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Advising Clients Who Feed Raw Diets to Pets
Food safety and nutritional integrity of raw meat or eggs are two important health issues that should concern veterinarians with clients who feed these items to the family pet. This article addresses food safety, because it is the more immediate health threat.
Food is contaminated with microbes. Meat from healthy animals becomes contaminated at slaughter. Meat surfaces become infected with microorganisms associated with food poisoning during handling, packaging, processing, storage, and transportation. Approximately one third of the poultry sold for human consumption has tested positive for Salmonella. Disinfected grade A eggs that caused salmonellosis were determined to have been contaminated during ovulation; as a result, they were contaminated with the bacteria before formation of the shell. Although many procedures have been incorporated into food processing procedures for both the meat and poultry industries to reduce the level of contamination, bacteria persist: All products should be considered contaminated. Raw-meat diets have been used by such industries as zoos, mink farms, and dog racing facilities; the FDA presumes these users are aware of the risks.
Thus, we should be concerned about pet owners who feed raw diets to their pets. Such diets have been documented to contain pathogenic Yersinia enterocolitica 4/0:3, Salmonella species, and Escherichia coli 0157:H7. Commercial raw products, sold frozen or freeze-dried, carry no claim to be pathogen-free; in fact, recent work strongly suggests that they are contaminated. Twenty-one commercially available raw-meat diets (beef, lamb, chicken, and turkey) cultured over a 4-month period were all positive for E. coli, and 10 were positive for S. enterica. The FDA now has guidelines for companies selling such products to pet owners.
Because most pathogenic organisms are found on the surface of the meat, searing the surface would significantly reduce the potential bacterial load. An option for pet owners who do not want to feed thoroughly cooked meat is to feed whole (not ground) meat, braise the surface, and feed the meat rare instead.
Pets fed contaminated raw meat shed viable organisms in feces. Evidence validated this public health risk. Salmonella was isolated from 80% of the BARF (i.e., bones and raw food) diets sampled and from 30% of the stools from dogs consuming those diets. Greyhounds and sled dogs fed raw-meat diets have been documented to shed the same subspecies of Salmonella in their feces as found in their diets. Serovars of Campylobacter species isolated from the diarrhea of dogs was the same as that isolated from the poultry carcasses consumed by the dogs. Only 36% of healthy dogs and 17% of healthy cats harbor low levels of pathogenic salmonellae, which refutes the notion that most household pets are “naturally” infected with these species.
Individuals who clean the cat’s litter box or pick up their dog’s stool should consider the feces contaminated with viable pathogenic microbes. Extra precautions should be taken when persons or pets in the household have immune-suppressive diseases, such as human immunodeficiency virus infection, feline leukemia, or feline immunodeficiency virus infection; are undergoing chemotherapy; or are using anti-inflammatory medication. Extra caution should also be exerted in households with young children to prevent fecal-oral contamination.
Handling Raw Diets
Feeding infected raw diets increases the risk for infection of both human and animal household members. Humans can become infected with food-borne pathogens when handling contaminated meat and egg products. Household transmission of food-borne pathogenic organisms from dogs to humans has been documented.
Veterinarians are trained in zoonotic diseases and thus have a responsibility to inform owners who feed raw meat or eggs of these potential health dangers. Safe practices during handling of the food, feeding dish, and feces should be emphasized, and the need for good personal hygiene must be reinforced. Veterinarians who recommend feeding raw meat or eggs without giving full disclosure of the risks and precautions may face legal ramifications. Salmonella, E. coli, and Campylobacter infection in humans are notifiable diseases, and physicians are required to report cases to local health departments.
Dispelling the Myths
The morphologic and pathophysiologic characteristics of the gastrointestinal systems of dogs, cats, and humans are remarkably similar. Many who advocate feeding raw diets contend that dogs and cats have a more acid stomach and shorter gastrointestinal tracts than do humans, protecting them from pathogenic bacteria. However, there is no difference among these species in regard to gastric pH and no evidence to suggest the difference in length of the gastrointestinal tract is protective to dogs and cats. All three species manifest similar clinical signs after ingesting food contaminated with pathogens. The severity of these signs is related to the dose of microbes or toxin ingested as well as the condition of the host.
Food Poisoning Frequency
Frequency of food poisoning in pets is difficult to determine. Veterinarians presented with a family pet for intermittent episodes of vomiting or diarrhea would treat the case symptomatically and are unlikely to send samples for bacterial culture and polymerase chain reaction identification. Hence, most if not all cases of food poisoning in the family pet are not reported because of a low level of suspicion and financial constraints.
Raw-meat advocates do not deny but downplay the potential health risks. No scientific evidence exists that a raw diet is superior to any dry or canned pet food. As a result, this practice is associated with health risks to pet and family with no demonstrable benefit.
Written: Rebecca L. Remillard, PhD,DVM,Diplomate ACVN, MSPCA Angell Animal medical Center, Boston, Massachusetts
NAVC clinician’s brief – November 2005
This article was published in PVMA NEWS February edition and submitted by Heidi Houchen, DVM and they have allowed us to reprint this article on our web page. We thank them and hope you find this information helpful.
For The Love of Chocolate
Submitted by Neidi Houchen D.V.M.
At Dove Lewis, the incidence of chocolate toxicity seems to peak between the months of November and February. This may reflect increased chocolate availability during the holidays — or increased chocolate consumption during the Northwest’s rainy season-you be the judge! Regardless of the reason, chocolate is a favorite food of dogs as well as humans and its presence can tempt even the most discriminating of canine palates to indulge.
The most toxic component of chocolate is the methylxanthine, theobromine, a relative of caffeine and theophylline. Theo-bromine can exert a wide range of pharmocologic effects, most notably stimulation of the cardiac muscle and central nervous system. The acute lethal oral dosage of theobromine in dogs is 100 – 200 mg/kg and 80 – 150 mg/kg in cats. However, there is wide variation in individual sensitivity to methylxanthines. Toxic effects of theobromine can be seen as low as 20 mg/kg. In dogs, theobromine is readily absorbed from the gut and has a very long half-life (17.5 hours) in comparison with other species. Because of the rate of absorption exceeds the rate of elimination, the long half-life may be responsible for the chronic chocolate poisoning seen in the dog.
Clinical signs of chocolate toxicity can vary from mild to se-vere. Brain stimulation by theobromine can result in tachypnea, vomiting, restlessness, tremors and even seizures It also stimulates cardiac muscle which can result in tachycardia and arrhythmias. Like caffeine, theobromine can induce diuresis and excessive urine production is often seen with chocolate toxicosis. Death can occur from cardiac arrhythmias or respiratory failure. Because there is no specific antidote for chocolate toxicosis, treatment is symptomatic. It is important to pre-vent further absorption, hasten elimination and maintain basic life support. If the patient is comatose or convulsing, gastric lavage should be performed-otherwise vomiting should be induced as soon as possible.
Because the half-life of theobromine is long and because chocolate tends to stay in a solid or semiplastic state in the stomach, repeated doses of activated charcoal should be administered every 4 hours for up to 72 hours after ingestion. The EKG should be closely monitored and if indicated, VPC’s and tachycardia can be controlled with lidocaine, propranolol, or metoprolol. If the patient is seizuring, diazepam is the initial drug of choice followed by barbiturate therapy. Fluid therapy, close continuous monitoring of cardiac and neurologic status and supportive care are essential to a successful outcome.
This time of year at Dove Lewis we receive a large number of calls by pet owners whose dogs have ingested chocolate. The most frequently asked questions are “How much is too muchchocolate?” and “Should we vomit our pet or bring it in to be seen?”. These are questions that are not quickly or easily answered for a variety of reasons. Most importantly, animals vary widely in their sensitivity to chocolate – i.e., schnauzers are more susceptible than labs (a.k.a. “the garbage guts”). Also, the amount of theobromine ingested varies depending on the type of chocolate consumed. Unsweetened baking chocolate and cocoa powder contain 392 mg/ounce whereas milk chocolate contains 44 mg/ ounce. As a general rule, the toxic level of theobromine is considered to be 50 mg/lb. In addition to theobromine, chocolate often contains fat and sugar in varying amounts and this makes diabetic animals and animals with predisposition towards (or a history of) pancreatitis at greater risk for developing more severe problems from chocolate ingestion. Finally, it is important to consider the paper and/or foil component of individually wrapped chocolates as this may put an animal at risk for developing a foreign body.
