and affects between 50% and 75% of asthmatic patients. Mild asthma is more frequent, more symptomatic, and less well controlled in children than in adults. Cohort studies from childhood to adulthood show that asthma severity usually remains stable over time. Nevertheless, mild asthma can lead to severe exacerbations, with a frequency ranging from 0.12 to 0.77 per patient-year. Severe exacerbations in mild asthma represent 30-40% of asthma exacerbations requiring emergency consultation. In mild asthma, inflammation and structural remodelling are constant, of varying intensity, but nonspecific. Therapy with inhaled corticosteroids (ICS) decreases bronchial inflammation, but has only a slight effect on structural remodelling, and, when stopped, inflammation immediately recurs. Permanent low-dose ICS therapy is the reference treatment for persistent mild asthma. Effectiveness is to be reassessed at 3 months, and if it is insufficient the patient is no longer considered mildly asthmatic, and treatment has to be stepped up. As mild asthma is the most frequent form of the disease, diagnosis and management require physicians' particular attention.

Asthma and allergies in schoolchildren of Maputo

AIM

The study aimed to determine prevalence and severity of asthma, rhinitis and eczema in Maputo, Mozambique.

METHODS

The International Study of Asthma and Allergies (ISAAC) protocol was applied in 27 schools in urban, suburban and semi-rural areas.

RESULTS

A total of 2630 completed questionnaires were obtained from students aged 13-14 years, and 2383 from schoolchildren aged 6-7 years. The prevalence of current asthma was 13.3% in the two groups, the prevalence of rhinoconjuctivitis and eczema was 23% and 10% in teenagers and 8.8% and 8.5% respectively in children 6-7 years old. Overall, 35% of the adolescents and 23.8% of children were found to have at least one atopic condition or asthma in the last year. In symptomatic adolescents, the conditions were: rhinoconjuctivitis (41.3%), asthma (20%) and eczema (12.4%). In symptomatic children, asthma was the principal condition (36.2%), followed by eczema (20.3%) and rhinoconjunctivitis (19.1%). In adolescents, asthma was more frequently associated with rhinoconjuctivitis (28%). About 4% of all surveyed children had three atopic conditions associated. In adolescents, past year rhinitis was more frequent and severe in the urban area. Hay fever was commoner in the semi-urban area. Eczema was significantly more recurrent in suburban and semi-rural area. Exercise-induced wheeze, nocturnal cough and ever asthma were more reported in children of suburban area.

CONCLUSION

Asthma and allergic diseases are important public health problems in Maputo and improvement in prevention and management plans are required.

Allergy to betalactam antibiotics in children: a prospective follow-up study in retreated children after negative responses in skin and challenge tests

BACKGROUND

Up to 10% of the patients in whom suspected betalactam hypersensitivity (HS) has been excluded by skin and challenge tests report suspected allergic reactions during subsequent treatments with the same or very similar betalactams. It has been suggested that the reactions may result from a resensitization induced by the challenge performed at the time of the allergological work-up. However, most patients did not undergo a second allergological work-up, to determine if the reactions resulted from betalactam HS or not.

OBJECTIVES

We aimed to determine if children diagnosed nonallergic to betalactams have tolerated subsequent treatments with the initially suspected and/or other betalactams, and, in case of a reaction, if the reaction resulted from betalactam HS.

METHODS

We sent a questionnaire concerning the clinical history of their children to the parents of 256 children previously diagnosed nonallergic to betalactams. A second allergological work-up was performed in the children reporting suspected allergic reactions during subsequent treatments with the same and/or other betalactams. Skin tests were performed with the soluble form of the suspected (or very similar) betalactams and other betalactams from the same and other classes. Skin test responses were assessed at 15-20 min (immediate), 6-8 h (semi-late) and 48-72 h (late). Oral challenge (OC) was performed in children with negative skin tests, either at the hospital (immediate and accelerated reactions), or at home (delayed reactions).

RESULTS

A response was obtained from 141 children (55.3%). Forty-eight (34%) of those children had not been treated with the betalactams for whom a diagnosis of allergy had been ruled out previously. Seven (7.5%) of the 93 children who had been treated again reported suspected allergic reactions. Skin tests and OC were performed in six of those children, and gave negative results in five children. In one child previously diagnosed nonallergic to amoxicillin associated with clavulanic acid, we diagnosed a delayed HS to clavulanic acid and a serum sickness-like disease to cefaclor. Thus, the frequency of reactions resulting from betalactam HS in children with negative skin and challenge tests is very low, and does not exceed 2.1% (2/93) if we consider that the child which refused a second allergological work-up is really allergic to betalactams.

