Cough and reflux esophagitis in children: their co-existence and airway cellularity

Official American Thoracic Society Clinical Practice Guidelines: Diagnostic Evaluation of Infants with Recurrent or Persistent Wheezing

BACKGROUND

Infantile wheezing is a common problem, but there are no guidelines for the evaluation of infants with recurrent or persistent wheezing that is not relieved or prevented by standard therapies.

METHODS

An American Thoracic Society-sanctioned guideline development committee selected clinical questions related to uncertainties or controversies in the diagnostic evaluation of wheezing infants. Members of the committee conducted pragmatic evidence syntheses, which followed the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. The evidence syntheses were used to inform the formulation and grading of recommendations.

RESULTS

The pragmatic evidence syntheses identified few studies that addressed the clinical questions. The studies that were identified constituted very low-quality evidence, consisting almost exclusively of case series with risk of selection bias, indirect patient populations, and imprecise estimates. The committee made conditional recommendations to perform bronchoscopic airway survey, bronchoalveolar lavage, esophageal pH monitoring, and a swallowing study. It also made conditional recommendations against empiric food avoidance, upper gastrointestinal radiography, and gastrointestinal scintigraphy. Finally, the committee recommended additional research about the roles of infant pulmonary function testing and food avoidance or dietary changes, based on allergy testing.

CONCLUSIONS

Although infantile wheezing is common, there is a paucity of evidence to guide clinicians in selecting diagnostic tests for recurrent or persistent wheezing. Our committee made several conditional recommendations to guide clinicians; however, additional research that measures clinical outcomes is needed to improve our confidence in the effects of various diagnostic interventions and to allow advice to be provided with greater confidence.

When is cough functional, and how should it be treated?

Key points

Educational aims

Summary

Involuntary cough without an identified underlying organic reason has been given various names and recommended treatments. Current experience in children and adolescents suggests that “habit cough” best describes this entity, and suggestion therapy is a highly effective treatment that most physicians can learn.

Diagnosis of the functional disorder called habit cough can be readily made by the unique clinical characteristicshttp://ow.ly/Al5B3094oxj

Update on Pediatric Cough

Despite the high prevalence of cough in children, the topic has been poorly researched. Although pediatricians recognize that chronic cough in children is different from that in adults, this difference seems less recognizable to other health professionals. During childhood, the respiratory tract and nervous system undergo a series of anatomical and physiological maturation processes that influence the cough reflex. Additionally, immunological responses undergo developmental and memorial processes that make infection and congenital abnormalities the overwhelming cause of cough in children. The lack of comprehensive clinical data regarding chronic cough in children has initially required pediatricians to adopt an adult approach to the problem. In the last 10 years, however, research has led to the reconsideration of the etiology of chronic cough in children. Currently, attention has focused on protracted bacterial bronchitis as a major cause of chronic cough in preschool-aged children and as a possible precursor of bronchiectasis. New research horizons are emerging for both the treatment and prevention of particular causes of chronic cough in children.

Mediators of neutrophil function in children with protracted bacterial bronchitis

BACKGROUND

Protracted bacterial bronchitis (PBB) is a common and treatable cause of chronic wet cough in children in which the mechanisms are not understood. This study investigates the IL-1 pathway and a neutrophil gene expression signature in PBB.

METHODS

BAL was collected from children in an experimental cohort (n = 21, PBB; n = 33, control subjects), and a second validation cohort (n = 36, PBB; n = 11, control subjects). IL-1β, IL-1 receptor antagonist (IL-1RA), and α-defensins 1-3 were assayed by enzyme-linked immunosorbent assay, western blot, and quantitative real-time polymerase chain reaction, together with selected IL-1 pathway members and neutrophil-related molecules.

RESULTS

In the experimental cohort, children with symptomatic PBB had significantly higher levels of IL-1β and α-defensin gene and protein expression. Expression of the neutrophil chemokine receptor C-X-C motif receptor 2 was also higher in PBB. IL-1RA protein was higher, however, the IL-1RA:IL-1β ratio was lower in children with PBB than control subjects. In the validation cohort, protein and gene expression of IL-1β and α-defensins 1-3 were confirmed higher, as was gene expression of IL-1 pathway members and C-X-C motif receptor 2. IL-1β and α-defensin 1-3 levels lowered when PBB was treated and resolved. In children with recurrent PBB, gene expression of the IL-1β signaling molecules pellino-1 and IL-1 receptor-associated kinase 2 was significantly higher. IL-1β protein levels correlated with BAL neutrophilia and the duration and severity of cough symptoms. IL-1β and α-defensin 1-3 levels were highly correlated.

CONCLUSIONS

PBB is characterized by increased IL-1β pathway activation. IL-1β and related mediators were associated with BAL neutrophils, cough symptoms, and disease recurrence, providing insight into PBB pathogenesis.

What is chronic cough in children?

