Differentials in Canine Illness

Chronic infection or inflammation process differential

Question: Hello Michael Richards,

I hope that you can help with the following with regard to Brogan my 4 (in October) year old Border Terrier bitch.

As a puppy Brogan was fine, bouncy and playful. When she became older, 1 year plus, we noticed that she didn't seem to have much energy. We have another Border - Jake - a male who is only 4 months older than Brogan. He is so energetic and keen.

On the regular health checks at our vets, we were told that she seemed normal. Her temp and heart rate etc. were all ok.

When she was just over 2 years old I took her to the vets and mentioned her lack of energy - the vet took a blood test and the result was that her white blood cells were high. She was given antibiotics. No further treatment at that time. The vet said that she probably had a little infection and that she seemed ok.

We mated Jake and Brogan in February 2000. Unfortunately there was only one pup and Brogan had to have a caeserean. Due to unforseen circumstances the pup did not survive. The vets recommended that we have her spayed at the same time which we did. Before the operation they took blood and noticed that she had a raised white blood cell count. This was not our usual vets (long story) so when I took her to our usual vets to have her stitches removed I mentioned this.

Her symptoms of lethargy remained. She was never keen to go out for walks. Often you had to pick her up from where she was sleeping to put her lead on and even then she did not act as though she wanted to go out - walking slowly and lagging. Compared to Jake who was really keen to get out.

They took some blood and the white blood cell count was high. She went on antibiotics. Blood tested again. The count was still high. She then had further blood tests to see if there was something causing the count to be high. Tests showed some liver function failure. More antibiotics. More blood tests. The vets advised us that they need to carry out an exploratory operation and liver biopsy. This was carried out 27 June 2001. The results showed that her liver was not functioning properly (copy attached) and the vet put her on Prednisolone tablets 5mg - 2 tablets every other day. After her first dose she had blood from her vulva so the dosage was reduced to 1 tablet every other day. A blood test was carried out approx. 20 days later and there was a little improvement but her white cell count was still high. She is due another blood test at the end of this week and is still on these tablets. The vet mentioned 2 or 3 months course of tablets.

I feel that she has not improved. She still sleeps a lot, has no energy. Of course there are moments when she perks up but it is only for minutes. I have mentioned this to the vets and he says maybe we need to 'up' her dosage again but is not sure because of the initial bleeding. My vet mentioned that I could have a liver specialist look at her but this may involve operating again which we are not keen to put her through. He says that at the moment he thinks that she is ok on the tablets. To be honest I am losing faith in him.

Do you have any idea what her problem can be? My partner thinks that her problem is genetic and that there is no cure and that she is the way she is. We know from the pathology report that her liver is not functioning properly so there is a problem but I would have expected some form of improvement by now.

Lab results

Lab results are normal except for: white blood cell count increased   22,300  (normal 5,000 to 15,000) neutrophils increased      16,950  (normal 3,000 to 12,000) band neutrophils increased 1780  (normal <300) 3 normoblasts seen per 100 wbcs

total protein 99.4  (55 to 75 g/l) globulin 61.7 (25 to 40 g/l) bilirubin total  66.2  ( normal 7 umol/L) bile acids, starved  16.2  (normal <15 umol/L)

I look forward to hearing from you.

Kind regards, Jane    

Answer: Jane-

The lab work and clinical history of Brogan's problems are difficult to reconcile.

There are dogs who have high white blood cell counts, compared to normal values,  their entire life, which are just normal for that dog. When normal lab values are established, then include 95% of the values from the dogs used in the original study, who appeared to be clinically normal in the established "normal range". So this means that 1 in 20 dog is likely to have a lab value outside the normal range when testing for a single lab value or that any dog tested is likely to have one lab value outside the normal range is over 20 tests are run on a single blood sample. On the other hand, it is important to try to establish whether the value seen is just this dog's normal or whether it does represent some sort of problem.  This same line of reasoning could apply to the high bilirubin test results and especially to the bile acid test result that fell just outside the normal range.

High white blood cell counts occur in the presence of infection, inflammation, hormonal regulation disorders and white blood cell cancers. Prednisone, which is a glucocorticoid, will usually cause increases in white blood cell count because it induces a physiologic stress response, which causes rises in neutrophil numbers and decreases in lymphocytes. There are a lot more neutophils than lymphocytes in the blood stream, normally, so the net effect is an increase in white blood cell count with a higher percentage of neutrophils. Usually, this rise does not cause the release of immature neutrophils (band cells), though. The presence of increased numbers of band cells is referred to  as a "left shift" and is a strong indication of an ongoing infectious or inflammatory process. Based on the presence of the left shift in Brogan's lab work, it seems likely that there is some continuous process inciting a reaction in her white blood cell system. Usually, an infectious cause of chronic stimulation eventually causes some recognizable sign. I would worry that the blood seen after administration of prednisone could be a sign of an infection in the reproductive or urinary system,  including pyelonephritis (infection of the kidney itself).  However, I can't see where infections in these systems would also cause an increase in bilirubin in the serum. The body system most prone to difficult to discern infectious processes is the gastrointestinal system (including the pancreas and liver). It is possible for there to be long term infections and inflammatory processes that cause very few visible clinical signs, although diarrhea, vomiting, abdominal pain, variations in appetite, weight loss and constipation may occur on an intermittent or continuous basis.

Rises in bilirubin levels occur most frequently due to diseases affecting the bile ducts or liver and diseases that cause destruction of white blood cells inside the body (hemolytic disorders). Less commonly, dogs can have rises in bilirubin levels that occur due to a secondary effect on the liver of a primary disease, such as septicemia (generalized infection), toxemias and chronic inflammatory processes (immune mediated diseases and theoretically severe allergies).

