Heavy Metal Toxicity In Dogs

Heavy metal poisoning refers to toxicosis due to excessive exposure to heavy metal-containing substances. Heavy metals are naturally occurring metallic chemical elements and metalloids that have a high atomic weight, quite high density (of at least 5 g cm⁻³) compared to water, and toxic even at low concentrations.

The most common heavy metals that are toxic to dogs are mercury, lead, aluminum, cadmium, and arsenic. Heavy metal toxicity can happen through both acute (sudden) and chronic (long-term) exposure to the metal.

Exposure to these probable carcinogens is mainly through medications, diet, environmental toxins, and vaccinations. Heavy metals enter the dog’s body through either inhalation, absorption through the skin, ingestion, or a combination of all three.

For instance, lead has the ability to replace itself with calcium and zinc (both play important role in various metabolic functions) and hence damages the metabolic activity and affects several biological processes. Lead concentrations above 0.25 ppm (or 25 mcg/dl) are considered to be diagnostic of lead poisoning.

General sources of lead include ceramic dishes, paint dust, car batteries, gasoline exhaust, solder, fishing tackle, drapery weights, lead-contaminated water, golf balls, etc. Lead poisoning is fatal and requires immediate veterinary intervention.

Unfortunately, early signs of heavy metal poisoning in dogs are completely ignored as the acute symptoms are so vague and mimic other illnesses found in pets.

Common Symptoms:

• Anorexia
• Nausea/Vomiting
• Fainting
• Increased urination (polyuria)
• Increased thirst (polydipsia)
• Hyperexcitability
• Stupor

Acute Symptoms:

• Diarrhea
• Vomiting
• Weepy or irritated eyes
• Sudden behavioral changes outside your pet's norm
• Sensory confusion
• Sleeping issues

Chronic Symptoms:

• Weight issues
• Movement or coordination problems
• Muscular-skeletal issues
• Cognitive issues
• Cancer
• Heart abnormalities
• Reproductive issues
• Bowel problems/ IBS
• Damage to the nervous system
• Respiratory issues
• Skin issues
• Anemia

Heavy metal toxicosis treatment modality involves stopping exposure, supportive care, and chelation therapy.

• Anti-vomiting medication (antiemetics)
• Intravenous (IV) fluids
• Antacids (e.g., aluminum hydroxide milk of magnesia)
• Anti-seizure medication (e.g., drugs like potassium bromide, phenobarbital, Levetiracetam, Primidone, etc
• Muscle relaxants (e.g., methocarbamol- Robaxin, Robinax, Robaximol)

The gastrointestinal tract must be cleared off from the heavy metals present before chelation can be considered:

• Activated charcoal binding with lead is poor
• Removal from the gastrointestinal tract via lavage, emesis, cathartics, bulking or enema can be considered

Chelation

The main chelators used with heavy metal toxicity are:

• Succimer or meso 2,3-dimercaptosuccinic acid (Chemet)
• Ca-EDTA - Calcium disodium ethylene diamine tetra-acetate
• D penicillamine (cuprimine)
• British-Anti-Lewisite (Dimercaprol)

The risks associated with chelation are acute kidney injury and worsening exposure. This should be done in moderation and carefully to protect the poisoned dog.

Check with your vet to help detox the dogs with herbs

• Liver Detox: Milk thistle
• Circulatory system and lymph system: Burdock
• Kidneys: Marshmallow root or cleavers
• Mercury: Coriander work with spirulina and basil
• Cadmium: Ginger

• Avoiding soil: Don’t allow the dogs from playing in the soil. Perhaps provide plant grass, mulch, wood chips, or a sandbox to cover patches of bare soil.
• Check running water and install a water filter: In unused homes or in old properties with unknown plumbing, run the tap water for some time before use. Change the pipes or it is better not to use tap water for cooking or drinking. Install a water filter to remove heavy metals in the water.
• Avoid certain seafood: Certain sea foods have a high concentration of mercury.
• Train the dogs: Instruct the dogs to reduce the risk of swallowing fragments of aluminum foils from scraps.
• Cleaning the environment: Make the indoor/outdoor environment as dust-free as possible. Clean surfaces with a damp cloth with sanitizer or mop and wipe floors.
• Canned foods: Take care of canned pet foods, especially imported, as long as there is no idea of from manufacturing processes or about the brands.

There is no breed disposition.

1. Causes:

Lead:

• Car batteries
• Lead pipes (and Lead-contaminated water)
• Roofing materials
• Soldering supplies and materials
• Linoleum/tile
• Wine bottle foil
• Rug padding
• Lead lubricants
• Curtain/shower curtain weights

Arsenic:

• Fungicides, herbicides, pesticides
• OTC flea treatments
• Rawhide chews
• Wood preservatives.
• Paints

Mercury:

Mercury-containing seafood such as marlin, king mackerel, Bigeye tuna, swordfish, etc.

Aluminum:

• Drinking water
• Vaccinations
• Pesticides
• Cosmetics
• Packaging materials

Cadmium:

• Grain products
• Soil
• Agricultural processes
• Contaminated food and beverages

2. Morbidity:

Heavy metal toxicity mechanism is not yet understood, however, it mainly affects the 3 main areas- immune system, endocrine system, and neurological system.

• Lead: Blood levels above 400 μg/L of lead are considered to be lethal.
• Arsenic: 5 to 10 mg of arsenic per pound of body weight.
• Aluminum: Small amount of aluminum is not harmful. Over time, when aluminum accumulates in the dog’s body, it will be really harmful.
• Mercury: 500 micrograms/day.
• Cadmium: Really high intake levels are only harmful.

3. Mortality:

Heavy metal poisoning is more common in puppies and in dogs living in underprivileged areas.

4. Diagnosis:

• Complete blood cell count
• Chest and abdomen radiographs
• Complete physical exam

5. Prognosis:

Prognosis in affected dogs is good if treated quickly. Prognosis will depend on the ingested quantity, proper diagnosis, and the timing of treatment.

Contact your vet immediately, if you notice any of the following:

• Intermittent seizures/ Tremors
• The dog regurgitates the meal often

• Plain steamed or baked white fish (whiting, pollock, cod, haddock, etc).
• Milk and milk products (Cottage cheese,

  yogurt

  ), Calcium-fortified foods, and beverages.
• Dark-green, leafy vegetables like spinach, broccoli, and watercress.
• Cooked spinach and potatoes, Rice, sweet potato, and mashed banana.
• Fiber-rich foods: Pears, Apples, oatmeal, and other foods.
• Tempeh, Tofu, legumes, nuts, and seeds.
• Citrus fruits, such as oranges and grapefruit.

Recovery will depend on the proper diagnosis, ingested quantity, and the timing of treatment. Earlier the diagnosis, recovery will be good.

Even large ingestions of poisons in dogs can be successfully treated if they get to the clinic at the right time. On the other hand, Mild ingestions may result in death if the poisoning was not found out until the dog succumbs or the cause is unknown.