Vetinfo Digest                June 1999

This Month:

What does the liver do?
Very Short Stories
Stuff You Shouldn't Say to Your Vet
Short Stories, Continued
Mixing and Matching Medications - potential risks for drug interactions
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at the VetInfo website.

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Stuff About Us...

We have finally succeeded in moving the VetInfo website to a new server.
The new arrangements allow us to provide a password protected directory for
subscribers.

We will be able to put more information online than we can send out in the
newsletter. Over time, we hope to build a really comprehensive information
center for pet owners, with information on anatomy, physiology,
pharmaceuticals, nutrition and disease conditions affecting cats and dogs.
As we do this, the VetInfo Digest information will be placed online as well
as being sent out in the newsletter. As that happens, we hope to make the
title of our newsletter more meaningful. We hope to make it a real digest
of information available online, in a condensed format. This will allow us
to continue to provide some storytelling while improving the quantity and
timeliness of information in the newsletter.

We will continue to try to answer subscriber questions in a timely fashion,
as well. The address for those remains unchanged -- mervet@inna.net.
Thanks for your support!

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What Does a Liver Do?

It occurred to me this month that many people don't have a clue what a
liver is for. It is just an important organ that dogs and cats have. When
it isn't working, they don't feel well. So what does it do when it IS
working right?

The liver is the storehouse for energy reserves in the body and a major
regulator of glucose in the blood stream. When there is excessive glucose
in the blood, the liver makes it into glycogen, which it stores. When the
glucose level in the blood is low, glycogen is broken down into glucose by
the liver and released into the blood stream. Since important organs, like
the brain, depend on a regulated supply of glucose, the ability of the
liver to perform this task is vitally important.

Fat metabolism is another of the liver's many jobs. The liver aids in
absorption of fats from the intestines through the production of bile. Once
the fats are absorbed, the liver makes the fat containing compounds
necessary for life, such as lipoproteins and cholesterol. The liver removes
some fatty acids from the circulation by metabolizing them and converting
them to energy for the body to use. Cholesterol produced by the liver is
used in the production of some other compounds, including bile acids. The
absorption of fat soluble vitamins is dependent on the liver functioning
properly in managing fats.

The liver makes proteins that the body requires. Without the ability to
produce specific proteins from raw materials there would not be proteins to
transport drugs and compounds the body needs. One example of a necessary
protein is albumin, which aids in maintaining osmotic balance in the
circulatory system and serves as a transport protein by binding to many
substances the body needs to move through the bloodstream. Other important
proteins include fibrinogen, which is necessary in the regulation of blood
clotting, other clotting factors, enzymes necessary to regulate cell
function, and antibodies. Low serum protein levels allow fluid to escape
from the blood stream, leading to problems with fluid accumulation in the
abdomen or under the skin.

There are a number of nutrients necessary for proper metabolism that the
liver is involved in processing or producing, as well. Vitamin K is the
nutrient the liver processes that disappears the quickest when the liver
fails. Since it is directly involved in blood clotting, this is an
important loss. Vitamin B12 and vitamin C are also produced or stored in
the liver. Storage of iron, copper, zinc, manganese and magnesium all occur
in the liver. Since copper is very toxic in an unbound state this is also a
critical mission.

The liver also detoxifies a number of substances that are produced during
metabolism or digestion in the body. The most important of these substances
is probably ammonia, which is efficiently removed from the blood stream and
metabolized to urea by the liver. The urea is excreted from the body
through the kidneys and intestines. There is a sort of loop in the
intestinal excretion, since bacteria in the intestine use it to produce
ammonia again -- making it even more important that the liver continue to
function properly to keep ammonia levels down in the body.

When ammonia levels rise, central nervous system damage occurs. Mercaptans
that are also produced in the digestive tract and which also cause CNS
damage tend to rise in the same circumstances in which ammonia rises.

Without normal function of the liver the body begins to lose protein, have
glucose regulatory problems, blood clotting is disturbed, vitamins may not
be available for critical needs, enzymes that regulate cell function are
missing and toxin levels, including ammonia and mercaptans rise. The
challenge for veterinarians trying to treat liver disease is to figure out
methods of regulating the body functions the liver is partially responsible
for and providing the materials the liver normally produces for the body.
If these tasks can be accomplished the liver has a chance to rest and recover

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Very Short Stories

Usually we include a short story with the VetInfo Digest but this month I
thought that we should go for the ultra-short stories that make up day to
day life in a veterinary practice.