I really thought when I first looked at the labwork that a hemolytic disease was likely, since the evidence of liver disease is pretty weak in the lab work.  In most cases it takes pretty severe destruction of red blood cells to produce bilirubinemia (increased bilirubin in the serum). There is no evidence for this in the lab work, either. The hemocrit is in the upper half of the normal range. While there is not a reticulocyte count included, which would indicate whether there was an increase in immature red blood cells, an indication of red blood cell destruction and regeneration, there really doesn't appear to be a strong indication for obtaining a reticulocyte count, either.

There was an interesting note about the presence of normoblasts in the smear. One of the reasons it is interesting is because I am not sure what it means. If it means there were three nucleated red blood cells per 100 wbcs (which is what I think it means), then the overall white blood cell count would be approximately 3% lower (not too significant) and that the body is releasing red blood cells prior to their full development (could be significant). Lead poisoning often causes increases in the number of nucleated red blood cells in the blood stream, as an example of the possible importance of this finding. Other things that can cause this sign include splenic disease, formation of red blood cells in tissues outside the bone marrow, hyperadrenocorticism (including prednisone administration, since it is an artificial means of increasing cortisol levels), leukemia and bone marrow inflammation or disorders.

The bile acid levels running just above normal would indicate a need to do bile acid response testing, to me, unless the value is from a blood sample taken within a few hours of a meal. This test is done by fasting a patient for 12 hours, then drawing a blood sample for the first bile acid level. A meal is then fed immediately and blood is drawn again in 2 hours for the second sample. Normally, the second sample will have higher bile acid levels than the first sample. If there is a significant rise, it indicates that the liver is not functioning as well as it should.

Globulins are antibodies, primarily. So the high globulin level indicates a level of chronic infection or inflammation sufficient to stimulate the overproduction of disease fighting proteins by the body. Since these are high, there is a rise in the total protein level.

OK, so that covers the abnormal lab work. What it says is that there is a chronic inflammatory or infectious process that has not responded to antibiotic therapy, spaying her (so her uterus is not the likely spot for an undiagnosed infection) and was not obvious on exploratory surgery. There was some sign of inflammation/infection in the samples taken from the liver but it is hard to be sure that this is significant enough to cause the total picture -- but it could be.

If the liver findings are viewed as only part of the problem, at least for the process of thinking through the clinical signs and the lab work, we have to ask what else might be going on that would lead to chronic stimulation of the immune system, an apparent lethargy or lack of energy and could go on for a couple of years without causing an an obvious clinical symptom to help in diagnosis.

The disorders that come to mind when thinking along these lines are chronic pancreatitis, inflammatory bowel disease, food allergies, hypoadrenocorticism, lead poisoning (although it is hard to figure out how she could be exposed and not Jake), hyperadrenocorticism (unusual in a dog her age), hepatic microvascular dysplasia, cholangiohepatitis (infectious or immune mediated), chronic immune mediated hepatitis (sometimes referred to as chronic active hepatitis), bile duct obstruction, gall stones (not too common in dogs), liver cancer and perhaps some cause of hemolytic anemia that is so chronic it is being masked by sufficient red blood cell production -- although I think this is a real stretch. There are probably some things that I am not thinking of.

To work through this set of problems may take redoing some of the things that have already been done and doing some additional testing, as well.  I know that this might be a really frustrating process, especially since there is some chance you won't get an answer by doing that. There are a few things that are relatively easy to do that seem like they are worth trying, though.

First, I think it would be worth redoing the complete blood cell count and adding a reticulocyte count. That isn't too expensive. Your vet can then call the lab if the normoblasts show up in this sample and talk to the pathologist at the lab about what that might mean. The pathologist can be very helpful in some cases in interpreting lab work and often have more to say on the phone than they are willing to put down on paper.  I think it would be worthwhile to do a bile acid response test, too. While doing this, running a general chemistry panel that included electrolyte measurements (sodium and potassium especially) could be helpful in ruling out hypoadrenocorticism. It would be an unusual problem but it does cause chronic long term illness and is difficult to rule out entirely without checking for it in a patient with a long term history of lethargy and vague illness. If the panel also included amylase and lipase levels it would help to rule in, or rule out, pancreatitis (but not entirely).

At this point, the redoing and reconsideration measures get a little harder. Try to think about any potential source of lead (old lead paint, caulking, fishing gear, lead shot, etc.). If no source is likely this possibility can probably be discounted since it is unlikely, anyway.  It would be a good idea to have an abdominal ultrasound examination to see if there is evidence of inflammatory bowel disease, pancreatitis, nephritis (just to be sure the kidneys weren't the source of the bleeding) and to recheck the liver. A bone marrow aspirate might be a reasonable test to consider, too, given the long history of white blood cell count elevations. It may be worth considering the possibility of inflammatory bowel disease. A food trial (hypoallergenic diet like Hills z/d tm or Purina HA tm) to rule out food allergies might be a reasonable choice to start this process, even in a dog with some liver involvement. Endoscopic examination of the digestive tract and biopsy of the tract during that procedure could be helpful and might also allow visualization of the junction of the bile ducts and intestine to determine if there is a problem there.  In some cases, the only way to rule in or rule out inflammatory bowel disease is to get full thickness intestinal biopsies, which would require a second exploratory surgery. If this is done, it would be a good idea to check the uterine stump for signs of a stump pyometra (unusual but does occur), to look at the kidneys and urinary tract carefully, to get a biopsy sample from the pancreas (vets don't like to do this but if a second surgery is necessary it should be considered), to get the intestinal samples and to get additional liver samples. Checking the gall bladder and visible bile ducts carefully would also be a good idea. In addition, it might be worthwhile to take bacterial culture samples from the liver and/or bile ducts while they are accessible. Obviously, I think everyone would like for redoing the exploratory surgery to be an absolute last resort. Getting the opinion of an internal medicine specialist who has an interest in liver disease might make it possible to avert this last step in some cases and I definitely think I'd recommend that to my clients prior to redoing the surgery. Also, I might prefer that the specialist be part of the team redoing the surgery, just to be sure that the best possible samples are taken. To be honest, I probably wouldn't be too keen on doing the surgery again if the other liver values (ALT, alkaline phosphatase, bile acid response) were not indicative of a major problem.

