What would cause very sudden respiratory distress?

What would cause a cat to have a sudden onset of labored breathing, crackling sounding lungs and a rapid heartbeat?

My cat was fine this morning, at 8am,and ate his breakfast as normal. I came home at 12:30 and found him with these symptoms. He has been an indoor only cat his entire 5 yrs. He has also been healthy, so our vet has said. Recently the cat he lived with his entire life moved away. He was an active kitten, but grew up, and has since then, been very lazy. I still have another cat who , the vet says, has IBS, and the IBS is still not under control, despite Prednisone, Pepcid, and the prescription I/D diet. I'm very worried my cat could be in danger.

Answer by Kate
Please take your cat to the vets as soon as possible. the symptoms you suggest sound rather severe and even if they do subside the cat still needs to be checked out by the vet as they could return.

i am not a vet and cannot diagnose the problem, However any symptoms like this could indication a infection which needs urgent treatment.

best wishes Kate and I hope your vet is able to sort the problem out for you quickly.

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