Airway nitric oxide in infants with acute wheezy bronchitis

Concentrations of nitric oxide (NO) in exhaled air are increased in children and adults with asthma, and NO measurements are used as a non-invasive marker to monitor airway inflammation in these patients. To define the role of NO in infants with acute wheezy bronchitis, we measured nasal and end-tidal NO concentrations in 17 infants with acute virus-associated wheezy bronchitis, in 22 term infants without respiratory disease, and in nine premature infants. Nasal NO measurements were performed with an olive placed in the infant's nose; end-tidal NO concentrations were assessed during tidal breathing through a snugly fitting face mask. Both end-tidal NO concentrations and nasal NO concentrations were reduced in infants with acute wheezy bronchitis. There were no differences in NO concentrations between term infants and premature infants. Measurements by both techniques were highly reproducible, as assessed by repeated measurements three times daily on three consecutive days in eight premature infants. Reduced airway NO concentrations in infants with virus-associated acute wheezy bronchitis are in contrast to findings in adults where both upper and lower airway NO levels are increased in patients with asthma. Whether this reflects a different inflammatory reaction to upper airway infections in acutely wheezy infants or pathophysiologic differences in airway response remains to be determined.     

Prevention of respiratory syncytial viral infections in late preterm infants

<正>1引言绝大部分儿童上呼吸道和下呼吸道感染病原体为病毒。呼吸道合胞病毒(RSV)是这类急性疾病最常见的病原体,主要影响呼吸系统,且病程各异。50%～90%的细支气管炎住院病例和25%的肺炎住院病例均由RSV所致。在新生儿中,小于32周的早产儿和有慢性呼吸功能不全(支气管肺发育不良     

From clinical practice to guidelines: how to recognize rhinosinusitis in children

Rhinosinusitis is a common childhood respiratory infection. Children have approximately six to eight viral infections of the upper respiratory tract each year, 5–13% of which may be complicated by a secondary bacterial infection of the paranasal sinuses. The diagnosis of acute bacterial rhinosinusitis in children is established by the persistence of purulent nasal or post-nasal draining lasting at least 10 days, especially if accompanied by supporting symptoms and signs, at which point antibiotic treatment has to be recommended. Appropriate antibacterial therapy should also be recommended if the draining has been present for less time, but is concomitantly associated with significant fever and localized signs of sinus inflammation in a child who appears ill. Imaging studies are not necessary to confirm the diagnosis of clinical rhinosinusitis for the purposes of treatment, but should be reserved for cases in which the diagnosis is in doubt or a complication is suspected, and for patients with recurrent or chronic rhinosinusitis. Under these circumstances, computed tomography is the preferred evaluation. Together with their clinical judgment, these suggestions may be useful for pediatricians in diagnosing this common condition.     

Usefulness of Heliox in the management of a serious airway obstruction caused by a subglottic hemangioma

Heliox therapy, alone or combined with noninvasive ventilation, has successfully been used in the treatment of infants and children with respiratory disease such as airway obstruction. We describe the case of a 1-month-old infant with severe upper respiratory airway obstruction (approximately 80 %) secondary to multiple cervical hemangiomatosis effectively treated with either Heliox alone or combined with nasal continuous positive airway pressure. This treatment provided symptomatic relief and facilitated diagnosis and subsequent application of specific treatment; the patient was free of signs of respiratory distress and the use of aggressive treatments such as endotracheal intubation or tracheal cannulation was avoided. Heliox can constitute a multipurpose, safe and useful tool in the noninvasive management of infants and children with serious obstructive respiratory disease.     

Upper airway obstruction

The airways in infants and children are anatomically different from adults, thus predisposing them to more acute upper airway obstruction. The causes of upper airway obstruction may be infective or non-infective. The presence of dysphonia, dysphagia, abnormal respiratory pattern, cough and abnormal posture suggests upper airway obstruction. The general management consist of supportive care with minimal invasive procedures. The specific treatment depends on the causes and is discussed in text.     

