Lead toxicity refers to poisoning due to ingestion or inhalation of products containing the element lead.
Cats may be exposed to lead from several different sources including:
Kittens 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. Cats from established urban environments are at higher risk for lead poisoning due to the presence of older buildings. Cats are at high risk due to their grooming behavior. When inhabiting a contaminated environment, cats may groom lead-based paint dust off their fur.
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
If you notice any of the following symptoms, call your veterinarian.
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:
Home Care and Prevention
There is no home care for lead poisoning. Seek veterinary care promptly if you suspect your pet has ingested lead-containing materials.
Administer as directed any medications prescribed by your veterinarian. Observe your pet'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 cats away from areas in an older house (pre-1977) undergoing renovation or remodeling. Also keep cats away from discarded materials during re-roofing of homes. Prevent pet access to garages that may store lead-containing objects.
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 cats 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 cats 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:
The foundation of treatment for lead poisoning involves administration of a chelating agent (drug that binds lead in the blood and allows the lead to be removed from the body). Only one chelating agent is used at a given time and the choice of chelating agent depends on availability. However, lead must be removed from the intestinal tract before beginning treatment with chelating agents, because these medications can increase the absorption of lead from the intestinal tract into the blood stream and worsening of the cat's symptoms.
Optimal treatment for your cat requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your cat does not improve rapidly.