Original ArticleAsthma diagnosis in infants and preschool children: a systematic review of clinical guidelines
Introduction
The diagnosis of asthma in children and adults depends on the concept we have of the disease.1, 2 This concept has evolved over time, and at present asthma is seen as a heterogeneous disorder or even as a syndrome in which the patient's signs and symptoms reflect or are attributable to a fluctuating increase in flow resistance within the intrapulmonary airway.1, 3 The causes underlying this physiopathological process have not been fully clarified, although the factors (endogenous or environmental) intervening in each individual, as well as the natural history of the disease and the response to treatment, are diverse – as reflected by the multiple phenotypes and endotypes that have been described.3, 4, 5, 6 Since there are no evidences or a gold standard, the concept and diagnosis of asthma depend on the consensus reached within the scientific community. Such a consensus is usually embodied in the form of national and international guidelines, most of which (including the GINA) have been produced by groups of experts selected on a scantly systematized basis. Although the Delphi method is regarded as the best strategy for consensuses of this kind, it has rarely been applied in the guides on asthma.
The issue about the diagnosis of asthma is not very different from that seen in other respiratory disorders characterized by airflow obstruction – easily recognizable from a clinical point of view, but not that simple when the manifestations are atypical or overlap with those of other diseases. In elderly individuals, asthma poses differential diagnostic problems with chronic obstructive pulmonary disease (COPD) – a circumstance that has led to the controversial purported existence of an asthma-COPD syndrome.7, 8, 9, 10 In the first years of life, other intrapulmonary airway disorders also face definition and diagnostic problems, such as bronchopulmonary dysplasia11, 12, 13, 14 and acute viral bronchiolitis.15, 16, 17 In this regard, some of the manifestations of these disorders can overlap those of asthma which could develop during this early stage of life.18, 19
Many children experience recurrent symptoms of bronchial obstruction starting in the first years of life. It is particularly difficult to establish a diagnosis of asthma in infants or preschool children, and the criteria used can vary greatly among different guidelines or studies, and among clinicians, even working in the same setting. This is a problem for determining the true incidence and prevalence of the disease.20 In many cases, the term “asthma” is avoided at such early ages for a number of reasons, including difficulties in performing the pulmonary function tests capable of demonstrating the existence of airflow obstruction,21 a lack of data on the underlying inflammatory substrate,22 or the fact that many children improve and appear to heal in the course of childhood.23, 24, 25 All this may cause clinicians to avoid giving a diagnosis that suggests a permanent illness. Spanish pediatricians with expertise in asthma have recently evidenced the lack of agreement referred to basic aspects associated to the diagnosis of asthma in preschool children.26 As a prior step to considering a consensus in Spain, the present study reports the results of a systematic review answering key questions on the concept and diagnosis of asthma in preschool children (i.e., children under six years of age) given in clinical guidelines on asthma. There are very few reviews on the diagnosis of asthma in small children27 or in children and adults28 in clinical guidelines. The selected key questions for this systematic review are presented in Table 1.
Section snippets
Working group
This review was promoted by the working group on respiratory allergy and asthma of the Spanish Pediatric Society of Clinical Immunology, Allergology and Asthma (Sociedad Española de Inmunología Clínica, Alergología y Asma Pediátrica [SEICAP]). Collaboration was requested from the working groups of scientific societies related to pediatric asthma in Spain: the Spanish Society of Pediatric Pulmonology (Sociedad Española de Neumología Pediátrica [SENP]), the Spanish Society of Outpatient and
Results
A total of 2338 references were obtained from the initial search in Trip Database and PubMed. The selection process of the valid documents is shown in Fig. 1. Finally, 23 documents grouped into 21 clinical guidelines were analyzed, since two of the guidelines were considered to be comprised by two different documents that were judged to be complementary. The selected guidelines, the constituting documents, and the answers of the guidelines to the key questions are summarized in Table 2. Ten of
Discussion
The concept and diagnosis of asthma is an unresolved issue affecting patients of all ages, although it is particularly relevant in childhood since this is the period in life when most patients develop the disease. The concept of asthma has gradually broadened and become more diffuse. It is presently understood to be a heterogeneous disease or a complex syndrome – this being an umbrella term encompassing patients with similar clinical manifestations but with a diverse or uncertain
Confidentiality of data
The authors declare that no patient data appear in this article.
Right to privacy and informed consent
The authors declare that no patient data appear in this article.
Protection of human subjects and animals in research
The authors declare that the procedures followed were in accordance with the regulations of the corresponding Clinical Research Ethics Committee and with the guidelines of the World Medical Association and the Declaration of Helsinki.
Conflict of interest
The authors have no conflict of interest.
Acknowledgements
We thank Agustín Acuña Izcaray for help in the systematic search of asthma clinical guidelines, and Ulla Aguilera Jacobsen for the Spanish translation of diagnostic aspects of the Danish guideline of asthma in children.
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