Purulent nasal discharge

Purulent nasal discharge is a common presenting symptom associated with infections of the upper respiratory tract. The most likely diagnoses are uncomplicated viral upper respiratory infections and bacterial sinusitis. Allergy may be an underlying problem in children with sinusitis. Less common considerations are adenoiditis, infections caused by B. pertussis, C. diphtheriae or Treponema pallidum or intranasal structural problems.     

Respiratory virus infection and airway hyperreactivity in children

A significant portion of infants and young children develop acute lower airway obstruction (wheezing) accompanying viral lower respiratory infections. These wheezing-associated respiratory illnesses, particularly bronchiolitis, are often associated with evidence of prolonged airway obstruction and airway hyperreactivity following the initial infection. The factors that determine the type of clinical infection that initially develops and long-term respiratory consequences of this infection are complex, including the genetic background of the child, the age at the time of infection, the respiratory virus involved, and environmental factors such as exposure to cigarette smoke. Several animal models have been developed to describe the pathophysiology of viral respiratory infection and have helped to define several potential mechanisms for the resulting airway obstruction. Data from these studies and studies in humans emphasize the importance of the immune system and of neural modulation of airway smooth muscle tone in determining the outcome of respiratory virus infection. These observations also help define the pivotal role of the airway epithelium in the regulation of airway smooth muscle tone and the host inflammatory response in the airway. Consequently, the interplay of host and environmental factors, as well as the relative importance of the different mechanisms potentially active in airway obstruction, determine the acute clinical outcome of infection for an individual child and the propensity of that child to develop recurrent episodes of wheezing (asthma).     

Eosinophil cationic protein in nasal secretion and in serum and myeloperoxidase in serum in respiratory syncytial virus bronchiolitis: relation to asthma and atopy

Eosinophil cationic protein (ECP) in nasal secretions was determined in 34 infants with respiratory syncytial virus (RSV) bronchiolitis during the acute infection stage and one and six months later. ECP in serum was determined in 19 of these children at the same time. Myeloperoxidase (MPO) was determined in the same 19 children at the acute infection stage and after one month. All children were followed prospectively for two years after the infection with regard to the development of bronchial obstructive symptoms. Asthma, defined as three or more episodes of bronchial obstruction verified by a physician, developed in 18% of children and less severe obstructive symptoms in 29%. A screening test for food IgE antibodies in serum was performed six months and a skin prick test two years after the acute infection. Nasal ECP/albumin ratios after six months were significantly higher than during the acute RSV infection. MPO, but not ECP, levels in serum were significantly elevated at the time of acute infection compared with levels after one month. Nasal ECP/albumin ratios at the acute infection were compared to a control group of 27 infants with non-RSV upper respiratory tract infections and did not differ. It was not possible to predict, either from ECP/albumin ratios in nasal secretion or from ECP and MPO in serum, which children would develop asthma, other bronchial obstructive symptoms or positive IgE tests.     

The Wheezy Child

ABSTRACT. Wheezing in association with viral respiratory tract infections occurs in 10-20 % of all infants and young children and usually indicates hyperreactive bronchi. Signs of airway hyperreactivity can usually be demonstrated many years after the child has stopped wheezing. This hyperreactivity is partly constitutional, but it may be further aggravated by viral infections in the respiratory tract. Similarly, allergic inflammation or long-term exposure to airway irritants may also cause or aggravate a state of hyperreactivity which may be expressed as a proneness to asthmatic reactions. As viral infections are among the most potent asthma-provoking factors known, the hyperreactivity does not need to be very pronounced before wheezing develops in the infant or young child, with its small-calibred airway. As long as wheezing only occurs sporadically and only in association with viral respiratory tract infections, the prognosis is usually excellent. However, recommendations regarding avoidance of potent allergens and airway irritants in the daily environment should be given to such families. Such advice is especially important for families with a proneness to atopic reactions or if wheezing begins to occur even during infection-free periods     

