Why is My Cat Not Using the Litter Box?

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Not all cats like all types of litter boxes (or litters, or locations), no matter how convenient they are for the owners.

I posted previously about one specific reason that indoor house cats might urinate on surfaces other than the litter box. But, I still get many questions about cats peeing where they shouldn’t. So, this is part 2, if you will. For background information and specifics on feline idiopathic cystitis, please read my previous post.

So, you’ve been finding pee outside the litter box. You’ve taking the kitty (or kitties) to the vet to rule out infection, cancer, etc. What now? First, you’ll need to determine:

Is He Urinating or Spraying?

Urinating outside the litter box and spray/urine marking are two distinctly different problems with different causes and different treatments. So, to treat him effectively, we need to know for sure whether the kitty is peeing or spraying.

If you see it happen, this is an easy one: is he backing his little rear up to a wall or other vertical surface, twitching his tail, and leaving urine running down that surface? If so, he’s almost certainly spraying. If he’s marching over to the corner of the rug (or onto a pile of clothes, or 6 inches from the litter box, etc.), squatting nicely, and leaving a large volume of urine behind, he’s likely peeing.

What if you never see it happen? You can still make an educated guess about whether it’s spraying or peeing.

Spraying is most often reserved for vertical surfaces and is usually in small amounts. It often happens near doorways, under windows, or by stairs; unfortunately, it can also be aimed at new household items, electrical appliances, and other items of interest to the cat. Spray marking is a message left by one cat for other cats; so those socially significant, high-traffic areas are the best places to broadcast the message.

In contrast, urination is aimed at emptying the bladder fully and, if the cat is not painful or arthritic, is performed in a squatting position. This leaves all of the urine on the floor/carpet/pile of clothes. Often, the location will be a low-traffic area and a soft substrate. The message here is not to other cats, but to you: He no longer wishes to use his litter box. Now, you must find out why.

What if He’s Spraying?

Urine marking is a normal activity in wild and domesticated felines. But, it is not desirable indoor behavior. Whether indoors or out, it’s done as a signal to other cats; and this cat’s relationship to those other cats is key to diagnosis and early treatment. It is important to note that, contrary to what many people believe, females and neutered males can participate in urine marking.

Treatment for Spraying:

First, clean up all urine with a GOOD enzymatic cleaner. My personal favorite for urine is Anti-Icky-Poo.

Next, determine whether your other cats or outdoor cats (strays, ferals, neighbors, etc.) are stressing the spraying cat. If outdoor cats are annoying him (he’s spraying mainly around exterior passage ways or sits in the window, growling), there are two good options. You can block his visual access to these other cats by using an opaque window film.  You can also keep these cats out of your yard by using a remote animal repellent device, like the Scarecrow by Contech or Spray Away by Havahart.

If your other cats are the big stressors, there are ways you can help everyone get along. First, create a “house of plenty,” in which each cat has free access to food and water dishes, litter boxes, perching spaces, hiding spots, and any other valuable resource. The goal is to prevent any bully cats from keeping other cats from the resources they need or desire.

What if “other cats” is not the problem? Determine what other things may have caused this stress: new pet, missing pet, new baby, new home, new roommates (or roommates leaving), new furniture, etc. can all cause stress in a sensitive cat. If you can determine the problem, talk to your vet about ways to address it.

If you make these changes and do not see any reduction in spraying frequency, you can discuss medications with your vet. There are a few medications that have showed improvement in spraying when combined with the plans presented above.

What if He’s Urinating?

There are several reasons a cat may vacate the litter box in search of another potty location: aversion to or preference for a specific location, substrate, or type of box; problems with litter box cleanliness; or extreme anxiety or physical pain causing problems getting to the existing boxes. To find out which cause (or causes) applies to your cat, you need to do some homework and be creative about solving the problem.

First, you must determine whether the cat is avoiding the box because he does not like its size, shape, location, litter, cleanliness, etc., or because he has developed a preference for a new location or the substrate he has begun using (carpet and clothes are the most common). Please remember that many litters and boxes are designed and marketed for the convenience of the owner, not because they are the most desirable for the cats that use them (or don’t).

