admin, Author at Paws Whiskers & Claws, The Feline Hospital

Feline Hypertension

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What is hypertension?

Hypertension is the medical term for high blood pressure. It occurs most commonly in older cats with certain conditions like kidney and thyroid disease. Hypertension can be primary or secondary in nature. Hypertension can also be caused by “white coat syndrome” or the stress of the vet visit – this is one of the many reasons why our staff do not wear white coats or other identifying clothing!

What causes hypertension?

Primary hypertension has no identified underlying cause; it is much less common and is poorly understood. Secondary hypertension occurs as a result of an underlying disease process. Chronic kidney disease (CKD) and hyperthyroidism have been identified as the two most common predisposing factors for development of feline hypertension. In humans, hypertension is related to several factors, including a stressful lifestyle. Although not all causes of feline hypertension have been identified, stress does not appear to play a role in the development of this disorder in cats.

· Kidney disease: It appears that several different mechanisms may lead to development of hypertension in cats with kidney disease. One theory suggests that as a cat ages, the kidneys undergo normal aging changes including a slow accumulation of scar tissue. With time, this scar tissue causes the kidneys to shrink in size. When the kidney shrinks, it is harder for the blood to filter through. Because the kidneys normally receive 20% of the blood with every heartbeat, blood backs up into the arteries and leads to an increase in blood pressure. One study found that about 60% of cats in old-age kidney failure have hypertension. Elderly cats in the early stages of kidney disease may also have hypertension.

· Hyperthyroidism: The thyroid gland is located in the neck and plays a very important role in regulating the body's metabolic rate. Hyperthyroidism is a disorder characterized by the overproduction of thyroid hormone and a subsequent increase in the metabolic rate. This is a fairly common disease of older cats. Although the thyroid gland enlarges, it is usually a non-malignant change (benign). Less than 2% of hyperthyroid cases involve a malignant change in the gland. Many organs are affected by hyperthyroidism, including the heart. The heart is stimulated to pump faster and more forcefully, and eventually the heart enlarges to meet these increased demands for blood flow. The increased pumping pressure leads to a greater output of blood and high blood pressure. About 25% of cats with hyperthyroidism have high blood pressure.

What are the clinical signs?

Visual abnormalities are the most common clinical findings with feline hypertension. These abnormalities can include dilated pupils that do not constrict with light, blood within the chamber of the eye, and blindness. Blindness develops because high blood pressure in the eye causes the retina to detach. Other possible indications of high blood pressure include restlessness, agitation, decreased grooming, head pressing, changes in appetite, thirst and/or weight. Oftentimes, owners feel that their cats are more restless or agitated at night. These problems may be temporary or permanent, just like in people and only time can tell which ailments will resolve and which will be long lasting. Cats that do not feel well, just like people, may act in ways we would refer to as cranky, easily agitated, or aggressive towards people, especially children, and/or other animals.

Why is hypertension bad?

Left untreated, hypertension can lead to a number of negative side effects including:

· Eye damage: hypertension can cause blindness due to damage of the retina from enlarged blood vessels

· Brain damage: hypertension can lead to seizures, stroke, altered mentation, head tilt, and neurologic deficits

· Kidney damage: damage to the tiny working parts of the kidney called the glomerulus can lead to further decreased kidney function as well as protein loss from the kidneys (proteinuria); proteinuria further damages the kidneys and can worsen kidney disease more quickly

· Heart damage: hypertension causes increased workload for the heart, which can lead to the development of heart disease which can in turn cause arrhythmias, infarcts to the heart (think of a stroke, but instead of the brain the heart is affected), and heart failure

How is it diagnosed?

Hypertension should be suspected in any older cat with kidney disease or hyperthyroidism. Onset of sudden, unexplained blindness should raise a strong suspicion for hypertension, and the associated diseases should be considered, meaning that labwork to detect kidney and thyroid disease should be performed. Also, the presence of a heart murmur or kidney-related problems may signal the presence of a hypertensive state.

Blood pressure is determined with a device that can detect blood flow in arteries. We use a pediatric blood pressure cuff in a manner very similar to the way human blood pressure is taken. We take the pressure on your cat’s leg.

What is involved in treatment?

