A pathogenic triad in chronic cough: asthma, postnasal drip syndrome, and gastroesophageal reflux disease.

BACKGROUND: Coughing may be produced by a number of different disorders in distinct anatomic sites. Chronic cough causes major functional limitation in a considerable patient population and requires careful evaluation. METHODS: Seventy-eight nonsmoking patients of both genders who complained of cough for > or =3 weeks and had normal findings on plain chest radiographs were studied prospectively. Their histories were obtained, and physical examinations were performed. The diagnostic workup included pulmonary function tests, CT of the paranasal sinuses and chest, carbachol provocation test, fiberoptic rhinoscopy, fiberoptic bronchoscopy, and 24-h esophageal pH monitoring. The final diagnosis depended on clinical, radiologic, and laboratory findings; a successful response to therapy was required for confirmation. RESULTS: The causes of chronic cough were determined in all patients. Coughing was due to a single cause in 30 patients (38.5%) and multiple causes in 48 patients (61.5%). The five most important causative factors were asthma (46 patients; 58.9%), postnasal drip syndrome (PNDS; 45 patients; 57.6%), gastroesophageal reflux disease (GERD; 32 patients; 41.1%), bronchiectasis (14 patients; 17.9%), and tracheobronchial collapse (11 patients; 14.1%). INTERPRETATION: Asthma, PNDS, and GERD, alone or in combination, were responsible for 93.6% of the cases of chronic cough. The presence of these three conditions was so frequent that the expression "pathogenic triad of chronic cough" should be acknowledged in specialized literature. It is essential to consider pulmonary and extrapulmonary causes in order to prescribe a successful specific therapy for chronic cough.

Frequency and site of gastroesophageal reflux in patients with chest symptoms. Studies using proximal and distal pH monitoring.

Prolonged ambulatory pH monitoring was performed on 89 patients with previous diagnosis of asthma (27 patients), chronic cough (28 patients), noncardiac chest pain (34 patients), and on 27 healthy control subjects. The extent of gastroesophageal reflux (GER) was determined using a catheter containing two antimony pH electrodes positioned 5 cm and 20 cm above the superior border of the manometrically determined lower esophageal sphincter. Reflux was defined as a drop in pH to < 4 in the distal esophagus. We compared both pH < 4 and pH < 5 as the beginning of reflux episodes for the proximal esophagus. Considering the confidence interval of 95% in healthy control subjects as a normality criterion, we found a prevalence of abnormal distal GER in 44% of asthmatics, 50% of patients with cough, and 53.8% of patients with noncardiac chest pain. Abnormal proximal acid exposure was found in 24% of asthmatics, 10.7% of patients with cough and 44.1% of patients with chest pain. Distal acid exposure was significantly longer than proximal esophageal acid exposure in all patient groups (p < 0.05). There were no differences in the evaluation of proximal GER comparing pH < 4 with pH < 5. The data also indicate a tendency toward upright, rather than supine acid exposure. These results support the use of 24-h pH monitoring in patients with chest complaints and indicate that GER may frequently be involved in the pathogenesis. They do not support the theory that proximal GER is a specific etiologic factor in chronic cough or asthma.