VetInfo Digest  January 2002

This Month:

Taking the Medical History

Doing the Physical Exam

Confusion over Cures

About VetInfo

 

This months note:

Have you ever wondered what was meant by the term "a zebra" in veterinary (and human) medicine?

Sometime in the past, a medical school professor said to his students, "When you hear hoofbeats, think horses, not zebras." In other words, symptoms should be related to common diseases first and uncommon diseases only when all of the common ones have been ruled out. This is really good advice and it has been repeated to every generation of medical and veterinary students since it was first uttered. Zebra has become a code word to signify a search that is going in the wrong direction. If you're looking for zebras, you're probably missing the horse standing in front of you.

Even though it really is best to look to the familiar diseases, it is also a good idea to keep an open mind, so that if you really are seeing a zebra, you recognize it for what it is. I hope that this issue of the VetInfo Digest will help you recognize normal signs and some of the more common abnormal ones. If you know what a horse looks like it helps a great deal in distinguishing it from a zebra!

 

Taking the medical history

Getting a good medical history is the first step of the examination process for dogs and cats. This is often as important, or nearly as important, as the physical examination process. Even for yearly physical examinations and other routine procedures it is important to let your vet know of any health problems you suspect may be present, any behavioral problems that you are struggling with and to address dietary concerns that you may have.

It is surprising to me how many pet owners are uncooperative about providing an accurate history for their pet's illness. It is understandable when people are unwilling to tell me that their pet has been sick for two weeks prior to bringing it into the office. But it never ceases to amaze me when I say "Why is Fluffy here today," and I get the answer, "I don't know, YOU'RE the doctor!". What your vet is asking is simple. What is the symptom, or what are the symptoms, that made you feel that Fluffy needed to be seen by a veterinarian today? A concise list of the problems is most helpful. Knowing when the symptoms first appeared can be very important so if there was a delay in seeking help it is best just to say so.

Make sure that your vet hears what you are saying. I had pneumonia once at a very inconvenient time. So I ignored it for some time. Finally I was sick enough that I simply couldn't ignore the problem any longer. I went to the doctor and he asked how long I had been ill so I told him. He didn't say anything but went off to look at the X-rays of my chest. When he came back he said to me, "You didn't get this sick in four or five days!" I don't think he believed me when I came back with, "I didn't say four or five days, I said forty-five days." I really hadn't lied but what I had said was so far out of the range of what he was expecting that he didn't hear it.

Once your vet knows the things that are worrying you, there may be a need to expand on the list and ask more specific questions. How often is the vomiting occurring? When does your dog cough? What are you feeding your pet? It is really important that you know the answer to this question sometimes, so please be prepared to answer it accurately. If you are feeding a specialized premium diet or making your pet's food it is helpful to bring a complete list of the ingredients or the dog food package if digestive problems are present.. When diarrhea is a symptom it is important to know how frequently the bouts of diarrhea occur, the general appearance of the stool and how much volume of stool is present. Please be prepared to provide some detail for symptoms like this. If you must send a child, a less involved spouse or a friend with your pet, please write down as much information as you can and send it along.

If your pet has intermittent symptoms that are unlikely to occur in the veterinary office, such as seizure activity, bouts of respiratory distress or stereotypic behaviors such as frenzied tail chasing, it can be very helpful to bring a video of the behavior or symptom occurring, if it is possible to do that.

There are many diseases that have a specific geographical area in which they occur. It is important to let your vet know if your pet has been outside of the area in which you live, especially if you have traveled to other countries or to areas in which the climate is markedly different. There are also a number of diseases that affect certain breeds more than others. If your pet is not a purebred, but you know for certain who the mother and father were, that can be important. If you don't know for certain, it is best not to guess. Just tell your vet that your dog is a mixed breed. Don't assume that your veterinarian recognizes your pet's breed readily, especially if it is one of the less common breeds. In fact, it is a very good idea to look at your receipt, rabies certificate or the medical record to ensure that your pet's age, breed, sex and even his or her name appears accurately on the records. This could be really important for pets who are taken on trips. It is awkward to find yourself at a border crossing trying to explain that Max is actually a Maxine and that the rabies certificate for a male dog is actually hers.

The medical history is an essential part of reaching a diagnosis. In some situations it is more valuable than the physical examination. If you are prepared to give accurate details about the symptoms that have occurred, travel history, dietary history and the other information listed above, you can be a great help in the diagnostic process.

 

Doing the Physical Exam

We believe that a yearly physical examination is important for pets. Most of our clients do not look at their pets in a systematic way in order to find ailments that might be present but causing few clinical signs. While we have not actually kept track over the years of the percentage of patients we find a problem the owners are not aware of, my best guess is that it is about 1/4th to 1/3rd of the patients we see. This month, I would like to cover how we do a physical examination and what we are looking for as we do it.