The most commonly used drug is amlodipine (generic) which is Norvasc. Daily oral medication is required to control high blood pressure. This is not a cure. If you stop giving the medication as prescribed, the blood pressure can rise up into the abnormal and potentially dangerous high range again. The medication is a very small pill available at our office as well as any human pharmacy. This medication can be made into a liquid by an outside compounding pharmacy for those who find liquid easier to administer. Rechecking blood pressure once medication is started and then at regular intervals dictated by your veterinarian is extremely important. This is the only way to know whether or not the medication is working and if adjustments to the dose of medication are necessary.

What is the prognosis?

The underlying disease that caused hypertension to develop must be cured or controlled. Long-term success depends on whether or not this is possible. If the cat has kidney, heart, or thyroid disease, it is important to treat those conditions aggressively. These conditions are not curable (with the exception of one type of treatment for hyperthyroidism), so management of the disease is essential. However, even those can be managed successfully in most cats for many years, with excellent quality of life.

If the cat has blindness due to detached retinas, a medical emergency exists. Blood pressure must be lowered quickly in order to regain vision. If the retinas remain detached for more than a day or two, the prognosis is poor for a return of normal vision. Therefore, the key to a successful outcome is rapid diagnosis and early administration of the proper medication to lower blood pressure.

When controlled, hypertension has an excellent prognosis. Continued monitoring with blood and urine samples is important to rule out concurrent disease contributing to hypertension.

Feline Arthritis

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steoarthritis or degenerative joint disease (DJD) is an irreversible, degenerative disease of the lining of the joint. The shoulder and elbow joints are those most frequently affected in older cats followed by the spine, hips, and knees. Cartilage is eroded from the ends of the bones making up the joint, and bony spurs (called osteophytes) and thickening occur in bones adjacent to the joint. Arthritis is a painful condition that should always be taken seriously.

How do I know if my cat has arthritis?

Most cats that are middle-aged or older have arthritis. Studies have shown that about 90% of cats over the age of 12 have x-ray evidence of arthritis in at least one joint, and most of the cats in this study did not have signs seen by the owner or veterinarian! Another study showed that of cats older than 6 years of age, 61% had x-ray evidence of arthritis in at least one joint and almost 50% had arthritis in multiple joints! All of this is to say that arthritis is incredibly common and just because your cat is not displaying arthritis signs does not mean they do not already have arthritis!

Most cats with arthritis do not have very visible clinical signs, like lameness. Cats often have arthritis in both joints (i.e., both elbows or both knees) which is why we often do not see them limping. Cats are also very good at hiding their pain. Instead, there are numerous other signs of arthritis such as:

Difficulty climbing stairs or jumping (longer anticipation time vs swift leap)
Decreased activity, especially play behaviors
Decreased interaction with the family – staying in one place/room
Decrease or changes in scratching post use, especially vertical use; arthritic cats tend to scratch horizontally as reaching up becomes challenging
Difficulty lying down or getting up
Favoring/laying down on one side specifically
Elimination outside of the litter box as posturing in a loose substrate becomes increasingly difficult; stable surfaces (hard floors and carpet) are often chosen
Increased stiffness or limping
Inability to groom or be groomed due to pain, resulting in poor coat condition or matting, especially on back half of the body as it is difficult to twist and contort to reach the hind end, groin, and rear
Aggression and petting intolerance, less tolerance with other pets/people and “busyness” around them due to their inability to react and move quickly
Heat-seeking behavior, such as lying by heat vents, coffee pots, sunny locations, laptops
Weight loss or a decreased appetite as cats will always choose to remain in a warm, comfortable bed vs walk down a flight of stairs to eat.

Many pet parents will notice that their cat prefers to jump onto a chair or stool before jumping onto or off a counter/higher surface. If there is no stool, the cat may slide their paws down the vertical surface so as to lower their center of gravity lower to the floor before making the jump. When jumping up, they may do a “rearing” motion instead of just jumping lithely up onto the counter!