Rhinovirus and acute respiratory infections in hospitalized children. Retrospective study 1998-2000]

OBJECTIVES: Rhinoviruses are the most common aetiological agents of colds, but the frequency and the severity of other locations of the infection are not well known. This study describes the clinical aspects and the severity of rhinovirus infections in hospitalised children. METHODS: Isolation in culture and a RT-PCR were performed for the detection of rhinovirus in nasal aspirates from hospitalised children from September 1998 to October 2000. A group of 211 children found to be positive for rhinovirus was studied. RESULTS: Rhinovirus-infected children suffered from the following clinical syndromes: 60 (28.4%) upper airway infections, 81 (38.4%) bronchiolitis, 25 (11.9%) pneumonias and 12 (4.7%) acute attacks of asthma. Clinical symptoms were wheezing (32%), ronchi (37%) and 29% of children presented with acute distress respiratory syndrome; 40% of the available chest X-Ray were abnormal. Eight children were hospitalised in the intensive care unit and two children died. Twenty-five children (10.9%) had a nosocomial infection; a dual infection was observed in 19 cases (9%) with the following viruses: RSV (3), influenza (2) parainfluenza (8), adenovirus (2), enterovirus (4); 19 (9%) children had a secondary bacterial infection. Rhinoviruses were detected in nasal aspirates in 112 cases (53%) according to the culture and in the rhinovirus culture-negative samples in 99 cases (47%) according to the RT-PCR assay. CONCLUSION: After eliminating cases of bacterial or viral dual infections, the clinical aspects of rhinovirus infections in children are the following: upper respiratory tract infections (25.6%), bronchiolitis ou bronchitis (25.6%), pneumonia (6.2%), acute attack of asthma (5.7%). The virological diagnosis according to culture is mainly improved by molecular techniques.     

The wheezy child

Wheezing in association with viral respiratory tract infections occurs in 10-20% of all infants and young children and usually indicates hyperreactive bronchi. Signs of airway hyperreactivity can usually be demonstrated many years after the child has stopped wheezing. This hyperreactivity is partly constitutional, but it may be further aggravated by viral infections in the respiratory tract. Similarly, allergic inflammation or long-term exposure to airway irritants may also cause or aggravate a state of hyperreactivity which may be expressed as a proneness to asthmatic reactions. As viral infections are among the most potent asthma-provoking factors known, the hyperreactivity does not need to be very pronounced before wheezing develops in the infant or young child, with its small-calibred airway. As long as wheezing only occurs sporadically and only in association with viral respiratory tract infections, the prognosis is usually excellent. However, recommendations regarding avoidance of potent allergens and airway irritants in the daily environment should be given to such families. Such advice is especially important for families with a proneness to atopic reactions or if wheezing begins to occur even during infection-free periods.     

Relationships among specific viral pathogens,virus‐induced interleukin‐8, and respiratory symptoms in infancy

Both virus‐mediated damage to airway tissues and induction of pro‐inflammatory cytokines such as interleukin‐8 (IL‐8) could contribute to symptom severity during viral respiratory infections in children. To test the hypothesis that IL‐8 contributes to the pathogenesis of respiratory symptoms during naturally acquired respiratory viral infections in children, nasal wash samples collected from infants with acute viral infections (n = 198) or from healthy uninfected infants (n = 31) were analysed for IL‐8. Nasal wash IL‐8 was positively related to age in uninfected children (r_s = 0.36, p < 0.05). Respiratory syncytial virus (RSV) infection caused more severe respiratory symptoms compared to infections with influenza A, parainfluenza viruses, or rhinoviruses. In addition, RSV, parainfluenza and rhinovirus infections increased levels of IL‐8 in nasal lavage fluid, and there were some differences in the ability of the viruses to induce IL‐8 production (RSV>influenza, p < 0.05). Finally, there were significant correlations between nasal wash IL‐8 levels and symptom scores during infections with rhinovirus (r_s = 0.56, p < 0.001) or influenza A (r_s = 0.45, p < 0.05), but not with parainfluenza virus or RSV. These findings provide evidence of a close relationship between the generation of IL‐8 and symptoms during acute community‐acquired infections with rhinovirus or influenza A. In contrast, for RSV and parainfluenza infections, factors in addition to IL‐8 production appear to contribute to the generation of clinical symptoms.     

