Furthermore, bronchiectasis and bronchial wall thickening were identified in 48% and 58% of patients, respectively, with only 30% reporting any symptoms. Ooi et al [6] were unable to correlate the frequency of acute symptom exacerbation (including cough symptoms) and the degree of bronchial wall thickening in 60 consecutive patients with CT-proven bronchiectasis. In a large single-center prospective study, Grydeland et al [39] used quantitative analysis of bronchial wall thickening and compared findings between patients with COPD (n = 463) and those without COPD (n = 488). Airway wall thickening was found to be statistically associated with chronic cough in patients with COPD but did not reach significance in the non-COPD group. Interstitial lung disease and pulmonary fibrosis have been reported as etiologies of chronic cough, although prevalence of diagnosed cases is variable, ranging between 0.4% and 8% of the reviewed case series [2,7,16,17]. Chest CT is considered the reference standard in the evaluation of interstitial lung disease. Although at least one study reported good correlation between chest radiography and chest CT in this setting [46], chest CT has been shown to be more sensitive than both chest radiography [31] and LDCT [27]. In 97 patients with chronic cough who also had normal chest radiographs, Truba et al [3] reported interstitial abnormalities in 4 patients. Association between cough symptoms and CT findings of interstitial lung disease has been variable. In a small prospective cohort of 36 patients with RA, cough was not found to be statistically associated with restrictive findings on either PFT or HRCT analysis [31]. In 107 consecutive patients with systemic sclerosis, cough was associated with HRCT findings [31]. In the setting of chronic cough after failed initial evaluation and/or empiric treatment, the limited evidence suggests a role for chest CT to identify underlying pulmonary disease.
Chronic Cough. Furthermore, bronchiectasis and bronchial wall thickening were identified in 48% and 58% of patients, respectively, with only 30% reporting any symptoms. Ooi et al [6] were unable to correlate the frequency of acute symptom exacerbation (including cough symptoms) and the degree of bronchial wall thickening in 60 consecutive patients with CT-proven bronchiectasis. In a large single-center prospective study, Grydeland et al [39] used quantitative analysis of bronchial wall thickening and compared findings between patients with COPD (n = 463) and those without COPD (n = 488). Airway wall thickening was found to be statistically associated with chronic cough in patients with COPD but did not reach significance in the non-COPD group. Interstitial lung disease and pulmonary fibrosis have been reported as etiologies of chronic cough, although prevalence of diagnosed cases is variable, ranging between 0.4% and 8% of the reviewed case series [2,7,16,17]. Chest CT is considered the reference standard in the evaluation of interstitial lung disease. Although at least one study reported good correlation between chest radiography and chest CT in this setting [46], chest CT has been shown to be more sensitive than both chest radiography [31] and LDCT [27]. In 97 patients with chronic cough who also had normal chest radiographs, Truba et al [3] reported interstitial abnormalities in 4 patients. Association between cough symptoms and CT findings of interstitial lung disease has been variable. In a small prospective cohort of 36 patients with RA, cough was not found to be statistically associated with restrictive findings on either PFT or HRCT analysis [31]. In 107 consecutive patients with systemic sclerosis, cough was associated with HRCT findings [31]. In the setting of chronic cough after failed initial evaluation and/or empiric treatment, the limited evidence suggests a role for chest CT to identify underlying pulmonary disease.