Take a Good Look at Your Current Litter Box(es):

Start by taking a good look at his litter box choices:

  • Size: Most cats prefer large, uncovered boxes; if the box is too tiny or the cover prevents the cat from keeping tabs on those who might be stalking him, it is less desirable. You cat does not care that this designer box looks far better to you than the big, open box he craves.
  • Litter: Cats generally like boxes filled with a couple of inches of unscented clumping litter. Crystals or other hard substrates can be a problem for those with sensitive feet. Litters with perfumes or those that smell too much of their source materials when wet, can be less desirable, even if they mask the urine smell better than unscented.
  • Cleanliness: Cats like clean boxes; ideally, they should be scooped daily and cleaned completely with dish soap and water every week or two.
  • Location: Cats prefer someplace with good ventilation, on the quiet side, and convenient to your cat. He would probably prefer that you not put any of his litter boxes in a closet (where you will forget to clean it), beside the noisy washing machine, in the darkest corner of the basement (where you don’t even like to go), or in the kids’ bathroom (where the comings and goings are far too unpredictable). Your older, arthritic cat would like a box on each level of your home, and one especially close to the place she sleeps most of the time.

So, how do your litter boxes compare? To tell the truth, one of ours is in the kids’ bathroom; but all of our cats (even the 23 ½ year old arthritic one) would die before they would “go” outside the litter box.

Maybe Litter Isn’t What He Wants

If you check out on all of the above, maybe your cat has developed a “substrate preference,” meaning that he simply prefers peeing in the rug/fabric/potting soil he has started using. To find out, give him three identical litter boxes. Fill one with the litter you already use. Fill the second with unscented clumping litter (unless that would be the same as box one). Fill the remaining box(es) with pieces of the substrate he is currently using. Yes, I am suggesting you put a carpet remnant, your pajamas, or potting soil in those remaining boxes. Then see what he uses. You may want to confine him to a smaller space, like a bathroom or bedroom, to force him to select from among these choices. If he chooses something other than the litter, you can “convert” him to litter by putting that item on top of litter and gradually removing it.

If he chooses litter, reassess the locations and cleanliness of the boxes he usually has access to.

Maybe He Doesn’t Like Where You Put the Boxes

Really, the only way to know is to try other locations. Start by putting one where he is already urinating. I’m sure you’re thinking that the location he’s chosen would be a terrible place for a litter box. But I hate to break it to you: as far as your cat is concerned, you already have one there. So, you may as well make it official. If he starts using the box in the new location, you may choose to reassess your aversion to having a box in the formal dining room/entry way/master bedroom. Alternatively, you can try to convince him that a similar location that you find more pleasing should be just as nice for him.

The Treatment for Litter Box Avoidance.

Clean the soiled area very well. Again, an enzymatic cleaner works best. Also, try Febreeze Pet Odor Eliminator for the area around the carpet that may have absorbed the smell.

Make area less desirable by putting food, a cat bed, or plant in each place your cat has chosen to urinate. Cats do not like to eliminate when they eat, sleep, or play. Alternatively, as noted above, you can give in and put a litter box there.

If none of these things works, see your veterinarian for more suggestions and to look again for medical explanations for the problem.

There is a great resource for cat and dog owners: www.indoorpet.osu.edu. This site focuses on understanding the particular issues that arise from keeping bright, active, and interactive pets inside our homes for extended periods of time. The suggestions for environment and behavioral enrichment are wonderful. Enjoy!

Why is my Brachycephalic Dog Having Trouble Breathing?

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Brachycephalic dogs can require special care to keep their breathing normal and healthy

I recently saw an English Bulldog as a patient. Despite the fact that I was treating him for generalized anxiety, the biggest challenge in the exam room was hearing the owner over the dog’s noisy breathing. Loud or difficult breathing is very common in a number of breeds that fall into the “brachycephalic,” or “short-headed,” category, which include the English Bulldog, French Bulldog, Boston Terrier, Cavalier King Charles Spaniel, Lhasa Apso, Shih Tzu, Pug, and Pekinese.

In fact, there is a medical condition named for this phenomenon: Brachycephalic Syndrome. Dogs that suffer from this condition often present to their veterinarians with stertor (a snoring sound while breathing), stridor (a high-pitched sound associated with breathing obstructions), shortness of breath or exercise intolerance, aspiration pneumonia, difficulty sleeping, or open-mouthed breathing. The number and severity of the issues can vary among individuals and over time for the same individual. The average age of onset of breathing problems is 3 years; and these problems often worsen with age.