In general, when dealing with an animal that has eaten chocolate, try to determine the amount and type of chocolate ingested. Then determine the potential toxic dose of chocolate using toxic levels of theobromine @ 50 mg/ pound and that one ounce of chocolate is equivalent to 30 mg. For example, only 2 ounces of baking chocolate as compared with 17 ounces of milk chocolate are toxic to a 15 pound dog. However, if the milk chocolate was contained in truffles and the animal ingesting it was an elderly schnauzer, the theobromine may be the last of your worries! Most importantly-“If in doubt, vomit it out”.
- Tremors, seizures and shaking.
- Vomiting, hyper-salivation.
- Rapid heart rate.
- Abdominal pain.
Slug bait contains a chemical called ‘metaldehyde,’ and dogs are attracted to the taste of the mixture. Ingestion of just 2 ounces by a 22 – pound dog will induce signs in one hour or less.
Many dogs die of Slug Bait Poisoning!
Try Non-chemical slug bait recommended by gardeners.
- Diatomaceous Earth: made from fossilized remains of one-celled algae. It feels like talcum powder but scratched and absorbs the wax layer on a bug’s surface, leaving it to die from dehydration.
- Fermenting Liquid: set out shallow container of yeast, water and spoiled yogurt or beer, bury the container flush with the soil surface. Slugs love the scent of the yeast.
- A quart of 3 % hydrogen peroxide
- A quarter cup of baking soda
- A teaspoon of liquid soap
Bathe pets in this solution and apply a tap-water rinse and the smell will instantly vanish.
Oregon’s first case of the emerging canine influenza was confirmed on Friday, September 30, by the veterinary virology laboratory at Cornell University in New York.
The sample was submitted by Dr. Zoe Tokar of Powell Blvd. Veterinary Clinic and was from a four-year-old spayed female who was presented to the Portland practitioner with a severe cough and a fever of 103.5 Fahrenheit. According to a notice sent to the OVMA office by Dr. Emilio DeBess, Oregon’s Public Health Veterinarian, the samples (oral swab and serum) were collected and sent to Cornell for testing. The serum titer was positive at 1:1024 and a PCR test was negative.
An article on the dog flu that ran in The Oregonian indicated the State of Oregon does not have the ability to test for the disease and that officials are waiting for the results on 12 other blood samples that were drawn from dogs at the Multnomah County Animal Shelter.
Dr. Edward Dubovi, director of the virology lab at Cornell, expects the lists of states with positive samples to grow, as the lab processes more tests. Positive cases have already been seen in Florida, New York, New Jersey, Massachusetts and California, with Oregon just added to the expanding list.
Below is additional information on the Canine Influenza, which was forwarded to the OVMA office by Dr. DeBess.
Situation: University of Florida researchers report that outbreaks of canine influenza virus, which causes and acute respiratory infection, have been identified in dogs in shelters, humane societies, boarding facilities and veterinary clinics in Florida, predominantly in Broward, Dade, Palm Beach and Duval counties.
This highly contagious virus is a newly emerging respiratory pathogen in dogs and causes a clinical syndrome that mimics “kennel cough.” Canine influenza virus infections are frequently mistaken for infectious due to the Bordetella bronchiseptical Para influenza virus complex.
Clinical signs: Because this is a newly emerging pathogen, all dogs, regardless of breed or age, are susceptible to infection and have no naturally acquired or vaccine-induced immunity. Virtually 100 percent of exposed dogs become infected. Nearly 80 percent have clinical signs. There are two general clinical syndromes-the milder syndrome and a more severe pneumonia syndrome. The milder disease syndrome occurs in most dogs.
In the milder disease, the most common clinical sign is a cough that persists for 10-21 days despite therapy with antibiotics and cough suppressants. Most dogs have a soft, moist cough, while others have a dry cough similar to that induces by the Bordetella bronchiseptical/Para influenza virus infection. Many dogs have purulent nasal discharge and a low-grade fever. The nasal discharge likely represents a secondary bacterial infection that quickly resolves with treatment with a broad-spectrum, bacterial antibiotic.
Some dogs develop a more severe disease with clinical signs of pneumonia, such as a high fever (104 to 106 degrees Fahrenheit) and increased respiratory rate and effort. Thoracic radiographs may show consolidation of lung lobes. Dogs with pneumonia often have a secondary bacterial infection and have responded best to a combination of broad-spectrum, bactericidal antibiotics and maintenance of hydration with intravenous fluid therapy.
Fatality rate: Fatal cases of pneumonia have been documented, but the fatality rate so far is low, at 1 percent to 5 percent.
Incubation/shedding period: The incubation period is two to five days after exposure before clinical signs appear. Infected dogs may shed the virus for 7 to 10 days from the initial day of clinical signs. Nearly 20% of infected dogs will not display clinical signs and become the silent shedders and spreaders of the infection.
Diagnosis: There is no rapid, real-time test for diagnosis of dogs with an acute influenza virus infection. Current diagnostic tests rely on detection of antibodies to canine influenza virus, which are detected as early as 7 days after onset of clinical signs. Paired acute and convalescent serum samples are necessary for diagnosis of recent infection. The convalescent sample is collected at least 2 weeks after the acute sample. There are many situations in which collection of an acute sample is not feasible. In this case, testing of a convalescent sample will indicate whether the dog was infected at some time in the past. Serology tests not only indicate if a dog was infected, but also serve to alert veterinarians that the virus is present in their community so they can take precautions with dogs presenting for “kennel cough.”
In addition to serology, the lungs and distal trachea from dogs that died of pneumonia can be tested for influenza virus by PCR analysis and virus culture.
Prevention: There in no vaccine for canine influenza virus at this time. This virus is spread by aerosolized respiratory secretions, contaminated inanimate objects and even by people moving back and forth between infected and uninfected dogs. This is an enveloped virus that is most likely killed by routine disinfectants, such as quaternary ammoniums and 10% bleach. Because the virus is highly contagious and all dogs are susceptible to infection, veterinary and, boarding facilities, shelters and pet stores should use isolations protocols for dogs that have a “kennel cough.”
What veterinarians can do: Veterinarians can submit serum samples for canine influenza antibody titers. Paired acute and convalescent samples are preferable for confirmation of infection, while single samples collected after seven day of clinical disease are also useful. In addition to determining infection, these samples will contribute toward virus surveillance in Florida and other states.
Veterinarians may also submit fresh (no formalin or freezing) lung and tracheal tissues from dogs that die from pneumonia. Canine influenza virus culture and PCR analysis will be preformed on these tissues. Virus recovered from these samples will greatly contribute toward development of vaccines and diagnostic tests.
Initially, Dr. Cynda Crawford was conduction ongoing tests for canine influenza. However, she presently is referring veterinarians to submit samples for testing to Dr. Dubovi.
According to Dr. Crawford, Dr. Dubovi is coordinating testing efforts with her and is the central point for canine flu. She said he is better equipped with trained personnel, expertise, supplies, and can handle a higher volume than can her research lab at the University of Florida’s College of Veterinary medicine.
The Web site for Cornell University’s veterinary laboratory is www.diaglab.vet.cornell.edu/news.asp. The site contains information regarding what samples to submit, how to submit, and pertinent charges. There is no limit on how many samples to send, except for associated costs. You and also contact the laboratory switchboard by calling (607)253-3900.
Copied from the OVMA Sept../Oct. 2005 issue
You should consider several factors before traveling by plane with your cat:
It is impossible to overemphasize the need to consult with the airline well in advance of your trip. This is essential if you hope to avoid last minute problems. Here are some basic tips for airline travel with your cat:
1. Determine whether the airline has requirements for “acclimation.” In the event that you are unable to secure a direct flight, the pet carrier may be left outside the plane for a period of time. To avoid liability on their part, many airlines require a letter from your veterinarian stating that the pet is acclimated to a minimum or maximum temperature (must be given in precise degree, e.g., 20 F) for a defined period of time.
2. Consult with the airline regarding baggage liability. In some cases, this can include your pet. If you are sending an economically valuable pet, you may need to consider additional liability insurance.
3. Have your cat examined by your veterinarian in advance of the trip, especially if it has been more than a few months since the last checkup. This is especially important for geriatric cats. Travel by plane can pose a risk for cats with pre-existing medical problems, such as heart or kidney disease. Also, some short-faced breeds of cats (Persians, Exotic Shorthairs) do not travel well in some situations.
4. Be sure that you have written proof of current vaccinations and, where required, a health certificate. These cannot be obtained “after the fact.” You must be able to present them on demand.
