2 DIAGNOSIS
Table 6: Differential diagnosis of asthma in adults, according to the presence or absence of airflow obstruction (FEV1/FVC <0.7). Without airflow obstruction Chronic cough syndromes Hyperventilation syndrome Vocal cord dysfunction Rhinitis Gastro-oesophageal reflux Heart failure Pulmonary fibrosis With airflow obstruction COPD Bronchiectasis* Inhaled foreign body* Obliterative bronchiolitis Large airway stenosis Lung cancer* Sarcoidosis* *may also be associated with non-obstructive spirometry
;; Consider performing chest X-ray in any patient presenting atypically or with additional symptoms or signs. Additional investigations such as full lung function tests, blood eosinophil count, serum IgE and allergen skin prick tests may be of value in selected patients. Criteria for referral to a specialist are outlined in box 1. Box 1: Criteria for specialist referral in adults
Diagnosis unclear Unexpected clinical findings (ie crackles, clubbing, cyanosis, cardiac disease) Unexplained restrictive spirometry Suspected occupational asthma Persistent non-variable breathlessness Monophonic wheeze or stridor Prominent systemic features (myalgia, fever, weight loss) Chronic sputum production CXR shadowing Marked blood eosinophilia (>1 x 109/l) Poor response to asthma treatment Severe asthma exacerbation
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