Risk Factors For Respiratory Infections Research Articles

Recurrent Lower Respiratory Tract Infections in Children: A Practical Approach to Diagnosis

Many children are affected by recurrent lower respiratory tract infections (LRTIs), but the majority of them do not suffer from serious lung or extrapulmonary disease. The challenge for clinicians is to distinguish the recurrent RTIs with self-limiting or minor problems from those with underlying disease. The aim of this review is to describe a practical approach to children with recurrent LRTIs that limits unnecessary, expensive and time-consuming investigations. The children can be divided into three groups on the basis of their personal and family history and clinical findings: 1) otherwise healthy children who do not need further investigations; 2) those with risk factors for respiratory infections for whom a wait-and-see approach can be recommended; and 3) those in whom further investigations are mandatory. However, regardless of the origin of the recurrent LRTIs, it is important to remember that prevention by means of vaccines against respiratory pathogens (i.e. type b Haemophilus influenzae, pertussis, pneumococcal and influenza vaccines) can play a key role.

Glucose Depletion in the Airway Surface Liquid Is Essential for Sterility of the Airways

Diabetes mellitus predisposes the host to bacterial infections. Moreover, hyperglycemia has been shown to be an independent risk factor for respiratory infections. The luminal surface of airway epithelia is covered by a thin layer of airway surface liquid (ASL) and is normally sterile despite constant exposure to bacteria. The balance between bacterial growth and killing in the airway determines the outcome of exposure to inhaled or aspirated bacteria: infection or sterility. We hypothesized that restriction of carbon sources –including glucose– in the ASL is required for sterility of the lungs. We found that airway epithelia deplete glucose from the ASL via a novel mechanism involving polarized expression of GLUT-1 and GLUT-10, intracellular glucose phosphorylation, and low relative paracellular glucose permeability in well-differentiated cultures of human airway epithelia and in segments of airway epithelia excised from human tracheas. Moreover, we found that increased glucose concentration in the ASL augments growth of P. aeruginosa in vitro and in the lungs of hyperglycemic ob/ob and db/db mice in vivo. In contrast, hyperglycemia had no effect on intrapulmonary bacterial growth of a P. aeruginosa mutant that is unable to utilize glucose as a carbon source. Our data suggest that depletion of glucose in the airway epithelial surface is a novel mechanism for innate immunity. This mechanism is important for sterility of the airways and has implications in hyperglycemia and conditions that result in disruption of the epithelial barrier in the lung.

S29 Mannose binding lectin deficiency in children with respiratory infection

IntroductionMannose binding lectin (MBL) plays a crucial part in innate immunity by activating the complement pathway. MBL deficiency is common, it has been associated with pulmonary disease, but low levels...

Associação do bruxismo, rinite e sinusite com as infecções respiratórias recorrentes em crianças

Introdução: São considerados fatores de risco, as infecções crônicas – rinite e sinusite – as condições socioeconômicas, o tabagismo passivo e o tempo de aleitamento materno. O conhecimento desses fatores e suas possíveis correlações são necessários para reduzir a morbidade das infecções respiratórias em crianças. Objetivos: O objetivo desse estudo foi investigar a correlação do bruxismo com os demais fatores de risco de infecções respiratórias em crianças em idade escolar. Métodos: Estudo observacional, com corte transversal em 62 crianças de uma creche pública, foi analisado por meio de questionário, aplicado aos pais, com questões referentes às condições de moradia, tempo de aleitamento, tabagismo passivo, tipo e freqüência de infecções respiratórias nos últimos doze meses e diagnóstico de bruxismo. Resultados: O bruxismo está presente em 55% das crianças com doenças respiratórias crônicas como rinite e sinusite (p= 0,04) e a prevalência de infecções nos últimos doze meses ocorreu em 90% das crianças com diagnóstico de rinite e sinusite. (p= 0,05). Conclusão: Bruxismo e infecções crônicas de vias aéreas superiores apresentam correlação positiva com infecções respiratórias em crianças em idade escolar.