5. You should also inquire about possible requirements to quarantine your cat should you be traveling outside the continental United States or to a foreign country.
6. Take direct flights and try to avoid connections and layovers. Sometimes, this is easier to achieve if the trip is planned during the week. The well-being of your cat could be a source of concern if the baggage connection between flights should be missed.
7. Some airlines will allow one pet in coach and one in first class, with some provisions. To find out whether there are limitations on the number of animals present in the cabin, you should advise the airline if you plan to travel with your cat in the cabin. Check on the cage dimensions so that there won’t be a problem stowing the carrier beneath the seat.
8. Consider in advance all medications that you might need for your cat. These might include heartworm preventive (a new product for cats), flea preventive, and heart or kidney medications. Also, give thought to any special diets that your cat may need and whether they can be obtained at your destination.
9. If there is any chance that your cat will be out of the carrier, give thought to an appropriate collar or harness and keep a leash with you. If possible, the collar should have a small pet identification tag. Order forms are available in most veterinary clinics.
At the time of your flight:
1. Do not tranquilize the cat unless you have discussed this with your veterinarian. As a rule, cats don’t tolerate medicines well and giving over-the-counter or prescription pharmaceuticals can be dangerous.
2. Make sure that the carrier has permanent identification, including your name, phone number, flight schedule, destination, and phone number at the point of destination.
3. Feed the cat before you leave home. Water should be available at all times, including inside the carrier. If you have a geriatric cat with marginal kidney function, it is important that the cat not be deprived of water. Discuss this with your veterinarian. Try to secure a direct flight with no layovers. The cat should have fresh water after arrival.
Consider the following when purchasing a carrier for the airline flight:
1. The cage should provide sufficient room for the cat to stand up and turn around easily, but not so large that it can be tossed about inside during turbulence. Remember size constraints if the carrier is to go on board.
2. The walls of the carrier should be strong enough to prevent the sides from being crushed. Also, the flooring of the cage should not allow urine to leak through the bottom. An absorptive underpad (designed for bedridden people with bladder control problems) can be placed in the bottom. See your pharmacist for these.
3. The cage should have sufficient openings for good ventilation.
4. The cage must have sturdy handles for baggage personnel to use.
5. The cage should have a water tray that is accessible from the outside so that water can be added, if needed.
Pet stores, breeders, and kennels usually sell cages that meet these requirements. Some airlines also sell cages that they prefer to use. Check with the airline to see if they have other requirements.
Try to familiarize your cat with the travel cage before you leave for your trip. Let your cat play inside with the door both open and closed. This will help eliminate some of your cat’s stress during the trip.
Some considerations for your point of destination include:
1. Be sure that your hotel will allow cats. Many bookstores carry travel guidebooks with this type of information.
2. Give thought to litter pan provisions and food bowls for the hotel room.
3. Place a “Do Not Disturb” sign on your hotel door so that housekeeping will not inadvertently let the cat escape. Plan to have your room cleaned only when you are present.
4. It is probably best to leave the cat in the carrier or inside the bathroom whenever you plan to leave the room.
5. Should your cat get lost, contact the local animal control officer.
Advance planning is the key to a safe trip with your pet!
One of the most common conditions affecting cats is allergy. In the allergic state, the cat’s immune system “overreacts” to foreign substances (allergens or antigens) to which it is exposed. Those overreactions are manifested in three ways. The most common is itching of the skin, either localized (one area) or generalized (all over the cat). Another manifestation involves the respiratory system and may result in coughing, sneezing, and/or wheezing. Sometimes, there may be an associated nasal or ocular (eye) discharge. The third manifestation involves the digestive system, resulting in vomiting or diarrhea.
Types of Allergy
There are four known types of allergies in the cat: contact, flea, food, and inhalant. Each of these has some common expressions in cats, and each has some unique features.
Contact allergies are the least common of the four types of allergies. They result in a local reaction to the skin. Examples of contact allergy include reactions to flea collars or to types of bedding, such as wool. If the cat is allergic to those, there will be skin irritation and itching at the points of contact. Removal of the contact irritant solves the problem. However, identifying the allergen can require some detective work.
Flea allergy is common in cats. A normal cat experiences only minor irritation in response to flea bites, often without any itching. The flea allergic cat, on the other hand, has a severe, itch-producing reaction when the flea’s saliva is deposited in the skin. Just one bite causes such intense itching that the cat may severely scratch or chew itself, leading to the removal of large amounts of hair. There will often be open sores or scabs on the skin, allowing a secondary bacterial infection to begin. The area most commonly involved is over the rump (just in front of the tail). In addition, the cat may have numerous, small scabs around the head and neck. These scabs are called miliary lesions, a term which was coined because the scabs look like millet seeds.
The most important treatment for flea allergy is to get the cat away from all fleas. Therefore, strict flea control is the backbone of successful treatment. Unfortunately, this is not always possible in warm and humid climates, where a new population of fleas can hatch out every 14-21 days. When strict flea control is not possible, injections of corticosteroids (or “cortisone” or “steroids”) can be used to block the allergic reaction and give relief. This is often a necessary part of dealing with flea allergies. Fortunately, cats appear relatively more resistant to the side-effects of steroids than other species. If a secondary bacterial infection occurs, appropriate antibiotics must be used.
The most common type of allergy is the inhalant type, or atopy. Cats may be allergic to all of the same inhaled allergens that affect us. These include tree pollens (cedar, ash, oak, etc.), grass pollens (especially Bermuda), weed pollens (ragweed, etc.), molds, mildew, and the house dust mite. Many of these allergies occur seasonally, such as ragweed, cedar, and grass pollens. However, others are with us all the time, such as molds, mildew, and house dust mites. When humans inhale these allergens, we express the allergy as a respiratory problem; it is sometimes called “hay fever.” The cat’s reaction, however, usually produces severe, generalized itching. In fact, the most common cause of itching in the cat is inhalant allergy.
Most cats that have an inhalant allergy are allergic to several allergens. If the number is small and they are the seasonal type, itching may last for just a few weeks at a time during one or two periods of the year. If the number of allergens is large or they are they are present year-round, the cat may itch constantly.
Treatment depends largely on the length of the cat’s allergy season. It involves two approaches. Steroids will dramatically block the allergic reaction in most cases. These may be given orally or by injection, depending on the circumstances. As stated previously, the side effects of steroids are much less common in cats than in people. If steroids are appropriate for your cat, you will be instructed in their proper use.
Some cats are helped considerably by a hypoallergenic shampoo. It has been demonstrated that some allergens may be absorbed through the skin. Frequent bathing is thought to reduce the amount of antigen exposure through this route. In addition to removing surface antigen, bathing alone will provide some temporary relief from itching and may allow the use of a lower dose of steroids. Antihistamines are usually of little value in the cat, but can be tried.
The second major form of allergy treatment is desensitization with specific antigen injections (or “allergy shots”). Once the specific sources of allergy are identified, very small amounts of the antigen are injected weekly. This is all in an attempt to reprogram the body’s immune system. It is hoped that as time passes, the immune system will become less reactive to the problem-causing allergens. If desensitization appears to help the cat, injections will continue for several years. For most cats, a realistic goal is for the itching to be significantly reduced in severity; in some cats, itching may completely resolve. Steroids are not used with this treatment protocol, except on an intermittent basis. This therapeutic approach is recommended for the middle-aged or older cat that has year round itching caused by inhalant allergy. This approach is not used with food allergy.
Although desensitization is the ideal way to treat inhalant allergy, it does have some drawbacks and may not be the best choice in certain circumstances.
1. Cost: This is the most expensive form of treatment.
2. Age of Patient: Because many cats develop additional allergies as they get older, young cats may need to be re-tested 1-3 years later.
3. Success Rate: About 50% of cats will have an excellent response. About 25% get partial to good response. About 25% get little or no response. The same statistics are true for people undergoing desensitization.
4. Food Allergies: Although tests for food allergy are available, the reliability of the test is so low that it is not recommended at this time. A food trial remains the best diagnostic test for food allergy.
5. Time of Response: The time until apparent response may be 2-5 months, or longer.
6. Interference of steroids: Cats must not receive oral steroids for 2 weeks or injectable steroids for 6 weeks prior to testing; these drugs will interfere with the test results.