Nasal IgA response in wheezy infants

It is unknown why some infants wheeze during upper respiratory tract infections. One possibility is that secretory IgA, which has a major role in mucosal defence against viral infection, might be deficient in wheezy infants. The nasal IgA response to upper respiratory tract infection in 32 wheezy infants (median age 5.8 months) was compared with nine siblings (median age 2.6 years) who had nasal symptoms only. Nasal lavage was performed during infections and on follow up when free from symptoms, using inulin as a marker of dilution to determine absolute concentrations of IgA in the nasal secretions. The two groups showed a similar increase in total IgA and total protein levels during infection, but secretory IgA concentrations were unchanged. This study shows that wheezy infants have a normal nasal IgA response to infection and that the increase in total IgA during early infection is due to plasma exudation rather than increased production of secretory IgA.     

Nasal IgA response in wheezy infants.

It is unknown why some infants wheeze during upper respiratory tract infections. One possibility is that secretory IgA, which has a major role in mucosal defence against viral infection, might be deficient in wheezy infants. The nasal IgA response to upper respiratory tract infection in 32 wheezy infants (median age 5.8 months) was compared with nine siblings (median age 2.6 years) who had nasal symptoms only. Nasal lavage was performed during infections and on follow up when free from symptoms, using inulin as a marker of dilution to determine absolute concentrations of IgA in the nasal secretions. The two groups showed a similar increase in total IgA and total protein levels during infection, but secretory IgA concentrations were unchanged. This study shows that wheezy infants have a normal nasal IgA response to infection and that the increase in total IgA during early infection is due to plasma exudation rather than increased production of secretory IgA.     

Incidence of streptococcal carriers in private pediatric practice.

OBJECTIVE: To determine the incidence of group A beta-hemolytic streptococcus (GABHS) carriers in children who are well, in children seen with presumed and documented viral illnesses with sore throat, and in children after treatment of acute GABHS tonsillopharyngitis with 10 days of oral penicillin V potassium, oral cephalosporins, or macrolides. METHODS: Prospective collection of clinical and microbiologic data from October 1996 to June 1997 in a private pediatric practice were obtained from children who were asymptomatic and well, from children with both presumed (and documented) viral sore throats, and from children who had completed a full antibiotic treatment course for acute GABHS throat infections. RESULTS: The incidence of GABHS carriers was 2.5% among well children (n = 227), 4.4% among children with upper respiratory tract infections including sore throat of presumed viral etiology (n= 296), and 6.9% among children with upper respiratory tract infections including sore throat from whom viruses were isolated (n = 87). Following 10 days' treatment of acute GABHS tonsillopharyngitis, 81 (11.3%) of 718 children treated with penicillin, 22 (4.3%) of 508 children treated with an oral cephalosporin, and 10 (7.1%) of 140 children treated with a macrolide were GABHS carriers (P<.001). CONCLUSIONS: A small percentage of children seen in private pediatric practices who are well or who have apparent viral upper respiratory tract infections with sore throat are GABHS carriers. Penicillin treatment of acute GABHS tonsillopharyngitis results in a higher GABHS carriage rate than occurs following treatment with cephalosporins and macrolides.     

