Poisoning

Poison and toxin are terms commonly used interchangeably but do have slightly different meanings. A toxic substance is anything that causes abnormal body function. This includes overdoses of medications as well as poisonous substances. A poison is a substance that can result in abnormal body function and has no medical use.

Damage to the body is based on the amount of poison ingested and how long the poison was in the body before treatment. The effect of a poison is not always immediate. Some poisons do not cause illness for days, weeks or even years after ingestion but the most common poisons usually result in signs of illness within 3-4 days of exposure. Every toxic ingestion is cause for concern and should prompt an immediate call to your veterinarian or local veterinary emergency facility.

What to Watch For

• Lethargy or sluggishness
• Vomiting
• Lack of appetite
• Stumbling or staggering
• Breathing difficulty
• Seizure

Diagnosing illness due to poisoning can be difficult if the exposure or ingestion was not witnessed. Sometimes, pets are treated based on a strong suspicion of poisoning and not a confirmed diagnosis. Due to the variety of poisons, specific tests to diagnose the exact poison are often not available.

• Witnessing. Diagnosing a poisoning is easiest when the ingestion or exposure is witnessed. Sometimes, you will find the evidence – medication packages, bottles, packages, trash or poisons – in the house or yard. Without known exposure, diagnosis becomes difficult.
• Diagnostic tests. Some poisons, such as antifreeze, have a test available to confirm its presence in the blood. Many poisons, unfortunately, do not have these types of quick reliable tests.
• Physical examination. Sometimes, a specific poison can be diagnosed or suspected based on physical examination findings or behavior of the pet.
• Routine blood and urine tests. Some poisons are diagnosed or suspected based on routine blood and urine evaluation. Some poisons are known to cause severe kidney damage, liver damage, electrolyte or mineral abnormalities. If these abnormalities are found on blood or urine tests, poisoning may be suspected.

Unfortunately, definitive confirmation of a poisoning is not always possible.

All poisoning's should be considered emergencies so call your veterinarian immediately. General treatment for poisoning is listed here.

Treatment

Reducing Additional Absorption

By removing as much of the poison as possible, additional absorption can be reduced. For topical exposures, bathe the animal in lukewarm water with a mild dish soap. Inducing vomiting or gastric lavage (stomach pumping) can be used if the poison was ingested less than 2 hours before examination. Inducing vomiting should only be attempted in conscious, alert animals and only if recommended by a veterinarian.

Delay Absorption

The most common method used to delay absorption of a toxic substance is to administer activated charcoal. This works by binding the toxin and preventing further absorption. The toxin can then pass through the gastrointestinal tract.

Reduce Continued Toxin Damage

There are antidotes available for certain poisons. Unfortunately, the antidotes are typically only effective early in treatment. If diagnosis and treatment are delayed, the antidote may no longer be effective.

Some Poisons or Toxins that have antidotes include:

• Ethylene glycol - A chemical compound widely used as an automotive antifreeze. In its pure form, it is an odorless, colorless, syrupy liquid with a sweet taste.
• Acetaminophen - Is a common analgesic and antipyretic drug that is used for the relief of fever, headaches, and other minor aches and pains.
• Organophosphates - They can be found as part of insecticides, herbicides, and nerve gases, amongst others. Some less-toxic organophosphates can be used as solvents, plasticizers, and EP additives.
• Anticoagulant rodenticides - Initial clinical signs are rather nonspecific and include lethargy, weakness, and pallor. Signs of external hemorrhage such as melena, petechial to ecchymotic hemorrhage of mucosal surfaces, hyphema, hematamesis, epistaxis, and hematuria may or may not be apparent. With second-generation anticoagulant rodenticide toxicosis, internal hemorrhage is common and may include hemothorax, hemoperitoneum, hemomediastinum, hemorrhage into fascial planes, and ventral hematomas. The treatment of choice for anticoagulant rodenticide toxicosis is vitamin K1, which can be administered subcutaneously or orally. If given orally, vitamin K1 should be given with canned food to enhance its absorption. Vitamin K1 should never be given intravenously because anaphylactic reactions have been reported. Vitamin K3 is not efficacious in the treatment of anticoagulant rodenticide toxicosis and, therefore, should not be used. In emergency situations (discussed later), Vitamin K1 should be given subcutaneously after the patient is stabilized; however, its effects will be delayed for several hours. Therefore, whole blood or plasma must be transfused to immediately restore activated vitamin K-dependent clotting factors.
• Metaldehyde - is a chemical that is commonly used as a pesticide against slugs and other gastropods. The central nervous system is either depressed or excited by metaldehyde or its metabolites. Metaldehyde is slowly decomposed in the body to a substance called acetaldehyde, a chemical that acts like a narcotic. Death from metaldehyde poisoning generally results from over depression of control centers in the brain that are responsible for the normal function of respiratory and vasomotor systems. Metaldehyde is readily absorbed into the bloodstream from the gastrointestinal tract. Its metabolites can cross the blood-brain barrier, as evidenced by their effect on the level of consciousness of animals. Autopsies of dogs poisoned with metaldehyde revealed congestion and hemorrhages in the liver, kidneys and heart. The treatment goals in animals exposed to metaldehyde are to prevent metaldehyde absorption, control clinical signs, monitor and correct acidosis and dehydration, and provide supportive care. No antidote exists for metaldehyde toxicosis. (
• Snake venom - Look for swelling, bite wounds where fangs may have entered, and noticeable discomfort, such as lameness or difficulty breathing (if bitten in the face). These are signs that your dog may have been bitten by a venomous snake. Transport your dog to your veterinarian immediately if he's showing any signs of a snakebite. Avoid wasting time by washing the wound. Also, avoid cutting the bite area in an effort to drain venom, as this can lead to other serious injury or infection. Keep your dog still, quiet and warm during transport. Any movement could cause the venom to spread. Attempt to identify the snake if possible, but avoid getting bitten yourself. Wash the wound if your dog has been bitten by a nonpoisonous snake. If you're unsure if the snake was venomous, take your dog to the veterinarian.
• Zinc - Zinc toxicosis has been reported in dogs, but it has not been described in cats, most likely due to their more discriminatory eating habits. It is characterized by an intravascular hemolytic anemia, gastrointestinal upset from direct irritation, and, potentially, multiorgan failure. Common sources of zinc contamination include galvanized coating on iron and steel (cages and nails, metal nuts from transport cages, and fencing), automotive parts, batteries, fungicides, and topical medications. There have been reports of dogs that have ingested large amount of zinc oxide ointment, used to combat skin irritation. Pennies minted after 1982 are made predominantly of zinc (96-98%) with a copper (2.5%) coating. Other sources of zinc include calamine lotion, paints, and shampoos. Note: Treatment of animals should only be performed by a licensed veterinarian. Veterinarians should consult the current literature and current pharmacological formularies before initiating any treatment protocol. The treatment of zinc toxicosis does not have a specifically defined protocol. However, removal of any ingested source of metal toxicity, either by gastroendoscopy or gastrotomy is absolutely necessary . Symptomatic and supportive therapy include correcting for and maintaining hydration, acid-base status, and electrolyte balance. Maintaining adequate renal perfusion is essential since renal failure is a potential sequela
• Arsenic - Clinical Signs: Arsenic is a severe gastrointestinal irritant and commonly produces initial signs of vomiting, restlessness. and abdominal pain evidenced by whining and a defensive abdominal wall. A profuse, often bloody diarrhoea results. This leads rapidly to weakness, dehydration and anaemia. Signs occur within 30 minutes of ingestion and death occurs in a few hours. The goals of treatment are to remove any residual poison, reduce the amount of poison absorbed and enhance elimination of the poison from the body.

Supportive Care

Even if there is an effective antidote available, supportive care may be required. If the toxin has already started affecting body systems, hospitalization with intravenous fluids is recommended. Based on the symptoms and poison ingested, additional supportive care may include:

• Heat support
• Oxygen therapy
• Pain medication
• Anti-nausea medication
• Medication for vomiting, diarrhea, stomach ulcers
• Blood or plasma transfusions
• Sedatives
• Seizure control

Despite all treatment, some poisonings are not amenable to treatment and the pet may not survive.