Many cats and dogs seen by the Emergency Referral Service at RVC Small Animal Referrals have signs of respiratory distress (dyspnoea).

This can be gradually progressive or come on very rapidly with few warning signs. Dyspnoea can be very distressing to the patient, can worsen rapidly and is life-threatening. This means that every animal with respiratory distress must be treated as an emergency, being quickly assessed and carefully monitored while emergency treatment is provided and a diagnosis is made.

Signs

Respiratory problems can manifest in lots of different ways, including coughing, noisy breathing, a change in voice or reduced ability to exercise. More severe signs of breathing difficulties may include:

• Rapid breathing or continuous panting
• Long drawn out breathing
• Being unable to settle and distress
• Standing with elbows pointed outwards and the neck extended
• Exaggerated or abnormal movement of the chest/abdomen while breathing
• Blue gums
• Collapse 
• Open mouth breathing (in cats)

Causes

Respiratory distress can occur for lots of different reasons. Some of the most common causes that we see at RVC Small Animal Referrals include:

Pneumonia. This refers to an infection of the lungs that can be caused by contagious diseases or from breathing in food/liquid, usually after vomiting or regurgitation has occurred.
Congestive heart failure. This is when the heart is not working properly, leading to the build-up of fluid in and around the lungs.
Asthma. This is where the airways become inflamed and spasm, making them narrower, causing severe breathing difficulties.
Pyothorax. This refers to the presence of an infection in the chest between the body wall and the lungs. This causes a build-up of fluid around the lungs, compressing them and restricting an animal’s ability to breathe.
Laryngeal paralysis. This is where the muscles in the throat do not function correctly, meaning that it does not open to allow enough air in, particularly during heavy breathing.

This is just a small selection of the many causes of breathing difficulties that we see in cats and dogs. In addition to problems with the respiratory tract, there are a number of “look-a-likes” that can have signs such as those above, without any true respiratory problems, such as anaemia and some hormonal problems.

Investigations

There are many different tests that may be indicated in a cat or dog with respiratory distress, both to guide diagnosis and treatment. Many important pieces of information are gained from the information provided by owners and the initial examination in the consultation room. Other tests often have to be delayed as animals are too unstable to undergo further testing and the stress of handling may worsen their condition. When it is considered safe to do so, some of the tests that may be performed include:

Bloodwork. This is sometimes done to look for specific conditions (e.g. lungworm) but is more often run as part of a general health screen to guide appropriate drugs for anaesthesia or other treatments that may be required.
Radiographs (X-rays). These can be used to look at the heart, lungs, airways, ribs and other structures involved in breathing.
CT scan. This is similar to x-rays but gives a more detailed 3-dimensional evaluation of the structures involved in breathing and can also be used to detect problems such as blood clots in the lungs.
Ultrasound. This can give rapid patient-side information about animals with very little stress/handling and is one of the best ways to look at the heart, but it can only give limited information about the lungs.
Bronchoscopy. This involves looking in the airways with a small camera to evaluate the airways and is performed under general anaesthesia. Biopsies can also be obtained this way and foreign material that has been inhaled can potentially be removed.
Airway washing. This involves flushing a small amount of sterile saline into the airways and collecting it again, usually under general anaesthesia. This allows cells or infectious agents to be collected to gather more information about the cause of an animal’s breathing difficulties.

Treatment and prognosis

Just as there are many different causes and varying severity of respiratory distress, the treatment and prognosis can be very variable. Most animals with breathing difficulties benefit from supplemental oxygen. This can be administered in a variety of ways, depending on the size of the patient and how unstable they are. Sedation is often used to keep animals calm in such stressful situations as that stress can make them try to breathe harder, worsening their problems.

Some animals with severe, life threatening, respiratory distress may require additional emergency procedures or therapies to help stabilise them. These may include drainage of fluid around the lungs (thoracocentesis), creating a hole in their airways to allow them to breathe past a problem in their upper airways (tracheostomy), placing them on advanced life support with a ventilator to help them breathe, or the administration of medication to treat a specific underlying cause.