Use of Dipstick Assay and Rapid PCR-DNA Analysis of Nasal Secretions for Diagnosis of Bacterial Sinusitis in Children With Chronic Cough

Song, Charles; Chorath, Jeena; Pak, Youngju; Redjal, Nasser

Chronic cough is defined as daily cough lasting 4 weeks or longer. 1 In children under 15 years of age, the causes of chronic cough include congenital defects, asthma, foreign body aspiration, infections, allergic diseases, gastroesophageal reflux, tumors, and other rare causes. 2 Among these, the most common etiologies include asthma, upper airway cough syndrome, protracted bacterial bronchitis, and nonspecific cough. 3, 4 The diagnosis of asthma or cough variant asthma can be made on the basis of NAEPP EPR-3 criteria and response to a bronchodilator. 5 Upper airway cough syndrome is a common entity, 3, 4 most likely triggered by postnasal drip due to either allergic and nonallergic rhinitis or bacterial and nonbacterial sinusitis. Protracted bacterial bronchitis is now recognized as one of the most common causes of chronic wet cough, especially in young children under 5 years of age. 6, 7 Once asthma and other conditions listed above are ruled out, upper airway cough syndrome or protracted bacterial bronchitis need to be considered as the most likely diagnoses. In approaching these clinical entities, our goal was to promptly detect the patients with bacterial sinusitis and the involved pathogens and to treat them with appropriate antibiotics. To this end, we decided to employ a novel method described by Huang and Small, 8 who reported that nasal secretion dipstick assay was highly correlated with sinus imaging studies and could be utilized for the diagnosis of sinusitis. We employed this simple approach for obvious reasons: speed, cost-effectiveness, and avoidance of radiation risk associated with sinus imaging studies. We also sought an equally simple and rapid method for identification of the pathogens for the suspected sinusitis. Positive findings in imaging studies of sinuses such as opacities and thickened lining indicate the presence of inflammation, possibly infection, but may have poor correlation with clinical disease 9,10 and do not reveal any information on etiologies. Although sinus puncture would yield such information, 11 this cannot be performed in most nonsurgical office settings. Studies have documented that nasal culture is a poor reflection of the microbes in the sinus cavity. 12 Therefore, we analyzed the microbes from the osteomeatal area utilizing a quantitative PCR method in an attempt to detect the pathogens that may cohabit both sinus and nasal cavities.