Clinical Approach: Coughing Dog or Cat

Coughing and respiratory distress are among the most common reasons dogs and cats present to veterinary practice. While many cases involve relatively straightforward diagnoses, others can deteriorate rapidly and become life-threatening. A systematic approach is essential for localising disease, identifying underlying causes, and initiating appropriate treatment without delay.

In this article, I'll walk through a practical clinical approach to evaluating coughing and dyspnoeic patients, including key differentiators between cardiac and respiratory disease, diagnostic clues, and common respiratory emergencies.

Step 1: Localising the Cough

Not all coughs are created equal. One of the most valuable early steps is determining where the cough is originating. Careful observation of the cough's character and identifying any triggers can help narrow down the differential diagnoses before additional diagnostics are performed.

Coughing and respiratory distress are among the most common reasons dogs and cats present to veterinary practice. While many cases involve relatively straightforward diagnoses, others can deteriorate rapidly and become life-threatening. A systematic approach is essential for localising disease, identifying underlying causes, and initiating appropriate treatment without delay.

In this article, I'll walk through a practical clinical approach to evaluating coughing and dyspnoeic patients, including key differentiators between cardiac and respiratory disease, diagnostic clues, and common respiratory emergencies.

Upper Airway Cough:

Upper airway coughs are typically described as harsh, honking, or productive in nature. They are often triggered by excitement, exercise, or tracheal palpation during physical examination.

Common causes include:

• Tracheal collapse

• Canine infectious respiratory disease (CIRD)

• Laryngeal disease

Owners frequently describe these coughs as sounding like their pet is "trying to clear something from their throat."

Lower Airway Cough:

Lower airway disease typically produces a soft, moist, productive cough. The cough may be most noticeable during exercise or early in the morning after secretions have accumulated overnight.

Common differentials include:

• Pneumonia

• Chronic bronchitis

• Congestive heart failure (CHF)

Although lower airway coughs may sound productive, many pets will swallow expectorated material, making true expectoration difficult to observe.

Parenchymal Cough:

Disease affecting the pulmonary parenchyma often results in a dry, non-productive cough. These coughs may occur during exercise or even at rest in more advanced cases.

Potential causes include:

• Pulmonary fibrosis

• Pulmonary neoplasia

• Pulmonary oedema

Parenchymal disease frequently presents with additional respiratory compromise and should prompt further investigation.

Pleural Disease:

Pleural space disorders often produce a dry, shallow cough and altered breathing patterns rather than a classic cough.

Common causes include:

• Pleural effusion

• Pneumothorax

In many cases, respiratory effort becomes the primary clinical concern rather than the cough itself.

Is It Cardiac or Respiratory?

One of the most important clinical questions when assessing a coughing dog is determining whether the signs originate from heart disease or primary respiratory pathology.

Several clues can help distinguish between the two.

Findings Suggestive of Cardiac Cough:

Cardiac-associated coughs are often accompanied by:

• A detectable heart murmur

• Cardiomegaly on thoracic radiographs

• Pulmonary oedema

• Markedly elevated NT-proBNP concentrations (>1800 pmol/L in dogs)

• Significant improvement following furosemide administration

Affected patients commonly belong to breeds predisposed to cardiac disease, including:

• Cavalier King Charles Spaniels

• Dobermanns

• Large-breed dogs

Additional signs may include:

• Exercise intolerance

• Weakness

• Syncope

Findings Suggestive of Respiratory Disease:

Patients with primary respiratory disease often demonstrate:

• No audible murmur

• A normal cardiac silhouette

• Pulmonary pattern changes on thoracic imaging

• Normal or only mildly elevated NT-proBNP concentrations

• Minimal or no response to furosemide therapy

Additional clinical signs may include:

• Nasal discharge

• Sneezing

• Fever

Unlike cardiac disease, respiratory disorders can affect any breed.