Ventilator-Associated Tracheobronchitis

Purpose of Review: This review focuses on the pathophysiology of proximal airway infection in the ventilated patient. Ventilator-associated tracheobronchitis (VAT) is increasingly recognized as an important entity not only as an essential step in the pathway from oral colonization to deep lung infection but also as an infection associated with its own morbidity. Recent Findings: Multiple recent clinical trials have focused on the effects of new devices and treatment protocols on the morbidity associated with the progression of airway colonization to VAT or with the progression of VAT to VAP. Continuous subglottic secretion suctioning (CASS), innovative types of endotracheal tubes, and targeted therapy for VAT in recent investigations have shown promise in improving clinical outcomes in the critically ill patient. However, even with diligent attention to all the modifiable risk factors for respiratory infection, complete elimination of VAT and VAP remains unlikely. As long as a patient requires an endotracheal tube which disturbs airway integrity, host defenses will be impaired, and resistant virulent organisms which result from our liberal use of systemic antibiotics will continue to challenge critical care specialists. Summary: This review will focus on: 1) the current understanding of the pathogenesis of VAT, 2) modifiable risk factors, and 3) new approaches to treatment and bacterial resistance challenges. Keywords: Ventilator-associated pneumonia, ventilator-associated tracheobronchitis, endotracheal tube complications, bacterial resistance

Ventilator-associated infection

Ventilator-associated pneumonia (VAP) is the most serious and controversial of the infections of the critically ill patient. The accuracy of standard methods of diagnosis remains under constant scrutiny, and at the same time there is increasing debate about whether it is a preventable disease. This review focuses on the pathophysiology of respiratory tract infection in the ventilated patient, and how the latest advances have grown from our current understanding of its pathogenesis. Data from many recent investigations have focused on the role of proximal airway infection, ventilator-associated tracheobronchitis (VAT), in respiratory tract infection. The goals of recent trials include reducing the morbidity associated with the progression of airway colonization to VAT or with the progression of VAT to VAP. Continuous subglottic secretion suctioning, innovative types of endotracheal tubes and targeted therapy for VAT in recent investigations have shown promise in improving clinical outcomes in the critically ill patient. However, even with diligent attention to all the modifiable risk factors for respiratory infection, complete elimination of VAT and VAP remains unlikely. As long as a patient requires an endotracheal tube that disturbs airway integrity, host defenses will be impaired, and resistant virulent organisms that result from our liberal use of systemic antibiotics will continue to challenge critical care specialists. This review will focus on: the current understanding of the pathogenesis of VAT and VAP, modifiable risk factors and new approaches to treatment, and bacterial resistance challenges.

Risk factors for croup in children with recurrent respiratory infections: a case‐control study

Croup accounts for approximately 15% of all lower respiratory disease in children, but little is known about risk factors or its recurrence rate. The aim of this study was to determine the risk factors for croup and recurrent croup and to find out whether it is possible to predict the course of the disease. We considered croup patients who visited the Paediatric Department of Oulu University Hospital as primary health care patients at night during 1996-2000. For most analyses we used sex- and age-matched control patients who had had other respiratory infection but for environmental factors we used population controls. We performed conditional logistic regression analysis on data applying to 182 pairs of patients and controls. The recurrence rate was high, as 61% of the croup patients had had at least three episodes. Family history of croup was the most significant risk factor for both croup itself and recurrent croup. In multivariable analysis the odds ratio (OR) for the parents having a history of croup was 3.2 (95% CI 1.5, 7.1, P < 0.01) and 4.1 (95% CI 1.4, 11.7, P < 0.01) for recurrent croup. Parental smoking appeared to be a risk factor for respiratory infections but not for croup. Patients with croup had a cat as a pet less often than the controls, with OR 0.5 (95% CI 0.2, 1.0, P = 0.04). Family history appeared to be an exceptionally strong predictive factor for croup and its recurrence. In this patient series prone to respiratory infections recurrence of croup was common.

Is silent aspiration a risk factor for respiratory infection in Parkinson's disease patients?

Objective To assess if silent aspiration is a risk factor for respiratory infection in patients with Parkinson's disease (PD). Method From February 2006 to June 2006, 19 PD patients with diurnal sialorrhea were evaluated by swallow videofluoroscopy (VF). Two patients moved away and contact with them was lost. The other patients were divided into two groups according to the presence or absence of penetration/aspiration and were followed up for 1 year. During this period, patients were assessed for airway infections, hospital admissions, weight loss, use of nasoenteral or gastric tube and to detect cases of death. Results Silent laryngeal penetration or silent aspiration (SLP/SA) was observed in four patients. During the follow up period, three of the four patients with SLP/SA developed respiratory infection, and one of the 13 patients who did not show SLP/SA had airway infection (RR = 9.75, 95% CI: 1.36–69.65). Two patients with SLP/SA developed airway infection and died, and there were two deaths in the group who had not been diagnosed for SLP/SA, one due to cardiac arrest and the other related to pancreatic cancer. Conclusion The results suggest that patients with Parkinson's disease with diurnal sialorrhea and SLP/SA have an increased risk of respiratory infections, which is the main cause of death in PD patients. The data support a greater emphasis on preventive interventions for silent aspirations and silent penetration to improve survival in patients with Parkinson's disease.