CONCLUSION

Our results in a very large number of children show that reactions presumed to result from betalactam HS are rare in children in whom the diagnosis of betalactam allergy has been ruled out previously. Moreover, they suggest that, as shown for the initial reactions, most of the reactions during subsequent treatments are rather a consequence of the infectious diseases for whom betalactams have been prescribed than a result of betalactam HS. Finally, they suggest that the risk of resensitization by OC is very low, and do not support the notion that skin testing should be repeated in children diagnosed nonallergic to betalactams.

Sublingual immunotherapy in the treatment of children

Children with controlled intermittent mild-to-moderate asthma, controlled rhinitis and a single sensitivity may be appropriate candidates for sublingual immunotherapy (SLIT). Positive effects of SLIT may depend on initiation in early childhood and a long duration of treatment. To ensure optimum compliance, sociological, economic and familial factors should also be taken in to consideration when prescribing SLIT. Evidence from recent long-term trials indicates that SLIT interfered with the atopic march and the allergic progression from rhinitis to asthma without any severe adverse side effects. Local immune response has been seen to be blunted with SLIT, which suggests that treatment has an immunomodulatory effect. In addition, it may also decrease the risk of new sensitizations. Ongoing developments in SLIT, particularly advances in dosing and new indications, such as food allergies, will increase the use of this treatment modality in children.

[Characteristics of mild asthma: descriptive epidemiology and nature of bronchial inflammation. Position of the Mild Asthma Working Group]

INTRODUCTION

Update on the state of knowledge in the mild asthma (intermittent and persistent mild asthma, according to the GINA classification) literature, and position of a French Mild Asthma Working Group.

STATE OF THE ART

The French Mild Asthma Working Group (11 lung specialists, 4 paediatricians, 1 pharmacologist, and 1 general practitioner) selected, analysed, and summarised the literature on the epidemiology, physiopathology, clinical signs, and management of mild asthma. The present article shows the position of the working group on mild asthma descriptive epidemiology (causal factors excluded) and the nature of the bronchial inflammation. Clinical signs and medicinal treatments will be presented in a second article.

PERSPECTIVES

Between 50% and 75% of asthma patients, depending on the study, present mild asthma. Childhood-to-adulthood cohort monitoring found severity to be unchanged over developmental time. Its generally benign evolution may in some (<10%) cases be complicated by severe episodes. Inflammation and airway-wall remodelling were always found, although of variable intensity, and non-specific (except for absence of infiltration by polymorphonuclear neutrophils). Corticosteroid therapy by inhalation reduces bronchial inflammation, but with little impact on airway-wall remodelling.

CONCLUSION

The present findings should help clinicians in identifying and understanding mild asthma.

[Prospective comparison of child asthma education in the emergency department and at scheduled follow-up consultation]

OBJECTIVES

To assess asthma control in asthmatic children attending the emergency department and to compare it with that for children with scheduled specialist follow-up.

POPULATION AND METHODS

Between September 2002 and September 2003, we included asthmatic children aged 6 to 16 years, attending the emergency department (group U) or pulmonology follow-up appointments (group C) at Necker Hospital, Paris, France. We used the Asthma Therapy Assessment Questionnaire (ATAQ), completed by the parents and children aged 10 years and over.

RESULTS

We interviewed 156 families and included 144 (92%) in the final analysis (77 in group U). The 2 groups did not differ in age, sex ratio, age at onset and asthma diagnosis and the frequency of asthma attacks. Children in group U received less daily maintenance treatment (P<0.01) but reported more severe asthma (P<0.05). They had also experienced fewer investigations for their asthma (fewer lung function tests P=0.01 and allergy tests P=0.001). The children in group C had better controlled asthma, as assessed by both the children themselves and their parents. They also had fewer problems relating to the behavior, communication and treatment control domains. The assessment of children and parents were similar in all areas except communication. The children considered their communication problems to be more serious than their parents did. Age-related differences were observed, with older children's parents having more difficulties in all domains investigated.

CONCLUSION

Clinicians should consider assessing asthma control in children attending the emergency department. There is clearly an opportunity to improve the quality of asthma education for these children. Clinicians could provide children with a written plan of action for asthma attacks and information about daily self-management. Improving communication between children, their parents and doctors should be considered a key educational project.

