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Dr. Kara
Dr. Kara, Veterinarian
Category: Cat
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Experience:  Over 20 years of experience as a veterinarian.
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I'm trying to figure out why my cat died recently, I had her

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Hello there, I'm trying to figure out why my cat died recently, I had her for 14 (I'm going to be 27) years and it's all I can think of.
She was diagnosed with mammary cancer in November 2011, had a bilateral chain mastectomy followed by 4 rounds of chemotherapy (doxorubicin). 2 years later, she had a little mass so that was removed, and then had 2 more rounds of doxorubicin. The cancer came back later (little tumors in her armpit with 1 lymph node involved) so just that area of tumors was excised. I didn't want to use doxorubicin anymore due to possibility of cardio toxicity so we switched to carboplatin. The carboplatin (3 rounds) was effective but tough on her kidneys, she was on fluids after getting each round because sometimes she would develop hypokalemia even though her kidney levels weren't bad at all. In April, she was vomiting 2-3 times per day and coughing a little and she developed open mouth breathing, I'm kind of puzzled about it because I only ever saw her breath with her mouth open maybe twice, although her purrs were a little congested. I took her to the vet and he said her heart and lungs both sounded fine and she wasn't open mouth breathing at the time, the vet also gave her anti-vomiting medicine. Then, in early May, before her 3rd carboplatin treatment, she stopped eating much. She would smell the food and walk away...she lost about 3-4 lbs (she was normally 12 lbs throughout her life). She was also lethargic and not interacting with me much so I took her to the vet where they said her heart and lungs sounded fine...they got her kidney levels and they were a little high but nothing crazy bun-49 creatinine-2.5 and she was a little hypokalemic-3.0. So They put her on sub-q fluids and I gave her potassium supplement. I also gave her anti-nausea medication but she was still laying around and not eating much or playing. About 2.5 weeks before she died I noticed her pupils were different sizes and one of her eyes looked very slightly cloudy, I attributed this to a tumor because she had a few of them (one under her chin that was getting big, about the size of a jelly bean), various ones under her armpit and around her body and one on her head, and her legs lymph nodes were swollen. Now that I look back and read more, I actually think this might be due to hypertension that went along with her kidney issues. 2 weeks before she died, she hadn't had fluids for a week and developed some dehydration and was hanging out in the bathtub, so I immediately ran out and got her fluids, she felt better after and was not in the bathtub anymore but she was still lethargic/not eating much but not vomiting anymore and had a glazed over look about her. For a week she was fine and receiving fluids but still not really eating or playing for the last couple months of her life. When I came home from work one night (she was ok in the morning) she was sitting and seemed to be fine except for a little back leg weakness which I attributed to hypokalemia or because of her swollen back leg lymph nodes. I took a shower and before I could give her her fluids or feed her her potassium supplement, she jumped off the bed and collapsed, meowing. I picked her up and took her to the bathroom where she peed while in my arms. She then meowed some more so I put her down but she couldn't walk, so I picked her back up and held her while she died in my arms, gasping and breathing heavily while having dilated pupils. She died in less than 10 minutes and it was so sudden and traumatic. I feel horrible that I didn't take her to the vet sooner...this was a Wednesday night and she had a vet appointment on Saturday (I get paid Friday's). I'm so overcome with grief and guilt that she had to go through that. I wish I would've given her the potassium/fluids immediately instead of taking a shower. I believe she died because of the untreated hypertension arrhythmias possibly mixed with the arrhythmias or murmur from the hypokalemia when she jumped off the bed? Also maybe she had underlying heart disease or fluid in lungs (open mouth breathing twice)? I wish I had more money to treat her and I wish I would've gotten an x-Ray. I just feel that I have unanswered questions about how/why she died so suddenly and feel horrible that I couldn't take her to the vet sooner. It all happened so suddenly and I wish I didn't put her on my bed so she wouldn't have jumped off and caused the cardiac arrest (if that's what it was?). Thank you so much for your time.
Submitted: 11 months ago.
Category: Cat
Customer: replied 11 months ago.
Also, her Creatinine Kinase level was 7,496
Customer: replied 11 months ago.
She was receiving 100 ml of fluids every other day or so
Expert:  Dr. Kara replied 11 months ago.

Hello, my name is***** and I have over 20 years of experience as a veterinarian. I understand that she had several chronic health issues (recurrent, metastatic, mammary cancer, kidney disease) but I am sorry to hear that your kitty passed away so suddenly and dramatically. It is perfectly normal to ask why and how this happened. It is part of the grieving and healing process to try to understand.

A severe, sudden allergic reaction is one possible cause of sudden respiratory distress and death. Animals with such a severe reaction will often have hives, facial swelling, swelling of the tissues around and in the pharynx, vomit, can have diarrhea and can collapse. This would be highly unusual in her case because you don't report any hives or facial swelling, but it is possible.

