Musings of a Veterinarian

Archive for April, 2009

Chocolate Toxicity

April 15, 2009 By: Dr. K Category: General

ChocolateMany veterinarians have answered the phone call from a panicked dog owner worried about Fido after he emptied the candy dish of chocolates. But how concerned should you really be? Most people have heard chocolate is toxic to dogs but many myths still surround the subject. Would you believe ingestion of large amounts of chocolate can prove toxic to humans as well?

The toxic principle behind chocolate involves how quickly its chemicals are metabolized by the body. The toxic compound in chocolate is theobromine. Theobromine is a methylxanthine derivative in the same family as caffeine and the respiratory medication theophylline. Methylxanthine compounds are found in some foods and plants, including the cacao plant, as well as in human and animal medications. Methylxanthines inhibit adenosine receptors leading to vasoconstriction, tachycardia, and central nervous system stimulation. These signs are frequently observed with the “caffeine rush” we get with our morning coffee: increased heart rate, blood pressure, and mental alertness. They also inhibit phosphodiesterase thus increasing cyclicAMP leading to increased catecholamine release. Catecholamines are hormones released from the adrenal glands in response to stressful events. The most common of these hormones is epinephrine (adrenaline). The effects of excessive catecholamine release manifest as vomiting and diarrhea, hyperactivity and hyperreflexivity, cardiac arrhythmias, tremors, seizures and even death. Humans metabolize theobromine much more effectively than dogs due to unknown biochemical differences.  Theobromine can accumulate in the dog’s system, making it more susceptible to intoxication.

methylxanthine_chartMethylxanthine levels vary based on type of chocolate with concentrations typically greater in darker chocolates. The minimal lethal methylxanthine dose in dogs is reported as 100-200 mg/kg. The reported potential lethal dose equates to about 7 grams of baker’s chocolate or 60 grams of milk chocolate per kilogram of dog’s weight. A regular sized Hershey Milk Chocolate bar is 43 grams containing about 86mg of methylxanthines. A 20lb dog would need to consume about 10 Hershey bars to reach deadly levels of methylxanthines. However, that same dog may only require consumption of 56 grams  (about 2 oz) of baker’s chocolate to achieve a lethal dose.  Gram to ounce conversion table.

Dogs who have potentially consumed a toxic amount of chocolate should see a veterinarian immediately. Emesis (vomiting) may be induced to prevent further theobromine absoprtion. Animals with seizures, intractable vomiting, or cardiac abnormalities will need more intensive care.

An occasional Hershey Kiss probably won’t affect your dog’s well being. Just try to keep the pan of brownies from Fido’s reach.

“Bo” Obama

April 12, 2009 By: Dr. K Category: Opinion

bo1_blog1Months of hype, speculation, and opinion surrounded the first family’s choice of dog. Until today. The White House announced Senator Ted Kenendy gifted a male Portugese Water Dog (PWD) to the Obama family. Since Obama’s election in November, the press has bleated Malia Obama’s dog allergies leading to many discussions on the factuality of the “hypoallergenic” dog.

The idea any dog is hypoallergenic is far fetched. Some dogs shed less, some dogs do not incite allergies as much as others, but ALL dogs produce dander. In a recent article on WebMD Health News, allergy and asthma expert Corinna Bowser, MD, describes the true trigger to dog allergies. The article reads:

The major allergen in dogs is a protein found in dog serum, and dogs excrete that allergen in sweat and shed it from their skin. “It also gets secreted into the saliva, and possibly a little bit in the urine,” Bowser says. Since all dogs have that protein, no dog is completely allergy-free, according to Bowser.

While the PWD certainly may have less dander, the Obamas may still fight itchy eyes and runny noses in the future. Time will tell.

Lily Toxicity in Cats

April 12, 2009 By: Dr. K Category: General

Easter Lily

Spring has sprung and it’s the Easter season. Many of us enjoy the smell of a hyacinth, the beauty of tulips, and the elegance of the Easter Lily in our homes. Few suspect a lethal foe waging war against cats. Did you know that ingesting a small leaf or petal from an Easter Lily can be toxic to your feline friends? Even drinking water from a vase of lilies can cause severe disease.

Easter lilies, along with other lilies of the Lilium genus, cause acute kidney failure in cats. Stargazer lilies and Asiatic lilies, along with Easter lilies, have proven the most toxic in this group of plants. Fortunately, Calla lilies and Peace lilies can cause GI upset but have not been shown to cause kidney failure as they do not belong to the Lilium genus. Cats who have consumed toxic lilies can have kidney failure within 36 to 72 hours of ingestion. Signs of acute kidney failure include vomiting, lethargy, and inappetance. Cats who have ingested lilies require urgent veterinary care. Research and anecdotal evidence reveal not all cats respond to the toxin equally; Some cats recover with minimal intervention while others require life saving diuresis and/or dialysis. Others aren’t so lucky and will die from complications of kidney failure.

The safest bet is to keep all lilies out of reach of your cats.