Cardiovascular Disorders of Cats


Cardiovascular Disorders of Cats

Congestive heart failure and CRF - Zack

Q: Dear Dr Richards, Thank you for your rapid and thorough responses to my questions about Zack, my cat with CRF and congestive heart failure. I took him in for a followup exam, after 2 weeks on 1 tablet Enacard, 1/2 tablet of Lasix, and decreasing to 50 ml saline per day. His heart sounds were normal (having been slow and/or hesitating, previously), as was his breathing. I was thrilled to hear it. However, the next day, I got his blood test results, and his BUN had risen from 33 to 40. We're back to where we started, before starting subq fluids. My vet has responded by decreasing his dose of Lasix to 1/2 tablet every OTHER day. It seems to me that increasing his fluids would be better, if flushing the kidneys is what we want. Does this seem like the right course to you? How can we know whether Enacard is doing anything for him, as opposed to Norvasc which I found out belatedly you prefer? You've written that CRF cats should be followed more closely than is usually done, to slow the progress of the disease, how often is ideal?

L and Zack.

A: L

I would tend to continue with daily fluid therapy with a willing owner in the situation you describe with Zack, in most circumstances. However there are times when a physical examination finding changes my opinion on this course of action, so it would be best to ask your vet why the change was made. There isn't all that much difference between a BUN of 40 and a BUN of 33. This probably falls within the normal variation for testing. So that may also be a factor in your vet's thinking on this. I think it is best to stick with either enalapril (Enacard Rx, Vasotec Rx) or amlodipine (Norvasc Rx) for at least 60 days once you start, because I think it takes that long, sometimes, to see the difference the medications are making. After that time, if there doesn't seem to be enough benefit from the Enacard, it would be worthwhile to try Norvasc, probably. Mike Richards, DVM 9/8/99

Sudden death in cats

Q: I'd like to pose a question about our cat, Mookie, who up and died while we were petting him this past Sunday.

I've searched the web and all pet sites about SUDDEN DEATH and have found this "affliction" only in the context of heartworm. I wonder if you have other ideas on this? Mookie was a healthy active 11-year-old Manx. All shots up to date. No lethargy or appetite suppression. He was purring one moment and the next he let out a blood-curdling scream, then died.

Thanks in advance.

A: Lisa-

Real "sudden death" is an unusual occurrence. As you noted, it can happen in cats infected with heartworms. It is also reported to occur in cats as the result of cardiomyopathy. This disorder can be very insidious and may not be detected prior to death. Cats probably get aneurysms that rupture, although I have only seen one report on these. Anything that causes thromboembolism can cause sudden death -- this can be seen as the result of cancers, blood clotting disorders, cardiomyopathy, trauma and other disorders. Low serum potassium can lead to sudden death, as can high serum potassium -- but usually there are other signs of illness making the process seem a lot less sudden in retrospect.

I am sorry to hear about Mookie. It is unfortunate but without a necrospy (autopsy) exam it is not possible to tell you what might have happened. It is hard when things like this can't be resolved.

Mike Richards, DVM 4/12/99

Aortic thromboembolism

Q: I was pleased to find your site. I recently lost my 2 and a half year old white socked tabby (Meshach) to saddle thrombosis. I feel terrible. I want to learn more about the disease, not because I think my vet could have done something and didn't want to, but because it seems like such a sticky problem. I am simply eager to learn about what the cutting edge research is. I am partly interested because I would like to know as soon as researchers have any ideas of how to treat it, either preventatively or as trauma. My wife and I have four other cats, one is Meshach's brother of the same litter. If you could point me to more information about who might be studying treatment for this, I would be grateful.

Thank you in advance, Ken

Also thank you for your encyclopedia entry on Cardiomyopathy.

A: Ken-

I am sorry for the long delay in responding to your email. In general we are only responding to subscribers to the VetInfo Digest at this time but we did not have much information on the site about this problem and therefore I set your mail aside to answer and have just gotten to it.

I am not sure if there is cutting edge research going on when it comes to this disorder. There may be, I am just not aware of anyone currently researching this and have not seen much information in the literature recently. Aortic thromboembolism in cats has not been very responsive to medical or surgical treatment in past studies, unfortunately.