If you think your cat may be showing signs of arthritis, they probably are! It’s best to schedule an appointment so we can discuss treatments. It’s very helpful if you can bring videos of your cat walking, running, using stairs, and jumping. This allows us to see how they move around at home since they are often too scared or sleepy on their pre-medications to move here! We also often recommend that all cats around 7-10 years old start on an arthritis therapy to help them be more comfortable. If your cat has had limb injuries or is handicapped in any way (declawed, three-legged, previous hit by car injury, broken pelvis, bad knees, etc.) then it is advised to start joint support earlier in life rather than waiting until they show symptoms. Prevention is the best medicine!

What treatments are available for arthritis?

There are numerous treatment options available for arthritis. Depending on how severely your cat is affected, we may recommend one or multiple of the below therapies.

Glucosamine and chondroitin: Glucosamine is a major component of cartilage, and chondroitin aids the formation of cartilage and inhibits enzymes in the joint that tend to break down cartilage. Cosequin is a tuna/chicken flavored powder which comes in a capsule that can be given orally or sprinkled over food. Dasuquin Advanced contains glucosamine and chondroitin like Cosequin as well as additional beneficial arthritis supplements like Boswellia extract, which is a plant based anti-inflammatory.
PSGAGs (polysulfated glycosaminoglycans): Adequan is an injectable PSGAGs that is given subcutaneously (under the skin). PSGAGs help to prevent cartilage breakdown and may help to increase the quality of the fluid within the arthritic joints.
Omega-3 fatty acids: diets and supplements containing omega-3 fatty acids, particularly DHA & EPA, may reduce pro-inflammatory factor production. Fatty acids from cold water marine mammals are best compared to those from plants. Green-lipped mussel extracts are often used as a great source of omega-3 fatty acids and are found in Antinol Plus, one of our preferred fish oils. Another great option is Vetoquinol’s Triglyceride OMEGA, which contains fatty acids from fish oils from Atlantic sardines, mackerel, and anchovies.
NSAIDs (non-steroidal anti-inflammatory medications): NSAIDs are anti-inflammatory and provide pain relief by blocking parts of the pain pathway. It’s similar to a human taking ibuprofen. Since cats cannot have ibuprofen, Tylenol, or some other human pain medications, there are NSAIDs that have been created specifically for cats, such as Onsior and Meloxicam. Unfortunately, in the US no NSAIDs are labeled for long-term use in cats; this does not mean we do not use NSAIDs off-label in cats long-term, because we absolutely do! However, care should be taken when choosing the medication, dose, and frequency of the medication to minimize as many side effects as possible. NSAIDs are processed through the kidneys and so monitoring kidney values is important for every cat on regular NSAID therapy. For many of our patients, receiving daily NSAIDs is what helps to preserve their quality of life and help them be pain-free in their older years.
Monoclonal antibody therapy: a miraculous medication that has become available in the US in recent years is Solensia. This injection is given once monthly subcutaneously. Solensia actually works to block a part of the arthritis pain pathway; specifically, it inhibits something called nerve growth factor (NGF) in the pain pathway. By inhibiting NGF, pain signals are inhibited allowing the cat to feel much better and pain-free. When first starting Solensia, the injection is given once monthly for three months; this is because there is an additive effect with each subsequent injection. If after 3 months your cat does not have improvement on Solensia, it is discontinued. Some cats may develop a tolerance to the medication over time which is why we do not recommend this as a first-line therapy.
Other pain medications: other pain medications, such as gabapentin, buprenorphine, tramadol, or amantadine, may be used. These medications do not decrease inflammation but instead focus on decreasing pain. We frequently use gabapentin early on because it has minimal side effects and we can adjust the dose easily over time.
Alternative therapies: many other options are available for decreasing inflammation and/or minimizing arthritis pain. These options can include acupuncture, laser therapy, PEMF therapy, and CBD therapies (ElleVet). We do not offer these therapies at PWC but can direct you to other local practitioners who offer these services if we believe it may be helpful for your cat!

What else can I do to help my arthritic cat?

Excess weight can overburden already painful joints. If your cat is overweight, talk with your vet about the best way to safely reduce the cat’s weight. Exercise provides a two-fold benefit: it aids in weight loss and it helps keep arthritic joints from becoming stiff. Play with your cat!