Anaphylaxis during anesthesia: results of a 12-year survey at a French pediatric center

BACKGROUND

Following adverse reactions to anesthesia, tests are carried out to determine the mechanism of the reaction and to identify the agent responsible. No specific data are available in France concerning such skin tests in children.

METHODS

Between 1989 and 2001, we assessed hypersensitivity reactions to general anesthesia in 68 children. Thirty underwent more than one operation, for congenital malformations. Immunoglobulin (Ig)E-mediated anaphylaxis was diagnosed on skin tests combined with the clinical history.

RESULTS

Grade I, II and III reactions were observed in 20, 27 and 21 children, respectively. IgE-mediated anaphylaxis was diagnosed in 51 children: 31 (60.8%) for neuromuscular blocking agents (NMBA), 14 (27%) for latex, seven (14%) for colloids, five (9%) for opioids and six (12%) for hypnotics. Vecuronium was the NMBA causing the largest number of reactions. Cross reactivity to NMBA available in France was observed in 23 of 30 children (76%), particularly for vecuronium and atracurium or pancuronium. The estimated frequency of IgE mediated anaphylactic reactions was one in 2100 operations. Based on our results, 25 children subsequently received a different anesthetic with no adverse reaction.

CONCLUSIONS

As in adults, NMBA, then latex were responsible for most anaphylactic reactions during anesthesia. Our results confirm that skin tests with anesthetic agents are feasible and safe in children and improve the safety of subsequent anesthetic procedures.

[The role of the small airways in childhood asthma]

INTRODUCTION

Asthma, the most common chronic disease in paediatrics, is characterised by an inflammatory process involving the proximal and distal airways, with remodelling of the airways and changes in respiratory function.

STATE OF THE ART

Recent studies in children have provided evidence of damage to the small airways identical to that occurring in adults. In fact inflammatory cells as well as structural alterations of the airways have been found in both bronchial biopsies and broncho-alveolar lavage fluid in infants and young children. At the functional level this damage is manifest by a reduction in maximum expiratory flow rates between 25-75% of the vital capacity. It also shows itself by the demonstration of thick walled bronchi and hypodense bands on the high resolution CT scan. It appears that conventional inhaled treatments have no effect on the small airways. Finally the main prognostic factors for this distal damage are respiratory infections and exposure to tobacco in utero.

PERSPECTIVES

Damage to the small airways in childhood asthma indicates the need for new therapies aimed at this part of the respiratory system.

CONCLUSION

Inflammation and remodelling of the small airways develops early in an asthmatic child whose respiratory system is growing rapidly and persists throughout life.

Anti-GM-CSF antibodies in paediatric pulmonary alveolar proteinosis

BACKGROUND

Auto-antibodies against granulocyte-macrophage colony stimulating factor (GM-CSF) may be central to the pathogenesis of adult sporadic pulmonary alveolar proteinosis (PAP). The role of anti-GM-CSF auto-antibodies in paediatric forms of PAP is as yet unclear.

METHODS

Anti-GM-CSF auto-antibodies were determined with the help of an antigen capture assay using serum and/or bronchoalveolar lavage (BAL) fluid from 27 patients with PAP (nine adults, 15 children, three neonates) and from 185 children with different diseases as disease controls (various pulmonary conditions and patients with malignancies).

RESULTS

Anti-GM-CSF auto-antibodies were detected in the serum of five of seven adult PAP patients. They were not found in the serum of any of the children or neonates with PAP nor in any of the disease control patients. Raised anti-GM-CSF titres were found in BAL fluid from three of four adult patients with PAP. Anti-GM-CSF auto-antibodies were detected in BAL fluid of only one of the 15 children (age at diagnosis 11 years, age at BAL 24 years) and in none of the neonates with PAP, nor in any of the disease control patients.

CONCLUSIONS

The presence of anti-GM-CSF auto-antibodies seems to define an autoimmune disease underlying most of the adult sporadic type of PAP, but age at diagnosis may cause an overlap with children in some rare instances. In most of the children and all of the neonates the anti-GM-CSF titres were not significantly increased, indicating that alternative explanations are needed for the pathogenesis of the disease in these patients.

[Inhaled treatment for asthma in practice]

The modalities of an inhaled treatment depends on the characteristics of the aerosol, on the age of the child, and mainly on the inhalatory system. Before the age of 8 years, the pressurised metered dose inhaler must be used together with a spacer device. Above this age, the use of a breath-actuated inhaler or of a dry powder inhaler can be proposed. Demonstration and educational instructions will increase the probability of compliance and efficiency of the treatment.

