GINA_WR_2006.qxp:GINA_WR_2006.qxp 7/20/07 4:12 PM Page 15CHAPTER2DIAGNOSISANDCLASSIFICATION
GINA_WR_2006.qxp:GINA_WR_2006.qxp 7/20/07 4:12 PM Page 16KEY POINTS:• A clinical diagnosis of <strong>asthma</strong> is often promptedby symptoms such as episodic breathlessness,wheezing, cough, <strong>and</strong> chest tightness.• Measurements of lung function (spirometry or peakexpiratory flow) provide an assessment of the severityof airflow limitation, its reversibility, <strong>and</strong> its variability,<strong>and</strong> provide confirmation of the diagnosis of <strong>asthma</strong>.• Measurements of allergic status can help to identifyrisk factors that cause <strong>asthma</strong> symptoms inindividual patients.• Extra measures may be required to diagnose<strong>asthma</strong> in children 5 years <strong>and</strong> younger <strong>and</strong> in theelderly, <strong>and</strong> occupational <strong>asthma</strong>.• For patients with symptoms consistent with <strong>asthma</strong>,but normal lung function, measurement of airwayresponsiveness may help establish the diagnosis.• Asthma has been classified by severity in previousreports. However, <strong>asthma</strong> severity may change overtime, <strong>and</strong> depends not only on the severity of theunderlying disease but also its responsiveness totreatment.• To aid in clinical <strong>management</strong>, a classification of<strong>asthma</strong> by level of control is recommended.• Clinical control of <strong>asthma</strong> is defined as:- No (twice or less/week) daytime symptoms- No limitations of daily activites, inlcuding exercise- No nocturnal symptoms or awakening becauseof <strong>asthma</strong>- No (twice or less/week) need <strong>for</strong> reliever treatment- Normal or near-normal lung function- No exacerbationsINTRODUCTIONA correct diagnosis of <strong>asthma</strong> is essential if appropriatedrug therapy is to be given. Asthma symptoms may beintermittent <strong>and</strong> their significance may be overlooked bypatients <strong>and</strong> physicians, or, because they are non-specific,they may result in misdiagnosis (<strong>for</strong> example of wheezybronchitis, COPD, or the breathlessness of old age). Thisis particularly true among children, where misdiagnosesinclude various <strong>for</strong>ms of bronchitis or croup, <strong>and</strong> lead toinappropriate treatment.CLINICAL DIAGNOSISMedical HistorySymptoms. A clinical diagnosis of <strong>asthma</strong> is often promptedby symptoms such as episodic breathlessness, wheezing,cough, <strong>and</strong> chest tightness 1 . Episodic symptoms after anincidental allergen exposure, seasonal variability ofsymptoms <strong>and</strong> a positive family history of <strong>asthma</strong> <strong>and</strong>atopic disease are also helpful diagnostic guides. Asthmaassociated with rhinitis may occur intermittently, with thepatient being entirely asymptomatic between seasons or itmay involve seasonal worsening of <strong>asthma</strong> symptoms ora background of persistent <strong>asthma</strong>. The patterns of thesesymptoms that strongly suggest an <strong>asthma</strong> diagnosis arevariability; precipitation by non-specific irritants, such assmoke, fumes, strong smells, or exercise; worsening atnight; <strong>and</strong> responding to appropriate <strong>asthma</strong> therapy.Useful questions to consider when establishing adiagnosis of <strong>asthma</strong> are described in Figure 2-1.Figure 2-1. Questions to Consider in the Diagnosisof Asthma• Has the patient had an attack or recurrent attacks of wheezing?• Does the patient have a troublesome cough at night?• Does the patient wheeze or cough after exercise?• Does the patient experience wheezing, chest tightness, orcough after exposure to airborne allergens or pollutants?• Do the patient's colds “go to the chest” or take more than 10days to clear up?• Are symptoms improved by appropriate <strong>asthma</strong> treatment?In some sensitized individuals, <strong>asthma</strong> may beexacerbated by seasonal increases in specificaeroallergens 2 . Examples include Alternaria, <strong>and</strong> birch,grass, <strong>and</strong> ragweed pollens.Cough-variant <strong>asthma</strong>. Patients with cough-variant<strong>asthma</strong> 3 have chronic cough as their principal, if not only,symptom. It is particularly common in children, <strong>and</strong> isoften more problematic at night; evaluations during theday can be normal. For these patients, documentation ofvariability in lung function or of airway hyperresponsiveness,<strong>and</strong> possibly a search <strong>for</strong> sputum eosinophils, areparticularly important 4 . Cough-variant <strong>asthma</strong> must bedistinguished from so-called eosinophilic bronchitis inwhich patients have cough <strong>and</strong> sputum eoinophils butnormal indices of lung function when assessed byspirometry <strong>and</strong> airway hyperresponsiveness 5 .Other diagnoses to be considered are cough-induced byangiotensin-converting-enzyme (ACE) inhibitors,gastroesophageal reflux, postnasal drip, chronic sinusitis,<strong>and</strong> vocal cord dysfunction 6 .16 DIAGNOSIS AND CLASSIFICATION
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