What is Pulmonary Edema in Dogs?

Pulmonary edema is a serious condition where an accumulation of fluid builds up in their lungs. It can be bought on for a variety of reasons which includes cancer, a traumatic event, strangulation or heart failure. Where trauma is the cause, it could be a bang to the head or electrocution that causes the oedema. There are some pretty clear symptoms to watch out for and if you notice any of these or have any concerns for your dog, you need to contact your vet immediately.

The good new is that in the majority of cases treatments and medication can be very effective and as such resolve the problem. However, this does depend on the underlying cause of the condition which would have to be determined by your vet.

Understanding Lung Functions

Lungs are made up of something known as alveoli which are minute clusters of air balloons and each of these are lined with a thin layer of cells which touch tiny blood vessels found in the lungs. When a dog (or person) breathes in air it fills these tiny air balloons and once full, the cells lining the alveoli together with the small vessels they are in contact with, take in all the oxygen. They then release carbon dioxide into the air on exhalation.

Should lungs fill with fluid rather than air, the available space for oxygen to build up is dramatically reduced and the expulsion of carbon dioxide is limited which is the condition known as pulmonary oedema. In fact, the word oedema is a general term used to refer to an accumulation of fluid found anywhere in the body. When your dog's lungs fill up the fluid typically comes from the blood vessels and tissues. These leaks into the lungs could be caused by many diseases or a trauma of some sort although heart failure and cancer can also be the underlying cause of pulmonary oedema.

The Symptoms to Watch Our For

It really depends on how much fluid has built up in your pet's lungs as to the severity of the symptoms. However, the clinical signs of pulmonary oedema can be either quite mild to very severe and may well include the following:

• Coughing
• A difficulty in breathing
• Rapid breathing
• Weakness – your dog may even collapse
• Your pet's lips and tongue may be blue in colour – this is a condition known as cyanosis and it occurs when there is limited oxygen getting to the body

It is important to bear in mind that several medical conditions can be the underlying cause of pulmonary oedema. This in turn means there can be certain clinical signs which could be associated with these medical conditions. An example of this would be when another injury could be linked with a traumatic episode and this caused the oedema.

Diagnosing the Condition

A vet would need to have your pet's medical history to hand and would perform a thorough examination so they could diagnose the condition. Your vet would listen to the dog's chest to see whether air is being inhaled and exhaled normally. They will check your dog's heart to see if there are any changes in their heart rate and rhythm, the vet would also detect if there is a heart murmur during the examination.

Your vet would typically take X-rays of your pet's chest to confirm the pulmonary oedema and once diagnosed, further tests would be done to find out what the underlying cause of the condition might be.

Treatment for Pulmonary Oedema

The treatment of pulmonary oedema typically works towards several goals which include the following:

To stabilise your dog's condition

• If your pet is having real difficulty in breathing or is disoriented and unstable, then oxygen would need to be given on top of other treatments to stabilise their condition. It is important to bear in mind that pulmonary oedema can be thought of as the first stage of pneumonia. Antibiotics are occasionally given together with other treatments.

To treat the oedema

• In the majority of cases, a course of medication would normally resolve the problem but if the build up of fluid is extreme, then your dog may need to be hospitalised. This is to ensure their condition is closely monitored and followed. A vet would need to take several X-rays in order to determine how the oedema is being resolved.

To treat the underlying illness or cause

• It is crucial for any underlying cause of the pulmonary oedema to be treated – an example would be if the oedema was caused by heart failure the condition would need to be managed and treated with other medications to support the heart. Your dog would need to be monitored and follow-up tests would need to be carried out.

What Would be the Outcome?

The outcome of a dog's condition following a pulmonary edema really does depend on the underlying cause. Should the edema have been caused by heart failure, the condition could recur if the heart condition is not treated effectively. Heart failure is considered to be a chronic illness which means there is a strong possibility a pulmonary edema might recur. However, should the edema be caused by a traumatic event which could include strangulation or some sort of head injury – the edema can be effectively treated so the edema does not recur as long as your dog recovers fully from their trauma.