[What environmental measures should be taken for the treatment of atopic dermatitis in children and the prevention of other atopic manifestations?]

The association of atopic dermatitis, asthma and allergy is frequent. Hence, it is logical to imagine that eviction of the main indoor allergens (dust mites, animal danders) would have a preventive effect on the onset and progression of atopic dermatitis and the risk of asthma. Recent epidemiological studies are generally negative with regard to primary and also secondary and tertiary prevention. Only one study appeared positive; it combined eviction of food allergens and of indoor allergens during the first year of life. Other studies are warranted to assess the interest and efficacy of eviction of inhalant allergens in atopic dermatitis.

La fibroscopie bronchique chez l’enfant

INTRODUCTION

Fibreoptic bronchoscopy (FB) is an important diagnostic examination in paediatric pulmonology. In 2002 the Paediatric Pulmonology and Allergy Club undertook a retrospective study to establish the current status of fibreoptic bronchoscopy among its members.

METHODS

In 2001 sixty five paediatric pulmonologists carried out an average of 116 examinations (+/- 111) in 35 paediatric centres. FB was performed either in an operating theatre (15 centres), a dedicated bronchoscopy suite (6 centres) or an endoscopy suite shared with gastro-enterologists (7 centres). Other examinations were performed in areas dedicated to, or associated with intensive care. General anaesthesia was routinely used in 18 centres. The others used sedation including an equimolar mixture of oxygen and nitrous oxide in 14 centres. Ten centres performed less than 50 examinations, 12 between 51 and 100, 4 between 101 and 200 and 8 centres more than 200 in the year. Seventy two per cent of the children were less than 6 years old. The washing and disinfection procedures were manual in 20 centres and automatic in 15.

RESULTS

Three principal indications were reported: persistent wheezing, suspicion of a foreign body and ventilatory difficulties. Cough, desaturation and fever were the most frequently reported side effects.

CONCLUSIONS

This is the first survey in paediatric pulmonology in France. It shows a wide variation in the practice of fibreoptic bronchoscopy in children.

Knowledge, attitudes, and behavior of the parents of asthmatic children in Maputo

Asthma is increasing in frequency worldwide. The education of affected children and their parents is fundamental for the management of the disease. The aim of our study was to describe the knowledge, attitudes, and behavior of the parents of asthmatic children. We studied 152 adults accompanying asthmatic children to consultations in the pediatrics department of Maputo Central Hospital (Mozambique). In general, knowledge about asthma was poor: 11% of the adults thought that asthma was contagious and transmitted from person to person, and 4% thought that it was transmitted by contaminated food. More than half the parents thought that the child could not lead a normal life even during the periods between attacks. A large proportion of the parents thought that asthma could be cured by medical treatment in 7% of cases and by alternative treatment in 43% of cases. The precipitating factors were well identified by the adults, but they had an inaccurate perception of the symptoms of an asthma attack. The actions of the various classes of drugs used were poorly understood. Education programs for both the children and their parents should be developed to improve the management of asthmatic children. Surveys of this type facilitate the targeting of such programs.

Risk factors for asthma among children in Maputo (Mozambique)

BACKGROUND

Few studies have looked at risk factors for asthma in African children. We aimed to identify the risk factors associated with childhood asthma in Maputo (Mozambique).

METHODS

This case-control study included 199 age-matched children (100 asthmatic and 99 nonasthmatic) who attended Maputo Central Hospital between January 1999 and July 2000. We collected information concerning their familial history of atopy, birth weight, environment and breast-feeding. Detailed information about morbidity and treatment was obtained for each asthmatic child.

RESULTS

The children were aged between 18 months and 8 years; 60% were male. The asthmatic children were hospitalized more frequently than the nonasthmatic children (P < 0.0001). Most of the asthmatic children lived in the urban area of Maputo [odd ratio (OR) = 6.73, CI = 3.1-14.0, P < 0.0001], had a parental history of asthma (OR = 26.8, CI = 10.8-68.2, P < 0.0001) or rhinitis (OR = 4, CI = 1.2-13.3, P = 0.005), had at least parent who smoked and were weaned earlier than the nonasthmatic children (OR = 2.4, CI = 1.3-4.4, P < 0.001).

CONCLUSION

Childhood asthma was strongly associated with a family history of asthma and rhinitis, the place of residence, having smokers as parents and early weaning from maternal breast milk. These results highlight the need to reassess the management of asthmatic children in Maputo.