The most common cause of sudden death in cats is collapse due to throwing a clot from undiagnosed hypertension due to primary heart disease, usually cardiomyopathy, or kidney disease.

Cardiomyopathy is a primary heart muscle disease which can be a silent killer. Cats with cardiomyopathy can appear to be normal, they will compensate for their heart disease for a period of time and when failure occurs it can be very sudden. In retrospect owners may report that their cat was slightly less active but that they assumed that was an age related sign rather then a sign of heart disease. Radiographs of the heart may look completely normal. The only good way to diagnose the disease is with an ultrasound of the heart, called an echocardiogram.

Kidney disease can also lead to hypertension and blood clots. This seems more likely with her because we know that she had kidney disease. It is possible that she had previous small blood clots thrown given her previous history of open mouth breathing. This time around I suspect that she suffered a saddle thrombus clot (a blood clot which blocks blood flow to one or both back legs) which would explain her rear leg weakness, as well as a possible clot to her brain or lungs which would explain her final collapse and vocalization and then death. Cats with cancer are known to have a much higher incidence of blood clots too. Cancer is an inflammatory process which predisposes to blood clots.

Another less likely for her cause of sudden difficulty breathing due to pulmonary edema is biting an electrical cord. Those cats should have signs of a burn on the gums or tongue. This is much more common in kittens then adult cats.

Other rare cases of sudden pulmonary edema and difficulty breathing are pancreatitis, systemic bacterial infections or cancer (due to blood clots and metastatic tumors in the lungs themselves).

A previously undiagnosed, ruptured, bleeding tumor in her abdomen could also cause the symptoms that you saw. We see this more in dogs then in cats, but it is possible as a sudden drop in blood pressure could explain weakness and sudden death.

Please don't think that you did anything to harm your girl, or that fluids a few minutes earlier would have changed what happened.

I believe that she probably had undiagnosed hypertension and her cancer led to an increased probability of forming dangerous blood clots and sudden death. It is horrible for you as you had no time to process her being sick as sick as she was, let alone her death, but please take comfort in knowing that she didn't suffer long after the blood clots and it sound like she enjoyed a wonderful life with you doing the best that you could for her until the end.

Creatinine kinase is a muscle enzyme which increases with the breakdown of muscle tissues. That increase too is a likely indicator of a blood clot that caused muscle damage and enzyme leakage.

Please let me know if you have any further questions.

Customer: replied 11 months ago.
Hi Dr. Kara, thank you for your response, in regards ***** ***** saddle thrombus, her legs were weak probably due to hypokalemia. Do you think potassium supplement would've saved her? Her legs were not in any pain like most cats have...could it still have been a clot? Also, did jumping off the bed have anything to do with disrupting her heart? Thank you so much
Expert:  Dr. Kara replied 11 months ago.

You are very welcome.

I don't think the potassium supplement would have made any difference once the cascade of events began. We supplement potassium in the hopes of controlling muscle weakness and irregular heart rhythms. Once events start oral potassium won't have time to be absorbed and address an active problem. Even intravenous injections aren't always enough in that instance.

Her dilated pupils indicate that she was painful and very anxious. I'm not sure that her clot completely blocked blood flow, as she was still able to get around, but I do believe blood clots were affecting her muscles to some degree given that we know she was running a higher than usual creatinine kinase.

Jumping off the bed was likely her attempt to get away from whatever was hurting and making her feel funny. The natural response to sudden pain or fearful events is to run away if we can. A jump down from a bed would not have affected her heart.

Customer: replied 11 months ago.
you do think hypokalemia is what caused an irregular heart rhythm and killed her?
Also, don't people sometimes die due to to over activity and having high blood pressure? Thanks again
Customer: replied 11 months ago.
Also, hypokalemia causes sudden cardiac that possible to be what killed her?
Expert:  Dr. Kara replied 11 months ago.

If she died of hypokalemia and an irregular heart rhythm I would have expected some sort of seizure type activity, or a syncopal (fainting type) episode, and while she seemed weak you don't report either one of those as happening.

I truly believe that your girl died of a blood clot. She may have had several small ones that produced minor symptoms, but perhaps suffered one fatal one to the brain.

Yes, people can die of hypertension from "overactivity" but that is usually due to a stroke type episode (a brain bleed). That can happen in dogs and cats too but is extremely uncommon. And the activity would be more than jumping down from a bed. It would be after running or panicking and raising blood pressure quickly for more than a few seconds.

Customer: replied 11 months ago.
Sorry for all the questions but, do you think cardiac arrest in a cat due to hypokalemia could possibly have her symptoms? Why would she have a seizure if it was from low potassium? Also, do you think the chemo caused a lot of heart damage to her? Why do you think she was lethargic and not eating towards the end? Thank you so much
Customer: replied 11 months ago.
If she did have a blood clot then why wasn't she in pain like most cats are in their legs? Or is a brain one different?
Expert:  Dr. Kara replied 11 months ago.