Michal's favorite customer quote, given after she asked, "Do you want to go
ahead and let the doctor give your dog a distemper vaccination today, too?"
To which the client replied, "That would be good, he has a really terrible
temper."

^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^

A client rushed into our waiting room with her dog, who was obviously
severely injured from being hit by a car. As soon as I examined the dog I
knew that it was dead. I told the owner, "I'm sorry, ma'am but Duke's
injuries were severe and he has died."

To which she replied, "Well, what are you going to do about it?"

Confused, I asked her what she meant, to which she replied, "I want to know
what you are going to do about it!"

So I asked what I thought was the obvious question, "Do you need help
caring for his body?"

She grabbed my arm and said, "I don't know what you mean! I want my dog
fixed! Can't you see he's bleeding?"

I explained as gently as I could that he had been bleeding but that it
had stopped, because he was dead. She became enraged and made several
threats to my health before her friend heard her from the waiting room and
came to my rescue. After several minutes we were able to convince her that
there really wasn't anything medical that could be done to bring her dog
back to life. I was very grateful for her friend being there. Death can be
very hard to accept, especially when it occurs suddenly in circumstances
that are unexpected. Helping owners to make it through the process of
accepting a death is sometimes a difficult part of veterinary practice.
Having a friend along for support is a big help.

>>>>>>>

I have two African lions who are patients in the practice. We don't really
do much exotic pet medicine but I did a preceptorship (short internship) at
a zoo and so I was comfortable enough about working with lions to accept
them as patients when none of the other local veterinarians would.

I asked their owner how she got them. She was a model. One of them was
being used in a model shoot she was at when its owner got arrested and
taken away. No one took the lion, so our client took it home in the back
seat of her car. This was a full grown lion! Somehow, she got the lion home
without problem. Eventually it was necessary to build an enclosure for
her, though. After a year or so, when no on claimed "Kenya" her new owner
decided she was lonely and got her a companion.

Our client has since founded a nonprofit rescue society for homeless
exotics and injured indigenous wildlife, with all the proper permits and
certifications. A life's work that started with the improbable act of
taking a lion home in an impulse decision. The ironic part of this story is
that she has to spend a lot of time trying to explain that buying or
adopting exotic pets is generally not a good idea because caring for them
is much more difficult than a regular pet and is hard to do in a manner
that is truly humane.

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Ten Things You Probably Shouldn't Say to Your Vet

1) I've paid for a wing of your hospital *

* unless you actually wrote a check for one wing of the hospital, of course

2) I'm paying for your kids to go to Harvard (substitute any college name
of your choice)

*unless you actually did write a check for their tuition or your veterinary
charges for the year have exceeded $34,000 or so (the average practice
nets 30% or less of charges for services)

3) After 3PM on a Friday, don't say "My dog has been sick all week and now
it looks like he won't live through the weekend so I have to have an
appointment today!"

OK, so sometimes you have to say this. Do it as infrequently as possible,
though.

4) "This costs more than taking my kids to the pediatrician's!"

You're either admitting to advanced age or forgetting about the insurance
premiums you pay so     you can afford to take your kids to the doctor's office

5) "My dog (cat) won't bite"

Almost all dogs and cats will bite. Some do take a lot more provocation
than others, but most of     the time the ones whose owners feel compelled to
claim they won't are the ones most likely to actually bite the vet. After
awhile, vets notice this -- and it becomes a warning rather than a
reassurance.

6) In an emergency situation, don't say "Do all you can, Doc!" *

Almost every vet I know hears this sentence as "Do all you can, Doc. I'm
not paying you for it, anyway." Say something like this, instead -- "I
can only afford to spend $800 without making financial    arrangements with
your clinic to pay the rest". That shows your intention to actually pay
and lets your vet know you are serious about helping your pet at the same
time.

7) "Are you going to use anesthesia when you spay her? *

Pets feel pain with the same mechanisms we do. A spay surgery is an
ovariohysterectomy. Hopefully, no further explanation is necessary.

8) " I have some antibiotics left over from the last time you saw him."