Personally, I am not a fan of prednisone for most liver disease, although it can be helpful in chronic immune mediated liver disorders. When I am pretty sure that something other than the liver isn't causing the problem and I am faced with a "mystery" liver disease because I don't have a definitive diagnosis, even after biopsy of the liver, then I tend to start out treating the stuff that I think might be curable and then work up to treating the problem as a chronic illness. Usually, I prefer to start out with long term antibiotic therapy when there is evidence of infection or inflammation that might the a reaction to infection, usually six to eight weeks of antibiotics and to use ursodiol (Actigal Rx) to try to stimulate bile flow. Lately we have also been using SAMe (Denosyl SD4 tm and generics) since it seems safe and is reported to help in many instances of liver disease. If this doesn't cause an improvement in the clinical symptoms and/or the lab work in after a couple of months then we would move on and we would probably try prednisone at that time (or earlier if it was obvious that the disease was progressive while we were doing other things).

I hope that this isn't so long that it just confuses the issue.

To get to a sort of bottom line, the most likely cause of a rise in bilirubin without a serious rise in other liver values, if hemolyis is not occurring and a primary disease affecting the liver is ruled out, is a bile duct obstruction. The most likely cause of bile duct obstruction is chronic pancreatitis, chronic inflammatory bowel disease (including food allergy even though it isn't highly likely) or bile duct infection. Trauma and perhaps a congenital disorder are also possible. So I would want to concentrate on trying to rule out these problems. Since infection might respond to antibiotics it seems like a reasonable first approach, except that antibiotics have been tried. I like amoxicillin (or amoxicillin/clavulonic acid) and metronidazole for initial liver disease problems but if these have been tried,  fluoroquinolones might be another good choice if they haven't also been tried. These are just general recommendations from the literature, it is best to base antibiotic choice on culture results if possible, although it is hard in a case of liver disease since the samples are hard to get. If antibiotics don't seem like a reasonable choice to you and your vet, then ultrasound examination is a relatively non-invasive approach to looking into these problems and repeat exploratory surgery is also a possible option. It makes sense to me to consider referral to an internal medicine specialist for the ultrasound examination since they have more experience with these than most veterinarians and it definitely would be something I would do prior to redoing the exploratory surgery. If the internal medicine specialist suggests doing the surgery again, you don't have to go along with the suggestion, you would just know that you were at an stopping point in the diagnostic process at that point.

Prednisone often leads to a weight gain when it is used. So if the weight gain came after the prednisone usage I would suspect it as the cause. If it was going on before the prednisone usage the weight gain is probably not a major factor in the process of thinking through what is going on  but could happen with hyperadrenocorticism, could be due to hormonal changes after spaying since excessive weight gain occurs in some dogs (5 to 10%) after spaying and it could just be an indication that whatever disease is present isn't bothering Brogan too much.

I hope this helps you think through this problem.

Mike Richards, DVM 9/18/2001    

Excessive drinking and urinating

    Question: Dear Dr. Richards:         Since March or April, my 3 year old- female spayed- chocolate lab has been drinking over 3     liters of water daily.  Whenever I fill her bowl, she  drinks it down.  Because of the amount of     fluid she drinks, she 'leaks' in her sleep and sometimes urinates in the house because she     can't hold it.         She weighs 70 lbs. and is not overweight.  She stays in an air conditioned house and is not     outside unless I'm with her.  My veteranarian has done tests for Cushings syndrome, Diabetes-     both urine & blood test for diabetes incipitus- thyroid tests, specific gravity, a test to see if she     can concentrate her urine, even a test for an undetected liver shunt.  She is currently on     'Wellness' fish and potatos diet- which is an allergy diet.  She has had 2 urinary tract infections     in the past which also caused her to have accidents in the house and drink alot, but her urine     tests came back clean.  This left my vet to conclude that she has a psychological problem and     that is why she is drinking so much. My vet suggested giving her challenging toys because she     may need more mental stimulation.  (I do take her to the park almost every morning to run in     the woods and socialize with other dogs. I also play with her in the afternoon and she gets a     half hour walk.) She is usually only alone for no longer than 5-6 hours per day.  We also have a     1 year old black lab who we are raising for Canine Companions for Independence.  We have     had her since last June and she will be leaving us at the end of July.         Could there be any other conditions that could be tested for? Could it be psychological and if     so, what can I do? Please let me know if you need to know exactly which tests were     performed.     Thank you for your suggestions.     Vicki & Bear

Answer: Vicki-

  This a list of disorders that cause increased drinking (polydipsia) and increased urinating   (polyuria) -- often referred to as pd/pu in veterinary circles. It may be helpful in sorting out the   possible causes of the excessive drinking that you are observing. I have tried to break it down   a little into "young dog" and "older dog" causes:

  Younger dogs:   kidney disease, liver disease, leptospirosis, pyelonephritis, pyometra (uterine infections --   occur rarely in spayed dogs but do sometimes occur in them), Fanconi's syndrome (Basenjis   are prone to this, not too common in other breeds), medication side effects (especially   corticosteroids), polycythemia (too many red blood cells), hypoadrenocorticism, diabetes   insipidus, bladder stones or other urinary obstruction and behavioral or psychogenic water   drinking.

