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Thursday, 20 October 2011

Difficulty breathing in dogs and cats

Welcome to PercyPods Pet Emergency blogs. This week we are going to discuss one of the most serious problems that can affect dogs and cats, namely difficulty breathing. As any of you that has had trouble breathing will know this can be very uncomfortable. It can also be life-threatening and so it is important for pet carers to be well informed about this problem.

The basics of breathing

In order to understand what can cause your pet to have trouble breathing it will be useful to briefly discuss how breathing happens and why it is important. So breathing is triggered by the brain and relies on various muscles of the chest as well as some nerves. Breathing happens in two stages. The first stage is when we breathe in, which is called inspiration. Air is sucked in through the nose but possibly also the mouth and passes the throat and vocal cords (the pharynx and larynx). It then flows down the windpipe (trachea) into the lungs.

The lungs consist of lots and lots of airways (bronchi, bronchioles) and millions of tiny little air sacs (alveoli) – you can think of these air sacs a bit like a sponge. When the air reaches these sacs, oxygen leaves the air and passes into the bloodstream. This is essential because the body needs to get enough oxygen basically to stay alive and difficulty breathing can compromise the amount of oxygen that the body receives with potentially disastrous consequences. As well as oxygen leaving the air sacs, carbon dioxide passes from the bloodstream into the air sacs. The carbon dioxide is then removed from the body as the animal breathes out; breathing out is the second stage and is referred to as expiration. Breathing out carbon dioxide is important as too much carbon dioxide is harmful for the body.

What can cause difficulty breathing?

So just to recap, breathing basically relies on the brain, some muscles and nerves, and the respiratory tract to be working well enough; the respiratory tract consists of the nose, the throat and vocal cord area, the windpipe and the lungs. An animal can therefore have trouble breathing if any one of these parts of the body has a problem. There are therefore lots of different causes of difficulty breathing and we will just mention a few of the most common ones here.

Nose, throat (pharynx) and vocal cord area (larynx)

So let’s start with the nose, throat and vocal cord areas. Problems affecting the nose usually do not cause difficulty breathing but instead may cause sneezing and discharge from the nose. However breathing can become laboured if the nose is severely blocked for example by a tumour of some sort or by severe infection; some cats with cat flu for example can develop breathing difficulty due to severe infections affecting the nose. Dogs with short-noses, such as Pugs and Bulldogs, can be affected by a condition known as Brachycephalic Airway Obstruction Syndrome. This condition includes a number of abnormalities affecting the nose and the throat areas; affected dogs may develop significant breathing problems especially on hot days, during exercise or when very stressed.

Certain dog breeds are prone to a condition known as laryngeal paralysis where the vocal cords fail to move properly which prevents them breathing in air adequately. Laryngeal paralysis typically affects large breed dogs, especially retrievers, and the problem often gets worse on hot days or during exercise. A characteristic noise can be heard when a dog with severe laryngeal paralysis breathes in. Cats can suffer for example from something called a nasopharyngeal polyp, which is basically a benign mass on a stalk that can affect the nose and throat area as well as the ear canals. They may also suffer from tumours or inflammation affecting the vocal cord area and actually tumours and inflammation of these areas are problems that can also affect dogs as well.

The windpipe (trachea)

As mentioned before, once air has passed the throat and vocal cord area it enters the windpipe or trachea. Problems affecting the windpipe are actually pretty rare as a cause of difficulty breathing. However some little dogs, such as Yorkshire terriers or Chihuahuas, can be affected by a condition known as tracheal collapse where the windpipe flattens during breathing hindering the flow of air. These dogs often have a cough that has a very characteristic sound; it is usually described as a ‘goose honk cough’ and often gets worse when the dog gets excited or stressed. Both dogs and cats can also struggle to breathe if a foreign object gets stuck in their windpipe; for example we have seen a cat with a tooth stuck in the windpipe and several dogs with little bones stuck in their windpipes.