Flexible endoscopy of paediatric airways

Paediatric fibreoptic bronchoscopy is used for ever wider indications, and increasingly used in many contexts, including paediatric and neonatal intensive care. The report of this Task Force contains an overview on the current applications of paediatric bronchoscopy. The report discusses the facilities and equipment needed for the procedure, including the newly developed bronchoscopes which are allowing intervention even in very small children. The indications of both flexible and rigid bronchoscopes in the context of newer and smaller flexible endoscopic equipment are also considered. The care of the instruments, including disinfection and sterilisation, is fully documented. Patient management is described, including the relative merits of conscious sedation and general anaesthesia, as well as special settings for the procedure, including the needs in intensive care. Special procedures, increasingly performed bronchoscopically are described. These include bronchoalveolar lavage, endobronchial and transbronchial biopsy, laser therapy, bronchography, and endoscopic intubation and drug therapy. Finally, neonatal bronchoscopy is discussed, and the ethics of bronchoscopic procedures, including bronchoscopic research in children. Advances in instrumentation, and also improved anaesthetic techniques, allow fibreoptic bronchoscopy to be safely performed in even very small, sick infants, provided proper precautions are taken.

[Latex allergy in children]

The aim of our study was to determine the prevalence of latex allergy and the clinical features of children with latex allergy.

PATIENTS AND METHODS

We prospectively investigated 243 children consulting in our allergy out-patients unit during 1 year. Parents answered a questionnaire, and children underwent skin prick tests with common allergens and latex. Latex-specific serum immunoglobulin E was determined by CAP test in children with latex sensitization. The results were compared in children with and without latex allergy.

RESULTS

The prevalence of latex allergy was 1.3%. A family history of atopy (75%) and a personal history of previous surgery was associated with latex allergy (P < 0.0001). In children with latex allergy, the frequency of sensitization to inhaled and food allergens, atopic dermatitis, rhinitis and conjunctivitis was higher than in children without latex allergy (P < 0.05). Avocado allergy was the food allergy most commonly associated with clinical symptoms. Balloon was the most common latex product causing symptoms (60%).

CONCLUSIONS

Due to its potential severe consequences, latex allergy should be investigated in children who had undergone multiple surgical procedures and in the children with pollen-food allergy syndrome. Avoidance of latex is an important preventive measure.

[Difficult asthma in children]

Difficult asthma in children is defined as the persistence of exacerbations or frequent symptoms requiring rescue bronchodilator, or persistent airway obstruction in spite of treatment with inhaled steroid >/= 800 microg/d beclomethasone or equivalent and beta-2 long acting agonist. Management of difficult asthma in children first requires to identify conditions that may mimic asthma, asthma with bad compliance to treatment, and difficult asthma in relation with avoidable factors that worsen symptoms. The pathological bases of genuine difficult asthma remain unknown. Different patterns have been described according to the cells that are involved (eosinophil, neutrophil), the degree of airway remodeling, or the distal localization of the lesions. Difficult asthma requires specialized management including airway inflammation evaluation. Studies on bronchoalveolar lavage and bronchial mucosa biopsies will perhaps help to better understand the pathophysiology and to improve the management.

Complications of flexible bronchoscopy in children: prospective study of 1,328 procedures

Complications of flexible bronchoscopy (FB) were prospectively evaluated during 1,328 diagnostic procedures in children, not in intensive care units. A total 92.8% of the procedures were performed in conscious patients under sedation and 7.2% under deep sedation. Supplementary oxygen was provided in approximately 80% of cases via endoscopic face mask (n=783) or nasal prongs (n=290). At least one complication was recorded in 91 cases (6.9%). Minor complications (n=69; 5.2%) included moderate and transient episodes of desaturation (n=15), isolated excessive coughing (n=22), excessive nausea reflex with coughing (n=20), transient laryngospasm (n=6) and epistaxis (n=6). Major complications (n=22; 1.7%) included oxygen desaturation to <90%, either isolated (n=10) or associated with laryngospasm (n=6), coughing (n=4), bronchospasm (n=1), and pneumothorax (n=1). Major complications involving oxygen desaturation were associated with age <2 yrs (13 of 529 versus 8 of 778) and laryngotracheal abnormalities (7 of 85 versus 14 of 1,222). The overall frequency of complications was similar in conscious (6.7%) but sedated patients and patients under deep (7.3%) sedation. However, the frequency of transient desaturation was significantly higher in children undergoing FB under deep sedation. Transient fever after bronchoalveolar lavage was observed in 52 of 277 cases (18.8%). Flexible bronchoscopy is a safe procedure with <2% major complications. Careful analysis of indications and clinical status for each patient, and proper anaesthesia and monitoring during the examination ensure that the procedure is successful, with a minimum of complications.

