Eleanor C. Hawkins, DVM, Diplomate ACVIM (Small Animal Internal Medicine), North Carolina State University
Productive coughs can be difficult to recognize and are usually caused by inflammatory or infectious diseases of the airways or alveoli or by heart failure. Differential diagnoses include pulmonary edema (cardiogenic or noncardiogenic), canine infectious tracheobronchitis, canine chronic bronchitis, allergic bronchitis, bacterial bronchitis or pneumonia, aspiration pneumonia, parasitic disease, and severe fungal pneumonia. Hemoptysis is an unusual clinical sign that most commonly occurs in animals with heartworm disease or pulmonary neoplasia. Cough associated with airway inflammation (tracheitis and/or bronchitis) or large airway collapse is often loud, harsh, and paroxysmal, whereas coughs associated with pneumonia and pulmonary edema are usually soft. Cough resulting from tracheal disease is exacerbated by pressure on the neck. Cough due to airway inflammation (bronchitis) tends to occur more frequently on rising from sleep or during and after exercise or exposure to cold air. Cough caused by heart failure tends to occur more frequently at night. Considerations for dogs with acute cough but normal thoracic radiographs include canine infectious tracheobronchitis, influenza, acute aspiration, and acute foreign body inhalation. For cases with radiographic abnormalities of the pulmonary parenchyma, obtaining specimens for cytology, microbiology, and possibly histology is indicated. Specimen collection techniques include tracheal wash, nonbronchoscopic bronchoalveolar lavage, transthoracic lung aspiration, bronchoscopy and bronchoalveolar lavage (or other specimen collection methods as indicated), and lung biopsy by thoracotomy or thoracoscopy.
COMMENTARY: This article reminds us to carefully assess history, physical examination, and thoracic radiography when presented with coughing dogs. An accurate diagnosis is essential before considering treatment options. The author provides a thorough approach to coughing, whether from respiratory, cardiac, or systemic causes.