Disease in Dogs pt. 4

Toxic substances

Dangerous foods

Some foods commonly enjoyed by humans are dangerous to dogs:

• Dogs love the flavor of chocolate, but chocolate in sufficient doses is lethally toxic to dogs (and horses and possibly cats). Chocolate contains theobromine, a chemical stimulant that, together with caffeine and theophylline, belongs to the group of methylxanthine alkaloids. Dogs are unable to metabolize theobromine effectively. If they eat chocolate, the theobromine can remain in their bloodstreams for up to 20 hours, and these animals may experience fast heart rate, hallucinations, severe diarrhea, epileptic seizures, heart attacks, internal bleeding, and eventually death. A chocolate bar can be sufficient to make a small dog extremely ill or even kill it. Approximately thirty grams of baking chocolate per kilogram (1/2 ounce per pound) of body weight is enough to be poisonous. In case of accidental intake of chocolate by especially a smaller dog, contact a veterinarian or animal poison control immediately; it is commonly recommended to induce vomiting within two hours of ingestion. Large breeds are less susceptible to chocolate poisoning, but still are far less tolerant of the substance than humans are.

Note:Carob treats are often available as dog treats; these are unrelated to chocolate and are safe.

• It has recently been confirmed that grapes and raisins can cause acute kidney failure in dogs (see also grape and raisin toxicity in dogs). The exact mechanism is not known, nor is there any means to determine the susceptibility of an individual dog. While as little as one raisin can be toxic to a susceptible ten pound dog, many other dogs have eaten as much as a pound of grapes or raisins at a time without ill effects. The dog usually vomits a few hours after consumption and begins showing signs of renal failure three to five days later.
• Onions, and to a significantly lesser extent garlic, contain thiosulfate which causes hemolytic anemia in dogs (and cats). Thiosulfate levels are not affected by cooking or processing. Small puppies have died of hemolytic anemia after being fed baby food containing onion powder. Occasional exposure to small amounts is usually not a problem, but continuous exposure to even small amounts can be a serious threat. Garlic is also known to cause diarrhea and vomiting.
• Macadamia nuts can cause stiffness, tremors, hyperthermia, and abdominal pain. The exact mechanism is not known. Most dogs recover with supportive care when the source of exposure is removed.
• Alcoholic beverages pose much the same temptation and hazard to dogs as to humans. A drunk dog displays behavior analogous to that of an intoxicated person. (However, beer presents another problem; see below.)
• Hops, a plant used in making beer, can cause malignant hyperthermia in dogs, usually with fatal results. Certain breeds, such as Greyhounds, seem particularly sensitive to hop toxicity, but hops should be kept away from all dogs. Even small amounts of hops can trigger a potentially deadly reaction, even if the hops are "spent" after use in brewing.
• Xylitol is a sugar substitute used in chewing gum, chewable vitamins, candy, toothpaste, and other products. Although empirical studies (1, 2, 3) indicate xylitol may be safe for dogs, there have been cases of foods, candies and gums containing xylitol causing toxic or even fatal liver damage in dogs and should be avoided (1, 2, 3).
• Some dogs have food allergies just as humans do; this is particular to the individual dog and not characteristic of the species as a whole. An example is a dog becoming physically ill from salmon; many humans likewise have seafood allergies.
• If dogs eat the pits of fruits such as peaches and apricots, they can get cyanide poisoning due to cyanogenic glycosides.

Common household substances

Some common household chemicals are particularly dangerous to dogs:

• Antifreeze, due to its sweet taste, poses an extreme danger of poisoning to a dog (or cat) that either drinks from a spill or licks it off its fur. The antifreeze itself is not toxic, but is metabolized in the liver to a compound which causes kidney failure, and eventual seizures, and death. By the time symptoms are observed, the kidneys are usually too damaged for the dog to survive so acting quickly is important. Immediate treatment is to administer apomorphine or peroxide solution in an effort to get the animal to vomit up as much of the antifreeze as possible. Next, it is critical to immediately get the animal to a veterinarian. Fomepizole (Antizol Vet® by Orphan Medical) is considered the preferred treatment for treating ethylene glycol toxicoses in dogs. Ethanol can also be used in cats and dogs, however it does have several unfavorable side effects. Ethanol occupies the enzymes in the dog's liver, long enough for the unmetabolized antifreeze to be passed out harmlessly through the kidneys. Dogs should not be allowed access to any place in which an antifreeze leak or spill has happened until the spill is completely cleaned out. Even a very small amount such as a tablespoon can easily prove fatal. Some brands of antifreeze that contain propylene glycol instead of ethylene glycol are marketed as being less harmful or less attractive to animals.

• Mouse and rat poison is commonly found in the house or garage. Dogs readily eat these poisons, which look like small green blocks and are very attractive to them. The poisons work by depleting stores of Vitamin K in the body, without which blood can not clot properly. Symptoms of poisoning include depression, weakness, difficulty breathing, bruising, and bleeding from any part of the body. These symptoms often take 3 to 4 days to show up. A blood test will show that the blood is not clotting properly. If the poison has only recently been ingested (within 2 to 3 hours), the dog should be given apomorphine or hydrogen peroxide to make it vomit. Activated charcoal can be given to absorb any remaining poison in the gastrointestinal tract. Then the dog is given Vitamin K supplementation for 3 to 4 weeks, depending on the type of poison. At the end of treatment, the clotting times should be tested again. The prognosis is good in these cases. However, if the dog is already showing signs of poisoning, it is too late to try and remove the poison from the body. A whole blood transfusion or plasma is given to treat the anemia and to try and control bleeding. Vitamin K is also given. The prognosis is poor in these cases.
  • Mouse and rat poisons containing cholecalciferol cause hypercalcemia and hyperphosphatemia in dogs. Symptoms include depression, loss of appetite, vomiting blood, weakness, and shock. Treatment is as above for recent exposure. When hypercalcemia occurs (which can take 1 to 2 weeks), treatment is with intravenous fluids (saline), diuretics, corticosteroids, and calcitonin. Long term prognosis is good once the dog is stabilized.

• Zinc toxicity, mostly in the form of the ingestion of US pennies minted after 1982, is commonly fatal in dogs where it causes a severe hemolytic anemia. ^[30]

Over the counter medications

A veterinarian should be checked before any OTC medicine is used. However, poisoning with pain medications is common. Aspirin, acetaminophen (Tylenol), ibuprofen (Advil), and naproxen (Aleve) can all cause severe symptoms in dogs, including vomiting blood, diarrhea, and abdominal pain. Specifically, aspirin can cause metabolic acidosis, acetaminophen can cause liver disease, ibuprofen can cause kidney disease, and naproxen can cause ulcers in the stomach, which can perforate. Treatment depends on the symptoms.

Contact your veterinarian or the ASPCA Animal Poison Control Center in case of possible exposure.

Public health risks

Sarcoptes scabiei

Most diseases that affect dogs or humans are not transferable between the two species. There are some exceptions of zoonoses. The most well known zoonosis is rabies, a viral infection transmitted through a bite. A common bacterial zoonosis is leptospirosis, transmitted through urine. Some of the most important zoonoses are parasitic. Zoonotic intestinal parasites transmitted through contact with feces include Toxocara canis (the canine roundworm), which causes toxocariasis, visceral larva migrans, and ocular larva migrans, and hookworms, which can cause cutaneous larva migrans. Zoonotic skin parasites include scabies, caused by the mite Sarcoptes scabiei. The most common zoonotic fungal disease is ringworm, caused in this case by Microsporum canis.

As rewritten from Wikipedia