It is really important that you finish antibiotic therapy once it is
started. There is enough of a problem with antibiotic resistance in
bacteria without adding to it by not using antibiotics as directed. Please
use all medications as directed.

9) "If I feed him any less he'll starve" *

Usually said about a pet that is extremely overweight. The bottom line is
this -- if your pet is overweight she is eating too much for her level of
activity. Period. Less food might produce behaviors indicating a desire to
eat more but will not cause starvation for some time.

10) "A vet on the Internet says...." Just try this one to see what we
mean !

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Very Short Stories, Continued...

I was working on a dog that had been hit by a car one morning when another
patient arrived on an emergency basis with a history of having been bitten
by a copperhead snake. Most of the time dogs with this history haven't
actually been bitten by a poisonous snake and the trauma patient I already
had really did require my total attention for a few minutes, anyway.

The owner of the other dog grew impatient and asked my receptionist if the
doctor was ignoring her because he didn't believe the dog had been bitten
by a copperhead. She told him I was actually involved in an emergency
treatment already and that he would just have to be patient. Whereupon I
heard a bloody scream as he reached in a bag he had with him and pulled out
a four foot long snake and began waving it around. Michal is the only
receptionist we have ever had who tolerated snakes and she wasn't there.
Linda, our receptionist that day, was rapidly disappearing out the back
door of the clinic as I ran into the waiting room to see what had happened.

"I just wanted her to know the snake was really a copperhead, Doc! It's
dead but you can see it really is one." He was right. I promised him I'd
work as fast I could to get to his dog and sent him to the hospital to get
some antivenin. His dog only weighed about 4 pounds and I thought it might
be small enough to die from a copperhead bite.

I asked him to let Linda know the coast was clear if he passed her anywhere
on the way to the hospital, too.

# # # # # # # # # #

We had a client whose "yard man" accidentally cut off his German shepherd's
leg just below the elbow with a bush trimmer. He had carefully packed the
leg in ice and brought it with him, fully expecting us to be able to put it
back on. Apparently, he had missed the part of the surgical description for
reattaching limbs that usually goes something like this: " A team of eight
surgeons spent fourteen hours reattaching a dismembered arm...."

I was flattered that he really believed I had the technical skill and
equipment to reattach a limb but it was simply not possible. Veterinarians
can do much more than we used to, but there are still economic and
technical limits on our practice. We can't put together a team of
specialists on a moments notice to reattach a limb or provide the kind of
intensive care that human trauma victims sometimes require. At least not
in the average general veterinary practice.

# # # # # # # # # # # #

I can't explain why, but one of my favorite memories of practice involves
an older woman who came into the waiting room while I was behind the
reception counter. She was clutching a toy poodle. She asked if I was the
vet. After I told her I was, she gave me a rather disdainful look and said
in an icy tone, "You're too young to practice on my dog!" . Remembering how
intensely she held this opinion still makes me laugh, today.

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Mixing and matching medications

There are a number of medications that interfere with actions of other
medications. If a patient is on more than four medications at one time it
is almost certain that there is some interference between the medications.
Sometimes this situation is unavoidable and medication dosages are just
adjusted to reflect the difference in activity or excretion based on the
use of the interfering medication. Other times it is better to reevaluate
the patient and try to determine which of the medications is more important
to the patient's health and withdraw the less important medication. In some
cases it is best to withdraw both medications and look for an alternative
or alternatives that will do the job of the conflicting pharmaceuticals.

Veterinarians do not always remember to think about the potential for
interference between medications. This is one of the reasons that it is a
good idea to check out the drug inserts or other reliable sources of
information for medications that are used chronically and to remember the
medications that might potentially cause problems, if you can. It is not a
bad idea in an acute illnesses to ask your vet if any of the medications
used are likely to interfere with each other, especially if more than two
or three medications are being administered.

Some examples of commonly used medications that have adverse effects on
other medications are listed below. This is by no means a complete list ---
there are thousands of possible drug interactions.