Warmth provides comfort for stiff, painful joints. You might provide a heated or thermal pet bed (such as K&H heated pet beds) or use a Snuggle Safe disk to supply safe warmth without electricity. Don’t forget that cardboard is insulating and helps your cat maintain their “thermal neutral zone” without having to use extra energy, so a cardboard box with soft bedding in the sunshine can work wonders!

Large-breed dog beds usually provide thicker cushioning than cat beds, making them an excellent resting spot for your arthritic cat. Many cats will also love the extra cushion provided by memory foam, fleece plush blankets, or orthopedic beds.

Be mindful of your cat’s changing needs. Having a wide variety of choices for all of their environmental needs can help greatly. For example, add a litter box closer to the cat’s favorite napping spot or add a feeding station on each floor so the cat doesn’t have to climb the stairs to eat or get a drink. As a rule of thumb, there should be at least a litter box on every level of the home. If your home is very long, there should be litter boxes on either side of the house. Additionally, you may need to change the type of litter box you have, such as opting for one with a lower side/cutout entrance. Food and water should be easily accessible in all of the places your senior cat spends their time. We recommended spreading out resources when they are young and healthy; when they are senior, think efficiency apartment! Make it easy for them to access their needs.

Add chairs, stools, or pet ramps/stairs between the floor and higher surfaces of the home, such as beds, couches, or counters. If your cat used to jump on the counter to eat their food, make sure the counter is now easily accessible or transition to having the food on a lower level.

With a little special care, your arthritic cat can not only enjoy their senior years, they can thrive!

Cats seek heat (sun) to soothe tender joints, be sure warmth is always available for your senior cat.

Feline Hyperthyroidism

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The thyroid glands are located in the neck and play a vital role in regulating the body's metabolic rate. Hyperthyroidism is a disorder characterized by the overproduction of thyroid hormone and a subsequent increase in the metabolic rate. This is a fairly common disease of older cats. Although the thyroid gland enlarges, it is usually a non-malignant change (benign). Less than 2% of hyperthyroid cases involve malignant thyroid gland tumors.

Many organs are affected by this disease, including the heart. The heart is stimulated to pump faster and more forcefully; eventually, the heart enlarges to meet these increased demands for blood flow. The increased pumping pressure leads to a greater output of blood and high blood pressure. Hyperthyroidism can also mask underlying other diseases such as chronic kidney disease (CKD).

What cats are more likely to become hyperthyroid?

Older cats are at increased risk for developing hyperthyroidism. Environmental and dietary risk factors have been investigated and may play a role in predisposing some cats to hyperthyroidism, though the specific mechanisms are not known. No individual breed is known to be especially at increased risk.

What are the clinical signs?

Cats afflicted with hyperthyroidism usually develop a variety of signs, which may be subtle at first but then become more severe as the disease progresses. The most common clinical signs of hyperthyroidism are weight loss, increased appetite, and increased thirst and urination. Cats may eat new or different types of food than they used to (ex. a cat that always ate dry food now wants to try wet food or people food!). Hyperthyroidism may also cause vomiting, diarrhea, and increased energy (excessive vocalizing, “busy”, pacing). It’s like they are having a caffeinated beverage every few hours. The coat may appear matted or greasy; they may also overgroom because they feel jittery from the excess thyroid hormone. If a cat previously had constipation issues, the bowel movements may now be normal.

Two secondary complications of this disease can be significant. These include hypertension (high blood pressure) and a heart disease called thyrotoxic cardiomyopathy. Hypertension develops as a consequence of the increased pumping pressure of the heart. In some cats, blood pressure can become so high that blindness occurs as a result of retinal hemorrhage or detachment. Heart problems develop because the heart must enlarge and thicken to meet the increased blood flow and metabolic demands. Both of these problems can be reversible with appropriate treatment of the disease.

Hyperthyroid cats, just like people with this or any other disease/illness, may act in ways we would refer to as cranky, easily agitated, or aggressive towards people, especially children, and/or other animals. Pain or discomfort from any source/cause often triggers cats to act out of their ordinary routine. They may hide, be less social, have different eating habits as described above, and/or different elimination habits which often means not using their litterbox to urinate and/or defecate. Sick or painful cats are not being spiteful or acting out of anger, just out of distress. It is their natural instinct to behave this way. In the wild, a sick cat is a weak cat and a weak cat is a potential victim. Changing their normal routine and/or demeanor may ward off a potential predator. So you see, what seems abnormal to the untrained human eye is actually normal to the feline survival instinct.