It is important to try to do physical examinations in approximately the same order from pet to pet or examination time to examination time. This really does help prevent a problem from being overlooked because the affected area was not examined. The following description of the physical exam is in the order that I look at my patients but an set order will work.

The first thing that I look at during an examination are the patient's eyes. I check to see if the eyelid margins are regular and free of cysts or tumors. Next I look at the conjunctivae, the pink tissues of the inner eyelids. The conjunctiva should be smooth and slightly moist. There should not be a deep red color, mucous accumulation or excessive tearing.

The sclera is the white portion of the eyeball. This should be bright white. Jaundice, or icterus, shows up first in the sclera in many dogs and cats when it is developing. It appears as a yellow background color early and becomes a golden yellow color when jaundice is severe. Jaundice usually occurs due to liver disease or internal blood loss. If the sclera is pink or red, it may indicate allergic irritation, uveitis (eye inflammation) or glaucoma.

The lens of the eye should be clear. In older dog and cats the lens appears to have a bluish tinge and there may be a visible white density in the center of the lens. This is a normal aging change that occurs because the lens becomes more compact as pets get older. It usually will not lead to blindness or major visual problems. This is most noticeable when the eye is examined with a bright light and many pet owners first notice it when they see their pet's eyes in a bright light at night.

Pets should blink when the corner of the eye is touched, indicating that the nerve pathways to the area are intact. The pupils should be the same size and the third eyelids should be retracted.

The most common cause of difference in pupil size is Horner's syndrome in both dogs and cats. Horner's syndrome occurs when there is damage to the sympathetic nervous system. The third eyelid is usually elevated on the side that has the smaller pupil when Horner's syndrome is present.

Cats and dogs have third eyelids. When looking at the eyes, the third eyelids are usually just barely visible at the inside corners of each eye. If the third eyelids are covering much of the cornea (the clear portion of the eye) they are considered to be elevated. Dogs sometimes have eversion of the tear gland on the inside of the third eyelid. This looks like a red lump that sits in the corner of the eye and is often referred to as a "cherry eye".

The iris of the eye should be uniform in color. A dark brown to almost black discoloration of a portion of the iris can be indicative of melanoma formation (a form of cancer) but can occur in older dogs and cats as a normal aging change, as well. If the iris is flat there is less chance that the discoloration is due to cancer. During most examinations we do not attempt to visualize the retina, although we will do this when it seems indicated based on findings during the examination. Recently a new ophthalmoscope has been developed that is supposed to allow for direct visualization of the retina without dilation of the pupil. If this really does work well, we may do more eye examinations during routine visits.

The lips should look symmetrical. If one lip droops there may be facial paralysis. The oral mucosa should be pink. Pale oral mucous membranes may indicate anemia or pain. When the gum is pressed the color should return at the spot that was touched within 1 to 1.5 seconds, a process referred to as capillary refill time. The teeth should be examined for chips, fractures and tartar accumulation. In puppies and kittens it is important that the baby teeth fall out when the permanent teeth erupt, so if there are two teeth in one space, the baby tooth should be removed. The oral cavity should be examined for lumps and signs of inflammation. The gumline should be checked for inflammation indicative of periodontal disease. If the gums do not come to a very fine edge that closely adheres to the tooth it is possible that gingivitis or periodontal problems are present. The gums should be moist. Tackiness of the gums is an indication of dehydration.

Dogs have 26 baby teeth and 42 permanent teeth, although there can be some variation in this number. The permanent incisor teeth come in at approximately 4 months of age and the permanent canine teeth come in at 5.5 to 6 months of age. Cats have 26 baby teeth and 30 permanent teeth. The permanent incisor teeth appear in cats at 3.5 to 4 months and the permanent canine teeth erupt around 5 to 5.5 months.

The pinna, or flap of the ear, should be examined for signs of inflammation. In many instances in which allergic ear disease is present there will be a rough consistency to the skin near the entrance to the ear canal. This is often described as "cobblestoning" due to the appearance. The tips of the ears should be examined for signs of hairloss or scabbiness. When this is present in dogs the most common cause is fly bite irritation but other problems can be the cause. In cats the most common problem leading to loss of hair on the ear tips is squamous cell carcinoma, a form of cancer. This is most common in cats with white hairs on the ears but can occur with other hair colors.