[Risk factors for early bronchiolitis at asthma during childhood: case-control study of asthmatics aged 4 to 12 years]

The group of general paediatrics of the French Paediatrics Society conducted a case-control study in order to verify the link between the occurrence of an acute bronchiolitis early during the first year of life, more specifically during the first trimester, and asthma during later childhood.

METHODS

Parents of 4-to-12-year-old children answered a questionnaire during a general paediatrics visit. Exposition was attested by a diagnosis of bronchiolitis mentioned on the personal health record of the child. Environmental factors and medical history, obtained from the parents and by checking the health record of the child, were studied using multivariate analysis.

RESULTS

Nineteen paediatricians included 80 children with asthma and 160 controls. Fifty-four per cent of asthmatic children had a medical history of bronchiolitis during the first year of life versus 17% of control children (P < 0.001). Mean age of bronchiolitis occurrence was 6.6 months in both groups (P = 0.98). Multivariate analysis showed that occurrence of bronchiolitis during the first year of life was significantly more frequent in asthmatic children (P < 0.001, OR = 5.6, IC95 = [2.6-11.6]) but this effect was not observed during the first trimester of life.

CONCLUSION

Bronchiolitis during the first year of life was significantly related to later asthma in 4-to-12-year-old children treated by general paediatricians. On the other hand, a very early bronchiolitis during the first trimester of life did not appear, in our set of data, as a contributive factor to explain asthma in later childhood.

Relationship between bronchial responsiveness and clinical evolution in infants who wheeze: a four-year prospective study

Recurrent illness involving wheezing during the first years of life is transient in most children. The role of bronchial hyperresponsiveness as a factor influencing the persistence of wheezing from infancy to school age remains unknown. In a prospective study we investigated whether infants who wheezed and subsequently developed persistent asthma differed from infants who wheezed and later became asymptomatic either in the initial degree of bronchial hyperresponsiveness or in the persistence of bronchial hyperresponsiveness with age. One hundred and twenty-nine infants with three or more wheezing episodes before 2 yr of age were followed during 4 yr with a clinical evaluation and a methacholine challenge performed every 6 mo until the child was 4 yr old and once per year thereafter. The clinical score significantly improved with time in most children. The proportion of children with persistent wheezing after 2 and 4 yr of follow-up was only 31% and 20%, respectively. Persistent wheezers had significantly lower VmaxFRC values at initial evaluation and higher SRaw values at the end of follow-up than infants who became asymptomatic. We used transcutaneous oxygen tension (PtcO(2)) to measure the response to methacholine. No significant difference in PD(15) PtcO(2) between groups with subsequently different clinical progression was observed at initial evaluation. Bronchial hyperresponsiveness persisted 4 yr later in all children but children with persistent wheezing showed significantly lower PD(15) PtcO(2) values than children who became asymptomatic, as early as 30 mo of age. However, an acceptable early PD(15) PtcO(2) cut-off point predictive for subsequent clinical progression could not be identified. The level of bronchial hyperresponsiveness in infants who wheezed was not predictive of the persistence of asthma 4 yr later.

Anaphylaxis to the 23-valent pneumococcal vaccine in child: a case-control study based on immediate responses in skin tests and specific IgE determination

Injections of the 23-valent pneumococcal vaccine are usually well tolerated. Skin tests (prick and intradermal) and a self-made RAST with pneumococcal vaccine and phenol were performed in a child reporting a severe anaphylactic reaction induced by a 23-valent pneumococcal vaccine, and in ten control children, including one child with a well-tolerated vaccination, and nine non-vaccinated children. Skin tests and RAST with the vaccine were positive in the child reporting anaphylaxis, and negative in nine of the control children. Intradermal test with the vaccine was slightly positive in a non-vaccinated child with negative RAST. Skin tests and RAST with phenol were negative in all the children. These results suggest that immediate responses in skin tests and specific IgE determination have a good diagnostic value in children reporting severe reactions suggestive of IgE-dependent hypersensitivity to pneumococcal vaccine.