  Older dogs:   hyperadrenocorticism, kidney disease, liver disease, leptospirosis, pyelonephritis, pyometra,   medication side effects (esp. diuretics and corticosteroids), polycythemia,   hypoadrenocorticism, hypothyroidism, hypercalcemia (usually from cancers), diabetes   mellitus, hyperthyroidism (rare in dogs, common in cats), low serum potassium levels (not too   common in dogs, common in cats), bladder stones or other urinary tract obstructions, cancers   (pheochromocytoma esp.), acromegaly, heart failure (diuretic use and pericardial effusions),   diabetes insipidus and behavioral or psychogenic causes.

  There is a lot of cross-over in the lists, obviously. Your vets have already tested for the   common causes of this condition.

  A somewhat logical approach to PU/PD behavior is to run a general blood chemistry panel   and cell count. If there is no evidence of polycythemia or infection based on the cell counts   and no abnormalities in the blood chemistry tests and a urinalysis is also normal, except   perhaps for specific gravity, then the diagnostic effort should be centered on ruling out the   causes of diabetes insipidus (kidney or brain origin) and hormonal diseases (Cushing's,   diabetes mellitus, hypothyroidism). If the results of testing for all of these problems seem   normal,  then pyschological PU/PDis most likely.  If there is evidence of a problem with the   kidneys or liver, such as increased blood urea nitrogen and creatinine (kidney) or increased   ALT and alkaline phosphatase (liver) then exploring these possibilities is best.

  Your lab is young for hormonal illnesses but these are the most aggravating to rule in or out,   since lab testing is specific for the illnesses, it is often expensive and a negative result doesn't   completely rule out these problems. We have had dogs have normal tests but continue with   clinical signs and then show up with positive results on tests a few months to a year or more   later.

  If you and your vet are convinced that there is not an underlying problem it is reasonable to   try behavioral medications along with the behavioral treatments your vet has recommended.   Clomipramine (Clomicalm Rx) or fluoxetine (Prozac Rx) might be helpful if separation anxiety   is playing a role in the PU/PD behavior.

  I know that it is frustrating to do testing and then have to do it all over again but you should   not rule out doing that if this behavior continues. Pretty often a second set of lab work will   show something the first set did not show.

  Good luck with this.

  Mike Richards, DVM   8/9/2001    

Differential for eye and balance problem in Golden mix

Question: My sons dog woke up one morning with a red right eye that doesnt blink and started drooling from her mouth. She seemed off balance in the beginning, but that seems to have gone away. Now she started the same symtoms on the left side of her face. They thought it was an ear problem which its not and suggested an MRI. They are not sure whether to do that or not. Any suggestions what it might be or where she can go for these unusual problems? They live in San diego and adopted this dog about six months ago. The vet feels the dog is about 4-5 years and looks to be a mixture of golden and maybe some lab or chow. She weighs about 80 pounds. I would appreciate any thoughts on this proble.  

Answer: Several possible conditions come to mind with the signs you are seeing.

Golden retrievers are prone to facial nerve paralysis. This usually occurs on just one side but it can occur on both sides. It makes it hard for the dog to blink, leading to sore eyes and causes the lips to droop, leading to salivation. In this breed, hypothyroidism is associated with this condition but that may just be coincidental, since they are prone to both problems. I would be worth considering this possibility, though. The facial paralysis often occurs for no apparent reason, which could explain why your son's vet is not finding much wrong. Our experience with facial nerve paralysis is that sometimes it clears up on its own but sometimes it doesn't. Usually it will go away within a month or two if it is going to do so.

Inner ear infections can cause facial paralysis but also usually only cause this problem on one side.

Myasthenia gravis sometimes causes facial muscle weakness as a solitary sign (or combined with laryngeal paralysis or megaesophagus) prior to generalized muscular weakness occurring. If there is any evidence of general muscular weakness, especially associated with exercise, this would be a strong consideration, since it is also pretty common in golden retrievers.

Trigeminal neuropathy might be present instead of facial nerve paralysis. Usually the lower jaw drops with this condition but that may be hidden by the lips. Sometimes Horner's syndrome occurs in conjunction with trigeminal neuropathy and that causes the third eyelid to rise on the affected side, which might be the redness in the eye. This condition occurs for no known reason, too. Fortunately, it usually resolves on its own within two or three weeks.

Rabies has to be a consideration but if vaccinations are current it is not likely.

Just about all of the hormonal illnesses, hypothyroidism, hypoadrenocorticism, hyperadrenocortisicm, diabetes, etc. have been associated with instances of facial nerve paralysis, so if there is any evidence of a generalized health problem, testing for these disorders may be reasonable.

Brain tumors are always a possibility but I'd sort through some of these other things before getting an MRI done. Waiting to see if the problem will resolve on its own in a week or two is reasonable too, if the dog is adapting OK and not showing other signs of serious illness.

Mike Richards, DVM 6/30/2000


Crying after eating - differential diagnoses

Question: hi - i got into the cybervet because i have a 13 year old westie who is now crying after she eats.  she walks around with her pillow in her mouth wailing for @ 15 minutes, no matter how much food i give her (tsp or plate).  she has been to the dog psychiartrist in the past for faking limping, but i would never forgive myself if she had a stomache problem and i dismissed it for that.  also, she has a malignant tumor in her arm pit 1.5 years ago, so i wanted her checked out.  my regular vet in on vacation until 8/11 so i took her to the associate who said she was faking for attention.  i am not comfortable with this, so i am taking her to the regular doctor when he returns.  do you think this is a real problem?  please help!!!

Answer:  L.-

 You should watch very very carefully for signs of swelling around either  eye with the symptoms you are seeing. There are a number of potential  causes for pain around the time of eating but the most serious one is a  retrobulbar abscess, or an abscess that forms in the space behind the eye.  These can cause serious problems fairly quickly, including blindness and in  severe cases, death. In most cases, dogs with retrobulbar abscesses are  really pained by having their mouths opened -- some dogs refuse to allow  this and others just scream when someone attempts to open the mouth beyond  a certain point.