Cats are not likely to be born with food allergies. More commonly, they develop allergies to food products they have eaten for a long time. The allergy most frequently develops in response to the protein component of the food; for example, beef, pork, chicken, or turkey. Food allergy may produce any of the clinical signs previously discussed, including itching, digestive disorders, and respiratory distress. We recommend testing for food allergy when the clinical signs have been present for several months, when the cat has a poor response to steroids, or when a very young cat itches without other apparent causes of allergy. Testing is done with a special hypoallergenic diet. Because it takes at least 8 weeks for all other food products to get out of the system, the cat must eat the special diet exclusively for 8-12 weeks (or more). If positive response occurs, you will be instructed on how to proceed. If the diet is not fed exclusively, it will not be a meaningful test. We cannot overemphasize this. If any type of table food, treats or vitamins are given, these must be discontinued during the testing period.
Because cats that are being tested for inhalant allergy generally itch year round, a food allergy dietary test can be performed while the inhalant test and antigen preparation are occurring.
INSTRUCTIONS: Those instructions that are specific for your cat have been checked:
___ 1) An injection of steroids was given. Relief should be apparent within 12-24 hours. If not, please call. The cat should feel better and itch less for about one month. If an increase in water consumption or urination occurs, please report this to us for future reference. These side-effects are common with steroid administration and will go away in a few days without treatment. Return for further evaluation when the first signs of itching recur.
___ 2) Begin oral steroids when the first signs of itching return. Give ____ tablets every other evening. Adjust dosage upward or downward to the lowest effective dose, with a maximum dose of __________ permitted. Stop giving the medication every 4-6 months to see if there are times of the year when therapy is not needed. Report any increase in water consumption to us at once.
___ 3) We have dispensed oral steroid tablets. Prednisone is most commonly used. The specific drug being dispensed for your cat is labeled on the bottle. Give ____ of the ____ mg tablets every other day for 3 doses (6 days), then ____ tablets every other day for 3 more doses (6 more days). Continue this downward progression (___________________________________) until the first signs of itching recur. At that time, go back to the next higher level and report that level to us (so we can be sure it is a safe level). Stop giving the tablets every 4-6 months to see if there are periods of the year when they are not necessary. When itching returns, begin immediately at the maintenance dose. If that does not stop the itching, increase the dosage slightly (to a maximum of ___ tablets) for a few doses, then return to the lower dose. Report any increase in water consumption to us at once. (This may occur at the initial dose but should stop on the maintenance dose.)
___ 4) Your cat is to exclusively eat a hypoallergenic diet. If it will not do so readily, mix it 25:75 with the current diet for several days, then gradually increase the special diet to 100%. If this does not work, contact us for an alternative plan. Discontinue any chewable treats or vitamins. Table food is not allowed. Offer only distilled water to drink, if that is possible.
___ 5) Your cat has a flea allergy or has enough fleas to make the other allergy problem worse. Flea control is very important and should include treating the cat and its environment. Bear in mind that flea allergies often accompany other types of allergies, especially inhalant allergy.
___ 6) Your cat has a bacterial skin infection secondary to allergy.
The following are recommended:
a) Antibiotics are to be used for the next _____ days. If the infection is not gone by the time the medication is completed, call for a refill or for a change in medication.
b) The medicated shampoo, _____________________, is to be used every _____ days. Allow the shampoo to stay in the hair coat for a few minutes before thoroughly rinsing the cat.
c) The topical medication, _____________________, is to be used ______ times daily for __________ days.
Obstructive and allergic lung diseases affect many cats and are sometimes called asthma, bronchitis, or bronchial asthma. Unfortunately, these diseases are not easily classified and probably represent a variety of lung disorders. They do share a common finding of “hyper-responsive” (over-reactive) airways.
When the airway of the cat is sensitive to certain stimuli, exposure to these agents leads to narrowing of the airways. The inciting agents are usually direct irritants to the airways or things which provoke an allergic response in the respiratory tract. Regardless of the cause, the end-result is the same: muscle spasms in the bronchi (breathing tubes), buildup of mucus, and accumulation of cellular material. In particular, the inability to clear the bronchi of this material leaves the cat susceptible to secondary infections.
The cat is most stressed during the period of expiration (exhaling). The difficulty with expiration is typical with obstructive disease of the lung. Air may become effectively trapped in the lungs, causing them to over-inflate. In some cases, this trapping leads to development of emphysema in the cat.
Obstructive lung disease is most common in cats from 2 to 8 years of age. Female cats and Siamese cats seem to be more susceptible.
Coughing and respiratory distress are the most commonly reported signs with obstructive lung disease. Coughing is a significant finding since there are relatively few causes of coughing in the cat. Also, many cats assume a squatting position with the neck extending during these coughing episodes. Wheezing is easily heard with the stethoscope and is sometimes so loud that it can be heard without a stethoscope. Occasionally, sneezing and vomiting are noted.
As mentioned above, this group of diseases is characterized by hyper-responsive airways. The small breathing tubes (bronchi and bronchioles) can react to a number of stimuli, such as:
1. Inhaled debris or irritants – dust from cat litter, cigarette smoke, perfume or hairspray, carpet fresheners, and perfumes in laundry detergent
2. Pollens or mold
3. Infectious agents – viruses, bacteria
4. Parasites – heartworms, lungworms
Several tests may be performed to achieve a diagnosis of allergic lung disease in the cat.
1. Minimum data base (complete blood count, blood chemistries, fecal exam and urinalysis). These tests help to assess the general health of your cat and may provide clues as to the underlying cause. One particular type of white blood cell, the eosinophil, is commonly associated with allergic events and may provide support for a tentative diagnosis of asthma. Also, in cats in certain geographic areas, special tests will be performed on stool samples for evidence of lungworms.
2. Heartworm test. This is not indicated for all cats, as heartworms are rare in some parts of the country. In areas where they are common, however, strictly indoor cats are still at risk.
3. Feline leukemia and feline immunodeficiency virus tests. These tests are helpful in determining the overall health of your cat.
4. Thoracic radiography (chest X-ray). Characteristic changes in the lungs are common on x-rays. Also, the x-rays can be suggestive of heartworms in some cases.
5. Bronchoscopy, cytology, and airway lavage (washing). Bronchoscopy is a procedure that allows us to look down the airways of the anesthetized cat with a fiberoptic scope. After a visual examination of the airway is completed, the lining mucus of the bronchi may be sampled with a small brush. The mucus can be examined under a microscope (cytology). Finally, a small amount of sterile saline can be flushed into the airways to retrieve samples of material from deep in the lung. This material can be cultured for micro-organisms and can also be carefully studied under the microscope. The sediment can be evaluated for evidence of lungworms.
In some cases, an underlying cause cannot be identified, despite a thorough diagnostic workup. Even when the underlying cause is not identified, many cats can achieve a reasonable quality of life with medical management.
Some owners decline the complete workup for a variety of reasons. In such cases, it may be acceptable to treat the cat with a course of corticosteroids (cortisone) since most asthmatic cats respond very favorably. However, these medications can complicate the management of cats harboring secondary bacterial infections; therefore, prophylactic antibiotics are reasonable in cases where a workup cannot be performed. In addition, cats that are coughing due to heartworms often improve with corticosteroids. Without heartworm testing, they may go undetected.
Successful management of allergic lung disease employs several therapies.
1. Any factors known to trigger or aggravate breathing problems should be avoided. In some cases, this may mean trying different brands of cat litter, eliminating cigarette smoke from the home, etc. The list above (see “Causes”) details some factors that should be considered. It is important to pay close attention to environmental factors that may aggravate the condition.
2. Bronchodilators. These drugs are used to open the airways and allow the cat to move air more freely. They should be used faithfully and as directed to obtain maximum effect.
3. Corticosteroids. Corticosteroids have a beneficial effect on decreasing inflammation, dilating the airway, and decreasing mucus production. In many cats, they are given daily. When the cat does not take tablets well, long-acting injections can be given. These drugs have potential for some side effects, but this problem is much less in cats than in humans.
4. Emergency treatment may employ bronchodilators, oxygen, rapid-acting glucocorticoids, and epinephrine. When the cat has heart disease, the attending veterinarian should be advised since epinephrine is best avoided.
Cats with obstructive lung disease are usually manageable. Sometimes “cure” may be achieved if a specific underlying cause can be identified and treated. Extreme respiratory distress constitutes an emergency, and the cat should receive immediate attention.
INSTRUCTIONS: Those instructions that are specific for your cat have been checked:
___ 1) An injection of corticosteroids (cortisone) was given. Relief should be apparent within 12-24 hours. If an increase in water consumption or urination occurs, please report this to us for future reference. These side effects are common with steroid administration and will go away in a few days without treatment. Return for further evaluation when the first signs of respiratory distress or noisy breathing return.
