Asthma: Screening, Diagnosis, Management, An Issue of Otolaryngologic Clinics of North America (eBook)

Karen Calhoun (Autor)

eBook Download: PDF | EPUB

2014 | 1. Auflage
100 Seiten
Elsevier Health Sciences (Verlag)
978-0-323-26675-8 (ISBN)

Infos

Asthma as seen by Otolaryngologists as part of the patient workup, diagnosis, and treatment of the spectrum of disorders of asthma is presented. Otolaryngologists are frequently the de facto allergy specialist for patients presenting with asthma. ENT physicians will find current information for Data gathering and Interpretation (screening and testing), Diagnosis, combined surgical and non-surgical Treatment, and Basic Science related to Asthma in this publication.

Textauszug

Why Otolaryngologists and Asthma Are a Good Match

The Allergic Rhinitis-Asthma Connection

Rachel Georgopoulos, MD, John H. Krouse, MD, PhD and Elina Toskala, MD, PhD∗[e-mail],     Department of Otolaryngology, Temple University Health System, 3509 North Broad Street, Philadelphia, PA 19140-4105, USA

∗Corresponding author.

Consideration of the unified airway model when managing patients with rhinitis and or asthma allows a more comprehensive care plan and therefore improved patient outcomes. Asthma is linked to rhinitis both epidemiologically and biologically, and this association is even stronger in individuals with atopy. Rhinitis is not only associated with but is a risk factor for the development of asthma. Management of rhinitis improves asthma control. Early and aggressive treatment of allergic rhinitis may prevent the development of asthma. In patients with allergic rhinitis that is not sufficiently controlled by allergy medication, allergen-directed immunotherapy should be considered.

Keywords

Asthma

Rhinitis

Allergy

Immunology

Key points

• In the unified airway model, the nose and the paranasal sinuses through the respiratory bronchi are considered as components of 1 functional unit.

• Rhinitis and asthma are linked epidemiologically and pathophysiologically.

• Rhinitis is not only associated with but is a risk factor for the development of asthma.

• Atopy/allergy and disease severity are important factors affecting the association between rhinitis and asthma.

• Hygiene hypothesis suggests that a lack of microbial exposures as a child may result in modification of immunity toward T helper 2 (Th2) skewing and the increased risk for asthma and other atopic diseases.

• Proper management of allergic rhinitis can concomitantly allow better asthma control.

• In evaluating and treating patients with rhinitis, the diagnosis of asthma should be considered.

• It is important that physicians managing rhinitis/rhinosinusitis become familiar with the diagnosis and management of asthma.

Introduction

Although rhinitis and asthma are frequently comorbid conditions, physicians managing patients with rhinitis and or rhinosinusitis have traditionally not taken part in the diagnosis or management of asthma. Rhinitis, sinusitis, and asthma are linked both epidemiologically and pathophysiologically and thus the nose through the paranasal sinuses to the distal bronchioles should not be thought of as separate entities but rather constituents of 1 functional unit. This unit is referred to as the unified airway model.1–3 Rhinitis is not only associated with but is a risk factor for the development of asthma.4–11 Although both allergic and nonallergic forms of rhinitis are associated with asthma, the association between asthma and allergic rhinitis (AR) is even stronger.4,11 The use of allergen-directed immunotherapy in young children with allergic rhinitis has been shown to prevent the development of asthma in later life.12–14 Irritants and allergens presented at one portion of the airway have distal effects. It is thought that the upper and lower airways communicate through a complex interaction of inflammatory mediators and the autonomic system. Furthermore, disease severities in rhinitis and asthma often parallel each other.4,15 Adequate treatment of allergic rhinitis can allow better asthma control and, in some situations, may even prevent the development of asthma.16–20 With the substantial evidence to support the link between upper and lower airway disease it is imperative that physicians who manage patients with rhinitis and sinusitis become familiar with the diagnosis and management of asthma.