  Our dog had a retrobulbar tumor and had similar signs -- but she would  open her mouth part way before it hurt. She continued to eat but sometimes  acted as if she was in pain afterwards. So this would be a concern, too.

 Dogs that have periodontal disease will sometimes have pain but I can't  recall a patient having severe pain for fifteen minutes after eating.

 Dogs with marginal liver function can have behavioral changes associated  with the period immediately after eating. In severe cases this can cause  severe neurologic signs, including stupor or seizures.

 Older dogs get a condition known as canine cognitive dysfunction that can  cause odd behavioral signs. We have one patient in our practice who wailed  for ten to fifteen minutes at a time, several times a day who responded  well to selegiline (Anipryl Rx), the medication approved to treat this  condition.

 Gastic problems are conceivable, as well.

 Westies are prone to craniomandibular osteopathy. If she had difficulty  with this as a puppy, there is some chance that she has arthritis in the  mandibular joints now. This can happen without having the craniomandibular  osteopathy, too. Recognizing TMJ in dogs isn't easy, since they can't  complain effectively.

 I think that it is worth continuing to look for a medical cause of this  problem, personally. I am sorry that the list of differential diagnoses for  the symptoms is long enough to make it difficult to search through. Please  keep checking to be sure she can comfortably open her mouth and that there  is no visible swelling around one eye. If these signs develop, don't wait  for your regular vet.

 Mike Richards, DVM 12/20/99  

Response: what are you taking about!!!???   IF she has all these problems?  i asked you a question.  i guess i appreciate the care you took in that but aren't we getting a little carried away?!  

Answer: L-

The only way to really figure out what is wrong is to consider all of the possible problems --- I don't think that all of them are likely to occur in a single patient but the big risk is not to think about one of them and to miss it because of that. Once a list of the potential causes can be constructed then it is possible to eliminate individual potential problems by the lack of supportive signs for that condition.

To give you an example, using the list that I constructed of possible differentials:

1) retrobulbar abscess or retrobulbar tumor

        is there swelling around the eye? pain on opening her mouth?

        if not, then these are less likely

2) periodontal disease

        does she have excessive tartar? mouth odor? bleeding from her gums?         loose teeth?

        if not, then this isn't too likely

3) liver disease

        do blood chemistry values support this diagnosis? is she jaundiced?         if not, then this isn't too likely

4) canine cognitive dysfunction

        has she forgotten she is supposed to go outside to urinate and defecate?         does she stand at the door and go out and then come right back in?         does she forget about mealtimes? have other odd behaviors that are new?         does she act confused or vocalize for unexplained reasons?

        if not, this diagnosis is less likely

5) temporomandibular joint arthritis

        this one is pretty hard to eliminate without taking X-rays -- and even         then it can be hard. it would be easier if dogs could talk, sometimes         if there is the perception that pain exists, it may be beneficial to    use a pain relief medication just to see if it helps.

6) gastrointestinal disease

        are there any other signs, such as regurgitation, vomiting, diarrhea         weight loss?

        if not, this is less likely, too

It is likely that I have not thought of all possible problems --- but the point is that it is necessary to consider all of the problems that could lead to a particular clinical sign and then to eliminate them based on the presence or absence of other clinical signs.

I didn't mean to worry you --- just to tell you that I supported your perception that there really could be a medical cause that may have been overlooked because your vet wasn't thinking about all of the possibilities.

It is hard in practice because we have to deal with a lot of variability in both the pet's ability to mimic illness and the owner's perception of when their pet is ill, which can vary widely. I have some owners who worry easily and bring their pets in when they are just a little off -- and other owners who if they call me I know that their pet is already in the midst of a medical crisis. If your vet knows you well and thinks you are in the first category, then he or she is going to put less weight on your perception of the illness and look for obvious clinical signs. The problem is that once in a while, your perception is going to be right when the clinical signs are slight ---- so you have to be willing to schedule more rechecks than the person who waits until their pet is actually bleeding or actually comatose prior to coming to the vet.

The thought process outlined above doesn't take very much time after making the list -- it is usually easy to eliminate many of the possible problems. So I don't look at it as getting carried away but as being careful.

Sometimes when one of my clients has paid for X-rays and lab work and a couple of rechecks and I tell them I really think their dog is normal, they think I got carried away, though. Deciding how far to go in looking for problems is one of the things that makes veterinary medicine challenging and difficult.

Mike Richards, DVM 12/20/99  

Liver Shunts

Signs of portosystemic shunts include poor weight gain, sensitivity to sedatives (especially diazepam), depression, head pressing (pushing the head against a solid object), seizures, weakness, salivation, vomiting, poor appetite, increased drinking and urinating, balance problems and frequent urinary tract disease or early onset of bladder stones. If the signs of problems increase dramatically after eating this is a strong supportive sign of a portosystemic shunt. Mike Richards, DVM    


Anemia occurs for a number or reasons but they break down into two major categories. Either blood is not being made in the first place (nonregenerative anemia) or else it is being destroyed in some manner even though it is being made by the body. If the destruction outpaces the production, anemia occurs.

Kidney failure, bone marrow disorders, some cancers, some toxins, inherited disorders, ehrlichiosis, drug reactions and iron deficiency can all lead to non-regenerative anemias.

