ABSTRACT
Sinus roentgenograms and allergy evaluation are utilized to determine the possible causes of PNDS; spirometry pre-and postbronchodilator or MIC to investigate asthma; and bar ium esophagography or esophageal pH monitoring for GERD. While barium esophagogra phy is a much less sensitive and specific test than 24-h esophageal pH monitoring, it may
occasionally be singularly helpful in diagnosing GERD as the cause of cough. It has been able to reveal reflux to the thoracic inlet at a time when refluxate from the stomach had pH values similar to those of the normal esophagus, precluding its detection in the esopha geal pH tracings. It is important to emphasize that diagnostic testing for GERD is recom mended only in patients who do not have prominent upper gastrointestinal symptoms of GERD (i.e., “ silent” GERD). It is not indicated in patients with cough who complain at least weekly of sour taste in the mouth, regurgitation, or heartburn, since the frequency of these symptoms is itself indicative of GERD. If the chest roentgenogram is normal or nearly normal, the order of tests is as listed above. On the other hand, if the chest roent genogram is abnormal (e.g., a central mass is seen), sputum studies and bronchoscopy should be ordered first. In patients with risk factors for aspiration due to pharyngeal dys function, a modified barium swallow may be helpful. Chest computed tomography may be used to assess for bronchiectasis not suggested by routine chest roentgenograms. Unless the clinical evaluation or chest roentgenogram suggests a cardiac cause, noninvasive car diac studies should be ordered last.