Phenobarbital - this medication is used commonly to control seizures in
dogs and cats. It can decrease the effectiveness of several medications,
including corticosteroids such as prednisone, doxycycline, metronidazole,
griseofulvin and theophylline. Phenobarbital effect is sometimes increased
by other medications, including narcotics, tranquilizers and
antihistamines. While it is not used too much anymore, chloramphenicol (an
antibiotic) can increase the effect of phenobarbital while its effect is
diminished by phenobarbital at the same time. There are new medications
appearing with frequency in veterinary medicine so it is always best to
check for interactions prior to using any new medication when a pet is on
phenobarbital chronically.

Corticosteroids (prednisone, prednisilone, triamcinilone,
methylprednisilone) - These medications are frequently used to control
itchiness in allergic pets, for immune system disorders and to control
inflammation associated with illnesses. They interact with some other
medications. When used in patients on diuretics for heart conditions
cortisones may cause increased loss of potassium. If the heart patient is
also on digitalis or digoxin this effect is even more severe. Use of
corticosteroids in diabetic patients can make regulating insulin dosages
very challenging. If it is possible it is best not to mix corticosteroid
usage and insulin usage. If cortisones are being used at dosages sufficient
to cause immune system suppression it is best not to give modified live
virus vaccinations during usage of the corticosteroid as there may be
increased susceptibility to adverse effects from vaccination. This is not
thought to be a problem at dosages sufficient to control itching,
especially when using alternate day dosing schedules. Using aspirin and
corticosteriods at the same time increases the ulcer producing ability of
both medications. When possible it is best not to use these medications at
the same time.

Enalapril (Vasotec Rx, Enacard Rx) - This is a medication commonly used to
treat chronic heart failure in older dogs and may be used for
cardiomyopathy or renal failure in older cats. When using diuretics such as
furosemide (Lasix Rx) with enalapril it is recommended that the dosage of
the diuretic be reduced by as much as half in order to prevent problems
related to low blood pressure. Any other medications that might lower blood
pressure should also be used with caution. It is possible to cause problems
with hyperkalemia (too much potassium in the blood stream) when giving
enalapril and potassium at the same time. In older cats with renal failure
this combination may be encountered. Non-steroidal anti-inflammatory
medications may reduce the effectiveness of enalapril. Since the NSAIDS are
used in older dogs for arthritis, this is another potentially common
interaction.

Selegiline (Anipryl Rx) - This medication is approved for use in treating
hyperadrenocorticism and canine cognitive dysfunction. It is a monamine
oxidase inhibitor (MOA inhibitor). This group of medications should not be
used with meperidine (Demerol Rx) and possibly other narcotic agents. It is
also a good idea to avoid fluoxetine (Prozac Rx) and amitriptyline (Elavil
Rx) while using Anipryl. Some older dogs develop demodectic mange, which
is treated with amitraz (Mitaban Rx), another medication that should not be
used at the same time as Anipryl.

Imidocarb (Advantage Rx)- This flea treatment is recommended for once
monthly application. It should not be used in combination with other
insecticides that inhibit cholinesterase. This isn't much of a problem,
since it is an effective medication alone, but it is best to remember not
to use it with other insecticides, anyway.

Levo-thyroxine (Soloxine Rx) - Hypothyroidism in dogs is fairly common and
is treated by supplementation with l-thyroxine. This medication can alter
insulin requirements. This is usually a problem when it is added after
insulin therapy begins but it is also important to maintain steady dosages
of thyroxine when also using insulin. Digoxin effectiveness may be lessened
when thyroxine supplementation is being used. Ketamine anesthesia should
be used with caution in dogs on thyroxine supplementation as rapid heart
rates and increases in blood pressure to dangerous levels may occur with
this combination. While thyroxine administration is not common in cats,
they do get hyperthyroidism naturally -- and ketamine should be used with
caution in cats with naturally occurring hyperthyroidism for the same reasons.

Mitotane (Lysodren Rx) - This medication is used to treat
hyperadrenocorticism (Cushing's disease). It should not be used in
conjunction with medications that may cause central nervous system
depression, such as sedatives or anti-anxiety medications. It may decrease
the effectiveness of phenobarbital. Successful treatment of Cushing's
disease may decrease the need for insulin. Spironolactone, an infrequently
used diuretic, may block the action of mitotane, so these medications
should not be used concurrently. Other diuretics are not known to have this
effect.

Some medications do not seem to interfere much with other medications. Some
of these are medications that are used commonly, so I have included a list
of them, as well.

