Lead Toxicity in Dogs

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Overview of Canine Lead Toxicity

Lead toxicity, also known as plumbism, refers to poisoning due to ingestion or inhalation of products containing the element lead.

Dogs may be exposed to lead from several different sources including:

  • Lead paint, paint chips or paint dust from when homes are being renovated or remodeled are a common source of lead poisonong. Paints produced prior to 1977 contain high lead levels.
  • Lead weights used as sinkers on fishing poles
  • Lead pellets and shot for use in guns
  • Household items such as drapery weights, linoleum, rug padding, and foil from the tops of wine bottles
  • Automotive parts such as batteries, wheel weights, leaded gasoline and discarded oil from cars using leaded gasoline
  • Construction materials such as solder, putty and caulking
  • Plumbing and roofing materials

    Puppies are more likely to ingest materials containing lead because of their normal chewing and play activities. Younger animals also seem to absorb larger amounts of lead from their gastrointestinal tract than do older animals. Dogs are more likely to eat lead-containing objects than are cats.

    Lead toxicity can cause anemia (low red blood cell count), gastrointestinal symptoms (vomiting, diarrhea) and nervous system problems (seizures). Lead crosses the placenta from pregnant mother to babies and is also excreted in her milk. Thus, the developing fetus and nursing young can be affected.

  • What to Watch For

    Signs of lead toxicity in dogs may include: 

  • Loss of appetite
  • Abdominal pain
  • Vomiting
  • Diarrhea
  • Anxiety
  • Aggressive behavior
  • Muscle tremors
  • Incoordination
  • Weakness
  • Seizures
  • Blindness
  • Deafness
  • Behavior changes
  • Mental “dullness” (not alert)
  • Increased thirst and urinations
  • Shortness of breath
  • Intolerance for exercise
  • Diagnosis of Lead Toxicity in Dogs

    Diagnostic tests are needed to recognize lead poisoning and confirm the diagnosis. Your veterinarian will take a complete medical history and perform a thorough physical examination. He may also recommend the following diagnostic tests:

  • A complete blood count (CBC or hemogram) to detect anemia, nucleated red blood cells, and other red blood cell abnormalities that often accompany lead poisoning (“basophilic stippling” of red blood cells).
  • Serum biochemistry tests to evaluate the general health of the dog, obtain baseline information about liver and kidney function before treatment, and assess the extent of systemic injury from lead poisoning.
  • Blood lead concentration gives the definitive diagnosis. Blood lead concentrations greater than 0.5 parts per million (abbreviated “ppm”) are considered diagnostic of lead poisoning.
  • X-rays of the abdomen and chest are taken to check for lead objects in the intestinal tract and to evaluate the patient for evidence of an enlarged esophagus (which can be seen in lead poisoning) or pneumonia. Lead objects are dense and appear white or gray on the X-rays.
  • Lead concentrations in the feces can be used in place of blood lead concentrations to diagnose lead toxicity.
  • Treatment of Lead Toxicity in Dogs

    Treatment consists of treating clinical signs and providing supportive care, removing the source of lead and giving drugs to bind the lead in the body (chelation),

  • Gastric lavage (pumping the stomach) and enemas are performed to remove any remaining lead from the stomach and intestinal tract. Surgery can also be performed if necessary to remove lead objects from the intestinal tract.
  • Administration of chelating agents (drugs that bind lead in the bloodstream and facilitate its excretion from the body via the kidneys). These include calcium ethylene diamine tetra-acetic acid (Ca-EDTA), penicillamine, and succimer.
  • Fluids are administered intravenously to correct dehydration and facilitate urinary excretion of lead.
  • Anticonvulsant drugs such as diazepam (Valium®), phenobarbital or pentobarbital can be administered to control seizures.
  • Home Care and Prevention

    There is no home care for lead poisoning. Seek veterinary care promptly if you suspect your dog has ingested lead-containing materials.

    Administer as directed any medications prescribed by your veterinarian. Observe your dog’s general condition. Note any symptoms that worsen and bring any changes to the attention of your veterinarian.

    The most important part of preventing lead poisoning is to evaluate the dog’s environment for potential sources of lead and remove them. If a source of lead has been identified and young children in the household have been exposed they should be evaluated by a pediatrician.

    Keep pets away from areas in an older house (pre-1977) undergoing renovation or remodeling. Also keep pets away from discarded materials during re-roofing of homes. Prevent your dog’s access to garages that may store lead-containing objects.

    In-depth Information on Lead Toxicity in Dogs

    Lead toxicity may be acute, due to ingestion of a lead object, or it may be chronic due to repeated chewing of lead paint or grooming the dust of lead paint from the skin and fur. The most common route of exposure is ingestion but lead paint dust may also be inhaled.

    Lead toxicity primarily affects the nervous system and gastrointestinal system. Common neurological symptoms include sudden onset of seizures, blindness, behavior changes, hysteria, chomping, muscle spasms and circling. Lead crosses the placenta and is excreted in milk, so it can affect unborn fetuses and nursing young.

    Gastrointestinal signs include abdominal pain, loss of appetite, vomiting, and constipation or diarrhea. Some animals develop megaesophagus (enlargement of the esophagus and decreased ability to move food from the mouth to the stomach) resulting in regurgitation. Aspiration pneumonia may result from regurgitation. Lead toxicity may also suppress the immune system making dogs more susceptible to infections.

    With chronic exposure, lead is deposited in the tissues of internal organs (liver, kidneys) and in the bones. Lead that is deposited in the bones serves as a “reservoir” and can cause lead levels to remain high despite treatment in some patients. These pets often require long-term therapy.

    Lead inhibits normal remodeling of the long bones of the body such as the femur, tibia, humerus and radius. As a result, specific areas in these bones look denser (whiter) on x-rays and these areas are referred to as “lead lines.” Lead lines do not represent lead deposits in the bone.

    The symptoms of lead toxicity are similar to the symptoms of the following diseases or toxicities:

  • Rabies virus can cause behavior changes and seizures. Dogs with rabies often have a history of exposure to a wild animal or a history of bite wounds of unknown origin.
  • Epilepsy (seizures due to an abnormality in the brain) is typically seen in dogs between the ages of 1 to 7 years. Epilepsy is idiopathic (of unknown cause), genetic, or secondary to trauma or another disease that caused structural changes in the brain. Epilepsy is diagnosed after exclusion of all other possible causes of seizures.
  • Thallium poisoning is rare but can cause gastrointestinal and neurological problems.
  • Strychnine poisoning can lead to seizures. Strychnine products are used to kill rodents but these products are rarely used in the United States.
  • Zinc poisoning can cause depression, loss of appetite, vomiting, diarrhea and anemia. The most common source of zinc is pennies minted after 1983, nuts, bolts and batteries. Zinc toxicity is differentiated from lead toxicity based on x-rays of the intestinal tract and measurement of blood zinc levels.
  • Chlorinated hydrocarbon poisoning (DDT, Chlordane, Dieldrin, Endrin, Aldrin, Chlordecone, and Endosulfan) is rare but can cause depression, vomiting, muscle tremors and seizures which look similar to symptoms caused by lead poisoning. Chlorinated hydrocarbons are used as insecticides.
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