Diagnosis:

When a brachycephalic dog is presented to the veterinarian for loud or labored breathing, the vet will begin to look for one or more of four physical anomalies that each contribute to the breathing issues and determine its severity. Anomalies include (from tip of nose to back of throat):

  • Stenotic nares. The two nostrils are narrower and droopier than in other dogs; this means that less air can enter the body with each breath.
  • Elongated soft palate. In these dogs, the soft palate can extend inches beyond where it should, allowing it to hang into the back of the mouth and partially block the air from reaching the trachea.
  • Everted laryngeal saccules. These saccules, which sit near the back of the throat, usually exist as pouches that invert into the sides of the mouth; if everted, they are inside-out and project into the airway, further interfering with air passage to the trachea.
  • Hypoplastic trachea. In some brachycephalic dogs, the trachea is narrower than one would expect for a similarly sized dog. This means that, even when the air negotiates the other obstacles, less of it can travel each breath into the lungs to provide oxygen to the body.

Some veterinarians maintain that collapse of the cartilage of the larynx or trachea may also contribute to brachycephalic syndrome; but we will limit our discussion to the four elements listed above.

Although it’s possible to identify the more superficial problems during a routine exam, general anesthesia or deep sedation is often required for a complete exam. X-rays of the chest may help to see tracheal narrowing and aspiration pneumonia.

Aside from the everted saccules, these anomalies are congenital, meaning that the dog is born with them. Most dogs diagnosed with brachycephalic syndrome have more than one of these problems; some unlucky dogs have all four.

Treatment:

Oxygen therapy and anti-inflammatory doses of steroids can provide short-term relief of breathing problems in these dogs. Long-term relief requires surgical intervention. In the case of stenotic nares, the openings of the nostrils can be made larger and any extra tissue removed. Elongated soft palates can be trimmed to a more typical length. Everted saccules can be removed. Sadly, nothing can be done surgically to enhance a narrow trachea.

For some severely affected dogs, these surgical corrections may not provide sufficient relief, and the dog may continue to have difficulty getting enough oxygen. In those cases, the dog may require a permanent tracheostomy, which is a hole in the trachea that is sutured open to provide an unobstructed airway to the lungs. Permanent tracheostomies carry serious risks, including increased threat of foreign-body inhalation and almost-certain drowning if the dog ever decides to submerge itself in water.

Prevention:

Most preventative measures need to happen before adopting a dog:

  • First, determine whether a brachycephalic breed is right for you. However cute you may think your aunt’s French Bulldog is, you need to be prepared to deal with possible breathing problems.
  • Then, find a breeder that carefully chooses sires and dams that are minimally affected; this is a challenge, given the relatively late onset and progressive nature of the problem, paired with a tendency of breeders to mate younger dogs.
  • Once you have adopted the puppy, accustom him to a walking harness, so that no undue pressure is placed on his trachea when he pulls against his leash.
  • Walk your dog during the mildest temperatures of the day and monitor carefully for panting and shortness of breath. The irony is that laryngeal saccule and cartilage problems appear to be exacerbated by harsh breathing, which is the very condition they cause; minimizing exercise when the weather is hot or humid can also minimize breathing difficulties in the first place.
  • Keep your dog lean. Excess weight puts an extra strain on an over-taxed respiratory system.

If, despite precautions, breathing problems do arise, seek veterinary assistance sooner rather than later.

One thing I get asked a lot is whether changing breed standards would correct this problem; my answer is, “I don’t know.” While there is no doubt that breeding for the extreme short noses of the affected breeds is directly responsible for the physical changes that cause brachycephalic syndrome, it’s not clear whether changing breed standards for the these breeds would actually lead to reversal of these problem traits. As far as I can tell, a push toward ethical breeding of only those individuals that appear to be free of problems and neutering of affected individuals is the current plan.

For those owners whose dogs are suffering from this condition, or those wishing to see images of the anomalies and surgical corrections, please see http://www.acvs.org/AnimalOwners/HealthConditions/SmallAnimalTopics/BrachycephalicSyndrome/.

Why is My Dog Such a Wreck When I Leave?

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Lately, the cases that have really got my attention are the dogs that destroy the house or hurt themselves when the owners leave. These dogs have been suffering from a condition called separation anxiety. I have had several severe cases lately and am beginning to think it’s more common of a problem than I imagined.

