Coughing is an expiratory effort producing a sudden, noisy expulsion of air from the lungs, usually in an effort to free the lungs of foreign material (real or imagined). Respiratory distress is a general term referring to difficulty, or a change for the worse, in breathing habits. The coughing reflex is the result of mechanical or chemical irritation of the pharynx, larynx, tracheobronchial tree, and some of the smaller airways. Occasionally, pathology of the pleura, pericardium, diaphragm, nose, and nasal sinuses may cause coughing.
General Approach. Past medical problems and all current medical activity should be reviewed. A complete physical and radiographic examination of the thorax and cervical region is part of the evaluation. Auscultation and palpation of the larynx, trachea, and thorax for physical deformities or pain are essential in all cases. A complete blood count, fecal flotation examination, heartworm examination, blood chemistry profile, electrocardiogram, bronchial wash, with culture, bronchoscopy, pleural tap, and blood gas analysis may provide the clinician with additional specific information.
Nature of the Cough. Knowing when the cough occurs, what, if anything, brings it about, whether it is moist or dry, and a description of the coughing sound itself may be useful information. The cardiac cough is most prominent at night initially. Pneumonia is likely to be worse initially during the day. Coughing due to infectious, parasitic, allergic, or neoplastic disease most commonly occurs in the daytime. Coughing due to collapse of the trachea and bronchi is stimulated by drinking water. The typical "goose-honk" sound occurs. Coughing that develops while eating or immediately afterward suggests upper airway obstruction, laryngeal paralysis, or an esophageal disorder. Hemoptysis is a sign of heart worms, neoplasia, foreign body, or coagulopathy.
Sound of the Cough. Moist coughing suggests free alveolar or bronchial pulmonary fluid. Inhalation pneumonia, pulmonary emboli, and pulmonary edema are examples.
Dry coughing sounds suggest a cardiac origin (without cardiac failure), bronchitis, tracheobronchitis, tonsillitis, most allergic coughs, diffuse pulmonary parenchymal disease or those associated with neoplasia when free alveolar fluid accumulation is not present. Goose's "honk" sounds are associated with the collapsing trachea main stem bronchi and segmental tracheal injury. Wheezing and rattling are noisy types of sounds often heard with bronchiectasis, chronic obstructive lung disease, and some allergies.
Terminal Retch. It tends to be nonproductive in early cardiac disease, tracheitis, bronchitis, and irritating lesions of the pulmonary tract. In diseases in which mucus, edema, mucopurulent materials, or hemorrhage accumulates, there is likely to be material expectorated following the coughing.
CAUSES OF COUGHING IN DOGS AND CATS
· Chronic bronchitis
· Pneumonia-bacterial, viral, fungal
· Chronic pulmonary fibrosis
· Collapsed trachea
· Hilar lymph node enlargement
· Secondary to achalasia
· Ribs, sternum, muscle
· Cardiovascular causes
· Left heart failure
· Enlarged heart (esp. left atrium)
· Heart failure (pulmonary signs)
· Pulmonary emboli
· Pulmonary edema (vascular origin)
· Allergic causes
· Bronchial asthma
· Eosinophilic pneumonitis
· Eosinophilic pulmonary granulomatosis
· Pulmonary infiltrate with esoinophilia (PIE)
· Other immune states
· Sinusitis (?)
· Reverse sneeze (postnasal drip?)
· Trauma and physical factors
· Foreign body- -esophageal; tracheal Irritating gases
· Collapsed trachea
· Hypoplastic trachea
· Hepatomegaly Inhalation-liquid; solid
· Visceral larva migrants Filaroides osleri (lung worm)
· Aelurostrongylus (feline lung worm)
· Paragonimus kellicoth (lung fluke-dog; cat)
· Dirofilaria immitis (dog; cat)
· Capillaria aerophilia (dog; cat
Accurate knowledge of the nature of the cough usually permits reasonable and accurate classification of the problem. In general, drugs that are used to treat the coughing pet include antibiotics for infectious disease, corticosteroids for allergic conditions; digitalis, diuretics, and vasodilators for congestive heart failure; and antispasmodic or antitussive agents for inflammatory, noninfectious lung and tracheal problems.