In most cats aortic thromboembolism occurs secondarily to heart disease in cats. Blood clots form in the damaged or inefficient heart and are sent into the circulation. They tend to cause blockages in the aorta in the lower abdominal region or the area in which the aorta splits to become the femoral arteries of the legs (this is where the term saddle blockage comes from, I think). Blood clots can form due to other circulatory disorders, infections, hyperthyroidism and probably other problems but these are much less common causes than heart disease.

Treatment is usually attempted using medications that inhibit or break up blood clots. Heparin is most commonly used in veterinary medicine but other medications have been used. The survival rate of cats in the initial bout of aortic thromboembolism is probably about 30 to 50% with treatment for pain, medications for blood clotting and correction of problems that are associated with thromboembolism, such as hyperkalemia. Some cats would probably live that are ultimately euthanized due to inability to recover the use of their legs even though they are stable otherwise. These would be reasonably good odds if it weren't for two problems. The first is that the underlying disease must be treated successfully (the heart problem, infection, etc.) in order for the cat to continue to do well. The second problem is that a lot of cats have recurrences of the thromboembolisms even when treatment for the underlying condition seems to be going well. I haven't found a figure for the recurrence rate or for survival at one year later for cats that suffer from aortic thromboembolism but I am pretty sure that both statistics would be disheartening. Due to these problems it is important that clients understand that treatment for this condition involves intensive care with attending potentially high costs and that the odds are still not good. If that is clearly understood and a client wants to pursue therapy, anyway, there are published treatments.

Catching any heart conditions early and treating for them may be the best way to prevent this problem. Older cats should be evaluated at least yearly for signs of heart disease and appropriate treatment measures taken if heart disease is found. I don't know of any other treatment options. If aspirin were a little safer to give to cats it might prove beneficial as a preventative therapy but I would be very hesitant to start a cat patient of mine on long-term aspirin therapy to interfere with blood clotting as is often advocated for humans.

Hope this helps.

Mike Richards, DVM

Pleural effusion - Chylous or Pseudochylous

Q: Dear Dr. Richards:

Our cat, Suggy, had a hacking cough for several months. Our vet. thought he had hairballs so she gave us some hairball medicine. The hacking cough persisted. We took him to the Vet again, and she said that maybe it was an allergy. So, she gave him an antihistamine shot. The cough disappeared, but about two weeks after, Suggy started having trouble breathing. We took him to the vet. again. She found milky fluid in his lungs and recommended that we give him Bactril and take him for a chest X-ray. Then, she said that what he really needed was an ultrasound.

We took him for an ultrasound. The second vet. found more fluid in his lung. He thought Suggy may have a mass on his right lung. He said that all we could do was wait two weeks and bring him back for another ultrasound.

By this time, Suggy had stopped eating and barely drank. He was growing weaker everyday.

Three days after the ultrasound, he was not able to breath again. We took him to the first vet. (our mistake, we should have taken him to the University of Pennsylvania Veterinary Hospital) who said that he still had fluid in his lungs, this time of a clear color.

Two days after the first vet. sent Suggy home, we had to rush him to the University of Pennsylvania Veterinary Hospital. He could barely keep his head up, could barely breath, and had not eaten or drank in days.

At the Penn Vet. Hospital, he was placed in an oxygen cage in the emergency room. The emergency room doctor said that she needed to run some diagnostic tests to find out exactly what was causing Suggy's CHYLOUS EFFUSION. She said that we still had a small chance of helping him recover.

The next day, Suggy had been moved to Intensive Care. The Intensive Care doctor said there was nothing else she could do - if she tried to do some diagnostic work on Suggy that he may suffer from cardiac arrest. She said he was too weak for her to do anything.

We had to agree to Suggy being put to sleep on Friday, July 31, 1998.

Our question now is: don't you think our first vet. should have clearly stated that fluid in the lungs is CHYLOUS EFFUSION, that we needed to ASAP find out what was causing it to treat it?

If we had had the diagnostic work done on Suggy while he was still a strong, otherwise healthy, cat then maybe we could have started him on treatment before he was too weak to hold his head up.