Liver failure, heat stroke, iron deficiency, trauma, immune mediated hemolytic anemia, drug reactions, babesiosis, hemobartenollosis, inherited hemolytic anemias, intestinal parasites (hookworms, esp.) and bleeding disorders (such as von Willebrand's disease) can all lead to regenerative anemias. Even severe flea infestation can cause significant anemia in young dogs. Mike Richards, DVM    

Bacterial Skin Infection

Q: My friend has an 8 year old female Samoyed with a skin problem The vet is treating it with antibiotics and the dog has been on them for 4 weeks. Started at tail with skin becoming scaly in spots. After shaving affected area skin appears to have brown rings on it. Areas clear up and hair grows back but then new areas appear on other parts of the body. We thought with the antibiotics the condition would not spread. But it is. Do you have any idea for alternate treatment? Diane

A: Diane- I would still be suspicious of a bacterial skin infection with the signs you describe, so continuing the antibiotics seems like a good idea to me. It might be worth attempting to get a culture from a skin lesion to identify the bacteria involved and get an idea of what antibiotics kill it, if this is possible. Sometimes this doesn't work and often it is expedient just to change antibiotics, making sure to stick to ones that have a good track record of helping with skin disease. Sometimes the bacterial infection has an underlying cause, such as allergies, immune mediated disease, systemic illness or skin parasites. Checking for these conditions may be necessary if the problem continues. There are veterinary dermatologists and it can be worth the drive to one for difficult skin problems. They see the resistant and atypical cases of skin disease and often can pick up patterns of disease not apparent to a general practitioner or do specialized testing not available at many veterinary offices.

Mike Richards, DVM  

Brain Tumors

Brain tumors often have identifiable clinical symptoms since they often damage nerves exiting the brain or the centers that control these nerves. Gait abnormalities, facial paralysis, vestibular disorders, blindness, or other signs of nervous system damage may occur with a brain tumor, helping to identify it.

Mike Richards, DVM  


Coughing - small dog

The most common causes of coughing in older small dogs are probably heart disease and collapsing trachea problems. Sometimes there are other problems, such as cancer or pneumonia. I think I would lean towards taking X-rays first since these are less invasive and rule out more problems but perhaps your vets have already done these or were planning to do X-rays at the time of bronchoscopy. If the X-rays are not helpful in delineating the problem then bronchoscopy is a good idea and can be very helpful.

Cushing's disease can contribute to heart problems and could cause coughing to develop in that manner. It probably is not helpful in cases of collapsing trachea, either, since it can lead to muscular weakness which could contribute to the problem. Mike Richards, DVM  

Coughing - intermittent

It can be really hard to identify a cause of an intermittent cough. It is possible to spend a great deal of money on various tests to find out that your dog does not have an identifiable problem -- or that he or she is "normal". On the other hand, the only way to figure out what is going on is to start eliminating possible causes, which means that the palate, larynx, trachea, lungs and heart all have to be examined carefully and that tests such as occult heartworm exams, X-rays, ECGs, endoscopy, bacterial cultures and examination under anesthesia may have to be done. Some dogs cough because of intestinal parasite migration, so fecal examination will sometimes reveal a clue. I don't mind testing until I find an answer as long as the pet owner is willing and understands that the answer might be "I don't know". Unfortunately, I have lost some clients after several hundred dollars worth of testing didn't reveal a treatable cause of coughing (or itching, or behavioral changes, or ... :)

Mike Richards, DVM  


All dog breeds are susceptible to various forms of encephalitis. Canine distemper and rabies are viral forms of encephalitis. A few unfortunate dogs develop encephalitis as a reaction to distemper vaccination. Bacterial and fungal encephalitis can occur, protozoal infections can lead to encephalitis and it sometimes occurs for no apparent reason in conditions such as granulometous meningoencephalitis. Mike Richards, DVM    

Epilepsy and seizure.

Epilepsy is a term used to describe seizures that can not be explained by identifying a source of the seizure activity. So it is a pretty broad term really. It covers any unidentifiable brain disorder that leads to seizure activity. Congenital epilepsy normally shows up in by the time a dog is two or three years of age.

Brain tumors are possible in almost any case of seizuring but brain tumors often have some other identifiable clinical symptoms since they often damage nerves exiting the brain or the centers that control these nerves. So gait abnormalities, facial paralysis, vestibular disorders, blindness, or other signs of nervous system damage may occur with a brain tumor, helping to identify it. Viral illness, fungal diseases, trauma, vascular disease or other problems can also lead to seizures by direct effects on the brain. Liver disease, kidney disease, and hormonal disorders cause seizures by more indirect effects. When nothing is found we fall back on the term acquired epilepsy to define the problem, even though it really just means we can't identify the problem.

Seizure control is usually possible. When to start is a issue of some debate among veterinarians. The standard rule of thumb has been to use seizure control medications (usually phenobarbital) when seizures occur more than once a month. Some veterinarians feel that it is wiser to start sooner than this because it appears that "mirroring" and "kindling" of seizures can occur in dogs. Mirroring is when a seizure focus occurs in one side of the brain and then an identical site occurs in the other side of the brain after several seizures. Kindling is when the seizure focus in the brain develops strong enough pathways that it makes it easier for the seizure to occur -- almost as if the brain "learns" to seizure. It is possible that by controlling seizures quickly through the use of medications that these effects could be stopped and that may lessen the amount or duration of need for seizure control medications.

We try to decide on an individual basis what the potential for all of these risks are, whether the pet owner can administer seizure control medications on a set schedule and the risks of the medications themselves. Then we decide when to start attempting to control seizure activity. If a dog has a really violent seizure we may start immediately. If there is a mild seizure and then subsequent seizures occur at long time intervals we may never attempt to control them. This decision just has to be made on a patient by patient basis.

Mike Richards, DVM    

Increased water intake and urination

There are several causes of an increase in water intake and urination in dogs, especially older dogs.

Drinking more water can be seen with Cushing's disease, kidney failure, diabetes mellitus (sugar diabetes), hypothyroidism, diabetes insipidus and several other conditions. Dogs being treated with corticosteroids also drink more water.