The cough reflex is modulated throughout growth and development. Cough—but not expiration reflex—appears to be absent at birth, but increases with maturation. Thus, acute cough is the most frequent respiratory symptom during the first few years of life. Later on, the pubertal development seems to play a significant role in changing of the cough threshold during childhood and adolescence resulting in sex-related differences in cough reflex sensitivity in adulthood. Asthma is the major cause of chronic cough in children. Prolonged acute cough is usually related to the long-lasting effects of a previous viral airway infection or to the particular entity called protracted bacterial bronchitis. Cough pointers and type may orient toward specific etiologies, such as barking cough in croup or tracheomalacia, paroxystic whooping cough in Pertussis. Cough is productive in protracted bacterial bronchitis, sinusitis or bronchiectasis. Cough is usually associated with wheeze or dyspnea on exertion in asthma; however, it may be the sole symptom in cough variant asthma. Thus, pediatric cough has particularities differentiating it from adult cough, so the approach and management should be developmentally specific.

Protracted bacterial bronchitis in young children: association with airway malacia

OBJECTIVE

To examine associated findings and clinical outcome in young children with prolonged cough, wheeze, and/or noisy breathing in whom high colony counts of potentially pathogenic bacteria were cultured from bronchoalveolar lavage (BAL) during diagnostic flexible fiberoptic bronchoscopy.

STUDY DESIGN

This was a retrospective review of all medical records of children from infancy to 60 months of age seen in our specialty clinic from 1999 to 2009 with protracted cough, wheeze, and/or noisy breathing in whom BAL found ≥ 10(4) colony forming units per milliliter of potentially pathogenic bacteria. Children with other major diagnoses were excluded.

RESULTS

With quantitative culture from BAL, ≥ 10(4) colony forming units per milliliter of Streptococcus pneumoniae, Haemophilus influenza, or Moraxella catarrhalis, separately or in combination, were found in 70 children. Neutrophilia was present in 87% of BALs. Tracheomalacia, bronchomalacia, or both was present in 52 children (74%). Symptoms were eliminated with antibiotics in all 61 children with follow-up data. Relapse and subsequent successful re-treatment occurred in 43 children.

CONCLUSIONS

High colony counts of potentially pathogenic bacteria associated with neutrophilia in the BAL identifies protracted bacterial bronchitis. The predominance of airway malacia in these patients suggests an etiologic role for those airway anomalies. The potential for chronic airway damage from protracted bacterial bronchitis warrants further investigation.

Bronchoscopy in cystic fibrosis infants diagnosed by newborn screening

BACKGROUND

There is evidence of early functional and structural changes in babies with cystic fibrosis (CF) diagnosed on newborn screening (NBS). The aim of the present study was to determine the yield of bronchoalveolar lavage (BAL) microbiology and cytology, and 24 hr pH monitoring in a group of CF infants diagnosed on NBS.

METHODS

Infants referred to a tertiary pediatric respiratory center between July 2007 and November 2009 underwent surveillance fiber-optic bronchoscopy (FOB), BAL, and insertion of a 24 hr dual pH probe under a single general anesthetic.

RESULTS

We studied 33 infants, median age of 100 days (47-215 days) at the time of FOB. In 9 of 33 (27%) bacterial organisms were identified. Seven of the nine patients (78%) were asymptomatic and only one had had a positive cough swab prior to FOB. Neutrophilia was identified in 18/27 (67%) cases with a median of 11% (6-73%). 13/31 (42%) had an abnormal pH study with a pH index >12%.

CONCLUSIONS

The high yield of microbiology, cytology, and pH probe investigations in NBS infants justifies invasive surveillance. Longitudinal studies to determine if early aggressive treatment results in improved outcome are awaited.

Food for Thought on Pediatric Feeding and Swallowing

“Food for Thought” provides an opportunity for review of pertinent topics to add to updates in areas of concern for professionals involved with feeding and swallowing issues in infants and children. Given the frequency with which speech-language pathologists (SLPs) make decisions to alter feedings when young infants demonstrate silent aspiration on videofluoroscopic swallow studies (VFSS), the need for increased understanding about cough and its development/maturation is a high priority. In addition, understanding of the role(s) of laryngeal chemoreflexes (LCRs), relationships (or lack of relationships) between cough and esophagitis, gastroesophageal reflux (GER), and chronic salivary aspiration is critical. Decision making regarding management must take into account multiple systems and their interactions in order to provide safe feeding for all children to meet nutrition and hydration needs without being at risk for pulmonary problems. The responsibility is huge and should encourage all to search the literature so that clinical practice is as evidence-based as possible; this often requires adequate understanding of developmentally appropriate neurophysiology and function.

[Cough in paediatrics]

Cough is perhaps the most frequently seen symptom in children and as such one of the most common reasons for physician appointments. The mechanics and causes of cough in children are different to those in adults and imply a different diagnostic and therapeutic management. This article reviews the physiopathology of cough in children, the most frequent causes, the initial evaluation and the treatment slant.