What do you think, Dr. Richards?

We are thinking of writing a "disappointment" letter to our first vet., with a cc: to the Veterinary Licensing Board in Harrisburg, PA, stating how we wish she would have given us the full picture when Suggy first started hacking and when she first tapped the milky fluid.

Thank you for your attention to this message. We really appreciate your concern. Mournfully yours, Frances

A: Frances-

I can not tell for sure from reading your email whether the effusion was a chylous effusion or a pseudochylous effusion. The first is a specific condition involving leakage of chyle into the pleural space and the second is effusion that looks like chyle but isn't, which can occur with other diseases.

Due to the difficulty in explaining pleural effusions I think it is important to start with an explanation of how the pleural lining normally functions and then try to explain what can go wrong and what the results are. This will make it easier to understand why your question is harder to answer than many that are sent to our web site.

The pleura is the lining of the chest cavity and the lungs. It is a thin layer of specialized cells that coats the inside of the body wall (the parietal pleura) and then in a continuous sheet also covers the lungs (the visceral pleura). The pleura in cats does not segment itself completely into a right and left side so cats usually do not have pleural effusions on one side only as happens in some species. Dogs also have connections between the pleura of the right and left sides of their thorax so they are similar in this aspect. This is really simplistic but it might help to think of the pleura as a bag stuffed between and adhered to the lungs on one side and the body wall on the other.

The pleura normally produces fluid and the fluid is normally absorbed. When things are working right, there is a small amount of fluid present to lubricate the two sides of the pleura so they can rub smoothly over each other. In general, the parietal pleura produces more fluid than the visceral pleura and this produces a flow of fluid across the pleural space from the body wall into the lungs as the visceral pleura absorbs the fluid through small capillaries and lymphatic vessels. Even though only a small amount of fluid is present in the pleural space at any one time a lot of fluid crosses the space.

Fluid accumulates in the pleura space when the production and absorption processes get out of synch. This can happen when too much fluid is produced by either side of the pleura. It can happen when the pleura can't absorb the fluid as it normally would but production of fluid remains normal. In some cases there are disturbances in fluid production and in fluid absorption which can lead to pretty rapid accumulations of fluid and severe respiratory distress as the fluid makes it impossible for the lungs to expand.

Heart failure, usually from cardiomyopathy in cats, is one cause of changes in the fluid pressures. As the heart function decreases blood accumulates in the lungs because it isn't being pumped out of them. This raises the blood pressure in the pulmonary capillaries which normally drain the fluid from the visceral pleura. The pressure in the parietal pleura vessels may remain the same or lessen. This makes it impossible for the fluid to flow from the parietal pleura to the visceral pleura so it just accumulates between the two sides.

If the lymphatic vessels leak or if the pressure in these vessels increases so that they can't absorb fluid then the pressure changes for a different reason but the effect is the same. Without the help of the lymphatic vessels to drain fluid, there is not enough movement of fluid into the visceral pleura and once again, the result is accumulation of fluid in the pleural space. True chylothorax occurs when the lymphatic vessels are torn or leak for some reason. Pseudochylothorax occurs as a secondary change after another type of effusion has occurred.

Fluid accumulation in the pleural cavity can be classified several ways. It can be convenient to think of the fluid as either a transudate (fluid accumulation with very few cells in it and low protein, usually the result of pressure changes only), modified transudates (fluid with some cells in it and higher protein) and exudates (fluid with lots of cells, even higher protein and generally too cloudy or turbid to see through).

Low blood protein levels are the usual suspect when there is fluid that can really be called a transudate.

Modified transudates occur with lots of diseases, including cardiomyopathy, heart failure for other reasons, lung damage for any reason, diaphragmatic hernias, cancer, hyperthyroidism in cats, heartworm disease, feline infectious peritonitis, feline leukemia virus (usually due to lymphoma), trauma, bleeding disorders and probably other stuff.