In a female middle-aged poodle the two most likely causes are diabetes mellitus and Cushing's disease. These two diseases occur simultaneously at times, as well.

Diabetes usually results in increased hunger, at least early in the disease, and excessive drinking of water and urinating. After a while, there begin to be signs of poor nutrition, such as haircoat changes. Diarrhea is not uncommon with more advanced diabetes. Early cataract formation can occur. Increased susceptibility to disease and poor healing are additional signs.

Diabetes is relatively easy to diagnose. Sugar in the urine and high blood sugar values pretty much confirm diabetes. No special lab tests are required. Cushing's disease is also fairly easy to diagnose but it does require specialized testing. This is a disease in which the adrenal glands produce too much adrenal hormones. The best test for spontaneous Cushing's disease is probably the dexamethasone suppression test. In this test, blood cortisol levels are measured as a baseline. Then dexamethasone is administered at a very low dose. In most dogs, this level will produce suppression of adrenal hormone and the blood cortisol level will drop significantly within 6 to 8 hours. Blood samples drawn at that time should be very low in cortisol. If they are not, then Cushing's disease is very likely. Your vet will have dexamethasone and can run this test.

As a screening test for these diseases, urinalysis is pretty useful and inexpensive. Sugar in the urine would be indicative of diabetes. Low urine specific gravity would hint towards Cushing's disease. If this is a consistent finding on several tests it is even more likely to be present.

The first step is eliminating diabetes mellitus as a possible cause. Then you and your vet can discuss the rest of the symptoms and decide whether to run general bloodwork and possibly the more specialized testing for Cushing's disease (hyperadrenocorticism).

Mike Richards, DVM  

Lymph nodes

 The lymph nodes under the jaw (usually at the junction of the jaw and throat, not actually at the chin area) collect lymph drainage from the head region. When they are inflamed it is a good idea to look for problems in this region. Chronic ear infection, tooth disease, sinus infections and problems of this sort are all possible. In some cases lymph nodes enlarge when allergies are present and sometimes they enlarge for no discernible reason.

Mike Richards, DVM  


Nosebleeds can occur for a lot of reasons. In older dogs a major concern would be nasal tumors or nasal infections. Tumors can be pretty hard to find even with endoscopy and X-rays in some cases but the tests for this make it less likely. In any age dog bleeding disorders need to be considered when nosebleeds occur. Ehrlichia canis, immune mediated thrombocytopenia, immune mediated hemolytic anemia and other causes of bleeding should all be considered. In older dogs a fairly common cause of bleeding disorders is hemangiosarcoma, a type of tumor. Heartworms can cause nosebleeds in the later stages of the disease. It can be difficult to identify the cause of bleeding disorders.

Mike Richards, DVM    

Neurological Problems

loss of balance, nystagmus (the rapid eye motion), freezing in place

This is a list of possible problems that I can think of that could potentially produce the symptoms you are seeing. Some of this list is very unlikely to cause only the symptoms you are seeing but it helps me to make a big list and then eliminate stuff from it, based on lab tests or as much common sense as I can muster (my staff is convinced that they represent the sole source of common sense available to me at a times).

Lack of oxygen to the areas of the brain controlling balance. This could happen because of traumatic injury to the region, blood vessel damage or blood clotting. It can also happen from things like carbon monoxide poisoning but that is probably not too likely with the chronicity of the symptoms. Lack of glucose getting to the areas of the brain controlling balance. This isn't all that unlikely in an older dog but I think hypoglycemia is more common in females. Increase in any metabolic toxin (kidney failure, liver failure, electrolyte imbalances). Increase or decrease in necessary metabolic hormones -- too much adrenal hormones (Cushing's disease) or too little (Addison's disease). Too much thyroid hormone (this is almost always due to excessive administration of the hormone in dogs) or too little (hypothyroidism). Toxins that affect the brain. Lead, other heavy metals, ethylene glycol (anti-freeze), fungal toxins and insecticides. Most of the time, people know that exposure to these is possible and there are usually lots of other signs, but lead can lead can be deceptive and fungal toxins (mycotoxins) are probably rare but would also be hard to know about. Peripheral vestibular syndrome (also known as geriatric vestibular syndrome and idiopathic vestibular syndrome and also often mistakenly referred to as a "stroke"). This syndrome occurs in any age dog but more commonly in older dogs. It has exactly the signs you are seeing but it is not usually episodic. It normally occurs suddenly and then takes a few days to a few weeks to disappear. However, we have seen a syndrome almost identical to what you are describing in a German Shorthair Pointer who did eventually recover completely, as far as we could tell. Almost all dogs do recover from this condition without treatment. Brain tumors. There is a saying "cancer does what it wants". Almost any neurologic symptom is possible with brain tumors. Granulometous meningioencphalitis (GME)is the last thing I can think of. This is a poorly understood (at least by me) nervous system disorder that leads to lots of bizarre neurologic signs, including nystagmus and episodes of balance loss or seizure activity. I know of no sure way to diagnose this disease in a living dog but making sure nothing else is causing the problems and then a good evaluation by someone familiar with the disease is helpful (i.e. -- a veterinary neurologist). I know that is a long list but it may explain why your vet and the internal medicine specialist are not able to provide a definite diagnosis.

Whether or not to go further with diagnosis depends on several factors. Eliminating all the easy diagnoses is possible through routine labwork and minimal specialized testing. It might be a little expensive but your vet can do all the necessary testing. Peripheral vestibular disease should clear up in a few weeks. If it doesn't, that leaves the things like brain tumors and GME. The question would then come down to whether or not you would consider brain surgery if that seemed possible. If so, going to a neurology specialist is definitely worthwhile. If not, there is less need unless you just have to know what is happening. I usually find myself needing to know as much as I can when I am trying to deal with difficult situations involving my pets but not everyone feels that way.

