In addition to cardiac disease, coughing can be a sign of another disease process. Coughing after eating or drinking suggests laryngeal dysfunction. Nocturnal coughs occur with cardiac insufficiency, pulmonary edema, and psychogenic conditions.10 If the cough is a dry hack or a goose-like honk, consider tracheitis, tracheal collapse, and compression of mainstem bronchi by left atrial enlargement or masses. Infectious tracheobronchitis or chronic bronchitis in dogs causes a productive cough and gagging. Cats with bronchial disease can experience episodic coughing, expiratory wheezes, and dyspnea. A soft, moist cough suggests pneumonia, parasitic or allergic disease, pulmonary thromboembolism, or edema.10
If coughing at home has been noted, the client should be asked what induces the cough (eg, exercise, excitement), about the quality of the cough (eg, dry, productive, moist), and how often the cough occurs. Clients often do not report coughing in cats but may report that the patient is gagging or retching, which sometimes progresses to vomiting. Thoracic radiographs should be obtained to determine if the cough is cardiogenic. Radiographic findings that indicate cardiomegaly (specifically, left atrial enlargement causing upward compression of the trachea and mainstem bronchi) may indicate a cardiac cause. In older, small-breed dogs, which are most commonly affected by congestive heart failure and airway disease (eg, tracheal collapse, chronic bronchitis), an airway cause for the cough should always be ruled out before diagnosing a cardiac cause. Pulmonary edema may be present radiographically in dogs with congestive heart failure but is unlikely to cause cough unless fluid accumulation is severe enough to build up in the airways.11