Exudates occur for most of the reasons above if the disease process continues long enough. The modified transudate may be present for a long time prior to the disease worsening or may be a very brief stage in the march towards an exudative process. Some disorders start out as exudates. Chylothorax due to damage to the lymphatic vessels from trauma, cancer or for no apparent reason is an exudate right from the start. Pleural abscesses and infective material from wounds to the chest are exudates right from the start, too.

Whether the disorder is a transudate, a modified transudate or an exudate, it is an effusion if abnormal amounts of fluid are accumulating in the pleural space.

By withdrawing some of the fluid from a pleural effusion and examining it for cells, protein levels, color, odor and specific gravity, it is often possible to make a pretty good guess as to the cause of the fluid accumulation. If the fluid contains cancer cells, if it is a true chylous exudate or if it looks like and smells like pus examination of the fluid gives a strong clue as to what is going on.

It is hard to differentiate between chylous effusions and pseudochylous effusions based on appearance alone. It is possible to get some idea of what the fluid is by letting it sit overnight and looking for separation of a "cream" layer or by mixing the fluid with ether to see if it clears. Most practices don't have ether around anymore, though. Submitting the fluid for lab evaluation is helpful because true chyle is high in triglycerides and low in cholesterol. Pseudochyle is lower in triglycerides and higher in cholesterol.

I am not sure why your vet or the vet who did the ultrasound exam did not attempt to identify the fluid or did not tell you what it was if they did. I am also not absolutely certain that the vet at the University of Pennsylvania was certain that the fluid was a true chylous effusion at the time that the comment was made (if it was made just after withdrawing the fluid as it appears to have been in your note) -- the diagnostic tests might have been necessary to determine whether the fluid was a chylous effusion or a pseudochylous effusion, especially with the history of it being clear the last time your vet took a sample.

The problem in answering your question is this: was the fluid really chyle? If so, then early aggressive treatment may have helped but medical treatment for chylous effusions is pretty difficult and works best when the effusion is occurring due to trauma that can heal itself. Surgical treatment isn't highly successful but can be attempted when medical treatment isn't working well. If the fluid was a pseudochyle, why was it occurring? If an underlying cause could have been identified and treated then there may have been some hope. If the cause was cancer or severe cardiomyopathy then a good outcome was still pretty unlikely.

If a necropsy (autopsy) was done then you may know the answer to these questions. If so, it would be best to review it and to try to make an assessment of the likelihood that treatment would have been successful. There is more likelihood that the outcome would have been the same than that successful long-term treatment could have been achieved but it might help to know that for sure. I think that it would have been best if your vet had realized that you wanted to treat this situation as aggressively as possible. It is easy for general practitioners in veterinary medicine to assume that people do not want to pursue aggressive diagnostic processes and aggressive therapies where the potential for a good outcome is small. Despite this, it is important to remember that some clients do want to go all out and to keep an open mind about that. It is also fair to expect your vet to make an attempt to explain the disease process so that you can understand it and make decisions accordingly. It is also pretty easy to make statements that are more definitive than the situation warrants when treating emergencies or in intensive care situations. It seems possible that this happened, too. For this reason, it is equally important for there to be follow-up and an explanation of whatever lab tests were done when a patient dies.

It is too late to change the situation now, but your email reinforces the need for veterinary clients to to remember that there are specialists in veterinary medicine and that asking for referral to one when any treatment or diagnostic process doesn't seem to be working well is a reasonable thing to do. It is not necessary to wait for your vet to suggest this.

I am sorry to hear of your loss. I hope that this explanation isn't burdensome. It would be best to contact your vet, either by letter or in person, to discuss all of this and to help to resolve whether more could have been done. If there was never a definitive diagnosis, either through the labwork done at the University of Pennsylvania or through an autopsy exam, it may be impossible to ever know for sure whether the outcome could have been changed. That would be true even in most cases in which true chylothorax was present or a disease process severe enough to cause a pseudochylous effusion was present due to the difficulty in treating many of the underlying disease processes. It is very very difficult to live with uncertainty in the death of a pet and I know that is making this whole thing harder for you. I hope that you do find some resolution through discussing this with your vet or the vets at the University of Pennsylvania.