Abbreviations

AR	Allergic rhinitis

BHR	Bronchial hyperresponsiveness

CGRP	Calcitonin gene-related peptide

ICS	Inhaled corticosteroids

LABA	Long-acting β2-agonists

RSV	Respiratory syncytial virus

SABAs

Short-acting bronchodilators

AR and asthma defined

AR is defined as a symptomatic immunoglobulin E (IgE)–mediated inflammation of the nasal mucosa.9 Symptoms of rhinitis are reversible and include nasal congestion/obstruction, rhinorrhea, sneezing, pruritus, postnasal drip, chronic cough, throat clearing, and conjunctivitis.9,21 Rhinitis is categorized, based on duration of symptoms and by the disease’s impact on quality of life, as intermittent or persistent mild or moderate to severe (Table 1).9

Table 1

Classification of allergic rhinitis

Adapted from Bousquet J, Van Cauwenberge P, Khaltaev N, ARIA Workshop Group, World Health Organization. Allergic rhinitis and its impact on asthma. J Allergy Clin Immunol 2001;108(5):147–336; with permission.

Asthma is a chronic inflammatory disorder of the airways that results in reversible airway obstruction and bronchial hyperresponsiveness (BHR) to a variety of stimuli. Inflammatory mediators and mainly mast cells, eosinophils, T lymphocytes, neutrophils, and epithelial cells are known to play an important role in this process. In advanced cases, airway remodeling can occur, with irreversible injury to the pulmonary mucosa. The airway inflammation and subsequent airway obstruction experienced by these individuals can result in symptoms of wheezing, breathlessness, chest tightness, and coughing.22,23

Although the focus of asthma pathophysiology was once on the hyperresponsiveness of the airways, it is now known that inflammation is the driving mechanism, with the increased bronchial reactivity being caused by this inflammatory state. This concept is important to understanding the pathophysiology and treatment of asthmatics.

Epidemiology

Asthma-Rhinitis Link

AR and asthma affect about 30% and 7% to 8% of people respectively.6,24,25 Between 75% and 80% of atopic and nonatopic individuals with asthma have rhinitis.9 Between 10% and 40% of individuals with rhinitis have asthma.26 Not only are rhinitis and asthma associated but rhinitis is a risk factor for the development of asthma. Twenty percent of individuals with rhinitis go on to develop asthma later in life. Studies suggest that individuals with rhinitis have a 3-fold increased risk for the development of asthma.4,5,7 Rhinitis often precedes the development of asthma.

This association is influenced by a variety of factors. The development of atopy in early childhood, before 6 years of age, is an important risk factor for the development of BHR in late childhood.27 However, although early sensitization to inhalant allergens is a known risk factor for the development of atopic disease later in life, only about 25% of individuals sensitized to one or more inhalant allergen go on to develop asthma.28 Among individuals with AR and atopy the type of protein to which the individual is sensitized correlates with differing propensities for development of asthma. Individuals sensitized to perennial allergens have a significantly higher likelihood for developing asthma than individuals sensitized to seasonal allergens.11,29 In a study by Linneberg and colleagues,11 compared with their nonallergic counterparts, individuals sensitized to pollen, a seasonal allergen, had a 10-fold increased risk for developing asthma, whereas those who were sensitized to dust mite, a perennial allergen, had a 50-fold increased risk for developing asthma.

Genetics

In addition, there seems to be a genetic predilection to the development of these diseases. In a study in northern Sweden, a family history of atopic rhinitis and atopic asthma increased the risk of developing those conditions up to 6-fold and 4-fold respectively.30

Geography

Significant geographic variability exists in reference to the prevalence of allergic respiratory diseases. Dahl and colleagues31 performed a study looking at the prevalence of patient-reported allergic respiratory disorders in 10 European countries. Spain had a significantly lower prevalence and Italy a significantly higher prevalence of allergic respiratory disorder compared with other European countries: 11.7% and 33.6%, respectively (Table 2).31

Table 2

Prevalence of allergic respiratory disorder in 10 European...

Produkt-Details

• Erscheint lt. Verlag: 28.2.2014
• Sprache: englisch
• Themenwelt: Medizin / Pharmazie ► Medizinische Fachgebiete ► HNO-Heilkunde
• Themenwelt: Medizinische Fachgebiete ► Innere Medizin ► Pneumologie
• ISBN-10: 0-323-26675-4 / 0323266754
• ISBN-13: 978-0-323-26675-8 / 9780323266758