Upper airway lesions in children after accidental ingestion of caustic substances

Of 33 children admitted within 24 hours after accidental ingestion of a caustic substance, 14 (42.5%) had evidence of upper airway lesions on direct laryngoscopy. Three patients, 10 to 12 months old, needed endotracheal intubation for acute respiratory obstruction; four patients younger than 2 years had severe dyspnea without obstruction; seven patients had mild or no respiratory symptoms. All were discharged without respiratory sequelae, although esophageal stenosis developed in six patients. Nine of 13 patients younger than 2 years, compared to five of 20 patients older than 2 years, had upper airway lesions (P less than 0.01). The frequency of respiratory tract lesions was higher in patients with severe esophagitis. Eleven of 17 patients with severe esophagitis, compared to three of 16 with mild inflammation, had respiratory tract lesions (P less than 0.025). No specific caustic substance predisposed to upper airway lesions.     

Predominance of rhinovirus in the nose of symptomatic and asymptomatic infants

Respiratory infections in infancy may protect against developing Th2-mediated allergic disease (hygiene hypothesis). To estimate the relative contribution of particular viruses to the development of the immune system and allergic disease, we investigated longitudinally the prevalence of respiratory viral infections in infants. One hundred and twenty-six healthy infants were included in this prospective birth cohort study in their first year of life. Physical examination was performed and nasal brush samples were taken during routine visits every 6 months and during an upper respiratory tract infection (URTI) (sick visits). The prevalence of respiratory viral infections in infants with URTI, infants with rhinitis without general malaise and infants without nasal symptoms was studied. Rhinovirus was the most prevalent pathogen during URTI and rhinitis in 0- to 2-year-old infants (∼40%). During URTI, also respiratory syncytial virus (∼20%) and coronavirus (∼10%) infections were found, which were rarely detected in infants with rhinitis. Surprisingly, in 20% of infants who did not present with nasal symptoms, rhinovirus infections were also detected. During routine visits at 12 months, a higher prevalence of rhinovirus infections was found in infants who attended day-care compared with those who did not. We did not observe a relation between breast-feeding or smoking by one or both parents and the prevalence of rhinovirus infections. The parental history of atopy was not related to the prevalence of rhinovirus infection, indicating that the genetic risk of allergic disease does not seem to increase the chance of rhinovirus infections. In conclusion, rhinovirus infection is the most prevalent respiratory viral infection in infants. It may therefore affect the maturation of the immune system and the development of allergic disease considerably.     

An approach to the diagnosis and treatment of membranous laryngotracheobronchitis in infants and children.

The purpose of this study is to report 18 cases of membranous laryngotracheobronchitis (MLTB) and to review 143 published cases in order to accurately characterize the epidemiology, presentation, clinical course, treatment, and outcome of patients with this disorder. The male:female ratio was 2:1; mean age was four years. Most patients presented with acute onset of respiratory distress with fever, toxicity, and stridor after a prodrome of upper respiratory tract infection lasting a few days. White blood cell counts varied over a wide range, and blood culture results were rarely positive. Respiratory cultures commonly yielded Staphylococcus aureus or Haemophilus influenzae. Diagnosis was usually confirmed by airway radiographs or endoscopy. An artificial airway was required in 83% of patients. Complications included respiratory failure, toxic shock syndrome, anoxic encephalopathy, and death. MLTB is a serious, potentially fatal cause of acute infectious airway obstruction in infants and children that requires an organized approach to diagnosis and management.     

Acute infectious upper airway obstructions in children

There are numerous causes of acquired acute upper airway obstructions in children but most are secondary to infections, foreign bodies, and trauma. Recognizing impending airway obstructions is important because cardiopulmonary arrest rarely is a sudden event but rather follows a progressive deterioration in respiratory function. From an anatomic perspective, acute obstructions may present in the pharyngeal or laryngeal regions. In the pharynx, fascial layers create several potential peritonsillar, parapharyngeal, and retropharyngeal spaces that may accommodate abscess formation. Within the larynx and lower airways, small changes in radius dramatically affect the resistance to flow as described by Poiseuille's law, allowing for small amounts of inflammation to cause significant obstruction. The clinical presentation of acute upper airway obstruction will depend on the degree and location of the obstruction. Therapy is aimed primarily at maintaining a patent airway and prescribing appropriate antimicrobials.