1.154 Is silent aspiration a risk factor for respiratory infection in Parkinson's disease patients?

1.154 Is silent aspiration a risk factor for respiratory infection in Parkinson's disease patients?

Outdoor air pollution and acute respiratory infections among children in developing countries.

Acute respiratory infections (ARIs) are the most common cause of illness and death in children in the developing world. This review focuses on outdoor air pollutants associated with pediatric ARI mortality and morbidity. Studies were identified using MEDLINE and other electronic databases. Four studies showed an increase in infant mortality in relation to outdoor air pollution. Short-term follow-up and time-series studies suggest that air pollutants act as risk factors for respiratory infection. Air pollution exposure increases the incidence of upper- and lower-respiratory infections in children. Because complex pollution mixtures are present in the studied urban areas, pollutant levels at which ARI risk would be expected to increase cannot be determined. Children may be at greater risk, given the poor environmental and nutritional conditions prevalent in developing countries.

In vitro therapeutic effect of epigallocatechin gallate on nicotine-induced impairment of resistance to Legionella pneumophila infection of established MH-S alveolar macrophages.

Epigallocatechin gallate (EGCg), a major form of tea catechins, has a variety of biological activities. Tobacco smoking, nicotine in particular, is one of the risk factors for respiratory infections. In the present study, a possible immunotherapeutic effect of EGCg on the nicotine-induced impairment of alveolar macrophages regarding antimicrobial activity, as well as immune function, was examined. The treatment of MH-S macrophages with nicotine significantly enhanced Legionella pneumophila replication in the cells and selectively down-regulated the production of interleukin (IL)-6, IL-12, and tumor necrosis factor (TNF)-alpha induced by infection but did not alter IL-10 production. The EGCg treatment of nicotine-suppressed macrophages reconstituted the resistance to the infection. Furthermore, EGCg diminished the nicotine-induced inhibition of cytokine production. Experiments with TNF-alpha treatment, neutralization of cytokines with antibodies, and analysis of interferon (IFN)-gamma messenger RNA showed that the mechanism of the EGCg-induced recovery of anti-L. pneumophila activity impaired by nicotine may be due to the recovery of TNF-alpha and IFN-gamma production by the macrophages.

Involvement of nicotinic acetylcholine receptors in suppression of antimicrobial activity and cytokine responses of alveolar macrophages to Legionella pneumophila infection by nicotine.

Although nicotine is thought to be one of the major immunomodulatory components of cigarette smoking, how nicotine alters the host defense of the lung and, in particular, immune responses of alveolar macrophages, which are critical effector cells in the lung defense to infection, is poorly understood. Nicotinic acetylcholine receptors (nAChRs) are the receptor for nicotine and may be involved in the modulation of macrophage function by nicotine. In this study, therefore, nicotine-induced suppression of antimicrobial activity and cytokine responses of alveolar macrophages mediated by nAChRs to Legionella pneumophila, a causative agent for pneumonia, were examined. The murine MH-S alveolar macrophage cell line cells expressed the messages for alpha4 and beta2 subunits of nAChRs, but not alpha7 subunits, determined by RT-PCR. The nicotine treatment of MH-S alveolar macrophages after infection with L. pneumophila significantly enhanced the replication of bacteria in the macrophages and selectively down-regulated the production of IL-6, IL-12, and TNF-alpha, but not IL-10, induced by infection. These effects were completely blocked by a nonselective antagonist, d-tubocurarine, for nAChRs, but not by a selective antagonist, alpha-bungarotoxin, for alpha7-nAChRs. Furthermore, the stimulation of nAChRs with another agonist, 1,1-dimethyl-4-phenylpiperazinium iodide, showed the same effects, which were blocked by the antagonist d-tubocurarine, on the bacterial replication and cytokine regulation with that of nicotine. Thus, the results revealed that nAChRs, the major exogenous ligands of which are nicotine, are involved in the regulation of macrophage immune function by nicotine and may contribute to the cigarette-induced risk factors for respiratory infections in smokers.