Clinical Signs: Some owners report that they come home to damaged doorways, carpets, plants, or furniture. Some find that their dog has started defecating in the house. Others tell of finding their pacing and panting dog (and parts of their home) covered in drool; in fact one dog’s constant drool caused the metal covers on the floor vents to rust. Others get complaints from the neighbors that their dog barks or cries the entire time they’re gone. In the most severe cases, the dog will do anything to break out of the house, crate, or kennel; these dogs break teeth, scrape their muzzles, break glass, and, sometimes, get hit by cars when their escape attempts are successful.

In many cases, the dog does not wait until the owners leave to become anxious. The owner’s routine of preparing to leave, including showering, getting dressed, or picking up briefcase or keys, can start the panic. Some dogs will refuse breakfast on days they know the owner will leave. Others will follow the owner around, whining. Still others withdraw and cannot be coaxed into interactions.

Cause: Separation anxiety can have a gradual onset as the dog matures – or can flare up suddenly. Sometimes owners can point to a specific experience, like someone moving out or a unusually loud event, that appeared to trigger the problem. In reality, however, the overwhelming majority of these dogs have always been somewhat anxious, whether or not the anxiety was noticeable. The core reason for their anxiety is, as always, some combination of genetics and experience. Anxious puppies often grow to be anxious dogs. But, not all anxious dogs were anxious puppies.

It is also important to note that dogs that suffer from separation anxiety have a greater-than-average chance of developing noise sensitivities or phobias. This can be limited to the classic triggers, like thunder or fireworks. But, owners also report fearful reactions to power tools, crackling fires, food processors, and other everyday sounds in their dogs with separation anxiety.

Diagnosis: The determination that a dog has separation anxiety is made based on history and, if possible, a video recording of the dog while the owners are not home. Other possibilities for destruction, barking, defecation, and other signs of mild separation anxiety can be attributed to boredom (especially in an energetic or focused breed of dog), illness, incomplete housetraining, or a reaction to loud or arousing stimuli outside the house. But, if the video shows a dog that is pacing, panting, vocalizing, or being destructive immediately after the owner leaves and for some significant percentage of the time the owner is gone, separation anxiety is diagnosed.

Treatment: Unless the clinical signs are very mild, the patient requires medication in addition to behavior modification. There are two medications currently licensed for dogs with separation anxiety; the first is a selective serotonin reuptake inhibitor (akin to Prozac) and the other is a tricyclic antidepressant. Clinical trials show improvement of over 60% of dogs on each of these medications. If one medication does not work in a given dog, the other might. In the case where neither drug has the desired effect, a veterinarian can prescribe similar human medications not actually licensed for dogs in an off-label fashion. Unwanted effects of these medications are usually mild, and include GI upset and reduced appetite.

The big downside of these medications is that they can take 3-8 weeks to take full effect. In the meantime, the owner has a destructive mess of a dog that they feel they can’t leave alone. There are several possible strategies for bridging the gap until medications can help. First, the dog can go do doggie daycare or a friend’s house when the owner leaves. Second, the owner can try working from home for a few weeks. Finally, the dog can be given a short-acting medication in the same class as Valium and Xanax. In some dogs, however, these medications cause increased agitation and cannot be used; in others, they allow the dog to be calm and relaxed when the owners are gone.

In addition to (not in place of) medications, the owner can use other calming agents. These may include a dog appeasing pheromone collar or room diffuser, lavender, anxiety wraps, calming music, etc.

Once the right combination of medication and other tools is identified, and the dog becomes calmer, the owners can begin the work of behavior modification. This can include:

  • teaching the dog to be more comfortable being away from the owners when they are home (how can you expect to leave the house when your dog won’t let you go to the bathroom without him?)
  • desensitizing the dog to cues that the owner is leaving
  • desensitizing the dog to the owner leaving for increasing periods of time (starting with seconds, working up to minutes, before attempting hours.

If the dog also suffers from noise phobias, he can be desensitized to those, as well.

With proper diagnosis and treatment, many dogs will improve. Some will need to remain on medications indefinitely; but the owners prefer this to the terrible situation that existed before treatment.

Separation anxiety in any form should be taken very seriously. Mild cases can progress. Severe cases can be life threatening. All cases are extremely disruptive for the owners, who typically feel some combination of anger, resentment, guilt, and fear for their pet. Proper diagnosis, by a licensed veterinarian that has experience with separation anxiety, is crucial to solving the problem.

Why Are my Two Dogs Fighting?