___ 2) Begin oral corticosteroids. The specific drug being dispensed for your cat is labeled on the bottle. Give the tablets per label instructions. Report any increase in water consumption to us at once.
___ 3) Begin oral bronchodilators. The specific drug being dispensed for your cat is labeled on the bottle. Give the tablets per label instructions.
Bladder stones, more correctly called uroliths, are rock-like collections of minerals that form in the urinary bladder. They may occur as a large, single stone or as dozens of stones the size of large grains of sand or pea gravel.
Although the kidneys and urinary bladder are both part of the urinary system, kidney stones are usually unrelated to bladder stones. When stones are found in the urinary tract, more than 90% of the time, they are in the bladder.
There are several different types of uroliths in cats. It is important to determine the mineral composition of the stones, when possible. Depending upon the type of stone, various risk factors may contribute to urolith formation. Diet, water intake, urinary tract infections, and urinary pH are all-important considerations.
For the most part, urolithiasis affects male and female cats with equal frequency. One particular type of stone (calcium oxalate) reportedly affects male cats more commonly than female cats; also, Burmese, Himalayan, and Persian cats may have a higher incidence of this stone. Some types of stones are more common in younger cats (struvite, or magnesium ammonium phosphate), whereas others tend to occur in more mature cats (calcium oxalate).
Bladder stones are responsible for about 25% of all cases of hematuria (blood in the urine) and dysuria (straining to urinate) in cats.
The two most common signs of bladder stones are hematuria and dysuria. Hematuria (blood in the urine) occurs because the stones mechanically irritate the bladder wall, causing bleeding from its fragile surface. Dysuria (difficulty urinating) occurs when stones obstruct the passage of urine out of the bladder. Large stones may cause a partial obstruction at the point where the urine leaves the bladder and enters the urethra; small stones may flow with the urine into the urethra and cause an obstruction at its narrow point.
When an obstruction occurs, urine cannot pass out of the body and the abdomen becomes very painful. Your cat may cry in pain, especially if pressure is applied to the abdominal wall. The cat may make frequent trips to the litterbox in a futile attempt to urinate.
Even if there is no obstruction occurring, hematuria and dysuria may be significant; the irritated bladder is quite painful. When bladder stones are removed surgically, many owners tell us how much better the cat feels.
There are several theories of bladder stone formation. Each is feasible in some circumstances, but there is probably an interaction of more than one of them in each cat. The most commonly accepted theory is called the Precipitation-Crystallization Theory. This theory states that one or more stone-forming crystalline compounds are present in elevated levels in the urine. This may be due to abnormalities in diet or due to some previous disease in the bladder, such as infection with bacteria. When the amount of this compound reaches a threshold level, the urine is said to be “supersaturated.” This means that the level of the compound exceeds its ability to dissolve in the urine, so it precipitates and forms tiny crystals. These crystals stick together, usually due to mucus-like material within the bladder, and stones gradually form. As time passes, the stones enlarge and increase in number.
Growth will depend on the quantity of crystalline material present and the degree of infection present. Although it may take months for a large stone to grow, some sizable stones have been documented to form in as little as two weeks.
Most cats that have bladder infections do not have bladder stones. These cats will often have blood in the urine and will strain to urinate. Therefore, we do not suspect bladder stones just based on these clinical signs.
Some bladder stones can be palpated (felt with the fingers) through the abdominal wall. However, failure to palpate them does not rule them out because many are too small to be detected in this manner.
Most bladder stones are visible on radiographs (x-rays) or an ultrasound examination. These procedures are performed if stones are suspected. This includes cats that show unusual pain when the bladder is palpated, cats that have recurrent hematuria and dysuria, or cats that have recurrent bacterial infections in the bladder.
Some bladder stones are not visible on radiographs. They are said to be radiolucent. This means that their mineral composition is such that they do not reflect the x-ray beam. These stones may be found with an ultrasound examination or with special radiographs that are made after placing a special dye (contrast material) in the bladder.
There are two options for treatment. The fastest solution is to remove them surgically. This requires surgery in which the abdomen and bladder are opened. Following two to four days of recovery, the cat is relieved of pain and dysuria. The hematuria will often persist for a few more days, then it stops. Surgery is not the best option for all patients; however, those with urethral obstruction and those with bacterial infections associated with the stones should be operated on unless there are other health conditions that prohibit surgery.
The second option is to dissolve the stone with a special diet. This avoids surgery and can be a very good choice for some cats. However, it has three disadvantages.
1. It is not successful for all types of stones. Unless some sand-sized stones can be collected from the urine and analyzed, it is not possible to know if the stone is of the composition that is likely to be dissolved.
2. It is slow. It may take several weeks or a few months to dissolve a large stone so the cat may continue to have hematuria and dysuria during that time.
3. Not all cats will eat the special diet. The diet is not as tasty as the foods that many cats are fed. If it is not consumed to the exclusion of all other foods, it will not work.
The prognosis is dependent upon the type of stone, presence of infection, location of the stones, presence of concurrent stones in the kidneys, and any other factors that complicate the health of the cat. In most cases, with appropriate therapy, a favorable outcome is expected.
Prevention is possible in many cases. As described above, there are at least four types of bladder stones, based on their chemical composition. If stones are removed surgically or if some small ones pass in the urine, they should be analyzed for their chemical composition. This will allow determination of the appropriate diet; hopefully, this will minimize the chance of recurrence. If a bacterial infection causes stone formation, periodic urinalyses and urine cultures should be performed to monitor response to treatment.
Cardiomyopathy literally means “disease of the heart muscle.” This is a disease that occurs in purebred and non-purebred cats of any age. Males and females are equally affected. There are three distinct forms and a variation of one of them. Each will be discussed separately.
Anatomy and Function of the Heart
The cat’s heart is comprised of four chambers: the right and left atria (singular: atrium) (the top chambers) and the right and left ventricles (the bottom chambers). The right side of the heart receives oxygen-depleted blood from the body and pumps it to the lungs so it can receive oxygen. The left side of the heart receives oxygenated blood from the lungs and pumps it to the body.
Each chamber has a valve at its opening and another valve at its exit. Each entry valve opens to allow blood to enter its chamber, and then it closes. At that precise moment, the exit valve opens and the walls of the chamber contract pushing blood out.
Cardiomyopathy principally involves the left side of the heart, the side that pumps oxygen-rich blood to the body. The left ventricle is involved first, and then the right ventricle often is affected.
Hypertrophic cardiomyopathy (HCM) causes the walls of the left ventricle to become thicker than normal. They are normally 4-5 mm thick; however, if HCM is present they may become over 10 mm thick. As they thicken they also become stiffer and less able to contract with the force needed to send blood to the distant parts of the body.
Most of the thickening that occurs in the ventricular walls is directed inward causing the left ventricular chamber to be smaller. This limits the amount of blood that can enter the left ventricle and the amount of blood that can be pumped to the body. In addition, it puts great stress on the mitral valve, the valve between the left atrium and the left ventricle. After a few weeks the valve weakens and begins to leak, creating a murmur. This murmur will often be present several weeks to months before the cat goes into heart failure and may be detected during a routine physical examination.
HCM is also a disease of humans, and 50% of the time it is an inherited disorder. There is mounting evidence that HCM in cats is also a genetic disease, especially since it is often seen in cats less than 2 years of age. It is suggested that littermates of HCM cats be tested for the disease.
The diagnosis of HCM is based on several tests. Hearing a murmur or an abnormal heart rhythm is a signal that other tests should be performed. An electrocardiogram (EKG) may show abnormalities that also suggest this disease. Radiographs (x-rays) of the heart usually reveal characteristic changes in the shape of the heart, especially in the latter stages when the left atrium enlarges. However, many cats in the early stages of the disease will have normal radiographs. An echocardiogram (ultrasound study of the heart) is the most precise means of diagnosing this disease. Ultrasound waves are directed into the heart and analyzed by a computer permitting precise measurements of the thickness of the heart’s walls and the size of the chambers. We can also observe the mitral valve to access its function.
