Poisonous Foods

Feeding our pets is one of the main ways humans interact with their animals on a daily basis. Whether the food is fed as the main diet, as a treat, or is accidentally (or purposefully!) ingested while the owner is not looking, we must be careful that the foods our pets have access to are not harmful to their health. As pets are not just small people, we must remember that some foods which are perfectly safe for humans may be toxic to our pets, and can lead to serious illness or even death if eaten.

Chocolate

Chocolate is a popular sweet amongst humans year around, but even more so around the Easter and Christmas holidays. Chocolates vary in toxicity depending on the percentage of cocoa used in making the chocolate - milk chocolate containing less cocoa then dark chocolate and those less then baking chocolate and cocoa powder. This does not mean that it is safe for animals to eat milk chocolate, but does mean that severe toxicity can be seen with a much smaller dose of baking chocolate. If you suspect your pet has eaten chocolate, it is important to identify the amount and type consumed and to provide this information to your vet - the amount ingested and the type of chocolate will be compared to your pet's weight and the expected toxicity calculated.

The main toxin found in chocolate is Theobromine, a chemical which the human liver is able to metabolize (break down), but dog and cat livers cannot handle. This toxin occurs naturally in cacao beans, from which chocolate is made. Ingestion by susceptible animals may cause hyper excitement, drooling, elevated heart rate, muscle tremors and collapse, eventually leading to death in severe cases. The fats used to create eating chocolate can also cause gastrointestinal irritation, leading to nausea, vomiting and diarrhea.

Treatment for chocolate ingestion is aimed at removing any undigested chocolate from the gastrointestinal tract, usually by inducing vomiting, or in severe cases - gastric lavage (pumping the stomach) and enemas under a general anesthetic. Activated charcoal may be administered by mouth to absorb any unremoved toxins. The patient may also receive intravenous fluids to combat shock and dehydration, as well as sedatives or other medications aimed at controlling neurological signs.

Onions, Garlic, Leeks and Chives

The ubiquitous members of the Allium family of plants grace most kitchens and plenty of barbecues. Though humans can eat this vegetable (and suffer only bad breath), dogs and cats are unable to break down the aromatic compounds, such as organosulfoxides, which give these plants their distinctive aromas and flavours. When consumed, these compounds cause a dysfunction in erythrocytes, the red blood cells which carry oxygen and carbon dioxide around the body. These damaged red blood cells then lyse (explode) as a result of this damage, leading to a decreased number of these cells. This condition is known as 'Heinz Body Anemia', due to the formation of toxic Heinz bodies in the cells.

The level of toxicity depends on the amount of toxin eaten, and typically concentrated products, such as powder, cooked products and juices contain more toxin then raw plants. Onion and garlic powders can be found in soups, stocks and prepared foods. Cats require less material to produce toxicity then dogs.

Signs of toxicity include weakness, lethargy, pallor (pale gums), difficulty breathing and death. There is no specific antidote for Allium toxicity, and treatment is aimed at removing unabsorbed toxin (through vomiting, oxygen supplementation, intravenous drips and blood transfusions if necessary.

Macadamia Nuts

These native Australian nuts are one of the lesser known known dangerous foods. These nuts contain a neurotoxin (a toxin which affects the nervous system). Signs of toxicity usually appear about 12 hours after the nuts are eaten, and include tremoring, nervousness, incoordination, drooling, fever and an elevated respiratory (breathing) and heart rate.

Treatment is similar to other toxicities and is aimed at removing undigested nuts from the gastrointestinal tract through inducing vomiting, enemas or gastric lavage under a general anesthetic. Activated charcoal may be given by mouth or by stomach tube to absorb any remaining toxin. An intravenous drip may be administered to maintain hydration, and other medications may be required to control tremors or seizures if they occur.

Raisins and Grapes

Though the exact toxin in grapes and raisins has not been identified, and is thought to possibly involve a mold toxin. Being dehydrated, raisins are a more concentrated source of toxin, but even a few raisins or grapes can result in toxicity.

The main effect of ingesting the fruit is kidney damage. Animals may show vomiting, Diarrhoea, lethargy, inappetance and changes in urine production. As more toxin is absorbed, the kidneys begin to fail, and pets may display increased bad breath, cease urine production and become increasingly lethargic.

If you suspect your pet has eaten raisins or grapes, treatment must be started as soon as possible in order to limit damage to the kidneys. Vomiting may be induced to remove any undigested fruit from the stomach and activated charcoal may be administered by mouth to decrease absorption of remaining toxin. Intravenous fluids and additional medications will be administered to maintain hydration and support kidney function. Repeated blood and urine tests are frequently used to determine whether kidney function has returned to normal.

Bread Dough

Though it may seem harmless, eating bread dough can result in a life-threatening emergency for pets. Fermenting yeast, which cause the dough to "rise" are producing gas and ethanol. When dough is cooked, these yeast are killed and the ethanol evaporates off, and turns dangerous dough into relatively harmless bread.

Pets which have eaten raw dough may display bloating, lethargy, and a staggering "drunken" gait. Once the dough reaches the stomach, it continues to expand and produce gas, causing the stomach to expand and can rupture.

Treatment immediately after ingestion can involve inducing vomiting and supportive care with an intravenous fluid drip, but in severe cases, emergency surgery may be required to remove the dough from the stomach before further damage can be done