How is it diagnosed?

In most instances, diagnosis of this disease is relatively straightforward. The first step is to determine the blood level of one of the thyroid hormones, called thyroxine (or T₄). Usually, the T₄ level is so high that there is no question as to the diagnosis. Occasionally, a cat suspected of having hyperthyroidism will have T₄ levels within the upper range of normal cats. When this occurs, other tests, called a Free T₄ (FT₄) or TSH (thyroid-stimulating hormone), may be performed. These blood tests evaluates thyroid function in a different manner. If this is not diagnostic, a thyroid scan can be performed at a veterinary referral center or the thyroid tests can be measured again in a few weeks.

What are my options for treatment?

Because less than 2% of these cats have cancerous growths of the thyroid gland, treatment is usually very successful. There are three choices for treatment; any one of them could be the best choice in certain situations. Many factors must come into consideration when choosing the best therapy for an individual cat.

Several tests are performed before choosing any form of treatment. These tests are needed to evaluate the overall health of the cat and predict the chances for treatment complications. Such tests include blood chemistry profile, complete blood count (CBC), and urinalysis. Sometimes blood pressure and/or cardiac ultrasound may be recommended.

The three treatment options for hyperthyroidism are:

1. Oral medication. Administration of an oral drug, methimazole, can control the effects of the overactive thyroid gland. Rarely, some cats have reactions to the drug, but that number is small. However, the side-effects may begin as late as six months after the beginning of treatment and can include vomiting, lethargy, anorexia, fever, facial/head itching, and anemia.

Methimazole does not destroy the abnormal thyroid tissue but rather prevents the production of excess thyroid hormone. Therefore, the drug must be given for the remainder of the cat's life. Periodic blood tests must be done to keep the dosage regulated and monitor for side effects. Initially, bloodwork such as a T4 (thyroid level) +/- other thyroid function tests (a FT4 +/- a TSH), CBC, and the kidneys should be checked 2-6 weeks (the doctor will dictate when) after starting daily medication as well as after any time the dose of medication is changed.

After the thyroid level is normal, the kidney values can increase. The hyperthyroid condition can mask underlying kidney disease. For this reason we recommend a trial with oral medication first, before RI¹³¹. If kidney disease becomes apparent, it is easier to manage both diseases with oral thyroid medication than with surgery or RI¹³¹. Once the thyroid level is stable, rechecks will be every six months.

The pill is very small, inexpensive, and has minimal to no taste. It is commercially available at all human pharmacies as well as our office. It also comes in a dissolving tablet called a “mini melt” that is easy to pill directly or dissolve in a small amount of special food. Cats require once to twice daily dosing and this can change spontaneously over the course of the cat’s life, especially because there is usually growth of the benign thyroid gland over time. That is why it is so important to monitor your cat’s weight and bloodwork regularly as determined by your vet. For those who find liquid medications easier to administer, either directly to their cat or mixed with a small amount of special food, the pill can be made into a variety of flavored liquids at an outside compounding pharmacy. It is also available in a new feline liquid called Felanorm that has a flavor most cats like. Finally, the medication can also be made into a transdermal gel at an outside pharmacy. The gel is applied to the non-haired inside portion of the cat’s inner ear.

Oral medication is by far the most common treatment. Surgery is just about obsolete now that we have other safer and easier options. Recurrence of the disease is a possibility in some cats when surgery is done, if abnormal thyroid cells are left in the cat. The remaining cells will likely grow causing the disease to recur. However, this occurs less than 5% of the time and usually 2-4 years after surgery. Another possibility for disease recurrence is that one lobe of the thyroid gland was normal at the time of surgery so it was not removed. Then, months or years later, it becomes abnormal.

