By Leslie Manis, Health/Genetics Chairman, ASTC
[Every effort has been made to ensure accuracy of information. However,
this is not a substitute for prompt veterinary care. Any similarity
to other publications is unintentional. Published
online at Sealyhealthguard.org, 8/1/11. Originally
published in ASTC The Barks 2004]
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While trying to keep the cookies away from the hostess's dog at a
holiday party I began to wonder about foods like chocolate that are
toxic to dogs. How much is dangerous? What are the symptoms and treatment?
We all know that antifreeze and many flowers are very toxic to pets.
A helpful chart can be found on:
Did you know that besides chocolate, onions, raisins, grapes and
macadamia nuts are also dangerous?
Chocolate contains theobromine, which is a heart stimulant
and diuretic. Theobromine and caffeine are both methylxanthines. These
are rapidly absorbed through the GI tract and metabolized in the liver,
then excreted through the kidneys.Theyinhibit adenosine receptors,
causing central nervous system simulation, tachycardia and vasoconstriction.
They also increase free calcium of muscle cells, increasing muscular
contractility. The half-lives of caffeine and theobromine in dogs
are about 4.5 hours and 17.5 hours respectively.
Symptoms include vomiting, diarrhea, polyuria, hyperactivity, weakness,
cardiac arrhythmias, tremors, seizures, coma and death, depending
on the amount ingested.
HOW MUCH IS DANGEROUS?
For a 20 pound Sealy, 16 ounces of milk chocolate
and only 2 1/2 ounces of unsweetened chocolate.
There is no antidote to theobromide poisoning. Treatment
is geared toward supporting the animal's basic life functions, preventing
further absorption of the chocolate. hastening elimination, and treating
the symptoms. If less than four hours have passed since ingestion,
induce vomiting. This should get rid of about 70% of the stomach's
contents. The chocolate can melt and form a ball in the stomach, which
can be difficult to remove. If the dog has eaten an amount that can
be toxic, he must be placed under the care of a veterinarian, who
will stabilize and monitor the dog, and administer activated charcoal
to move the poison along through the system faster and with less absorption.
Cocoa bean shell mulch is a relatively new product used by many
home gardeners. It is attractive and even has a nice fragrance. However,
it may contain from .19 to 2.98 percent theobromine,
and is also dangerous if your dog chooses to eat it.
Onions, whether cooked, raw or dehydrated, contain the toxic
ingredient thiosulphate. These are hydrolyzed to disulfides which
are oxidizing agents that can cause hemolysis of erythrocytes (red
blood cells). This can cause anemia.
An early study showed that onions are toxic when a dog eats more
than .5 percent of his body weight. For a 20 pound dog that would
be .1 pound of onion. In chronic exposures of low doses, the anemic
effect is lessened because erythrocytes are being regenerated simultaneously.
The hematocrit may not reach its lowest point until several days after
Severe onion toxicosis can be lethal. If they were eaten within the
last two hours, vomiting should be induced using 3 percent hydrogen
peroxide, followed by the administration of activated charcoal. Syrup
of ipecac is not recommended; it is unreliable and can cause protracted
vomiting. The dog's hematocrit should be monitored over a period of
time to determine the severity of anemia and whether it is improving.
It may take several days after onion Ingestion for the hematocrit
to reach its lowest point. Whole-blood transfusions may be necessary
for critically ill dogs.
GRAPES AND RAISINS
Grapes and raisins pose another threat. The ASPCA's
Animal Poison Control Center has an AnT ox database, a computerized
system that contains nearly 500,000 animal-related medical conditions.
Veterinarians can use this to quickly identify toxic-substance exposures,
recognize clinical signs and administer proper treatment. By tracking
these cases, similarities in animal medical conditions nationwide
can be logged and trends identified.
Around 1989, the APCC began noticing a trend in dogs who had eaten
grapes or raisins: nearly all developed acute kidney failure. As more
cases were reported, enough data was generated in the database to
help veterinarians identify and treat dogs at risk. In all of the
cases, there was a potential for acute kidney failure. Whether the
ingested grapes were purchased fresh from a store or grown in private
yards didn't seem to matter, nor the brand eaten. The ingested amounts
varied considerably, from over a pound of grapes to as little as a
single serving of raisins. The cases weren't from any specific region
of the U.S. Suspect grapes and raisins have been screened for various
pesticides, heavy metals (like lead and zinc) and mycotoxins (toxins
from fungi). So far, all tests have come back negative.In cases where
the grapes were grown in private yards, owners confirmed that no insecticides,
fertilizers or antifungals had been used on the fruit.
Dogs in the database who ate grapes and raisins typically vomited
within a few hours of eating them. Some dogs would stop eating and
develop diarrhea. They often became quiet and lethargic and showed
signs of abdominal pain. These symptoms lasted several days and sometimes
Blood chemistry panels showed consistent patterns. Blood calcium
and blood urea nitrogen levels were often elevated, as well as creatinine
and phosphorous (substances which reflect kidney function). Even though
the exact cause of kidney failure is unknown, dogs can be treated
to prevent its development. Inducing vomiting shortly after ingestion
then administering activated charcoal helps prevent absorption of
potential toxins. Blood chemistry should be monitored daily for at
least three days. If all blood work is normal after three days, it's
unlikely that kidney failure will occur.
Macadamia nuts can cause weakness or paralysis of the
hindquarters, muscle tremors and sometimes painful and swollen limbs.
The toxic compound is unknown. Dogs have been affected by eating as
few as six macadamia nuts, while other have eaten as much as 40. Symptoms
appear less than 12 hours after ingestion. Luckily, the symptoms seem
to be short in duration, and most dogs return to normal within 24
to 48 hours with only observation at home.
The avocado fruit pit and the plant are toxic. They can cause
difficulty breathing and fluid accumulation in the chest, abdomen
Pancreatitis can be caused by excessive fats.
AN OUNCE OF PREVENTION
Obviously, preventing your dog from eating
the above toxic products is the best solution. But if an accident
should happen, now you know some of the symptoms and how to proceed
with the best treatments.