Dear Doctor - August 2015
Letters to Tufts Veterinarians
The vet won’t treat my dog for Lyme disease
Q At my five-year-old Maltese’s last checkup, I was told somewhat casually that her blood test came back positive for Lyme disease. Having lost a dog years ago to kidney disease resulting from Lyme disease, I was quite distressed. However, I was advised that if the urine test did not show any protein in the urine, no treatment would be required and that I should just continue to monitor her for symptoms. Maggie’s urine test came back negative, and she appears to be healthy and happy. I, on the other hand, am not happy. I don’t understand why antibiotics are not administered to prevent the infection before it becomes a problem. Did my vet make the right call?
Schenectady, New York
Dear Ms. Tommasulo,
A Based on the information you’ve provided us, it would appear that yes, your vet made the right call. The usual test for Lyme disease is not a test for the organism itself; it is a test for antibodies to the organism. The majority of dogs that test positive for Lyme disease are not ill and will never develop signs of illness. Instead, a positive test simply means that your dog was exposed to the organism at some point in the past and that she still has antibodies against the organism. In other words, very few dogs infected with Lyme disease ever get sick. And it appears that only in the event that a dog does become sick will an antibiotic do any good. Otherwise, it can be worse than a waste of time because the over-prescribing of antibiotics only serves to make dogs (and people) more resistant to their effects should they ever actually need the medicine to get over an illness.
Your dog’s doctor told you to monitor Maggie for symptoms because if she does come down with any of the classic signs for the disease — loss of appetite, listlessness, limping (the offending bacteria cause inflammation of the joints) — the vet will then immediately prescribe antibiotics. If there’s a quick response to the antibiotic treatment (within 48 hours), Lyme disease may indeed have been the culprit. If there’s not — and that would be very possible because signs like loss of appetite and listlessness are very non-specific and could be due to any number of illnesses — Lyme disease probably isn’t the problem, and further diagnostic testing for other diseases will be required.
We should note that the one instance in which administration of antibiotics won’t work to treat Lyme disease is if the infection is associated with kidney damage. Dogs with Lyme disease recover beautifully with administration of antibiotics, even if they have been having symptoms for a while, but not in the case of kidney complications, which, unfortunately befell your previous dog. By checking to make sure there was no protein in Maggie’s urine, your vet was ascertaining that the Lyme disease bacteria, which were transmitted by a tick, did not have an effect on her kidney function at this time. We should note, however, that Lyme nephritis — compromised kidneys resulting from Lyme infection — could conceivably develop months or even years down the line. That said, while a single negative test doesn’t guarantee that a dog is at zero risk, the chances that your dog’s kidneys will develop problems are very, very remote. And because there is no proof that antibiotic treatment will prevent the development of kidney disease combined with concern for overuse of antibiotics, treatment is not encouraged.
You are not alone in feeling nervous about your dog testing positive for Lyme disease. In fact, sometimes people’s anxiety, even in the absence of any clinical signs of the illness, leads to situations in which veterinarians over-treat. The best bet is to channel concern about Lyme disease into monthly tick prevention (topical, oral, or collar) and perhaps an annual vaccine against the illness as well. Living in the Northeast as you do puts you in an endemic area for the infection.
Omega-3s for arthritis
Q I found your comments on glucosamine for arthritis pain interesting [June issue: “The Three Most Common Supplements for Older Dogs”], and after talking with my vet have decided to try glucosamine-containing Dasuquin for my 11-year-old black Lab/border collie mix. Her arthritis has been getting the better of her, and I’m hoping to see an improvement in her pain. My vet also talked to me about administering omega-3 fatty acids, or at least a diet richer in omega-3s than dog food typically is. You talked about omega-3s for heart disease but not for arthritis. What do you think?
Dear Mr. Fleigel,
A We think it’s worth considering. The data are intriguing. In one study of more than 100 dogs with osteoarthritis conducted with the help of researchers at Kansas State University’s College of Veterinary Medicine, the animals were randomly assigned either to a typical diet or a test food containing a significantly higher amount of omega-3s than usual and a significantly lower amount of omega-6 fatty acids (which can potentially interfere with the workings of omega-3s in high concentrations). The result: those dogs on the diet high in omega-3s were reported by their human families to have an improved ability to rise from a resting position and play at six weeks compared with those dogs on the regular diet and an improved ability to walk at both 12 and 24 weeks.
In other research, 38 dogs examined at two different veterinary clinics were assigned to receive a typical commercial food or a test food containing omega-3s. After three months, most of those dogs fed the omega-3-rich diet had greater weight-bearing in their most severely affected arthritic limb. This did not improve for the majority of the dogs fed the typical diet.
Yet other research showed that dogs fed a diet with omega-3s were able to undergo a reduction in the medication carprofen, administered to them to reduce arthritis pain.
Admittedly, all of this research was conducted by many of the same researchers and was supported by Hill’s Pet Nutrition, which makes food for dogs with arthritic joints called Hill’s Prescription Diet j/d. But the scientific investigations passed muster with peer review for publication in the prestigious Journal of the American Veterinary Medical Association. That is, they met accepted standards for valid scientific inquiry.
There are also other diets from other companies that are supplemented with omega-3s and designed for dogs with joint problems. We recommend discussing with your veterinarian whether any of these diets or supplementation with omega-3s on top of your current diet may be appropriate for your dog. Also make sure the amounts you’re serving are appropriate for your dog to maintain a healthy weight, which is so critical in the management of arthritis symptoms.
Eyes gone cloudy
Q My dog is 10 years old, and his eyes have gone cloudy. He has a cataract, doesn’t he?
New Braunfels, Texas
Dear Ms. Pryor,
A A cloudy lens does not necessarily signify the presence of a cataract. There’s a normal change in the eyes associated with aging called lenticular or nuclear sclerosis, which in fact tends to occur in both eyes at the same time — apparently the case with your pet. Lenticular sclerosis, too, can create a cloudy lens, but it doesn’t significantly affect vision. That’s why any dog with an eye that has turned cloudy or bluish-gray needs to be taken to the veterinarian for a reliable diagnosis and course of action.
If your dog does turn out to have a cataract (or cataracts), it does not automatically mean that surgery will be recommended. Even a dog with up to 30 percent opacity of the lens as a result of a cataract may be able to see reasonably well and therefore not need to undergo a procedure to correct the problem. The dog should be monitored, though, because some cataracts, including those that form as a result of diabetes, can progress quickly. The thicker and denser a cataract becomes, the more likely that it will lead to blindness.
In addition, an untreated cataract has the potential to slip out of place and float around the eye. Depending on where it settles, it can block fluid drainage that results in glaucoma — another cause of blindness, one that can prove debilitatingly painful.
If your dog undergoes cataract surgery, the procedure will involve removing the lens and replacing it with a clear plastic or acrylic lens to allow light to properly reach the back of the eye. The success rate is good, although you’ll have to do your part by making sure he wears an Elizabethan collar until his eye heals, keeping him relaxed, and administering eyes drops several times a day for a few weeks. (It sounds like a lot until you consider that you’re saving his sight.)
Note that along with old age and diabetes, breed type can be a cataract risk. A dog of any breed can develop a cataract, but those breeds that tend to be predisposed include the smooth fox terrier, American cocker spaniel, Havanese, bichon frise, silky terrier, miniature and standard Poodles, miniature schnauzer, and Boston terrier.