At this time, there are no known drug interactions with the monthly or
daily heartworm prevention medications. Other medications that are often
used chronically in pets that have few interactions include Methimazole
(Tapazole Rx), fipronil (Frontline Topspot Rx) and cyclosporin ophthalmic
ointment (Optimune Rx).

If your pet must be on a medication for extended periods of time it is best
to know the potential adverse effects of the medication and to know which
other medications are likely to interact with it. The package insert will
list known interactions so it is best to read it. If you find references to
interactions in magazines or on the Internet that are not in the package
insert it would be best to check the validity of these with your veterinarian.
 
 

Small things to remember:

Tapeworms do not show up on a normal fecal exam in most circumstances.
These worms are diagnosed based on the presence of the egg cases in the
stool or around the rectum. The egg case is one segment of a tapeworm's
body that is shed intact. It has muscular action and can move around for a
few minutes after being expelled, making many people think that they are
seeing the worm itself rather than just one segment.

Prednisone usage causes a rise in the serum alkaline phosphatase (SAP)
levels in many dogs. This enzyme is strongly associated with liver disease
in dogs and sometimes in cats. However, it is also produced by the
intestines, muscles and other organs. Rises in SAP associated with
prednisone are not usually from the liver.

If you have a camcorder and your dog has intermittent problems that are
difficult to reproduce in the vet's office it can help a great deal to
videotape them. If you can capture a symptom on videotape you vet can see
what is happening and can often make a preliminary diagnosis or at least
obtain a better understanding of what you are seeing.

Make sure you ask if there are any special directions before scheduled lab
tests or other diagnostic procedures. It is sometimes necessary to fast
your pet for 12 to 24 hours prior to a blood test. When doing blood
monitoring of certain drugs it is necessary to try to draw blood at
specific times of the day when the drug should be at the peak or the low
point (trough) of it's blood concentration.

It is always better to measure the amount of dry dog and cat food you are
feeding with a real measuring cup at least once. Write the amount down in
case you need to refer to it. If you use some measuring device other than
a measuring cup on a routine basis please let your vet know that the "cup"
you refer to when you say you give a cup of food a day is actually a Big
Gulp cup or a feed scoop. Dietary recommendations are not useful if you
are not using the same size cup that your vet is referring to --- and your
vet is almost certainly talking about a real measuring cup.

Skunk odor can be lessened (nothing I know of really removes it entirely)
using the commercial product Skunk Off (TM) or by mixing 1 teaspoonful of
detergent, 1 quart of 2% hydrogen peroxide and 1/2 cup of baking soda
together and using it to rinse the dog well after bathing. You have to be
careful about fabrics the dog might come into contact with after using the
home made solution --- it can bleach some fabrics.

If your pet is NOT spayed it is important to remind your vet of this if
your dog or cat needs medical attention for vaginal discharges, mammary
gland problems or whenever your pet seems to be seriously ill. This is
especially true if increased drinking and urinating are part of the
symptoms. In many veterinary practices most of the middle aged and older
female patients have been spayed. If your vet is not thinking about the
fact that your pet is NOT spayed, it is easy to overlook uterine infections
and other illnesses that only occur in intact pets.

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New Web Site for Vet Info

We have created a password protected directory just for subscribers. If you
send us an e-mail with a desired user name and password, we will set up
access for you. The username and password can only contain alphanumeric
characters. This area will be developed over time but we hope to provide
more specific information on medications, some of the questions and answers
we don't put online and a more "in-depth" database for subscribers.

We are having some growing pains associated with managing a new business
while attempting to keep an active veterinary practice running. As we learn
to automate some tasks and figure out ways to sort through e-mail faster,
we should be able to respond better to subscriber questions. We are also
going to have to develop a method of letting everyone know when we go on
vacation or can not be available for short periods of time due to other
commitments. The VetInfo web site and VetInfo Digest are very important to
both Michal and me. We will do our best to make it worthwhile for each of
you. Please do not hesitate to send a second copy of a question we have
been slow to answer or to drop us a line if you do not receive your VetInfo
Digest through the mail. As always, Michal and I truly appreciate your
support.

Copyright, TierCom, Inc., P.O. Box 476, Cobbs Creek, VA 23035. All opinions expressed in this newsletter are those of Michael Richards, DVM.