What this means
A collapse can look like a sudden buckling of the legs, a failed jump, a tumble after a few steps or a complete loss of consciousness. After fainting a cat may recover quickly and behave as if nothing happened, which makes it tempting to forget it. Even if your cat looks fine, every faint or collapse is a reason to see a vet.
Loss of consciousness and weakness can have many causes. With heart disease a cat can faint or its back legs can suddenly weaken, especially if it also breathes faster and tires sooner. Muscle weakness from low potassium in the blood can come on suddenly and be so severe that the cat cannot lift its head or walk. In a kitten that stumbles and falls, it can be a sign of an inherited nerve disease.
Write down what happened just before the collapse, how long it lasted, whether your cat was aware, what colour its gums were, how it was breathing and how it behaved afterwards. Film it if you can. These details help a vet find the cause, but they do not replace an examination.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your cat.
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Heart disease
When the heart no longer pumps blood as it should, a cat can faint or its back legs can suddenly weaken. Fast or laboured breathing often goes with it.
About the condition: Heart disease -
Muscle weakness from low potassium in the blood
The weakness can come on suddenly, and the cat cannot lift its head or walk. Between episodes it can look healthy.
About the condition: Hypokalemic polymyopathy -
An inherited disease of the nerve cells in a kitten
When certain substances build up in a kitten's nerve cells, it starts to stumble, fall and lose coordination.
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Low blood sugar
When the body does not get enough energy, especially in a very small kitten or a sick cat, it can weaken and collapse.
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A seizure
Sometimes a collapse is a seizure, after which the cat may seem confused. A vet needs to find the cause.
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Shock after an injury, or something toxic
After a severe injury or contact with something toxic a cat can collapse and not get up again. This is an emergency.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- What happened just before: play, running or rest
- Whether your cat was aware and responded to your voice
- What colour the gums were: pink, pale or bluish
- How your cat breathed before and after
- Whether it happens again and how long it lasts
- Whether your cat tires quickly, eats less and hides more
When to book a routine visit
A cat that has fainted or collapsed needs to be seen by a vet immediately, even if it looks fine a few minutes later. If a kitten stumbles and falls, book a check-up as soon as you can. Tell the vet what happened and show a video if you have one.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- GM1 gangliosidosis Nerves and muscles An inherited storage disease in which the body lacks an enzyme that breaks down certain fatty substances. They build up in nerve cells, especially in the brain, and gradually disrupt their work.
- Heart disease Heart A general name for conditions in which the heart can no longer pump blood properly: the heart muscle, the valves or the heart's rhythm can be affected, and some defects are present from birth. In cats heart disease can stay hidden for a long time, so it sometimes comes to light only once it has advanced.
- Hypokalemic polymyopathy Nerves and muscles Muscle weakness that sets in when there is too little potassium in the blood, a mineral the muscles need in order to contract properly. The weakness can come on suddenly and be so severe that the cat cannot lift its head or walk.
Body systems: Nerves and muscles Heart