Diaphragmatic hernias in cats

Diaphragmatic hernias in cats

Health & Safety

Having a veterinary surgeon tell you they believe your cat has a diaphragmatic hernia can be very scary and upsetting – with good reason, as this condition does need surgical attention and in some cases can prove too much for your pet. This article explains exactly what a diaphragmatic hernia is and how it is treated.

So what is diaphragmatic hernia?

The diaphragm itself is a large muscle that acts as a barrier between the chest space, (which contains the heart and lungs) and the abdomen – which holds amongst other things the stomach, liver, spleen and intestines. Although the diaphragm is a thin muscle, it should provide an airtight barrier - so if it gets damaged there can be big problems. Its function is to allow the chest space to have a negative pressure, which means the lungs can expand outwards rather than collapsing inwards. The diaphragm moves down in the body with each breath and the lungs with it, causing them to expand even further when your pet (or us), breathe in. Because it is a muscle when breathing out, it moves up again, helping the lungs contract and forcing the air out. So you can see if the muscle has any damage, it will not stop the cat (or any animal/human) breathing, but they will not be able to breathe very well.

The definition of a hernia is “the protrusion of an organ through a hole in the body cavity which normally contains it”. In the case of a diaphragmatic hernia, the diaphragm has a hole in it and something from the abdominal cavity is protruding into it.

The problem lies in that some diaphragmatic hernias are emergencies and they need immediate medical attention, while some can go unnoticed for several days – it is all according how much damage the diaphragm has sustained and the size of the hole in it. The problem also means that the organ that has filled the hole, may have its blood supply cut off, causing further worries and complications. As owners, much of the time they will be the first to realise something is not quite right.

The causes and symptoms of a diaphragmatic hernia.

In cats the main cause of a diaphragmatic hernia is trauma, usually by a road traffic accident where the car strikes the cat in such a way as to cause a rupture. Some cats, especially younger ones, can also cause a diaphragmatic hernia by simply misjudging a jump between two surfaces and landing awkwardly or on the edge of one of the surfaces. Naturally as their diaphragms are not so developed, they are thinner and can be damaged easier.

That is why it is important, if you think your cat has been involved in a road traffic accident, to seek veterinary advice for them. They may have sustained other injuries which can even mask a diaphragmatic hernia.

The symptoms of a diaphragmatic hernia are fairly simple –

  • Faster breathing - as there is not the correct lung expansion due to the hernia.
  • Reduced appetite – not always the case, but again according to how much trauma there has been and if the cat is in pain.
  • Lethargy and reluctance to move – you may see your cat be quieter than normal, this can also mean pain but they may have discomfort in breathing as well. This is more prevalent in kittens that always seem on the go and also seem to have boundless energy!

Diagnosis of a diaphragmatic hernia

If a vet examines a cat with a suspected diaphragmatic hernia they will still undergo a full examination. The one main area they will look at and listen to is the chest. They will see if there is any visible bruising around the chest area which would indicate trauma and they would also of course listened to the chest, with a stethoscope.

Listening to the chest will give a very good indicator along with the respiratory rate (which would seem very high), the sounds in the chest will let the veterinary surgeon know if the cat is having problems struggling to get enough air inside the lungs.

They may admit the cat for an x-ray, using normally only light sedation, as they still want the cat to breathe for themselves without a full general anaesthetic. X-rays of the chest will give a definitive diagnosis of a diaphragmatic hernia and a very good indication of how bad the hernia is.

Treatment of a diaphragmatic hernia

The treatment to correct a diaphragmatic hernia is surgery. The cat will be opened up so the surgeon can see inside and assess the extent of the damage. They will then repair the injury by carefully removing the organ causing the hernia and putting it back where it should be, and sewing up the hole. Whilst the surgery is taking place a veterinary nurse will keep the cat stable under anaesthetic and using the rebreathing bag, skilfully keep the cat breathing artificially, until the hole is repaired.

Before the cat is sutured up, the veterinary surgeon will check all the other organs look okay and seem to have a good blood supply. In most cases a needle is also inserted into the chest space, before the cat is woken up and extra air removed, to allow negative pressure to take place. By doing this the cats breathing will immediately improve.


Once surgery has finished most cats will be absolutely fine. It will take a while for the injuries to heal, and during this time the cat must be kept quiet by the owner – and definitely not allowed to jump up anywhere! If the injury was a result of a road traffic accident, other trauma may also take a few weeks to heal – especially in the case of broken bones.

Sadly sometimes injuries are far too severe and even with surgery some cats are just too poorly to survive a general anaesthetic – especially if they have a suspected diaphragmatic hernia as well, which complicates the anaesthesia.

If you suspect your cat may have been in a traffic accident or having trouble breathing, please contact your vet as an emergency.



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