Sunday, May 28, 2023

Feline Thrombosis/FATE-Feline Arterial Thromboembolism-the Affect of Blood Clots in Cats

When Bette first went lame, many readers thought it could be thrombosis. So, what is thrombosis? Thrombosis is when a clot forms in (typically) the heart and travels and cuts off blood supply to the affected region. It can be to the heart-heart attack, stomach-vomiting (typically a symptom), or front or rear legs (the rear legs are saddle thrombosis or FATE-feline arterial thromboembolism.) Clots can be formed due to injuries or disease but for cats, it's mostly due to heart disease.

We know it was not thrombosis because we eventually learned with an MRI that it was Nerve Sheath Tumor. The tumor damaged the nerves to the rear part of her body, especially the left leg. But it did not affect blood flow in the legs. (A tumor could of course, depending on location on the body.)

A clot that travels in a blood vein will damage the arteries to the legs and arterial blood pressure will not register. Hopefully, the normal blood veins in the leg will continue to work and supply blood to the legs and the leg will be healthy. This may not always be the case. Cats can be paralyzed by loss of blood flow to the legs. In January, Bette's leg weakness went away while on prednisolone. Thrombosis isn't cured with prednisolone. And she maintained normal arterial blood pressure.

A cardiac ultrasound by her cardiologist in January showed no signs of heart disease, or clots having formed in the heart. With thrombosis due to HCM, an ultrasound would show changes to the heart and clots. When the problem of weak legs returned in March, that is when she had an MRI that showed the tumor.

When a clot forms in the legs, this can happen over days even if the onset seems sudden. The PAWS of the affected leg will be pale, not pink (or pale gray), and the paws will feel cool or cold to the touch. This is why you should always check cat's paws for color and feel of temperature so that YOU know when the paw is normal and may not be normal. If you suspect the paws are getting cold, see the vet and cardio as soon as possible.

When the clot settles in the artery of the leg, the cat will be in pain-typically over time-a few hours, a day; may go weak, may not want to move around; may begin to breathe heavily due to the clot having formed in the heart and passed along the body; may begin to breathe heavily due to increasing pain as the clot forms in the legs until the artery is cut off; the cat eventually will likely scream out in pain, and panic, and try to move around, as if to get away from it. The cat will not be able to stand or move the affected leg or legs. The cat will need immediate attention at the ER, the cardiologist office, or from the regular vet (you should discuss with your regular vet if they have experience with thrombosis and what treatments they can offer in the way of emergency care so that you know if they can treat the cat or if the cat needs the ER.)

We went through this with Myrna Loy. She had a heart attack in 2013, and FATE in 2015. With her heart attack, it was difficult to assess what was happening. She had begun to breathe heavily that morning and I gave her extra diuretic. She then hid and I spent a couple of hours trying to get her out from under the bed. I monitored her but saw that her breathing was getting worse. I finally had to chase her out with the vacuum. She ran, then laid down in the hall. I gave more diuretic but that didn't change her breathing. I called the cardiologist and she suggested that Myrna was having a heart attack. I rushed her to the ER which the cardio shares, and she was treated and the ultrasound showed a heart attack. Luckily, she was on Enalapril so the blood veins were kept open in her body so that the heart rate wasn't driven up, damaging the heart even more. She received oxygen, diuretic, other ER drugs, and stayed overnight until stable; was put on a twice weekly dose of aspirin in addition to the Plavix she was already on.

When she had FATE in 2015, she woke up and began to have a difficult day. She seemed uncomfortable; she wasn't eating well; her breathing eventually increased. I remember her paws were cool to the touch, but it was May and the AC was on and she had been on the floor. I ignored a major first sign. I was with her upstairs all night as she didn't want to move, didn't want to be touched, didn't want to eat, and seemed more and more in discomfort. As her breathing increased, I increased the diuretic. Her breathing rate fluctuated. She had just settled down on the bed for awhile, resting, breathing comfortably when she suddenly raised up, seemed to look surprised, and then leapt up from the bed and cried out in pain. She jumped down onto the floor and her rear legs were not moving. I picked her up, placed her back on the floor to make sure, and saw she couldn't use them. I immediately took her to the ER. By the time we arrived, it had resolved itself. She was treated, kept overnight, and saw the cardio the next day. She luckily had lost only the use of the artery. The other blood veins in the legs had taken over and supplied the legs with blood so that she never lost the use of her legs.

There is more information at the blog about what we went through and there is this information from a conference I attended in 2011. You can do word/category searches at the blog to learn more about thrombosis and thromboembolism.

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