Mike Richards, DVM

Heartworms and cats

Q: Dear Dr. Richards,

I have spoken with cardiologists at various teaching universities who surgically remove heartworms from cats. Dr. Gavaghan (U.C.-Davis), Dr. Rawlings (U. of Georgia), and Dr. Eyster (Michigan State Univ.) remove the worms through the jugular vein. Dr. Bill Brown (Michigan Veterinary Specialists) uses a different approach which is thoractomy and incision into the right atrium to lift them out. All combined the number of surgeries using both methods totals approximately 16, so there's not a lot of experience doing this although they seem to be successful, based on what they've told me.

The purpose for my note is to ask your advice regarding how to decide which avenue is best for the cat's survival based on the procedures described above or to continue treating the symptoms with Prednisone and Aminophylline. How would you recommend that a person base this decision (removing cost as a factor)?

In my cat's case, she was diagnosed in May '98. Her symptoms became very serious for several days in early July - vomiting, diarrhea and gasping. My vet injected her with Prednisone and added Aminophylline and Furosemide to the menu. Of course, we don't know what happened, whether a worm died or not, but she suddenly stabilized and has been 100% without symptoms for the past 6 weeks.

A second question that I have for you is what your thoughts are regarding the fact that she has no symptoms now and that I'd like to reduce the amount of medications she is taking. We recently decided, since her lungs sound clear now, to drop the Furosemide to once a week. I am also considering dropping the frequency of Aminophylline (currently 25mg twice/day) to once a day, and perhaps removing it entirely if she continues to be free of symptoms. The reason for this is that I travel for business and, considering my responsibility for giving her all these meds each day, have been unable to leave her. She was once a feral cat who has become very attached to me. No one else can get near her. It's a bit of a dilemma especially considering the long duration of this disease. That is another reason why I am gathering information on a surgical approach, it would bring this disease to an end, hopefully successfully.

Thank-you for your time.


A: Nancy-

It might be a good idea to consider retesting for heartworms. It would not be unusual for a cat to have a single heartworm and the symptoms you have seen would be consistent with death of a heartworm. We have seen the antigen disappear from the bloodstream in as little as two months in one cat. If there was a positive antigen test previously and it becomes negative that would be a good sign. Ultrasonagraphy is another method of assessing whether or not worms are still present. University practices may offer even more sophisticated testing such as nuclear scintigraphy using radiolabelled antibodies against heartworms.

If heartworms are still present it would be necessary to continue to consider which form of therapy to go with. While I don't have any personal experience with heartworm extraction in cats to go on I do think that I would consider it as an option. Both the presence and eventually the death of the heartworm are dangerous for the cat and eliminating the worms surgically would reduce that risk immediately if successful. Since some sort of imaging to identify the location and number of worms would be a good idea prior to surgery the testing mentioned above would probably be part of the work-up for the procedure.

When clinical symptoms diminish we taper off the medications. So far, this has worked well for us when the cat has been symptom free for 6 weeks or more prior to withdrawal of the medications but the number of cases we have treated in this manner is still only about 3 cats. We chose 6 weeks arbitrarily.

If possible I'd base these treatment options on confirming that heartworm disease is still present. If that is not possible and symptoms have lessened I think it is reasonable to taper off the medications and see what happens. If that is not possible and symptoms remain then I think the choice is harder. Since there are few cases to base a decision on you may just need to make a choice arbitrarily. Trust your instincts if it comes to this.

Mike Richards, DVM

Heart disease and hyperthyroidism

Q: Dear Dr. Mike, My cat Linus is 13 years old and was diagnosed yesterday with a heart murmur. Our vet did a blood panel and discovered a slight elevation in his thyroid levels with low K and phos. levels. With this info I will be starting him on Tapazole 1/2 tab dailyin addition to K supplement. My concern lies in his dental care since I normally have his teeth cleaned annually. I am very afraid with this condition to expose him to anesthesia. However he does have bad tartar build up which makes yearly cleanings necessary. I would appreciate your advice in this matter. Do we jepordize his teeth or just take the chance that the anesthesia will not be rough on him. Thanks Linus and Cathy

A: Linus and Cathy- Heart murmurs can occur with hyperthyroidism and may disappear with treatment. If your cat can be stabilized and the clinical signs improve it should be reasonably safe to use anesthesia. Choosing an anesthetic with minimal cardiac effects (we use isoflurane gas) is helpful. While there is undoubtedly increased risk of anesthesia when a cat may have cardiomyopathy associated with hyperthyroidism we have not had an anesthetic death yet while anesthetizing cats we know have hyperthyroidism. I would work at stabilizing the problem with hyperthyroidism before considering routine care if at all possible but if this can be done it should be OK to consider the teeth cleaning.