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Two household dogs fighting can be very stressful for owners

I recently saw a very interesting case of two dogs in the household fighting with each other. The older dog is 5 years old and the owner has had him since he was 10 weeks old. The younger dog is 13 months old and has lived with the owner since he was 4 months old. According to the owner, the younger dog began to attack the older one about 4 months ago. Over a short time, the attacks increased in frequency to several times a day and were so upsetting to the owner that she explored the possibility of re-homing the younger dog. She saw our appointment as his last chance to stay in her family.

There are many reasons one dog may attack or be aggressive toward another: He may be guarding a very valuable resource (rawhide, toy, etc.) and think the other dog wants it. He may be of a breed that has been selected for dog aggression. He may have been poorly socialized to dogs. He may have had bad prior experiences with this particular dog.

But, for two dogs that live in the same house, the most common type of aggression is called “Dominance-Status Aggression” (DSA), also sometimes called “sibling rivalry.” In this setting, the dogs know each other well, and get along very well much of the time. Generally one dog is consistently the aggressor and the fights/attacks happen most commonly when the owner is present. Other possibilities for two household dogs fighting include pain/injury, illness, territorial aggression, or maternal aggression.

So, what causes DSA and what can be done about it?

Causes of DSA.

Usually, the owner is the cause. It is over-simplistic to say this; but, the reality is that the average dog owner will often completely ignore his dogs’ social hierarchy and attempt to impose what he believes to be equitable. This leads to tension between the dogs, which then leads to aggression when the owner is present.

What does it mean for dogs to develop a hierarchy? Speaking generally, dogs have a flexible but fairly strong social structure, in which one dog is the most dominant, followed by a more subordinate dog, then the next most subordinate, and so on. If you are watching a group of dogs that know each other well, you will see which one has easiest access to the best resources (toys, treats, lounging spaces, etc.); this is typically the most dominant dog in the group. The dog that most willingly gives up resources is generally the most subordinate. The others fall in line in the middle. This is a gross generalization (and some very subordinate dogs will fight for certain resources); but the principle is reliable.

Unfortunately, owners have their own sense of fairness. Usually, they give the older, more frail, or most beloved dog the best of the resources and the most attention, regardless of his status in the group. This is a perfectly human thing to do. Yet, if the owner chooses to lavish attention and resources on a less dominant dog, the more dominant dog may feel compelled to put the favored dog in its place, through growling, biting, or other aggressive act. The owner, who generally responds negatively (yelling, scolding, or other form of punishment) to the aggressor, may increase his attention on the attacked dog, thus escalating the problem.

What about two dogs that start fighting suddenly after having been “fine” with each other for months. If a younger subordinate dog is becoming socially mature or a previously-dominant dog is failing in health, there may be the opportunity for a shuffle in the dominance hierarchy. If the owner inadvertently lavishes attention on the wrong dog, there can be aggression as a result.

It should be noted that not all dominant dogs care enough to interfere with the owner’s interactions with the other dog.

Treatment of DSA.

Often, treatment is as simple as correctly identifying the dominant dog and supporting him as such. This is accomplished by giving him the most attention, providing him with better resources (nearer the owner on the bed or sofa, first access to the house or yard, etc.), and asking for less “work” (aka fewer commands) before giving him things. If the dominant dog has to sit for his dinner, the other dog must sit and shake paws before the food dish touches the ground. If a battle does break out, owners should leave the room, as their presence is typically required to fuel the conflict. Under no circumstances should either dog be punished for his actions.

If one or more of the dogs is unneutered, surgical intervention in the form of spaying or neutering can also help relieve some tension.

Owners are occasionally resistant to these changes, because they have been favoring the subordinate dog for a reason. But, when they see the difference their actions can make to the stress level in the house, they usually come around. They also get creative about spending quality time with their favored pet without the other being aware.

Challenging Cases.

Dominance within the hierarchy is determined by some combination of health, age, size, sex, and overall confidence. But, what if you have two dogs of the same sex from the same litter? You have two dogs that are likely equal in most factors that determine hierarchy. As they come to social maturity, one of three things may happen: If they are pretty mellow, they may never establish an obvious hierarchy and be perfectly willing to share the lead. If one cares more than the other, he may simply declare himself dominant without contention. Or, you may have a situation in which the two dogs spend their adulthood struggling for dominance, possibly without resolution. This is a particularly challenging situation for which there is no simple solution.