The ear canals should be clean. It is often possible to diagnose an external ear infection before examination of the ear canal with an otoscope but it is still important to examine the ear canal and to attempt to visualize the ear drum to be sure that it is intact. In some cases this is not possible without using anesthesia. Ear mites are usually visible if they are present. They appear to be small white dots moving on the surface of the ear or the exudate in the ear canal. Ear mites are a common cause of dark black exudate but are not the only cause. If an exudate is present in the ear it can be very helpful to make a smear of the exudate and examine it for the presence of inflammatory cells, bacteria and yeast to see if the cause of the inflammation or infection can be determined.

In most cases in which both ears are infected there is an underlying cause to the ear problems. The most common underlying cause is allergic disease, with both inhalant allergies (atopy) and food allergies contributing to ear disease in many instances. Hormonal diseases, especially hypothyroidism, can also lead to external ear infections. When ear disease is present it is important to look for clues that other skin disease is present during the rest of the examination.

Cats frequently develop purple granulomas in and around the ear canals. This is a sign of chronic irritation and should prompt a search for an underlying cause. Cats often have much more subtle signs of ear infection than dogs do and it is important to consider treatment whenever a cats ear canals are not clean. Tumors are not especially common in the ear canals but they do occur. In cats squamous cell carcinoma and cerminous gland adenomas or adenocarcinomas are the most common ear tumors. In dogs the ceruminous gland tumors are the most common tumor affecting ear canals. Yellow cats often have dark spots around the base of their ears or around their lips, which are normal pigmentary changes in most cases.

In dogs the trachea should be palpated (examined with the hands) and gently stimulated by applying a little pressure to see if a cough occurs. It is not uncommon for older small breed dogs to have tracheal collapse and documenting this early can help to limit confusion between coughing associated with tracheal collapse and coughing associated with heart disease. Tracheal collapse can occur in any dog breed but is more common in the smaller breeds. In cats over five years of age we also palpate along the trachea but we use it mostly as a guide to finding the thyroid glands, which are nestled right alongside the trachea. Usually they are hard to locate but when hyperthyroidism is present they are often enlarged enough that they can be easily located.

The front legs should be examined for signs of arthritis, such as a decrease in the range of motion of the joints. Flexing the joints reveals changes in the range of motion. It is often possible to palpate grating in the elbows that is suggestive of arthritis. The easiest way to identify this is to cup the palm of one hand over the point of the elbow while flexing and extending the leg with the other hand. The joints should be the same size on both legs and there shouldn't be any lumps on the legs.

A check is made for enlarged lymph nodes. The palpable lymph nodes are located at the angle of the jaw, at the point of the shoulder, in the axillary (armpit region), the inquinal region and on the back side of the knee. In most cases it is possible to locate these lymph nodes during an examination but they should not be enlarged. The two most common causes of lymph node enlargement are "reactive lymph nodes", or nodes that are responding to a disease process or other condition such as allergies, and lymphosarcoma, a form of cancer.

The chest is examined by palpation to check for lumps and to judge the pet's body score. This is an way to assess how close to its ideal weight a pet is. Ideally, it should be possible to feel the ribs with very gentle pressure on the skin and it is acceptable if the last three to five ribs are visible. The rate of respiration and the ease of respiration are assessed by watching the pet during the examination. If you feel that your pet is having some difficulty breathing at home be sure to mention it. The heart and lungs are assessed by auscultation, or listening with a stethoscope. In cats, the best place to listen for heart murmurs is directly over the sternum. In dogs most murmurs are detectable by listening to the left side then the right side of the chest. We don't have the luxury of telling our patients to "take a deep breath and hold it", so auscultation is a little more subject to error in veterinary medicine. On several occasions I have been convinced I was listening to heart murmurs that turned out to be breathing sounds superimposed on the heart sounds. This is an especially common error in basset hound and dachshund puppies.

Normal Heart Rates and Respiratory Rates:

Pet: Heart Rate in Beats/Minute   Respiratory Rate Resp/Min
   
Average for All Dogs 70 to 120 10 to 35
Puppies < 3 months 80 to 220  
Toy Breeds 80 to 180  
Large Breeds 70 to 140  
Panting Dogs     up to 200
       
Average for All Cats 120 to 140   16 to 40
Range for Cats 90 to 220    
Panting Cats     up to 300

Normal heart rates: puppy up to 220, toy to small breeds 80 to 180 bpm, large breeds 70 to 140 bpm ; cats 90 to 220 bpm (some authors say 240 bpm). Most dogs have heart rates between 70 and 120 and most cats have heart rates between 120 and 140 bpm.

Normal respiratory rates vary from 10 to 35 breaths per minute for dogs and 16 to 40 bpm for cats. It is not unusual to have an increased respiratory rate during an examination. Dogs can pant at about 200 respirations per minute and cats can pant even faster than that.