Mike Richards, DVM  

Panting excessively

Panting excessively is a sign of Cushing's disease (hyperadrenocorticism), may show up with other hormonal diseases such as hypothyroidism, can occur with heart disease and is seen with conditions that result in lowering of the body's ability to carry oxygen -- but most of these are not long term problems. One example would be hemorrhage associated with hemangiosarcomas. We have seen a couple of these in which the owners recognized panting as the first clinical sign. There is usually an acute crisis shortly after that, though. Panting is commonly seen in dogs being treated with corticosteroids such as prednisone.

Mike Richards, DVM    

Rectal Bleeding

Rectal bleeding may be the result of a number of problems. Probably the most common causes of this are mild constipation leading to hard, irritating stools, colitis and proctitis. Dogs get rectal polyps which can lead to intermittent bleeding. Tumors can occur around the anus or in the colon. Rectal fissures and anal sacculitis can lead to intermittent rectal bleeding. The constipation/colitis problem can sometimes require a bit of a workup and rectal polyps can be pretty frustrating to find without an endoscope. Dogs have rectal bleeding at times for no apparent reason. Most dogs with occasional rectal bleeding do not have serious problems as a result of it.

Mike Richards, DVM    

Regurgitation behavior

If the regurgitation occurs immediately, esophageal problems seem likely. Megaesophagus is one possibility. Other possible problems include persistent aortic arches (though most puppies with this condition don't grow well), hiatal hernias, esophageal diverticulums and gastroesophageal reflux.

Vomiting should occur immediately upon eating any solid food with persistent aortic arches and starts as soon as the puppy begins to eat solid food. Gastroesophageal reflux is caused by a number of conditions and it usually is associated with weight loss or slow weigh gain as well.

If the regurgitation is delayed a little after eating, stomach problems may be more likely. In this case, pyloric stenosis and gastritis may be more likely. Testing for these conditions usually involves using barium or other contrast X-rays and possibly endoscopy

.Mike Richards, DVM    

Seizures - causes

Trauma -- even if it happened a long time ago, primary epilepsy, infectious diseases, shunts in the liver circulatory system, low blood calcium levels, low blood sugar levels, high blood sugar levels (diabetes), kidey damage, toxic substances (antifreeze, lead, insecticides and strychnine are the ones we have seen causing seizure activity), liver failure and possibly hormonal disorders such as Cushing's disease and hypothyroidism.

There are also things that people sometimes mistake for seizures. These are heart disease causing fainting, sleep disorders (narcolepsy), peripheral vestibular syndrome, inapparent sources of pain leading to odd behaviors, muscle tremor disorders and obsessive/compulsive disorders that lead to repeated behavior patterns.

Mike Richards, DVM    

Older dog urinating in house

When an older dog who has been well trained in the past begins to urinate in the house it is always a good idea to have a physical exam done to make sure that there is not a physical cause for the problem. When the change in urinary habits is accompanied by an increase in drinking and urinating, a lab work up should be done. Diabetes mellitus, diabetes insipidus, kidney failure, hyperadrenocorticism, hypothyroidism and several other conditions can lead to an increase in drinking and urinating -- and sometimes this is sufficient to make a previously well housebroken dog urinate in the house. Bladder infections (cystitis) and bladder stones can lead to an increase in the urge to urinate to the point that accidents occur in the house, as well. This is a fairly common cause of dogs that seem to be urinating "spitefully" --- often dogs with these problems will feel the urge to urinate so strongly that they will urinate even with the their owner present in the room.

Mike Richards, DVM    

Weight Problems

Puppy not gaining weight

Whenever a German shepherd puppy doesn't gain weight properly it worries me a lot. The shepherds have a lot of problems and several of them can lead to poor appetite and poor weight gain. They are prone to megaesophagus and are one of the breeds we have seen heart ring anamolies. They can have pancreatic enzyme insufficiencies. We have seen a portosystemic shunt in a shepherd puppy. German shepherds are one of the breeds in which dwarfism occurs. Other, more mundane problems, like worms and other intestinal parasites are also possible. In several of these conditions, poor weight gain is the only problem.

Vascular ring anomalies are not likely, because they usually cause persistent vomiting anytime a puppy eats solid food. This is a condition in which some fetal blood vessels which should degenerate remain. The most common ring anomaly is a persistent right aortic arch. The arch forms a "ring" around the esophagus along with other structures and prohibits passage of solid food. Obviously, this is not too likely in your puppy but it is just worrisome.

Megaesophagus is a weakness of the esophageal muscles leading to dilation of the esophagus and poor passage of food. Coughing after eating or retching of food are commonly seen with this condition, early on. It is a cause of poor weight gain. Porto-systemic shunts are another fetal circulation problem. When puppies are born, their circulatory system has to adapt to live without the support of the placenta and doing this involves reversing the blood flow through most of the circulatory system. Sometimes, the liver gets bypassed in this process and fails to develop due to the lack of blood flow. This is a correctable situation in many dogs. It isn't all that likely but it needs to be considered.

Pancreatic enzyme deficiencies usually cause diarrhea, which you do not mention as a symptom. Failure of any large organ system can lead to poor growth -- so congenital liver, kidney, heart or other organ damage can be a problem. Of course, it is important to rule out the more common problems like worms and other parasites.

Mike Richards, DVM    

Weight Loss

There are a number of causes of weight loss and any dog that is persistently losing weight when you are not deliberately trying to enforce a diet, should be examined by a vet. Diabetes, heart failure, liver or kidney disease, internal parasites, cancer, maldigestion and many other things can lead to weight loss. It is much easier to treat problems if they are caught early. Mike Richards, DVM


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...