My Case

In the case I saw, the owner was amenable to making changes in the way she treated the dogs. She was not excited to reward the “upstart” in favor of her long-time companion. But she saw the merits. She also saw the tension between the two dogs melt away. One month later, the two dogs rarely scuffle and the owner is delighted.

Adventures with Osteosarcoma, Part III: The Adventure Ends

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Brick in his younger days, enjoying the great outdoors

I apologize for an extended absence from this space. Family obligations, a house purchase, and career changes are mainly to blame. In addition, on June 6, our dog Brick lost his battle with osteosarcoma. With chemotherapy, we were able to buy some extra time with him – most of it quality time.

In the end, Brick did us the honor of making it clear that it was his time to go. After all, no owner wants to waffle for long periods over the decision to euthanize. Trust me, no waffling was necessary that morning. We had been so focused on controlling his lung metastases that we were surprised when a spinal tumor (at T7) began to cause increased pain and, rapidly, the inability for Brick to stand or walk without assistance. Since he weighed nearly 100 pounds, assistance was not easy to provide, and his pain quickly became quite severe.

Brick was euthanized by his oncologist at the teaching hospital, where it is the custom for euthanized pets to be necropsied (autopsied) by veterinary students during in their pathology rotations. Having been through that service as a student – and knowing how difficult but important necropsies are for the learning process – I had no qualms about providing consent. The final pathology report was posted and I have mustered the courage to read it. By the time of his death, the osteosarcoma had reached his lungs, T7 vertebral body, thyroid glands, liver, kidney, spleen, and adrenal glands. The cancer had ravaged his body.

We are recovering, slowly, from our loss. My husband lost a best friend. I lost a wonderful companion that made me and our children rest better on those nights my husband travels. We still expect to see him at every turn, even after moving houses three weeks after he died. The kids are learning how to process such a life-altering event, while we adults realize that our grieving will take time.

On a much happier note, I soon begin a new professional chapter: next Monday (8/1), I become the newest behavior resident at UC Davis. It is a three-year program in which I will be trading flea treatments and radiographs for in-depth, probing appointments designed to help people with their unruly pets. Cases most typically involve some form of aggression, anxiety, or elimination issue. I will be treating mainly dogs and cats. While I would love to see other species, I think I may be limited to the occasional feather-picking cockatoo or cribbing horse.

I’m quite excited about this new opportunity and hope that some cool behavior cases work their way onto this blog.

Aural Hematomas in the Dog and Cat

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Aural hematomas are puffy pockets of blood

I always thought that aural hematomas (blood pockets in the ear flap) were the curse of floppy-eared dogs. Then I saw one in a German Shepherd Dog. Still, I was sure that these annoying complications were limited to dogs – until I saw one in a cat. So, what causes these big, puffy blood pockets that owners despise so much?

How hematomas form: Many people are familiar with the concept of a blood blister, like the kind you get when you pinch your finger in a door or pair of pliers (or am I the only clumsy one?). Aural hematomas are very similar to these blood blisters. They form when an ear vein is damaged and leaks blood under the skin of the ear flap. The pressure of the blood against the skin causes a pocket to form, which allows more blood to leak from the vein. This vicious cycle continues, sometimes until all available space has been used, leaving the ear very puffy and heavy. At this point, pressure or trauma may cause a small opening in the ear flap, allowing blood to ooze, pour, or otherwise escape into the environment. More typically, however, the owner is able to get the pet veterinary care while the blood is contained. More

Urolithiasis: Urinary Stones

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Most bladder stones can be seen on plain x-rays.

This week, we had several discussions around the clinic about bladder stones in cats and dogs. I thought this might be a good topic, as these often take owners totally by surprise.

Urinary stones can form from many different inorganic compounds and can make trouble anywhere along the urinary tract. Common types include struvite (magnesium-ammonium-phosphate, sometimes still referred to as “triple phosphate”), calcium oxalate (“CaOx,” which come in monohydrate or dihydrate varieties), urate, and cystine. Struvite and CaOx constitute by far the majority of stones seen in cats and dogs. Each type develops based on fairly specific conditions, such as urine pH, the presence of bacteria (struvite in dogs), or a primary disease process (urate with liver disease). In addition, breed-specific mutations may permit large amounts of the precursor compounds that lead to stone formation; this is true of cystine (Newfies, Dachshunds, and English Bulldogs) and urate (Dalmatians). More

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