The cough reflex is critically important in the clearance of abnormal airway secretions and protection of the lower respiratory tract from aspirated foreign matter. A weak or ineffective cough can lead to respiratory compromise from even a relatively minor bronchial infection. Persistent cough is often one of a constellation of symptoms indicative of respiratory disease—a potential clue in the differential diagnosis of the patient’s illness. Given the widespread distribution of sensory nerve endings of the cough reflex throughout the upper and lower respiratory tract, it is not surprising that myriad respiratory diseases, involving lung parenchyma and airways, can manifest with cough. Sometimes cough is the sole or predominant symptom in a patient who is otherwise well. Evaluating and treating the patient with persistent cough who has few, if any, other respiratory symptoms is a common challenge for the practicing physician. This review covers the normal cough mechanism, impaired cough, pathologic cough, cough suppressant therapy, and new developments. Figures show a flow-volume loop during cough, a posteroanterior chest x-ray in a patient presenting with chronic cough, flow-volume curves and spirograms documenting expiratory airflow obstruction, and the approach to the patient with chronic cough. The table lists selected examples of extrapulmonary physical findings of potential importance in the assessment of cough.
This review contains 4 highly rendered figures, 1 table, and 94 references.
UTILITY OF NOVEL FLOW VOLUME LOOP INDEXES IN DIAGNOSING AIRFLOW OBSTRUCTION
