Rinitis y síndrome tusígeno. ¿Son de utilidad las características epidemiológicas, clínicas y funfcionales en el diagnóstico diferencial con el asma bronquial?

Abstract

Patients often visit family practitioners or respiratory specialists complaining of cough. In non-smokers, the most common cause is postnasal drip secondary to rhinitis. The second most common cause is bronchial asthma. a) To know the epidemiological, clinical and functional features of patients who visit our outpatient pneumology clinic complaining of chronic cough as an isolated symptom, in whom bronchial asthma is suspected, but who have received a diagnosis of rhinitis. b) To analyze the differences between such patients and those in whom chronic cough has been attributed to bronchial asthma. One hundred thirty-one patients with chronic cough were enrolled for study under the following protocol: 1) taking of a detailed case history (epidemiological and clinical data), 2) physical examination, 3) blood work-up, 4) paranasal sinus and chest X-rays, 5) spirometry at baseline and after 200 micrograms of salbutamol if obstruction was present, 6) methacholine challenge test, 7) skin tests for common respiratory tract allergens, 8) other techniques, depending on suspected diagnosis (CT chest scan, fiberoptic bronchoscopy, consultation with a gastroenterologist or otorhinolaryngologist). One hundred seventeen (89.3%) patients received a diagnosis of rhinitis. Chronic cough was attributed solely to rhinitis in 61 (46.5%) patients. Forty-four (33.5%) were diagnosed as bronchial asthma; 38 (29%) also had rhinitis. Chronic cough was attributed to a different diagnosis in 26 cases (19.8%). The 61 patients with rhinitis as the sole cause of chronic cough were aged 23.8 +/- 10.8 years (9-63 years); 33 (54% of the 61) were men and 28 (46% of the 61) were women. We found that patients with rhinitis more often suffered nasal symptoms (chi 2 = 22.4; p = 0.01), pharyngeal irritation (chi 2 = 9.63, p = 0.05), dry cough from the upper respiratory tract (chi 2 = 16.4, p = 0.001), atopy (chi 2 = 18.1, p < 0.001) and greater FVC (F = 5.28, p = 0.006) than did patients with asthma or other diagnoses. 1) Rhinitis was the most common cause of chronic cough in the studied patients in whom a diagnosis of bronchial asthma had been suspected. 2) Epidemiological characteristics did not aid differential diagnosis between rhinitis and bronchial asthma (with or without associated rhinitis). 3) A detailed medical history focusing on upper airway symptoms can be useful, although there may be cases of silent postnasal drip syndrome. 4) Paranasal x-rays help to rule out complications of rhinitis. 5) A positive bronchial challenge test does not necessarily indicate a diagnosis of bronchial asthma. 6) Allergy to pollen is the most common finding among atopic patients with rhinitis.