Treatment is determined by the stage of the disease at the time of diagnosis. Cats in advanced disease are in congestive heart failure and treated with several drugs to keep the cat from dying. Diltiazem is used to relax the walls of the left ventricle so more blood can enter and so it can contract with more force. Propranolol is used to slow the heart rate when it is beating too fast. Furosemide is a diuretic that stimulates the kidneys to remove fluid that may have collected in the lungs (pulmonary edema). Aspirin is used to prevent blood clots that often form around the mitral valve. Eventually, they dislodge from the valve and cause obstruction of arteries in various parts of the body. Enalapril is a new drug used for this disease. One study has shown that its use may result in thinning of the left ventricular walls and even return to normal thickness in some cats. However, this drug takes 2-4 months to cause these results.
If HCM is detected before the onset of congestive heart failure, enalapril and aspirin may be the only drugs that are needed. However, because the disease appears to be genetically caused, it is thought that enalapril probably should be given for the rest of the cat’s life to prevent recurrence.
The prognosis is largely dependent on when the disease is diagnosed and how successful treatment is in correcting congestive heart failure. If it is diagnosed early or if congestive heart failure is controlled, many of these cats live for several years.
Dilated cardiomyopathy (DCM) results in thinning of the walls of the left ventricle. Instead of being 4-5 mm thick, they may become only 1-2 mm thick. As they become thinner they also stretch and become unable to contract properly. This results in enlargement (dilation) of the left ventricle. Even though more blood can enter the ventricle, the walls become so weak that they cannot pump the blood with enough force to send it to the distant parts of the body. The end result is congestive heart failure.
In the 1980’s, DCM was almost as common as HCM. However, it was discovered that a deficiency of the amino acid taurine was the cause of this disease in many cats. Cat food manufacturers were notified that cats need more taurine than was previously thought, and they responded by increasing its level in commercial cat foods. Consequently, DCM has almost disappeared. However, it is still seen in cats that eat primarily dog food or table food and occasionally in cats that eat commercial cat food. The latter causes us to realize that taurine deficiency is not the only cause of this disease, although other causes are not known at this time.
The diagnosis of DCM is based on several tests. An electrocardiogram (EKG) may show abnormalities that suggest this disease, although most of these cats have normal EKG’s. Radiographs (x-rays) of the heart often reveal characteristic changes in the shape of the heart, especially in the latter stages when the left ventricle is markedly enlarged. However, many cats in the early stages of the disease will have normal radiographs. An echocardiogram (ultrasound study of the heart) is the most precise means of diagnosing this disease. Ultrasound waves are directed into the heart and analyzed by a computer permitting precise measurements of the thickness of the heart’s walls and the size of the chambers.
Treatment consists of drugs to control heart failure. Digoxin is usually used to cause an increase in the force of the contractions of the walls of the left ventricle. Furosemide is a diuretic that stimulates the kidneys to remove fluid that may have collected in the lungs (pulmonary edema). Aspirin is used to prevent blood clots that often form around the mitral valve. Eventually, they dislodge from the valve and cause obstruction of arteries in various parts of the body. Enalapril has shown some promise in treating this disease even though the mechanism of action is not understood at this time.
Unfortunately, we do not have a drug that reverses the thinning of the left ventricular walls. Therefore, the long-term prognosis is not very good in many of these cats.
Restrictive cardiomyopathy (RCM) is an uncommon variation of HCM. The walls of the left ventricle are thickened in some areas and not in others; they also become very stiff. One distinct difference is the presence of inflammation in the walls of the left ventricle. This finding raises the question of some type of infection as a possible cause of this disease.
RCM progresses to congestive heart failure, just as the other types. A murmur is common, and the left atrium often dilates. Treatment is much the same as HCM, but the results are often not as good. Enalapril has not been used on enough of these cats to determine its effect.
Thyrotoxic cardiomyopathy is a very mild form of cardiomyopathy compared to the others. This disease is the result of another disease of cats, hyperthyroidism. Hyperthyroidism results in thyroid gland enlargement and overproduction of thyroid hormone. Excess thyroid hormone stimulates the heart resulting in mild thickening of the left ventricular walls; However, in this disease the force of heart contractions is usually greater than normal and these cats often have high blood pressure.
Thyrotoxic cardiomyopathy resolves when hyperthyroidism is treated; therefore, it has a very good prognosis if proper treatment for its underlying disease occurs.
When the heart is functioning normally, blood flows through it in a laminar (straight path) fashion. Each of the forms of cardiomyopathy cause abnormal flow patterns, especially around the mitral valve. This often results in blood clot formation on the valve. These clots get larger and larger until parts of them break off and are carried with the blood into the aorta and other major arteries. Most commonly, a clot will be carried down the aorta toward the rear legs. When the aorta splits to go to the rear legs, each new artery is smaller than the aorta, much like a tree that branches. The clot then is too large to continue down either artery so it suddenly stops, usually in such a way that blood flow is prohibited to the main artery of each rear leg. Suddenly, the cat is in severe pain and cannot use either rear leg. Within a few minutes to hours the feet become cold and the pads become bluish. This creates a severe crisis for the cat. It cannot walk on its rear legs, and it is in a great deal of pain. The clot that obstructs these arteries is commonly called a saddle thrombus.
Fortunately, there are other arteries that go to the rear legs. Although they are not as large, they are able to supply enough blood to the legs to keep the tissues from dying, in most cases. Over the next 5-10 days, these smaller arteries send new branches to the blood-deprived parts of the legs. During that time, various drugs are used to make the cat more comfortable, and massage and physical therapy are performed to support the muscles until they become functional again. The vast majority of cats will regain their ability to walk.
Surgery has been performed on some of these paralyzed cats to remove the blood clot. Sometimes the surgery is very successful, and the cat resumes walking almost immediately. However, the underlying disease that causes the blood clot to form is cardiomyopathy, so many of these cats will die during surgery because of heart failure.
Blood clots may obstruct other arteries. If one enters the renal (kidney) artery, kidney failure will result. If one goes to a front leg, lameness (but usually not paralysis) will occur. If one goes to the brain, a seizure or stroke is likely.
We do not have a drug that will dissolve the blood clots on the mitral valve or in the smaller arteries. However, aspirin is used to prevent their formation. The average 10 pound cat should receive an 81 mg aspirin 2-3 times per week (every 2-3 days). Eighty-one milligram aspirin is sold as “children’s aspirin” or “low-dose adult aspirin.” Children’s aspirin (formerly known as baby aspirin) is usually chewable and orange flavored, a taste that is generally objectionable to cats. Low-dose adult aspirin is often enteric (hard) coated and more easily swallowed; that works best for most cats.
You may have heard that aspirin should never be given to a cat. Obviously, that is not a true statement. However, cats are able to break down aspirin very slowly. One dose remains in the cat’s body for 48-72 hours. Therefore, as long as the dose is correct and the dosing interval long enough, it is very safe.
DO NOT SUBSTITUTE ACETAMINOPHEN (TYLENOL) FOR ASPIRIN. ACETAMINOPHEN IS VERY TOXIC TO CATS.
Warfarin is another drug that may also be used to prevent blood clots. It appears to be somewhat more effective than aspirin in some cats, but overdosing results in severe bleeding. Therefore, its use requires very careful monitoring of the cat’s blood clotting ability.
The cornea is the clear, shiny membrane that makes up the surface of the eyeball. It is much like a clear window. To understand the significance of a corneal ulcer, you must first understand how the cornea is constructed.
The cornea is comprised of four layers. The most superficial layer is the epithelium. Actually, this layer is comprised of many, very thin layers of cells. Below the epithelium is the stroma. The next deeper layer is called Descemet’s membrane. The deepest layer is the endothelium; it is composed of a single layer of cells. Because all of these layers are clear, it is not possible to see them without special stains and equipment. The cornea must maintain its transparency to ensure clear vision.
Corneal Abrasion vs. Corneal Ulcer
An erosion thorough a few layers of the epithelium is called a corneal erosion or a corneal abrasion. A corneal ulcer is an erosion through the entire epithelium into the stroma. If the erosion goes through the epithelium and stroma to the level of Descemet’s membrane, a descemetocoele exists. If Descemet’s membrane ruptures, the liquid inside the eyeball leaks out and the eye collapses. At times, differentiation of the two may not be straightforward. For this reason, cats with corneal disease should be rechecked frequently, usually every few days.
Because a corneal ulcer is quite painful, most cats rub the affected eye with a foot or on the carpet. To protect the eye, they keep the eyelid tightly closed or will frequently squint in an attempt to the eye closed. Some cats will seek dark areas because light is painful; they may hide under the bed or in a closet. Occasionally, there will be a thick white or yellow discharge that collects in the corner of the eye or runs down the face.