Mike Richards, DVM

Part 2 - the good news

Dear Dr. Richards, I just wanted to take a few minutes to thank you for your reply. Due to the information in your e-mail and the information contained in your web page ( Cardiomyopathy )I talked to my vet about doing an echocardiogram on Linus to check for any heart disease. Well the test are in and due to early detection of his hyperthyroidism their was only a slight thickening of the cardiac muscle. With treatment he should be well on his way to a good 5 more years maybe more. This just proves that yearly visits to the vet are critical in detecting these treatable conditions that can cause so much damage. Thanks again your web page is wonderful. Cathy and Linus.

Mike Richards, DVM

Heart failure - kidney failure

Q: Dear Dr. Mike, My cat was euthanized one day ago. My cat Sam (15 yrs) had been diagnosed in January with kidney disease. After he was in doctors care for 1 week, we took him home to care for him. His bun was brought down from the 120 range to the mid 40 range. His creatnine levels were reduced from mid 7 to normal range. However, by March, these levels were up again. Bun was 90's. Reading on the web about sub-q fluids, I started administering to him 100cc daily. A further check up one month later, still showed a high bun of 120. I proceeded to double the dosage and was giving 200 cc daily, 100cc morning and 100cc night. He seemed to be in fairly good spirits, up until a week ago, when we noticed he was not eating or drinking. Then two days ago he was breathing harder. We took him to an emergency clinic (Memorial Day) and was told he was suffering from respiratory failure. They put him in an oxygen tent overnight and were giving him diuretics to remove the fluid that was found by x-ray to be around the lung cavity as well as inside the lung. They hoped that thru the night he would urinate, which he did, and that he would breathe without the need for oxygen. Unfortunately, he was not able to leave the oxygen tent without gasping for air. At that point the following morning, we made the decision to end his suffering.

My question to you, since we did not have our regular vet available due to the holidays, is the congested heart failure, usually an end result to renal failure? I had been ,up until a month ago, giving him epogen shots, because he had anemia. Once that was under control, the vet said I did not need to give them to Sam, until the next visit, which we were coming up against almost one month later. Could the lack of epogen have caused his sudden heart problems? The vet said his heart was enlarged at the time we brought him into the emergency clinic. I am wondering if this could have been prevented, in any way. I know he was old, but if I could have prolonged his life without suffering I would have done it.I am very saddened by my loss. Thank you for your help and advice in this matter. Faye

A: Faye- It sounds like you and your vet were making the best possible effort to care for Sam. Epogen (Rx) is used to treat the anemia associated with chronic kidney failure. Discontinuing use of it should not have caused cardiomyopathy, to the best of my knowledge. The most common cause of cardiomyopathy in older cats is probably hyperthyroidism. Unless there were clinical signs of this, it seems unlikely that it would have been advanced to the stage where it would affect his heart, though. Heart enlargement is not always due to cardiomyopathy in cats. Sometimes heart failure occurs for other reasons and still results in an increase in the size of the heart. It really does sound to me like you and your vet were providing Sam with good medical care. Please don't make yourself feel guilty unnecessarily. Sometimes, the best we can do is not good enough.

Mike Richards, DVM

Congestive heart failure after

Q: Dear Dr. Mike, I brought my eleven year old cat to my veterinarian today for a dental prophylaxis. A few hours later, I received a call that she had experienced congestive heart failure immediately after she was administered anaesthesia. She was placed in an oxygen tank for several hours. When I visited her, she was breathing quite deeply. Tomorrow she is scheduled to undergo Ultrasound, an EKG, as well as have blood work completed. I am extremely distressed and cannot dismiss the notion that she had an adverse reaction to the anaesthesia. She had a normal heartbeat during her annual examination one month ago, as well as immediately prior to her treatment today. She has never had labored breathing or any of the other symptoms associated with congestive heart failure. I would truly appreciate any advice or suggestions regarding this matter. Thank you. Sincerely, J.