The lungs

Finally air that is breathed in reaches the lungs. Dogs and cats can be affected by a variety of diseases and other processes that affect the lungs. Unfortunately it is quite common for cats to be hit by cars and many of these cats develop laboured breathing. In some cases this is because of air leaking from the damaged lung, a condition known as pneumothorax, with the air then collecting around and compressing the lung. This compression is a bit like squeezing a sponge so it collapses. Another common cause of difficulty breathing after a traumatic episode is bruising of the lungs; just like any other part of the body, if the lungs are injured they can become bruised and this will hinder the movement of air and removal of oxygen from the air.

Other common conditions that can affect the lungs and cause difficulty breathing include heart failure, infections in the lung causing pneumonia, and cancer. Cats can also get a condition that is similar to asthma in people and in fact it is often referred to as feline asthma or feline bronchial disease. This condition is thought to be due to an allergic problem in many cases and is especially common in certain breeds such as Siamese and Abyssinian cats. There are various worms that can also cause difficulty breathing by different means; examples are lungworm and heartworm. Some dogs in particular may also get a foreign object of some sort trapped in their lungs. The most common example of this is when dogs such as Springer spaniels who like to run in the long grass inhale a grass awn or other plant material.

And lastly we would also like to mention that there are some diseases that can affect the nerves or muscles which are involved in breathing and these can cause your pet difficulties. For example infections such as tetanus or botulism or tick bite paralysis can do this; you should note that tick bite paralysis is not found in all parts of the world.

How will I know that my pet is having difficulty breathing?

Okay so now that we have discussed some of the causes of difficulty breathing, let’s move on and talk about what signs your dog or cat may show if they are affected by one of these conditions. In many cases it will be obvious to you that your pet is struggling to breathe. You spend a lot of time with your pet and are therefore used to seeing them with normal breathing. If they are struggling to breathe, they will usually have either an increase in the rate of their breathing or an increase in the amount of effort they use to breathe; in many cases there is an increase in both rate and effort. You may notice for example that there is more movement of their chest and tummy area or that there is flaring of the nostrils.

Some of the most severely affected animals show what we call ‘postural adaptations’ – this means that they do things such as sit upright rather than lying down, stand with their elbows out, or breathe with their neck extended to help them move air. In very severe cases, you may notice that your pet’s gums take on a bluish or purplish appearance rather than their normal salmon pink colour. This is referred to as cyanosis and should prompt immediate veterinary attention.

Some animals that are affected by conditions that cause difficulty breathing may show other signs for a period of time before they really start struggling to breathe. Such signs include coughing and not coping as well with exercise, and in other cases the signs may be even more vague such as being lethargic or off their food. It goes without saying that if you are worried about your pet’s breathing you must consult your veterinary practice immediately.

What will my vet do to help my pet?

Before we finish this blog let’s discuss briefly some of the things that your vet may have to do to find out why your pet has difficulty breathing and try and treat the problem. As we have already discussed there are lots of different reasons why a dog or cat may have trouble breathing and we can only really speak in general terms here. The first thing to stress is that dogs and especially cats that are struggling to breathe are in a very vulnerable position and it is very important not to stress these animals as this can cause them to deteriorate further. So you should handle these animals gently when getting them to your vet and your vet may want to approach the management of your pet in a slow and steady fashion, taking their time to do the various necessary tests and treatments rather than risking stressing your pet. More severe cases receive oxygen therapy and sometimes various drugs to try and make them feel better and make them more stable for further tests and treatments. It may also be necessary for example to remove air or fluid from around the lungs using a needle, a procedure known as thoracocentesis.

Tests that are commonly performed in animals with difficulty breathing include ultrasonography and taking x-rays, and an ECG may be done in some cases where heart failure is suspected to see whether the heart is beating with a normal rhythm. In some cases an endoscope, which is basically like a tiny video camera, is passed into the respiratory tract under a general anaesthetic and other tests that may be performed include analysing your pet’s faeces and taking blood tests.

Depending on the diagnosis that is made your pet may need to be on medications, sometimes for the rest of his or her life, or they may need an operation. Their exercise may need to be restricted, sometimes just for a while but sometimes also more long-term. Unfortunately in some cases the cause of the difficulty breathing is one that has a very poor outlook and you and your vet may decide together that putting your pet to sleep is the kindest thing to do.

Okay so that brings us to the end of this blog on difficulty breathing in dogs and cats. It is quite a common and a serious emergency problem for which there are lots of different causes and the outlook very much depends on the cause. Your priority should be to have your pet examined by a vet and then take it from there.