A number of different disorders may lead to corneal ulceration. Some of these include trauma, foreign bodies, abnormalities of the eyelid, decreased tear production, chemical irritation to the cornea, and certain infectious diseases. In cats, viral respiratory disease is associated with a variety of corneal problems. Fortunately, ulcers rarely develop with these common respiratory viruses. Corneal ulcers can be seen more frequently in animals that have a lot of facial folds; when these folds occur close to the eye, they allow hair to constantly rub the cornea.
Superficial corneal abrasions are usually not visible without special stains. They can be seen when a drop of fluorescein stain is placed on the cornea. The dye will adhere to an area of ulceration and is easily visualized with a special black light called a Wood’s light or Wood’s lamp. This is the most basic test performed and may be the only test needed if the ulcer is acute (sudden) and very superficial. If the ulcerated area is chronic or very deep, samples are taken for culture and cell study prior to applying the stain or any other medication.
Treatment depends on whether there is a corneal abrasion, corneal ulcer, or descemetocoele present.
Corneal abrasions generally heal within 3-5 days. Medication is used to prevent bacterial infections (antibiotic ophthalmic drops or ointment) and to relieve pain (atropine ophthalmic drops or ointment). Antibiotic drops are only effective for a few minutes so they must be applied frequently; ointments last a bit longer but still require application every few hours. It is suggested that an antibiotic preparation be instilled in the eye 4 to 6 times per day. On the other hand, the effects of atropine last many hours so this drug is only used twice daily. If the corneal ulcer does not heal within these first few days, complicating factors must be identified, if possible.
If a deep corneal ulcer or descemetocoele is present, measures must be taken to protect the eye and to promote healing. Since cats do not wear eye patches well, surgical techniques are often used to close the eyelid and cover the ulcer or descemetocoele. These measures protect the eye for several days, then are reversed so the cat can use the eye again. This approach is also taken if a superficial ulcer is very slow in healing.
Ulcers that do not heal well often have a buildup of dead cells on the edge of the ulcer. These dead cells prevent the migration of new, normal cells over to the ulcer defect. If this appears to be part of the healing problem, the dead cells are removed from the edges of the ulcer before the eyelids are surgically closed. In some cases, removing the dead cells may be all that is needed to start the healing process, so surgical closing of the eyelids may not be necessary.
Drugs Commonly Used
A cat with a corneal ulcer has quite a bit of pain inside the eye, so it keeps it tightly shut. Atropine is used to relieve that pain. However, atropine also dilates the pupil widely. This means that the cat is very sensitive to light in that eye. Because of the light sensitivity, the eye will be held closed in bright light. Atropine’s effects may last for several days after the drug is discontinued. Do not be alarmed if the pupil stays dilated for several days. Should you accidentally get atropine in your own eye, the same prolonged pupillary dilation will occur.
Antibiotic drops or ointments are commonly used on ulcers. They do not cause the ulcer to heal better, but they treat or prevent bacterial infections from occurring within the ulcer. Bacterial infections greatly slow or even stop healing of a corneal ulcer. Antibiotic drops and ointments remain on the cornea for a short period of time. Therefore, they must be used several times each day. Ointments remain in contact with the cornea longer than drops, but many cats will object to the gooey medication in their eyes.
A topical anesthetic is often used to numb the cornea so the diagnostic tests may be performed. However, these drugs are toxic to the corneal epithelium; they prevent proper healing. They are safe for one time use, but they should not be used as part of treatment.
The Danger of Topical Steroids
It is important that steroids not be used in the eye too soon because they will stop healing of a corneal ulcer and may worsen it. Therefore, the fluorescein dye test should be performed before beginning this type of medication. If steroids are used and the eye becomes painful again, discontinue the steroids and have the eye rechecked. Steroids can cause the corneal ulcer to eventually perforate.
Side Effects of Treatment
Rarely, a cat will be allergic to an antibiotic that is instilled in the eye. If your cat seems more painful after the medication is used, discontinue it and contact the veterinarian.
If you see your cat drool or paw at the mouth after instillation of eye medications, do not be alarmed. The tear ducts carry tears from the eyes to the back of the nose. The eye medications may go through the tear ducts and eventually get to the throat where they are tasted. Atropine has a very bitter taste that may cause this response. Again, you are seeing your cat’s response to a bad taste, not a drug reaction.
Discontinuation of Medication
The best way to tell that the cornea has healed is to repeat the fluorescein stain test. This should be done after about 2-3 days of treatment. If healing is progressing well, the eye should be checked again before treatment is discontinued to be sure healing is complete. Please consult with us before discontinuing medication unless you have been instructed otherwise.
The normal cornea has no blood vessels going through it. However, when a corneal ulcer or descemetocoele occurs, the body senses a need to increase its healing capabilities. New blood vessels are created by a process called neovascularization. The new vessels begin at the sclera (the white part of the eye) and course their way to the ulcer. You may be able to see these new vessels as a small red spot adjacent to the ulcer.
Neovascularization is a good response because it hastens healing. However, after the ulcer is healed, these vessels remain in the cornea. They are not painful, but they do obstruct vision. Therefore, it is desirable to remove them. This is done with steroid (cortisone) ophthalmic drops or ointment. Cortisone is used for a few days to several weeks, depending on how many vessels exist.
The prognosis is usually good for uncomplicated corneal ulcers that receive prompt treatment. The prognosis is less certain when the ulcer is deep, the ulcer does not respond to medication, or a complication of the ulcer cannot be successfully treated.
The knee joint of the cat is one of the weakest joints of the body. Just as football players frequently suffer knee injuries, the cat also has knee injuries. Fortunately, cruciate ligament injuries are relatively uncommon in the cat.
The knee joint is relatively unstable because there is no interlocking of bones in the joint. Instead, the two main bones, the femur and tibia, are joined with several ligaments. When severe twisting of the joint occurs, the most common injury is a rupture of the anterior cruciate ligament. When it is torn, instability occurs that allows the bones to move in an abnormal fashion in relation to each other. It is difficult for the cat to bear weight on the leg without it collapsing.
Obesity or excessive weight can be a strong contributing factor in cruciate rupture. The ligament may become weakened due to carrying too much weight; this causes it to tear easily. Obesity will make the recovery time much longer, and it will make the other knee very susceptible to cruciate rupture. If your cat has a weight problem, there are prescription diets that can be used to assist weight reduction.
This type of injury is relatively uncommon in the cat, although it can and does occur. It is a much more common injury in the dog.
Most owners report the sudden onset of moderate to severe lameness in the cat. If the lameness is not addressed with medical attention, there is usually improvement after 4-5 weeks.
Trauma can be responsible for cruciate injuries, although the trauma may not always be observed by the owner. As noted above, obesity can predispose the cat to this type of injury, also.
The most reliable means of diagnosing this injury is to move the femur and tibia in a certain way to demonstrate the instability. This movement is called a “drawer sign.” It can usually be demonstrated with the cat awake. If the cat is in pain, has very strong leg muscles, or is uncooperative, it may be necessary to use sedation in order to examine the joint thoroughly.
Correction of this problem requires surgery. A skilled surgeon can fashion a replacement ligament and stabilize the joint so it functions normally or near normally. If surgery is not performed within a few days to a week, arthritic changes will begin that cannot be reversed, even with surgery.
Occasionally the injury that causes a ruptured anterior cruciate ligament will also result in tearing of one or both of the menisci or “cartilages.” At the time of surgery, these are examined and removed if necessary.
Occasionally, the cat that has a ruptured cruciate ligament will become sound (will no longer limp) even if surgery is not performed. However, arthritis will usually begin and result in lameness a few months later. That cause of lameness cannot be corrected.
The prognosis is dependent upon successful management, either surgical or medical. As noted above, cats that do not receive surgery will often develop irreversible arthritis in the joint even though their lameness may go away for a few weeks or months.
“Dog-On-It’ Lawn Problems Revisited
By Steve Thompson, DVM, DABVP
Dog urine and feces can often be a frustrating problem when considering the issue of lawn care. Small amount can produce a “green up” or fertilizer effect, whereas larger amounts often result in dead brown patches or lawn burn, which are frequently surrounded by a green outside ring. While most burn spots can recover the time and regrowth, they can be sufficiently severe to require reseeding or sodding. For homeowners who are also dog lovers, this can present a difficult challenge, especially when one family member prefers the dog and another prefers a well-manicured lawn. An understanding to the interaction between dogs and he lawn can keep the yard at peace, not in pieces.