A: Iwould be suspicious if I was in your position, too. We have discovered cardiomyopathy in a cat in our practice with anesthesia in much the same manner, though. This is an insidious problem and can be hard to detect prior to the onset of symptoms or prior to a stress such as anesthesia. The testing should help clarify this situation. It is always hard to accept when "routine" things turn out to be not so routine. I hope all turns out well.

Mike Richards, DVM

Congestive heart failure after anesthesia - Part 2

Q: Dear Dr. Mike, Thank you so much for addressing my concerns regarding Tasha. Although Tasha's EKG was normal, the ultrasound indicated that she was suffering from cardiomyopathy. My DVM still has a number of questions for the Dr. who evaluated the ultrasound and will contact me when he receives a more definitive answer. We brought Tasha home on Thursday and she appears to be getting stronger each day. She just began eating on her own today and is taking a quarter tablet of Atenolol daily. I often wonder, had Tasha not been anesthesized, would she have lived to age fifteen without ever having exhibited signs of heart failure. I was always extremely fearful of anesthesia and now I am very distressed that I may have significantly shortened Tasha's life by allowing her to be anesthesized. I would truly appreciate any thoughts which you may have regarding my concerns. Sincerely, J.

A: I am not sure if the episode you had will have any long lasting effect. The cardiologist may be able to answer that more definitively. So far, we have had pretty good luck treating cats with this problem when we have been able to identify it. I guess I'd hope that finding it now may save some damage that would have occurred while it continued to develop.

It is good to have a healthy respect for anesthesia. You always have to weigh that against the benefit of what you are trying to do. I really think that most animals live longer if things like dental disease are taken care of, even with the anesthetic risk factored in. It is just not entirely safe and some pets come out on the losing end of the risk/benefit ratio. It never seems consoling enough to say that the odds were in a pet's favor when things have gone badly. There just isn't much to say when good decisions have bad outcomes.

I hope that Tasha continues to improve on the medications and that she does keep going for a number of years.

Mike Richards, DVM

Secondary Myocarditis and Diabetes

Q: I am trying to find information about congestive heart failure in cats. My cat is diabetic and has had a bout of kidney disease. He is currently taking insulin and is on diet therapy. I was told that congestive heart failure is a possibility. I am interested in knowing what symptoms I should look out for and what the possible treatment is. Thanks.

A: Diabetes mellitus can lead to a secondary myocarditis (malfunction of the heart muscles). This can eventually cause heart failure. The signs that this is happening include a decrease in activity or weakness associated with normal activities, difficulty breathing or increased respiratory rate, decrease in appetite and sometimes pain or paralysis of the rear legs. Unfortunately, most of these signs can also occur for other reasons, including other complications of diabetes, like diabetic neuropathy leading to hind limb weakness or decrease in appetite associated with a loss of control of insulin regulation. With diabetes, it is important to work very closely with your vet to monitor the treatment. Teamwork makes a huge difference in the successful maintenance of a dog or cat with diabetes.

I hope that you never have to worry about this complication of diabetes.

Mike Richards, DVM

Fluid in lungs - possible Pulmonary edema

Q: Dr. Mike, For the past two weeks I have been desparately trying to find out what is wrong with my cat Miles. For the last month, Miles (age 6) has been laying around a lot, but sometimes he does that. Then on 2/26/97, I came home from school and he acted, funny he meowed a lot did not eat, when he went out to potty, he stumbled down the steps, he was also breathing fast. It looked like his rear end was pretty shaky. I took him to the vet, they tested for leukemia and FIV, both negative, they tried to get more blood to do more tests and Miles got really stressed. They gave him some injections of steriods and antibiotics and sent him home with amoxicillian. His balance came back, but he hasn't been eating much, unhappy with the service from my regular vets office, we took Miles to a new vet for his continued rapid breathing. He took X-Rays, the vet said from the x-rays he could not see a diaphragm, because of fluid build up, Miles has been getting shots (anti-inflam., antibiotic, diruetic) almost daily from the new vet to reduce the fluid in order to get a better xray. The vet said it could be a torn diaphragm or any number of other things. Tomorrow they are supposed to re x-ray him. For the past two days Miles has had shots to increase his appetite, they have worked so-so. Miles' breathing is much improved, but I don't know what to prepare myself for. I feel like this is my child and want to know what to do as quickly as possible. Any ideas, comments, or suggestions that you may have would be greatly appreciated!