2. Radioactive iodine (RI¹³¹). A very effective way to treat hyperthyroidism is with radioactive iodine therapy. It is given by a subcutaneous injection, exactly like a vaccine is, and destroys all abnormal thyroid tissue without endangering other organs. This essentially cures the disease. However, a very small percentage of cats can regrow abnormal thyroid tissue, but this is very rare. If this occurs, retreatment is necessary. Treatment requires an average stay of 2-4 days at a veterinary hospital licensed to administer the therapy. Sometimes, but not always, the expense can be greater than for the other options. This option may make more economical sense if you have a younger cat diagnosed with this disease. We see cats living into their early 20’s (average 16 years old). A 10 year old cat needing daily medicine and at least biannual blood rechecks for this disease (see below) for 10 years could cost about the same. Every once in a while a cat can become hypOthryoid after this treatment (or the next one) and still end up needing daily medication.

3. Surgery. Surgical removal of the affected thyroid lobe(s) is also very effective. Because hyperthyroid cats are usually over eight years of age, there is a degree of risk involved. There is also potential for secondary post surgical complications. If the disease involves both lobes of the thyroid gland, two surgeries may be required, depending on the surgeon’s choice of procedures. In many cats, only one thyroid lobe is abnormal, so only one surgery is needed. The cost is approximately the same as RI¹³¹ treatment. Therefore surgery is only necessary for malignant tumors which are extremely rare.

If surgery or RI¹³¹ is the treatment method chosen, the cat is usually treated with an anti-thyroid medication for several weeks prior to the procedure. During that time, the ravenous appetite should subside and the cat will probably gain weight. Some cats also have a very fast heart rate and high blood pressure; these problems can be managed with medication before surgery. After one to two weeks, another T₄ level is measured.

With surgery, there is also a risk of damaging the parathyroid glands which sit near the thyroid gland. This is particularly of importance if both thyroid glands are removed. The parathyroid gland controls calcium levels; if it is damaged or removed, low calcium can occur which can lead to seizures or heart arrhythmias. Calcium supplementation is necessary if this occurs.

Is the prognosis good?

The outcomes following consistent medication are excellent, most cats have a very good chance of returning to a normal state of health. Of all the common disorders we see in older cats, this is the “good” one to get. Cats can live many, many years with this disease which is easily managed with one of the above treatment options. It gets complicated when they have other medical issues that were masked by the hyperthyroid state. The more we can do to manage other issues that surface as the thyroid normalizes, the better the prognosis.

It is important to note that once a cat is treated for hyperthyroidism and we slow the thyroid levels back to normal, they act their age. Cats with untreated hyperthyroidism have been acting great, often like a young cat again, but this has been a façade. Once we start treatment and normalize the thyroid level, cats will sleep more, eat less, potentially play less, and may gain weight. The older and more medical problems they have, the harder it is for them to gain weight.

With untreated hyperthyroidism, the high thyroid level suppresses the kidney levels so their kidney disease is missed or doesn’t look as bad as it truly is. When we treat hyperthyroidism, we often unmask kidney disease and needed to start therapies for chronic kidney disease, which is very common in older cats. We can also see more problems with arthritis because now these cats are slowing down and acting their age, leading to us seeing more arthritis symptoms. The arthritis and kidney disease were there all along, but masked by the over active hyperthyroid state. If a cat was previously constipated, we may see constipation issues recurring. These are all manageable issues and we can help make managing them positive for you and your cat.

Can it be prevented?

There are no preventive measures to adopt, but middle-aged and geriatric cats should all receive a complete physical examination by a veterinarian every 6-12 months. Special attention should be given to thyroid enlargement and the typical clinical signs of hyperthyroidism. Annual senior bloodwork that includes a T4 can screen for this and other diseases so that we can catch them before they make cats feel badly, lose weight, stop eating, etc.

Mousin’ Around by Petstages

These cute little mice are such great foraging toys! They are small, easily manipulated, offer appealing textures, and can be picked up and carried around the house just like real prey! They do not hold a lot of food so they are great for portion control as well. They really require some batting around to get the food to dispense and are not quite as easy as one might expect.

This post and all of its content is written by and property of Ingrid Johnson, CCBC Certified Cat Behavior Consultant of Fundamentally Feline,LLC.

Melon Madness by Nina Ottosson

This is an intermediate level stationary foraging toy for wet or dry food. The cat must learn to uncover the wells by moving the "seeds" or green pegs to uncover the snacks below.