Canine Respiratory System and Associated Pathologies

The canine respiratory system, responsible for gas exchange, can be affected by various conditions leading to respiratory distress manifested as audible wheezing and coughing. Understanding the underlying mechanisms is crucial for accurate diagnosis and treatment.

Anatomical Considerations

The canine respiratory tract comprises the upper respiratory tract (nose, pharynx, larynx, trachea) and the lower respiratory tract (bronchi, bronchioles, alveoli). Each component can be the site of disease processes.

Causes of Canine Respiratory Symptoms

Upper Airway Obstruction

• Tracheal Collapse: Weakening of the tracheal cartilage, leading to airway narrowing, particularly during inspiration. Common in small breed dogs.
• Laryngeal Paralysis: Loss of function in the laryngeal muscles, resulting in incomplete airway opening. Predisposing factors include age and breed.
• Foreign Body Aspiration: Inhaled objects obstructing the airway.
• Infections: Upper respiratory tract infections (e.g., kennel cough) can cause inflammation and mucus production, leading to coughing.

Lower Airway Diseases

• Bronchitis: Inflammation of the bronchi, often accompanied by mucus production and wheezing. Can be acute or chronic.
• Pneumonia: Infection of the lungs, causing inflammation and fluid accumulation. Symptoms include coughing, often with labored breathing.
• Asthma: Bronchial hyperresponsiveness leading to airway narrowing and wheezing, often triggered by allergens.
• Parasites: Lungworm infestations can cause coughing and respiratory distress.
• Heart Failure: Congestive heart failure can cause fluid buildup in the lungs, leading to coughing, particularly at night.

Other Contributing Factors

• Allergies: Exposure to environmental allergens can trigger inflammatory responses in the respiratory tract.
• Irritants: Inhaled pollutants or irritants can cause coughing and inflammation.

Diagnostic Approaches

Diagnosis often involves a combination of physical examination, radiography (chest X-rays), bronchoscopy, and blood tests to identify the underlying cause of the respiratory symptoms.

Treatment Strategies

Treatment depends on the underlying cause and may include medications (bronchodilators, corticosteroids, antibiotics), supportive care (oxygen therapy), and surgical interventions (e.g., tracheal surgery).