High viral frequency in children with gastroesophageal reflux-related chronic respiratory disorders

INTRODUCTION

In the pediatric population chronic respiratory disorders (CRDs) include many pathological entities in which gastroesophageal reflux (GER) may play a role in the induction or persistence of clinical symptoms. It is not well established whether infective agents may be present in lung aspiration. The aim of the work was to investigate whether different infective agents could be found in children with GER-related CRDs.

MATERIALS AND METHODS

Extensive microbiological investigations including culture for bacterial agents, serology, direct fluorescent antigen and polymerase chain reaction analyses for different respiratory viruses were performed in 32 children (18 males, 14 females, mean age 5.0 +/- 2.4 years). Fifteen children out of 32 considered as "aspirators" (lipid-laden macrophage index-LLMI->or=86 and pathological pH-assay) were compared to 17 "non-aspirators" (LLMI < 86 and normal pH-assay).

RESULTS

Aspirators were older (6.0 +/- 1.9 vs. 4.2 +/- 2.5 years, P = 0.006) and less frequently atopic (13% vs. 59%, P = 0.01) than non-aspirators. A high frequency of viral infections (20/32, 62.5%) was found, with frequent occurrence of multiple infections (10/20, 50%). Aspirators showed more frequent viral infections than non-aspirators (87% vs. 41%, P = 0.01). Rhinovirus and respiratory syncytial virus were the principal detected viruses in the aspirator group.

CONCLUSIONS

Viral infections could play a key role in the pathogenesis of GER-related CRDs.

Comparison of atopic and nonatopic children with chronic cough: bronchoalveolar lavage cell profile

Chronic cough is a common complaint in children and its relationship with asthma is controversial. The aim of the present study was to determine the pattern of airway inflammation in atopic and nonatopic children with chronic cough, and to investigate whether atopy is a predictive factor for eosinophilic inflammation in cough. Bronchoalveolar lavage (BAL; three aliquots of 1 ml/kg saline) was performed in the right middle lobe of 24 (11 atopic and 13 nonatopic) children with persistent cough (8 females, 16 males), mean age 4.7 years (range: 1-11). Atopy was defined as an elevated total serum IgE or a positive RAST test. Both atopic and nonatopic children with persistent cough had an increase in total cells/ml in BAL (atopic: median 39 x 10(4), range: 20-123; nonatopic: median 22 x 10(4), range: 17-132) compared to nonatopic controls (median 11 x 10(4), range 9-30). The increases were mainly in neutrophils (atopic: median 17%, range 2.5-88.5%; nonatopic: median 6%, range 1.0-55.0%) compared to controls (median 1.55%, range 0.5-7.0%; atopics vs. controls, P < 0.005). There were no significant increases in eosinophils, lymphocytes, epithelial cells, or mast cells. Eosinophils were elevated in only 5/11 atopic and none of the nonatopic children. The increased percentage of neutrophils in the BAL fluid of atopic and nonatopic children with persistent cough could be due to an underlying inflammatory process driving the cough, or even conceivably, due to the effect of coughing itself. In this highly selected series, the absence of eosinophilic inflammation in the majority suggests that most would be predicted not to respond to inhaled corticosteroid therapy. This study underscores the need to be cautious about treating coughing children with inhaled corticosteroids, even in the context of a tertiary referral practice.

Defining the relationship between gastroesophageal reflux and cough: probabilities, possibilities and limitations

The common co-existence of cough and gastroesophageal reflux disease (GORD) is well established. However, ascertaining cause and effect is more difficult for many reasons that include occurrence by chance of two common symptoms, the changing definition of GORD, equipment limitations and the lack of randomised controlled trials. Given these difficulties, it is not surprising that there is disparity of opinion between respiratory and gastroenterology society guidelines on the link between GORD and chronic cough. This commentary explores of these issues.

Cough throughout life: children, adults and the senile

We review cough from premature birth, mature neonatal life, in childhood and adult life, and in old age. There is a regrettable lack of definitive studies, but many clues in the literature. The cough reflex seems weak in premature infants, but develops with maturity. It is pronounced in childhood, but there seem to be no studies comparing its strength then with that in adulthood. In old age the cough may weaken, as indicated by the prevalence of aspiration pneumonia. These changes are presumably related to the development and degeneration of the afferent and central nervous pathways for cough, which may be reflected in the changes in laryngeal muscle function with age. There is much evidence that age influences the development of the respiratory system in general, and of the immune system which would affect the degree, frequency and clinical issues of cough. Other factors that limit our understanding of the changes in cough with age include the reporting of cough by parents in infants and carers in old age and the use of different diagnostic criteria throughout life. Age-related variation in cough sensitivity seems to be well established, but its quantitation and mechanisms require much further research.