The abdomen should be palpated for lumps under the skin as well as internally. In cats it is usually possible to palpate both kidneys, much of the digestive tract and the urinary bladder easily. In dogs it is sometimes possible to palpate part or all of the left kidney and less commonly part of all of the right kidney. It is possible to palpate most of the digestive tract, the spleen and the urinary bladder. If there is liver enlargement it is sometimes possible to palpate it in either species. It is often possible to determine if there is a pregnancy by palpation but this is most reliable between 28 and 35 days of pregnancy and it is not too unusual for developing puppies or kittens to be missed by palpation. It is important in female dogs, both spayed and unspayed, to check for mammary gland tumors while checking the abdominal region. The testicles should be palpated to be sure that they are both the same size and to make sure one testicle is not significantly harder or softer than the other one. If there are differences in size or consistency of the testicles it should prompt a search for the reason why.

The rear legs are examined in the same fashion as the front legs. It is helpful to pick up the feet of all four legs and look for inflammation or infection between the toes, especially if there is any lameness. We often wait to do this until we are examining the rear legs because many dogs are more comfortable with the examination at that time and will allow us to examined the feet more easily, since this is often something that dogs resent. We try to check the nails for damage and to ensure that they are not overgrown. This is especially important for dogs with rear dewclaws because nail overgrowth is very common on dewclaws.

The rectum is examined to be sure that there are no signs of diarrhea. Gentle palpation on the edges of the rectum, at approximately the 4 o'clock and 8 o'clock positions can reveal enlargement of the anal sacs. These are present in both dogs and cats but anal sac impaction is more common in dogs. In most dogs and cats the anal sacs are expressed as the pet has a bowel movement, or can be voluntarily expressed, but in a few pets this doesn't occur and it is necessary to periodically drain the anal sacs manually. Small long haired dogs and overweight cats often have stool caught in the hair around the rectum. It can be very helpful to trim the hair short around the rectum when this is a problem, as the situation can progress to the point that the matted hair completely blocks the rectum, causing obstipation (the inability to have a bowel movement). There should be no tapeworm segments, which like rice granules when they have dried and small mobile white worms about ½ inch long when they have just exited the rectum.

We often take a pet's temperature at this stage of the examination. Some vets think that the temperature should be taken first thing, to try to limit the amount of stress the dog is in prior to taking the temperature and some vets feel that the temperature should be taken late in the examination to allow the effects of outdoor heat, car rides, etc. to wear off prior to taking the temperature. In calm dogs and cats the average body temperature is approximately 101.5 degrees Fahrenheit, or 38.5 degrees Centigrade. It is not unusual for the temperature to vary a degree or two from this average, so we tend to see a fair number of normal pets whose body temperatures are as high as 103.5 degrees Fahrenheit ( 39.7 degrees Centigrade). I have to admit at this point that we do not take the temperature of every pet on every visit because we have found this to be less useful than many other aspects of the examination.

The haircoat should be clean and there should not be areas of hairloss. When the skin is touched the pet should not react immediately with scratching motions or rippling of the skin. The skin is examined for signs of lumps and tumors. Skin lumps are very common in dogs and it is sometimes difficult to decide when it is important to do further diagnostic procedures, such as skin biopsy, for lumps on dogs. Often, a fine needle aspirate of the lump, in which a small amount of tissue is sucked up into a hypodermic needle, will allow for a diagnosis of the type of lump. Veterinary dermatologists warn that it is not possible to identify skin lumps based on appearance alone, but there are a few lumps that appear that really do have typical appearances, so it is probably not necessary to biopsy every lump or bump on dogs. Subcutaneous lumps in cats are very worrisome, though. It is probably best to biopsy most lumps that occur in cats, especially those around sites of previous vaccinations. The skin should be assessed for signs of dehydration, as well. A quick test for dehydration is to pinch up a small pouch of skin and then let go of it. The skin should snap back into place quickly. If it stays pouched up or very slowly settles back to it original shape there is a strong chance that a pet is dehydrated.

While checking the skin and haircoat it is important to look for fleas and ticks. This can be a little tricky, especially for a pet with flea allergies. Dogs and cats can remove fleas from their bodies very efficiently. In one study in which known numbers of fleas were applied to cats with flea allergies it was impossible to find a find a surviving flea after twenty-four hours, but the cats still showed signs of flea allergy as most were bitten before they could kill all the fleas. So not finding fleas during an examination is not sufficient evidence that there is not a flea problem. Since the most common forms of tapeworm in pets are transmitted by fleas the presence of tapeworm segments strongly signals the presence of fleas in the pet's environment. Ticks can be hard to find, so if you know where a tick is attached to your pet but are reluctant to remove it, show your vet where it is.