The next blog will be in approximately 2 weeks time when we will talk about seizures or fits in dogs and cats. Remember that if you have any comments or questions on this blog, or indeed any suggestions for future blogs, you can contact us in the usual ways. Via email on percypods@gmail.com; via the PercyPods Facebook page; or via Twitter on @PercyPods. Also don’t forget to subscribe for future episodes via the RSS feed. So thank you for reading and until next time, may you and your pets be safe.

Saturday, 8 October 2011

Collapse in dogs and cats

Welcome to PercyPods Pet Emergency blogs; we hope that you and your pets are well. This week we are going to discuss the problem of “collapse”. Not all collapse is the same and we will describe what collapse is, what can cause it in dogs and cats, and what your vet might have to do to discover and correct the problem.

What is collapse?

Okay so let’s start this blog by explaining what collapse is and what can cause it. A dog or cat is usually described as being collapsed if they are unable to get up. To understand the causes better you need to know that in order for your dog or cat to be able to stand up a number of different parts of the body have to be working well enough. These are basically the brain and the nerves, the muscles, bones and joints, the heart and a good blood supply containing enough oxygen, all of which are also tied in with for example factors such as the level of glucose or certain hormones in your pet’s blood. So when your pet collapses it could be because of a number of different reasons.

In some cases the pet will be walking or at least standing up and then fall either into a sitting position if just their back legs give way or into a lying position if complete collapse occurs. He or she will then be unable to get up. There are however some animals that collapse after a period in which they have been sleeping or at least apparently resting normally; in other words an animal does not have to fall over to be described as ‘collapsed’. Some collapsed animals are conscious although they may appear confused or dazed; others can lose consciousness either very briefly or for a more prolonged period. Some animals collapse but then make an apparently complete recovery within seconds to minutes, while others remain collapsed and will not improve without veterinary attention. Animals with more localised problems causing collapse, that is problems that only affect their back or legs, are often quite bright and aware in themselves. They will often respond to and interact with you relatively normally unless they are in a lot of pain.

What causes collapse?

So let’s move on now and consider the causes of collapse. As we mentioned before, in order for your dog or cat to be able to stand up a number of different parts of the body have to be working well enough and it is therefore helpful to separate the causes of collapse along these lines – although the reality is that many causes of collapse affect a number of different parts of the body.

Causes affecting the brain

So a number of the causes of collapse mainly affect the brain. Seizures or ‘fits’ are one potential cause of collapse and it is common for animals to be collapsed for quite some time after a seizure. Animals with other brain problems such as a tumour or a blood clot – like a ‘stroke’ in people – may also collapse as a result.

Spinal cord/peripheral nerve causes

Some causes of collapse mainly affect the nerves supplying the legs either at the spinal cord which is in the neck and back or actually within the legs themselves. For example, just like people with so-called ‘slipped discs’, it is possible for cats and especially dogs to get problems with the discs in their neck or back and this can cause them to be collapsed. This problem is one we see commonly for example in Dachshunds.

Musculoskeletal causes

Another group of causes of collapse are ones that affect the muscles, bones or joints. In such cases symptoms such as limping, difficulty getting up, or inability to sit up or jump are often present and getting worse for days, weeks or months before collapse occurs.

Causes affecting the heart or blood supply

A number of the causes of collapse affect the heart or the blood supply to the body. Lack of a good blood supply can be a localised problem. For example there is a relatively common condition in cats with heart disease where a blood clot blocks off the blood supply to their back legs; they are completely unable to use their legs and this condition is usually very painful. However it is more common for collapse to occur because of lack of a good blood supply to the whole body causing the animal to be very weak or their nerves and muscles to fail.

So what can compromise the blood supply to the whole body? Well, one example would be heart disease where the heart muscle becomes very weak or the heart starts to beat very irregularly. The heart not working properly means that blood does not flow around the body well enough and the animal collapses. We see this type of problem for example in some dogs, such as Boxers and Dobermans, which are predisposed to certain heart diseases.