A: I am not going to be able to help you decide which of the following conditions I list is actually affecting your cat, Miles. There isn't enough information in your letter to tell if this is pulmonary edema (fluid in the lungs) or a pleural effusion (fluid around the lungs). Based solely on probability I would guess that this is a pleural effusion because they are a lot more common - but it is a guess.

Pulmonary edema is seen with heart failure, conditions causing low blood protein levels, cancer, pneumonia, "shock lung" or acute respiratory distress syndrome and some other less likely problems. Identifying the cause helps a lot. It is hard to do when there is a lot of fluid present in the lungs, so it is sometimes necessary to treat symptomatically for a while in order to be able to get reasonable X-rays.

Pleural effusion is more common in cats. The most common cause of pleural effusion is cardiomyopathy (weakness of the heart muscles). Other causes include abscesses in the pleural space (pyothorax), chylothorax (leakage of chyle from the lymph ducts into the pleural space), other causes of heart failure, cancer (feline leukemia causes cancer), diaphragmatic hernias, lung lobe torsion and lots of other less common things cause fluid in the pleural space. We like to draw the fluid off the chest if we think it is pleural fluid. It took me a long time in practice to get comfortable doing this, though. I'm not sure why it took me so long to quit worrying about damaging the lungs and just do this, because it seems to help a lot in many cases. Another advantage of doing this is that you get to look at the fluid and analyze it. That can be really helpful in deciding how to treat the problem. It is not possible to draw off fluid dispersed throughout the lungs so this won't work with pulmonary edema. Many vets prefer to treat aggressively with diuretics to get rid of fluid in that manner. We have to do that even after drawing fluid off in most cases.

Just based on your cat's age, feline leukemia and FIV negative status and the clinical signs you describe, this is likely to be cardiomyopathy. X-rays after the fluid is controlled will help with a diagnosis but this condition is best diagnosed with ultrasound exam, so you may be facing more than one round of testing at this point. It is important to do this, even though it is frustrating to keep having to go back over and over again to reach a final diagnosis. As you can tell from the lists of possible problems above, there is also a really strong possibility that this is something else, entirely. Hope this information doesn't just make it all the more confusing for you.

Mike Richards, DVM


Q: Dr. Mike, Thanks for your information on Miles' probable condition Today's xray still showed too much fluid. The vet gave us the following options: him do surgery to try and find out what is going on, or take Miles to the local university for an ultrasound. The vet said given Miles' stress level that he should be considered extremely high risk for surgery. The vet also said that getting the ultrasound would probably cost $600. I don't know what to do. The vet said cardiomyopathy is a possibility as is a torn diaphragm. If it is cadiomyopathy that is it treatable? For easily stressed animals, should surgery be a last resort? Miles has not eaten since yesterday and he looks like he is on his last leg. Any help that you can offer is greatly appreciated. Thanks in advance.

A: I can't tell for sure from your note, but if the local university has a veterinary school, I would definitely go and at least get a second opinion. If this is cardiomyopathy it will be necessary at some point to have an ultrasound exam done. I am not sure what they cost in your area, but the ultrasound exam itself tends to be around $150 in our area. Of course, the total bill may be significantly more than just the cost of the ultrasound exam alone. One advantage of the school is that they will also have a clinical pathologist who can examine the fluid and it is very likely that they will be able to give you a pretty good idea of the prognosis before doing an ultrasound exam, based on an analysis of the fluid.

I really think it would be worthwhile to go, if there is a veterinary school near you.

Michael Richards, DVM

Last edited 09/17/02


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...