Answer is D (Small airways are not involved): Asthma involves both large and small airways but alveoli are not involved Charcot Leyden crystals may be seen in sputum: Pathology by woolf lsr (1998)/434 Sputum from Asthmatics show ceain characteristic features, including charcot leydencrystas The microscopically identifiable features described in sputum are three 'C's Charcot Leyden crystals - Derived from granules of eosnophils andfbund only in Asthma Curshmann spirals - Curiously twisted casts of airways : Whorls of shed epethelium Creola bodies - Clumps of cells or isolated metaplastic cells Reversible Airflow obstruction is a charachteristic feature (Davidsons 18th/55, 326) Reversible Bronchoconstriction is the hallmark of Asthma The charachteristic feature of Asthma is Intermittent and Reversible airflow obstruction. Narrowing of airways is usually reversible, but in some patients with chronic asthma there may be an element of irreversible airflow obstruction Asthma involves both large and small airways Asthma involves Large and small airways hut not alveoli - 'Allergic Diseases: Diagnosis Treatment' 3rd/ 120 The large and small airways are both involved in Asthma -'Childhood Asthma: Diagnosis, Treatment & Management' r/15 Intermittent Asthma responds better to bronchodilator therapy than persistant Asthma Bronchodilators are effective drugs for the treatment of acute exacerbations or intermittent episodes of Asthma but they are not sufficient to control asthma in patients with persistant symptoms (persistant asthma) Bronchodilators are not sufficient to control Asthma in patients with persistant symptoms'