Another time when the blood supply to your pet’s body would be compromised is if he or she loses a lot of blood. The body needs a good blood supply to be able to stand and move and as an animal loses more and more blood, he or she will become weaker and weaker until they are completely collapsed. We see this type of problem for example in dogs such as German shepherd dogs or Golden Retrievers who quite commonly have tumours in their spleen or liver that rupture and bleed into their tummy area; you should note that this is not bleeding that you could detect just by looking at your dog as it occurs internally.

And yet another cause of poor blood flow around the body would be if your pet goes into ‘shock’. Although people often use the word ‘shock’ to describe how someone feels emotionally when they receive terrible news or lose someone close to them, it is actually a medical term which describes poor blood flow around the body. There are lots of causes of shock in animals, two of the most common examples of which are ‘bloat’ or gastric dilation and volvulus (GDV) syndrome in dogs and blocked bladders in male cats. We have discussed both of these conditions in previous blog so please have a listen if you haven’t already.

Lack of oxygen in the blood

Other causes of collapse that we would like you to be aware of include a lack of enough oxygen in the blood because of a problem with your pet getting oxygen into their lungs or from their lungs into their bloodstream. Oxygen is essential for the body to work properly and reasons why your pet may not have enough oxygen include: severe lung diseases such as pneumonia; heart failure; or obstructions of their airways for example in so-called ‘brachycephalic’ dogs such as Pugs and Bulldogs, or in cats with feline asthma.

Metabolic/hormonal causes

The last group of causes of collapse that we would like to mention includes problems with parts of your pet’s metabolism or with their hormones. For example low blood glucose is one cause that we see relatively commonly. This may occur for example in dogs affected by a certain tumour of the pancreas organ known as ‘insulinoma’, in puppies and kittens, or indeed if you accidentally administer too much insulin to your diabetic pet. Collapse is a relatively common symptom in dogs with a hormonal disease known as “Addison’s disease” or hypoadrenocorticism where they do not produce enough of certain essential hormones in the body, and collapse can also be seen in other hormonal diseases.

What will my vet do and what treatment might be needed?

In general we would recommend that you have your pet examined by a vet if they are collapsed and this is especially urgent if your pet appears to be depressed or non-responsive. This would not be a time to wait and see. So now that we have discussed the causes of collapse, let’s move on and briefly discuss what your vet may need to do and what treatment your pet may need. As you can see there are a lot of different causes of collapse and your vet will need to use whatever information they have available to help them decide what to do. This will include information that you provide, for example about what happened to your pet when he or she collapsed, whether there was a loss of consciousness, and whether there has been any change at all. Your vet will also get very important information from examining your pet about how well their heart is working, their blood is flowing, their nerves and muscles are functioning and so on. Using this information your vet will be able to decide whether your pet needs to be admitted to the practice for immediate stabilisation and monitoring and also what some of the more likely causes are and this will help guide them in terms of what tests they need to perform and how urgently this needs to be done.

Some tests that are commonly performed early on in some collapsed patients include blood tests, for example to check for blood loss or blood glucose concentration, and an ECG test to see how the heart is beating. In some cases x-rays and ultrasound are used and in others your pet may need to be sent to a more specialist centre where more advanced tests such as MRI or CT scans can be performed. The tests that your pet needs will very much depend on his or her particular circumstances and your vet will be able to go through all this with you.

As there are many different reasons why your pet may collapse it will not be surprising that there are also many different possible treatments. These range from supportive measures and time to various medications and in some cases surgery. Unfortunately some animals are diagnosed with a condition that has a very grave outlook and you and your vet may decide that putting your pet to sleep is in his or her best interest. As always, your vet will discuss all this with you as and when information becomes available.

Okay so that brings us to the end of this blog on collapse in dogs and cats. It is quite a common and a serious emergency problem for which there are lots of different causes and the outlook very much depends on the cause. Your priority should be to have your pet examined by a vet and then take it from there.

The next blog will be in approximately 2 weeks time when we will talk about animals with difficulty breathing. Remember that if you have any comments or questions on this blog, or indeed any suggestions for future blogs, you can contact us in the usual ways. Via email on percypods@gmail.com; via the PercyPods Facebook page; or via Twitter on @PercyPods. Also don’t forget to subscribe for future episodes via the RSS feed or iTunes. So thank you for reading and until next time, may you and your pets be safe.