The general attitude of a pet should be assessed during an examination. Pets are usually alert in the veterinarian's office and they pay attention to their surroundings. They should respond to attention and should react, at least a little, when vaccinations are given or blood drawn. Changes in mental state should be noted during an examination if they are present and detectable.

Checking for signs of subtle neurologic damage is a good idea during physical examinations. Standing with a normal posture is a good sign that many of the nerve pathways are intact. You may notice your vet turn your pet's foot back so that the pet is standing with the foot curled up underneath, a posture referred to as "knuckling". Pets with normal neurologic function should correct this sort of posturing. When the feet are touched it should register with the pet's brain and cause the pet to look back or show some other sign that indicates it is aware of the way its foot was placed. When the thermometer is inserted the pet should react by "puckering" the muscles around the rectum. If the temperature is not taken the same sign should occur if the area around the rectum is touched lightly. The tail should have voluntary movement and should be held in a normal position. There should be some evidence of normal vision. If there is any question about this, putting the pet down in a dimly lit room that it is unfamiliar with can be helpful in determining if there is a decrease in visual acuity.

It may be necessary for your vet to do some testing during the yearly physical examination. Heartworm examination is recommended in heartworm endemic areas. It takes approximately six months for heartworms to develop into adults after they enter the dog's body from a mosquito bite. It is only possible to test for adult heartworms, so there is no reason to test a puppy for this disease prior to starting it on preventative medications. The American Heartworm Society recommends testing for heartworms every two to three years after the initial test. when using monthly heartworm preventatives or the injectable preventative moxidectin (ProHeart 6, tm).

It is not a bad idea to do a simple urinalysis whenever it is possible to obtain urine easily. This test can help to rule out kidney disease, diabetes and several of the hormonal diseases. A fecal examination can help to ensure that no internal parasites are present. The major worry from year to year in cats is the presence of roundworms that have not been suppressed by the cat's immune system. At the present time it is considered to be reasonable to deworm cats yearly if it is not possible to check a fecal sample or if cat owners do not wish to have the samples examined. Most feline medicine specialists recommend testing all kittens for feline leukemia virus since clinical signs of this virus may not show up for several years. Testing for both feline leukemia and feline immunodeficiency virus is recommended for all severely ill cats, even if they have had negative tests in the past.

A yearly physical examination by your vet is an important part of routine health care for your pet. There is no reason that you can't do a monthly physical examination at home so that you gain familiarity with your pet's physical condition and to help you detect problems as early as possible. It is a good idea to do this, but it isn't a replacement for your vet's examination. Even though I do these quick examinations of my pets at home, I still bring them to my office once or twice a year to do a more thorough examination. I want my pets to have good health care and I know that I do a better job at the office, with all my equipment, good lighting and the assistance of my staff.

 

Confusion over Cures

A recent paper published in the AVMA Journal (Margo et al, 9/2001)) reviewed four cases of spontaneous remission of osteosarcoma tumors in dogs, without chemotherapy. These were tumors confirmed through biopsy at a major university. This paper is important because it reveals that there really are spontaneous remissions from some major cancers. If these tumors had been treated in any way, it is likely that the treatment would have gotten credit for the apparent cure. Another clinical case report from Dr. Osbourne at the University of Minnesota detailed the spontaneous recovery of a dog from rupture of the bladder, without surgery. These papers point out the need to have some data on what happens naturally with many disease processes and the risk of interpreting treatment outcomes without knowing this data. It is hard to collect this sort of data, since most pet owners and most veterinarians really want to try something to cure problems, but when we do get a chance to look at unexpected outcomes without therapy, it does help to keep us honest. Over time, enough spontaneous cures should have us looking in new directions for therapy!

 

VetInfo News

Michal Justis and I started the VetInfo web site in December, 1996. Since we started, 2281 people have subscribed to the VetInfo web site and the VetInfo Digest. Some of you have renewed those subscriptions each year. This support has enabled us to continue to produce the site. With the exception of our initial investment and the few months of advertising revenue during 2000, subscribers have provided all of the monetary support for our site. We thank you for your support!

 

The VetInfo Digest is published by TierCom, Inc., P.O. Box 476, Cobbs Creek, VA 23035. The opinions expressed in this newsletter are those of Michael Richards, DVM., author. Please send e-mail for Dr. Richards to mervet@inna.net

Copyright 2002, TierCom, Inc.

This page was last edited  06/15/04

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  1. This page is authored by
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