Increased bronchoalveolar lavage CD8 lymphocyte subset population in wheezy infants

Episodes of wheezing are very common in infancy but, despite their high prevalence, their mechanism is still poorly understood. To better understand the airway inflammation of wheezing infants, we examined cells of the bronchoalveolar lavage (BAL), focusing on the phenotype of lymphocytes and macrophages by using cytofluorimetry. Twenty-one wheezers (mean age 15.4 months) and seven non-wheezers (mean age 24.1 months) were studied. BAL was collected at fiberoptic bronchoscopy. Total and differential cell counts were similar in both populations. Eosinophils were not detected in the BAL fluid. The cell-surface markers CD2, CD3, CD4, CD7, CD8, CD19, and CD45 were studied for the lymphocyte sub-population analysis. The cell-surface markers CD14, CD54, CD62L, and human leucocyte antigen (HLA)-DR were studied for the macrophage sub-population analysis. A significant increase in the CD8(+) lymphocyte population (p = 0.03) was observed in wheezers (median 43.1%, 25-75% percentile: 30.1-54.9%), as compared to non-wheezers (median 29.3%, 25-75% percentile: 13.5-34.7%). A significantly (p = 0.04) decreased expression of HLA-DR (mean fluorescence intensity [MFI]) was detected in the macrophage population of the wheezers (median MFI, 7,016; range 2135-7986), as compared to non-wheezers (median MFI, 8,369; range: 6478-8860). The results of the present study suggest that viral infection may have induced a CD8(+) response in BAL cells.

Cardiopulmonary exercise testing in children: an individualized protocol for workload increase

OBJECTIVES

To investigate the feasibility of individualized workload increments, as used in adults, for exercise testing in children; and to investigate whether this individualized protocol makes it possible to satisfy the usual criteria for maximal exercise (clinical exhaustion, predicted maximum heart rate [HRmax], oxygen uptake [O(2)] plateau, maximal respiratory exchange ratio > 1.1).

DESIGN

Prospective clinical study.

SETTING

Pediatric exercise testing laboratory.

SUBJECTS

Ninety-two children aged 5 to 17 years with various cardiac and respiratory diseases (33 with asthma, 11 with bronchopulmonary dysplasia, 6 with cystic fibrosis, 10 with congenital heart disease, and 32 miscellaneous).

INTERVENTIONS

Individualized maximal incremental exercise testing. The increase in workload was adapted to the individual and was calculated from predicted maximal oxygen uptake (O(2)max) for each child. The test lasted 10 to 12 min.

RESULTS

The exercise test was well tolerated by all children and was maximal in all but seven patients. A total of 65.7% of children reached the predicted O(2)max and 68.4% satisfied the criteria for a O(2) plateau at peak exercise. The predicted HRmax was achieved in all but two children. The mean maximal respiratory exchange ratio was 1.06.

CONCLUSION

The individualized protocol for increasing workload, based on O(2) rather than power, was well tolerated by children. In our view, the best two criteria for assessing the maximality of the tests were clinical exhaustion and HRmax, especially if the O(2) plateau was not reached. These results suggest that individualized protocols could be used instead of standardized tests for exercise testing in children.

Increased eosinophil cationic protein levels in bronchoalveolar lavage from wheezy infants

Although studies examining the serum suggest a role for eosinophils in wheezing episodes in infants and toddlers, the presence of a chronic eosinophilic inflammation within their airways remains to be demonstrated. In this study we investigated whether eosinophil cationic protein (ECP) levels are increased in BAL fluid (BALF) from infants and toddlers with recurrent wheezing episodes, during an asymptomatic period. The levels of ECP in BALF were quantitated by radioimmunoassay in 61 children (36 with severe recurrent episodes of wheezing and 25 who were non-wheezy), aged 6-36 months, in whom flexible bronchoscopy was clinically indicated. BALF eosinophil counts were < or = 1% in all patients and did not differ in wheezers, compared to non-wheezers. In contrast, ECP levels in BALF were > or = 2.2 micrograms/l in 18 of 36 (50%) wheezy infants but in only three of 25 (12%) control infants (p < 0.01). Neutrophil counts were significantly higher in the wheezer group than in the non-wheezer group (8.1 x 10(3) cells/ml vs. 3.0 x 10(3) cells/ml). ECP levels in the BALF were not correlated with the absolute number of eosinophils (r = 0.03; p = 0.8) but were correlated with the absolute number of neutrophils (r = 0.54; p = 0.001). There was no association between high ECP levels in BALF and the atopic status of the wheezers. In conclusion, ECP levels are increased in BALF from young children with recurrent wheezing episodes, even during relatively quiescent periods, suggesting a chronic increased cell activation in the lower airways.

