By R.G. Elmore, D.V.M.
Copley News Service

Q: We have noticed recently that while playing with a ball our little Lhasa apso sometimes stops very suddenly, usually yelps as if in pain, and holds her left rear leg up. After a few minutes she drops her leg and plays as if nothing happened. Our dog is about 8 months old and has never had any other problems.

Why does our dog have these episodes? Is there a problem with her leg that needs attention by a veterinarian?

A: It is impossible to tell you what is causing your dog to have the painful episodes that you have described without actually seeing her and knowing much more about her health history. Therefore, you should have your veterinarian conduct a comprehensive physical examination to determine if there are any physical abnormalities causing the episodes. Your veterinarian might recommend taking radiographs (X-rays) of your dog's left rear leg to determine if there are any anatomical abnormalities.

If your dog has not been injured in an accident such as being stepped on, it might be that she has a common abnormality known as patellar luxation. This is the scientific term for displacement of the kneecap. It is interesting that patellar luxation is most commonly diagnosed in toy and miniature breeds such as Pekinese, Pomeranians, Chihuahuas, terriers and miniature poodles. In most dogs with displaced kneecaps, the diagnosis is first made at 6 to 8 months of age. Either one or both legs can be affected.

In most affected dogs, the kneecap dislocates to the inside of the leg. It is not uncommon for the kneecaps in affected dogs to move freely back and forth between the normal and dislocated positions. Many dogs with dislocated kneecaps appear to be bowlegged.
Most veterinarians diagnose patellar luxation based on the history of intermittent lameness in young, small breed dogs; by feeling the affected leg; and by evaluating radiographs  of the rear legs. Successful treatment of patellar luxation usually requires surgery. Affected dogs in which corrective surgery is not performed usually develop arthritis and permanent damage to the ligaments in their legs. These problems usually cause unnecessary chronic pain. Your veterinarian can give you a definitive diagnosis and advice regarding how to handle your dog's problem.

Q: Recently our cat started gagging and went though a period of retching after which she threw up a mass of material containing a lot of hair. Since this is our very first cat, we do not know whether or not to be concerned. We cannot remember any of the many dogs we have owned over many years ever doing this.

Is throwing up hair normal for cats? While we are hoping that our cat is not sick, we are also hoping that she will not be doing this for the rest of her life. We are not sure that we are "cat" people!

A: Unfortunately, throwing up hairballs is common and considered normal behavior in cats.
However, many cat owners, just like you, find this behavior very distasteful. Recent surveys indicate that 50 percent to 80 percent of all cats throw up hairballs as often as once per month. Since most normal cats spend a lot of time licking and grooming themselves, this is not surprising.

Fortunately, there are many remedies available to reduce the occurrence of hairballs. These include medications, dietary supplements and scientifically formulated diets. You should take your cat to your veterinarian for a complete physical examination and advice regarding how to reduce the development of hairballs. Hopefully, this will not ruin your relationship with your cat.

Send e-mail to copleysd@copleynews.com or write to Pets, Copley News Service, P.O. Box 120190, San Diego, CA 92112-0190. Only questions of general interest will be answered in this column.

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