Diseases That Cause Respiratory Distress In Dogs

The origin of difficult and problematic breathing in dogs is quite varied. This leaves both owners and the veterinarian with a real challenge to avoid complications.

There are numerous pathologies that trigger respiratory distress in dogs. The history, symptoms, and physical examination are usually sufficient to determine which areas of the respiratory system are involved. In this way, the vet can be more effective in determining a proper diagnosis.

To do this, the respiratory tract is divided into several areas: airways, lung parenchyma (the tissue that makes up the organ) and the pleural space. If you want to know more about this world of pathologies in dogs, keep reading.

Diseases that cause respiratory distress in dogs

Next, we will talk about a series of pathologies that affect the respiratory system and that cause difficulty in breathing.

Upper respiratory pathologies

First, the upper airways are made up of the nostrils, mouth, pharynx, glottis, and epiglottis. The pathologies that affect these organs usually present with loud abnormal respiratory sounds. It is what is known as stridor or rales and they are audible without the need to use a stethoscope.

As a general rule, respiratory distress originating in the upper airways results from an obstruction. This makes symptoms worse with exercise or excitement, because it increases the narrowing of the pathways. However, at rest, the respiratory parameters can become almost normal.

Many patients with these pathologies come to the veterinary clinic with recurrent episodes of fever. They are unable to effectively thermoregulate because, during panting, the volume of air that passes over the tongue is insufficient.

In addition, the increase in temperature starts a vicious cycle. Stimulates increased respiratory rate and panting, narrowing the airways even more.

What are the most common causes of obstruction?

It is important to note that brachycephalic breeds (such as bulldogs or pugs ) are genetically predisposed to have blocked upper airways. Some of the most common causes of these obstructions are the following:

• Paralysis of the larynx.
• Tracheal collapse.
• Polyps or tumors in the lumen of the upper respiratory tract.
• Aspiration of foreign bodies.

Lower respiratory pathologies

In this case, the larynx, trachea, bronchi, bronchioles and  alveoli may be affected . The most common is that they are abnormalities of the bronchi and bronchioles, of inflammatory origin, and cough is the most common clinical finding. It is usually a harsh cough and tends to exacerbate inflammation, creating a new vicious cycle.

What are the most common causes?

The normal thing is that there is an obstruction of the pathways closest to the lung due to an increase in mucus production. This mucus builds up and weakens the rest of the respiratory system. Hence, they are often complicated by bronchopneumonia.

Among the most common causes of these pathologies are:

• Canine chronic bronchitis.
• Masses or foreign bodies in the lumen of the lower respiratory tract.

Pathologies of the lung parenchyma

Any disease that affects the lung will present with varying degrees of hypoxia (lack of oxygen in the blood) and, therefore, respiratory distress. This is due to an imbalance in ventilation due to inflammation or closure of the alveoli.

On auscultation, it is common to hear abnormal breath sounds, such as crackles. It is also necessary to carefully analyze the dog’s heart for signs of congestive heart failure.

What are the most common causes?

We present the most common causes of lung parenchymal diseases:

• Pneumonia, there are several types. For example, aspiration pneumonia after vomiting.
• Pulmonary edema and hemorrhage, ultimately an abnormal accumulation of fluid in the lung. Typical, for example, of congestive heart failure.
• Pulmonary thromboembolic disease.
• Tumors

Pleural space pathologies

The pleural space is defined as the virtual gap between the chest wall and the thoracic organs. It is virtual because there really only exists a real space in the case of pathology, that is, in the event that fluid or air improperly accumulates inside.

This will lead to some degree of lung dysfunction with increased respiratory rate and dyspnea. In addition, when listening to the chest the lung and heart sounds will be diminished or muffled. Why? because there is a foreign substance occupying that virtual space and moving the organs away from the chest wall.

Pleural effusions are classified according to the type of fluid they contain. One of the most common is hemothorax (accumulation of blood) after an accident, or pneumothorax, for example when a rib breaks and passes through the chest wall allowing air to enter.

Protecting canine respiration

At the moment of truth, the exact diagnosis of the cause of this problem is a real challenge for the veterinarian. The possibilities are almost endless and many times several things happen at the same time, especially when it comes to an infectious disease.

Therefore, carrying out complementary tests such as analysis or X-rays can be the best allies of a professional in distress to find out the reasons for respiratory distress in dogs.