It is possible, of course we cannot completely rule it out without potassium blood levels at the time of her death, but given your description it seems less likely. When I said seizure type or syncopal episode I meant an episode that looked like a seizure but truly was due to low levels of oxygen reaching the brain which would happen with an irregular heart rhythm episode. It can be hard to differentiate between the two for owners, but most people understand what a seizure looks like.

Chemotherapy can certainly cause heart damage in some individuals. But given that she did not have any pulmonary edema or signs of heart disease on exam her hypertension was likely due to kidney disease.

She may have had blinding pain in her head from the clot, but that wouldn't affect her leg muscles.

Either way

Customer: replied 11 months ago.
I haven't read anything that says that hypokalemia causes seizures...aren't seizures associated with hyperkalemia?"High potassium levels may cause heart problems, which in the worst case could result in heart failure.
hypokalemia can cause death due to myocardial depression
Potassium is VERY dangerous when it's too low, this effects the muscles in the body and affects the heart rate(very slow).
arrhythmia after becoming severely hypokalemic."Also, does hypokalemia cause hypertension or hypotension?Thanks so much :)
Expert:  Dr. Kara replied 11 months ago.

Both high and low levels of potassium affect muscle strength and can cause heart rhythm abnormalities.

High potassium (such as in cats that have a urinary tract blockage) leads to a very slow heart rate and death.

Low potassium leads to an irregular rhythm (tachycardia) which is inefficient and leads to death too.

Neither one causes seizures but the changes in the way the heart functions, and oxygen getting to the brain as a result can cause some strange symptoms/behavior which some owners interpret as a seizure.

Likewise neither directly lead to hypertension, and in fact both likely lead to low blood pressure at their extreme states due to poor heart function and blood flow.

Primary kidney failure causes hypertension however.

If you are really interested in potassium and its effects here is a link to a veterinary proceedings article about potassium's effects on a cat's body.

Customer: replied 11 months ago.
what happens when a cat has both hypertension and hypokalemia...don't they have high blood pressure and low blood pressure concurrently...or is the heart just completely irregular?Thank you so much for your help
Expert:  Dr. Kara replied 11 months ago.

If the hypokalemia gets to a dangerous level that it is affecting heart function then the completely irregular rhythm supersedes the effects of hypertension because there cannot be hypertension if the heart isn't pumping blood. At that point blood pressure drops very low simply because there isn't blood flow.

Customer: replied 11 months ago.
Is it possible that she had a blood clot due to the hypokalemia? Also, why do you think she stopped eating 2 months before she died? Is it possible that she could've survived had I brought her to the vet before this occurred?
Expert:  Dr. Kara replied 11 months ago.

Hypokalemia does not lead to blood clot formation.

Kidney failure decreases appetite, so does inflammation from cancer and so does hypertension.

In her case probably all 3 things played a part.

If her hypertension was addressed perhaps she would have done better for a longer period of time. But she had many challenges, so if the clot was secondary to inflammation from cancer then it is unlikely anything you did would have changed things much. Sometimes the issue isn't any one problem, but rather a combination of health issues that together lead to poorer than expected outcomes and health.

Customer: replied 11 months ago.
Thanks Dr. Kara,
I guess it bothers me so much because I worked so hard to combat the cancer that she fought against for almost 5 years, and she ended up dying from something else (which I know was indirectly related to the cancer/chemo). I know the end was coming because the chemotherapy wasn't working anymore and she had a large tumor under her chin as well as tumors all over her body...and her legs were swollen from the lymph fluids and she had been eating less and less/not wanting to be by me) but it was so difficult having her pass so suddenly. I thought she had at least a year left. Thanks so much for your help,
Customer: replied 11 months ago.
I also wish I had taken her in for the hypertension...I didn't know it was hypertension because when i was researching the pupil asymmetry, it said it could be due to a tumor and I figured there must've been one by her spine or brain (she had one by her ear too).
Expert:  Dr. Kara replied 11 months ago.

You are very welcome.

The idea that her asymmetrical pupils were secondary to a tumor was very plausible given her multiple metastatic tumors. It is possible that either or both kidney failure and hypertension with a retinal bleed and/or a tumor was behind that symptom. It's tough to know at this point.

Likewise cancer is an inflammatory process so we see secondary blood clots with metastatic cancer as well as with hypertension.

You may have treated her for hypertension and still lost her to a clot.

Her time was short if her legs were swollen from inability to process and move lymphatic fluid properly. That overloads the cardiovascular system and causes tissue damage. Only very sick kitties have that symptom. It isn't comfortable either to have that sort of pressure, and that too may have been playing a part in her poor appetite.

I know that you loved her and weren't ready for her to go, but her poor body was very overwhelmed and as much as you tried to help her, her quality of life was failing. I am so sorry for both of you that things had to end the way that they did.

Expert:  Dr. Kara replied 10 months ago.

Hello, I wanted to make sure that you didn't have any further questions for me, please let me know if you do, thank you, ***** *****