Risk factors for respiratory tract infections in children aged 2-5 years

Objective - To study risk factors for respiratory tract infections (RTIs) in children aged 2-5 years. Design - A questionnaire was used to chart the number of visits to doctors and the number of antibiotics courses because of RTIs during a 1-year period. The risk factors studied were age, sex, birth weight, breastfeeding, atopy, siblings, smoking and childcare. Setting - The catchment area of Oxie health centre in southern Sweden. Subjects - 190 pre-school children. Main outcome measures - Number of visits to doctors and number of antibiotics courses. Results - The risk of having to consult a doctor, as well as the risk of receiving treatment with antibiotics, because of RTIs was greater among children at daycare centres than among children who were mostly at home (adjusted OR 2.78 (95% CI 1.34?5.78) and 2.73 (1.38?5.43), respectively). Conclusion - Attending a daycare centre is the most important risk factor for RTIs in children aged 2?5 years.

Environmental risk factors for respiratory infections.

In this study, the authors investigated the possible relationship between environmental-including dietary-factors and respiratory and ear infections in children. A sample of 304 children, aged 4-5 y, in Geneva, Switzerland, was studied. Mothers filled out a questionnaire that the authors provided. The questionnaire included items on food frequency, infections, and background factors (e.g., education, housing conditions, parents' smoking habits). Allergy was a risk factor for all infections, and mother's age was a protective factor. Humid conditions at home was a significant risk factor for cold, sore throat, and otitis (odds ratios = 2.71, 3.03, and 2.77, respectively); mold in the home was a significant risk factor for otitis (odds ratio = 2.80); and attending day-care centers was a significant risk factor for cold and bronchitis (odds ratios = 1.36 and 1.89, respectively). Dietary factors were not related to disease risk nor were environmental tobacco smoke or housing conditions generally related to an increased risk.

Preventing acute respiratory infections and diarrhoea in child care centres

This study was designed to explore the physical characteristics and child care practices of child care centres as potential risk factors for respiratory infections and diarrhoea in children 3–35 mo of age. A dynamic cohort averaging 667 children from 40 child care centres in Campinas (Brazil) was followed up for 8 mo. Direct structured observations were made to collect information on the centres' physical structure, child activities and child care practices. Despite their good infrastructures, hand washing in the centres was infrequent, and nearly 30% of diaper changes were unhygienic. Risk factors for diarrhoea included the presence of flies during meals, infrequent child hand washing before meals, and infrequent child hand washing after defecation, with relative risks of 1.33, 1.73 and 1.63, respectively. There was 33% less diarrhoea in classes where soap was frequently used during diapering. Contrary to our hypotheses, ventilation, group size and child density were not associated with respiratory infections, as was the case for most other factors studied. Only mixing of groups and a larger classroom area were found to be negatively associated with lower and upper respiratory infections, respectively. The results indicate that improving hygiene practices is the only intervention in child care centre characteristics with good potential to reduce diarrhoea among attendees. For respiratory infections, no modifiable characteristic with intervention potential was identified.

A CASE OF "EXOPHTHALMIC OPHTHALMOPLEGIA WITH THYROTOXICOSIS"

<b>Background:</b> There are few school environment studies from tropical countries. We studied associations between wheeze, current asthma and self-reported respiratory infections among students and formaldehyde, nitrogen dioxide (NO2) and volatile organic compounds (VOC) in schools in Malaysia. <b>Methods:</b> Totally 462 pupils from 8 randomly selected secondary schools in Johor Bahru, Malaysia, participated (96% participated). Formaldehyde, NO2 and VOC were measured by diffusion sampling during 1 week inside and outside the 32 classrooms. Carbon dioxide (CO2), an indicator of the ventilation in the classroom, was measured during class by a direct reading instrument. Multilevel logistic regression was applied. <b>Results:</b> Totally 10.3% had current wheeze, 9.3% current asthma (asthma medication or attacks of breathlessness), 18.8% respiratory infections in the past 3 months and 21.1% a history of pollen or furry pet allergy (atopy). Wheeze was associated with ethnicity (p=0.02; lower among Chinese), atopy (p=0.002) and current smoking (p=0.01) only. Current asthma was associated with ethnicity (p=0.001; lower among Indian) and the concentration of para-dichlorobenzene in classroom air (p=0.001). Current respiratory infections was associated with atopy (p=0.002) and the concentrations of ethylbenzene (p=0.03) and para-dichlorobenzene (p=0.01) in classroom air. There were no associations between CO2, NO2 or formaldehyde in classroom air and respiratory health. <b>Conclusion:</b> Para-dichlorobenzene in classroom air can be a risk factor for current asthma and respiratory infections among students in the tropical country Malaysia. Para-dichlorobenzene is commonly used indoors in Asia against insects. The aromatic compound ethylbenzene can be another risk factor for respiratory infections in the schools.