Understanding the Causes
The Bigger Problem: Urine or Feces?
The fundamental problem with the presence of urine or feces on the lawn is related to the concentration and nitrogen content of these waste products. As a waste product in animals, urine primarily removes excess nitrogen from the body via the kidneys. Nitrogen waste products are the result of protein breakdown through normal bodily processes. Carnivores, including cat and dogs, has a substantial protein requirement, and urine volume and production vary according to a pet’s size and metabolism. Urine is a bigger problem for lawns that feces because it is applied in concentration as a liquid fertilizer, whereas feces slowly release the waste products over time. Because stools are usually solid, owners have the option of frequently removing the waste themselves or hiring a commercial pooper-scooper business. If feces are removed frequently, there is less time for the nitrogen by-products to dissolve and therefore less damage than can occur from urine.
Considering Human Health Concerns
Removal of feces also reduces bad odors, fly breeding, and human health concerns related to the transmission for some diseases from dogs to humans, including Salmonella, Campylobacter, roundworms (visceral larval migrans), and hookworms (cutaneous larval migrans ore creeping eruption). As all veterinarians know, children are primarily at risk because they are likely to wash their hands after playing in areas where dogs may have defecated. The canine roundworm Toxocara canis is of particular concern because the eggs passed in canine stools are resistant to disinfectants and weather extremes for many years. Although uncommon after being ingested by a child, then worm can migrate through the body and cause problems related to vision, breathing, or neurologic disorders. This is the primary reason many communities enacted pooper-scooper laws and why canine and feline feces should not become part of composting.
The Worst Culprit: Dogs or Cats?
Dogs are a greater concern that cats to the lawn-conscious pet owner because of the smaller volume of feline urine and cat’s elimination behaviors. Cats generally mark bushes ore trees as sent posts or bury their wastes in a garden rather that eliminating on the lawn, as a dog typically prefers. Young dogs of both sexes frequently squat to urinate. Leg lifting is often learned by male dogs around 1 year of age – castration or neutering does not seem to affect nature’s timetable for this behavior. Although most male dogs hike their leg and mark, a few males do continue to squat when urinating, which is more typical of female dogs. Female dogs may also mark, although less commonly than male dogs.
Once dogs begin urine marking the often find many sent posts, resulting in numerous, small-volume urination rather that large-volume puddles. Grass can handles small-volume nitrogen bursts easier that fertilizer overload. Unfortunately, the young bush, scrub, vine, or tree sprout that becomes a marking post may die because of nitrogen (fertilizer) overload from repeated marking.
Addressing Some Primary Concerns
When addressing urine damage to lawns, the primary concern is minimizing the amount of urine being added to the lawn during a given time. Female dogs, being less likely to urine mark and more likely to squat are the primary culprits of lawn damage because they urinate anywhere are usually all at once. This results in single nitrogen dump confined to a small patch of grass. The brown spot that results often has a green ring around the outside. The nitrogen overload at the center causes the burn, bus as the urine is diluted toward the periphery, is has a fertilizer effect. These characteristic brown spot, green-ring pattern has been called “female dog spot disease” by some horticulturists. As might be expected, lawns are most susceptible to nitrogen burns when a maximum amount of standard fertilizers are applied to the lawn, especially in homes with a comprehensive lawn care program. Homeowners making the extra effort to maintain a green lawn may become discouraged by the degree of damage caused by neighbors or their own dog.
Speculation on the actual cause of lawn burn has resulted in numerous theories on what else in the urine may be contributing to the damage. A.Wayne Allard, DVM, a Colorado veterinarian, examined numerous variations in dog urine and its effects on several common lawn grasses. His results supported the fact that urine concentration and volume of urine (nitrogen content) had the most deleterious effects on lawns. The pH of urine did not have a variable effect, nor did common additives designed to alter urine pH.
Of the four grasses tested, Festuca spvar Kentucky (fescue) and Lolim perrene (fine-bladed rye) were the most resistant to urine effects. In fact, urine routinely produced a fertilizer effect on these grasses at diluted concentrations. Poa pretensis (Kentucky bluegrass) and Cynodon sp var fairway (Bermuda grass) were very sensitive to urine concentration and severe burns, persisting longer that 30 days after initial exposure to even 4 oz of dilute urine. Even on the most urine-resistant grass that was tested (fescue), urine concentration was a larger problem than urine volume. Concentrated urine with volumes of as little as 30cc (1 oz) caused lawn burn, even on fescue grasses.
Avoiding Problem Areas
Obviously, fences can be used to prevent neighboring dogs from eliminating on the lawn. Advising dog owners about leash laws, where applicable, can also restrict damage to areas near sidewalks, on trees and lawns, and on median right of ways.
Unfortunately, no commercial repellants are universally effective in protecting lawns, although a variety of home remedies have been tried. Hot and bitter products are most likely to have taste or odor-adversive properties to dogs. Most repellants function better as taste repellants that touch or odor repellants. Some odor repellants may actually encourage a dog to overmark the strange odor with their urine. Some of the better commercial repellants, such as Garbage Protectors and Ro-Pel, have these limitations as well. A motion-activated sprinkle designed to keep cats and rabbits out of gardens may be beneficial, such as the Scarecrow marketed by the Canadian firm ConTech. In addition, the sprinkler may be advantageous in small yards or along corners of front yards, where damage is most likely to occur. The presence of numerous squirrels, stray animals, or children in the neighborhood, however, may result in high water bill is they continuously trigger the device.
Although is can be time consuming, walking the dog in a park or field away from the home is a simple remedy. The time can also be beneficial because exercise has physical and emotional benefits for both dogs and their owners. Homeowners should therefore be encouraged to choose an appropriate destination rather than create problem lawns for neighbors.
Another option is to litter box train a dog, as breed size and residential space permit, but a more feasible approach is to train the pet to eliminate in a designated area of the yard. This area could be landscaped specifically to handle the dog’s urine of feces. It would need a substrate-like pea gravel or mulch that the dog finds acceptable and may even include a marking post, such as a large boulder, bird bath, lawn ornament, or even faux hydrant. Collecting the dog’s urine in a cup and using it in this area for several days can provide some odor-attractant value that draws the dog to the area. Feces can also be collected and transported to the new, designated area. Consistency is important for at least 2 to 3 weeks to establish a routine, trained behavior. Several months may be necessary in some cases.
It is important that the dog not be allowed to eliminate anywhere except the designated place during the training process. This can be accomplished by taking the dog out on a leash to the designated spot and rewarding it with a food treat when it eliminated in the appropriate area. It is often easier to train a young puppy that an adult dog to a particular area, but such behavior modification is never impossible in a dog of any age. Many dog owners also find it helpful to train their dog to obey a verbal elimination command. A dog can also be trained to eliminate on a verbal signal by simply saying the word immediately before it eliminates and rewarding it with a food treat after it finishes. Common commands include “potty”, “piddle”, “do your business”, and “hurry up.” Using a command also makes it quicker to accomplish the task during inclement weather.
Many dietary modifications to control nitrogen content in the urine have been tried for dogs, often-based on home remedies or anecdotal experience. A veterinarian should always be consulted before an owner makes any dietary modifications, whether they include additions or subtractions from the standard nutrient guidelines. As stated earlier, the pH of urine has little or no effect on urine damage to lawns.
The addition of acidifying agents, including such nutritional supplements as DL-methionine (methio-form), ascorbic acid (vitamin C), or fruit juices, has no benefit and may predispose a dog to developing an increased incidence of certain bladder stones. Likewise, alkalinizing agents, including baking soda and potassium citrate (UrocitK), can predispose a dog to other types of bladder stones or infections. These dietary supplements can be harmful and have limited to no known benefits to the lawn. Thus, they are not recommended.
When owners have reported successes, they often can be attributed to increasing the dog’s liquid consumption, which dilutes the urine concentration. However safer ways to accomplish more dilute urine include feeding canned food, moistening dry food with water before feeding, and adding salt or garlic to the regular food.
One home remedy, tomato juice, likely has it primary benefit through both increased salt and water intake. While salt can make a dog drink more and thereby dilute the urine, increasing salt intake can also cause problems in dogs with existing kidney or heart conditions. With high doses of salt, even healthy dogs can develop hyernatremia. Therefore, owners should not alter their dog’s diet without consulting with their veterinarian.
This is the ultimate kitten care guide written by your friendly Crossroads Veterinary Hospital team.
- The Kitten Manual (free PDF download)