[Clinical, biological and genetic heterogeneity of the inborn errors of pulmonary surfactant metabolism: SP-B deficiency and alveolar proteinosis]

Pulmonary surfactant is a multimolecular complex located at the air-water interface within the alveolus and to which a bulk of functions has been assigned, physical (surface-active properties) as well as immune or depurant. This complex consists of a surface active lipid layer (mainly phospholipids), and of an aqueous subphase. From discrete surfactant sub-fractions, one can isolate very hydrophobic proteins SP-B and SP-C as well as the collectins SP-A and SP-D, which were shown to have structural, metabolic, or defensive properties. Inborn or acquired abnormalities of surfactant, qualitative or quantitative in nature, account for a number human diseases. Beside hyaline membrane disease of the preterm neonate, a cluster of hereditary or acquired lung diseases have been characterized by the storage of periodic acid Schiff-positive material filling the alveoli. From this heterogeneous nosologic bulk, at least two discrete entities presently seem to emerge: 1) SP-B deficiency, in which an essentially proteinaceous material is stored within the alveoli, and which is a bona fide autosomal recessive Mendelian entity linked to the SFTPB gene (MIM 1786640), generally entailing neonatal respiratory distress with rapid fatal outcome, although partial or transient deficiencies have also been observed; 2) alveolar proteinosis, characterized by the storage of a mixed, protein and lipid material, and which constitutes a relatively heterogeneous clinical biological syndrome, with regards to age at onset (from the neonate through to adulthood) as well as the severity of associated signs. Murine models with a targeted mutation of the gene encoding GM-CSF (Csfgm) or the beta subunit of its receptor (Il3rbl) support the hypothesis of an abnormality of surfactant turnover in which the alveolar macrophage would be a key player. Beside SP-B deficiency, in which a near-consensus diagnostic chart can be designed, the ascertainment of other abnormalities of surfactant metabolism is not straightforward. The disentanglement of this disease cluster is however essential, with aim to propose differentiated therapeutic procedure : repeated bronchoalveolar lavages, GM-CSF replacement, bone marrow grafting or lung transplantation.

Blood histamine levels (BHL) in infants and children with respiratory and non-respiratory diseases

BACKGROUND

Blood histamine levels are decreased after severe allergic reactions and in various chronic diseases.

AIMS

To study blood histamine levels in infants and children with acute infectious and non-infectious, non-allergic, disease.

METHODS

Blood histamine levels were investigated by a fluorometric method in infants and children admitted to hospital with bronchiolitis, non-wheezing bronchitis, acute infections of the urinary tract, skin and ear-nose-throat, gastroenteritis, or hyperthermia of unknown aetiology. Results of blood histamine levels and white blood cell counts were compared with those obtained for children recovering from benign non-infectious, non-allergic illnesses.

RESULTS

As compared with control children, white blood cell numbers were significantly increased in children with acute infections of the urinary tract, skin and ear-nose-throat, and were significantly decreased in children with gastroenteritis. Blood histamine levels were significantly lower in children with gastroenteritis and hyperthermia than in children with other diseases and control children. It was not possible to correlate blood histamine levels and the number of blood basophils.

CONCLUSIONS

BHL are significantly decreased in infants and children with acute gastroenteritis and hyperthermia of unknown aetiology. The mechanisms responsible for the decrease in blood histamine levels in children with gastroenteritis and hyperthermia are discussed.

Spontaneous pneumomediastinum in children

SUMMARY. Spontaneous pneumomediastinum (SPM) is rare in children, mainly affecting male adolescents. It is usually secondary to alveolar rupture in the pulmonary interstitium, followed by dissection of gas towards the hilum and mediastinum. Many pathological and physiological events can lead to alveolar rupture, but the most common cause in children is asthma. The clinical diagnosis is based on the symptom triad of chest pain, dyspnea, and subcutaneous emphysema, and is also based on Hamman's sign. The diagnosis is confirmed by chest radiography. The main differential diagnosis is esophageal perforation, which requires an esophagogram with contrast when there is the slightest doubt in the diagnosis. Spontaneous pneumomediastinum generally resolves spontaneously within a few days, meaning that ambulatory treatment is usually appropriate. Management consists of treating the underlying cause (if identified), rest, analgesics, and simple clinical monitoring. Predisposing factors should be identified and controlled to prevent recurrence. Cases of idiopathic SPM necessitate diagnostic pulmonary function tests after the acute episode, to establish whether the child has asthma.