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Article © 1996 Darlene Arden. First published in Catsumer Report, February 1996.


Unleaded Cats
Is your cat UNLEADED? Here's what you need to know about Lead Poisoning.


Claudia Arrau. Photograph courtesy Diane Smith.

Ted Kreiter, Executive Editor of The Saturday Evening Post noticed something wrong with his award-winning American Silver Tabby. Catamus lost about half of his body weight over a period of "a month or two, at least." When Catamus would finish eating, he'd throw up. The last thing for which the veterinarian tested turned out to be the cause: lead poisoning.

Kreiter's other cat, Bratamus, a Burmese was unaffected. After three weeks in the veterinary hospital, Catamus returned home and went on a special diet. The culprit? Kreiter isn't sure, but suspects either the crockery bowl from which only Catamus would drink, or possibly lead paint from the old house he's been restoring. (When lead paint is stripped off the walls, it goes airborne. When people or animals inhale the paint dust, it accumulates in the body.)

For insight into lead poisoning in cats, we consulted Paul C. Gambardella, VMD, MS, Diplomate ACVS, Chief of Staff at Angell Memorial Animal Hospital in Boston, MA. According to Dr. Gambardella, older city homes with old chipped paint have been primary causes of lead poisoning in the past. Said Gambardella, "Even if it's not chipping, pets may chew on woodwork or other objects painted with lead paint, and at times the owner won't even know until it's too late." Other major sources of lead are linoleum, old putty around windows; and even drapery weights and newspaper ink.


Terzo minds his P's and Q's.  Photo: Bobbi Florio Graham


Gambardella said that a lead pellet shot under a cat's skin with a gun isn't a hazard. "The lead that's in those, to our knowledge, is not a serious threat -- it doesn't leach out. It's what gets into the digestive tract -- the lead that gets absorbed into the system -- which can cause the toxicity."

Dr. Gambardella says that lead poisoning in pets was a major problem some years ago in Boston. Cases of lead poisoning appeared in his hospital regularly. The animals came in with GI (gastrointestinal) symptoms, and/or neurological signs. Lead poisoning was immediately suspected -- until proven otherwise -- so a blood sample was always submitted for testing for lead.

In some obvious cases, veterinarians would automatically start the lead poisoning treatment after drawing the blood sample, but before getting the results. If the results proved positive, which it did in most of the cases, they would continue treatment. Otherwise, a further work-up was done. At that time, lead was even found in the water, leaching out of lead pipes.

The most common source of lead today is still the older house with lead paint and linoleum, and those inner city areas that have junk piles. What's the leading source from which a cat can get lead poisoning? Household items. "They're not getting this from the soil," Gambardella states. No one knows how much lead must be ingested before a cat gets sick. Gambardella says the amount ingested before a cat dies varies. "That's because if they ingest a small amount over a long period of time, they can take in a lot more before it will reach a lethal level than ingesting a large amount all at once."

How soon the cat will get sick or die if it's not treated depends upon when the poisoning is discovered. "We don't see them until they're ill. Once it reaches a certain level in the blood, it will affect the nervous system and the gastrointestinal tract. Then they get sick," said Gambardella.

The good news is that lead poisoning's not always fatal. "We can give chelating agents to get rid of the lead and take it out of the system -- if you get them in time," said Gambardella.

If a cat ingests a small enough amount of lead that his body can handle, he will not necessarily get sick and die. According to Gambardella, "The difference between a cat and a person is the the person may be affected mentally over a long period of time." A child who has ingested lead for years and who is not developing properly will not do well in school. Sometimes the child doesn't feel well, but can't explain the problem.

Gambardella says, "A chronic problem is hard to measure in an animal. It is very possible that there are cats and dogs that have ingested toxic levels of lead and have lived a fairly normal life, from the owner's standpoint. The lead level may not have been high enough to cause them to have overt signs of illness. Yo have to have a certain level of it before it causes overt signs."

The amount of lead ingested determines how long it will take for signs to appear, "If they eat small amounts, it's going to take perhaps several months; if the cat ingests a large amount quickly it's going to happen right away," reports Dr. Gambardella.

The signs to watch for include: diarrhea, vomiting, seizures, anorexia, hysteria, and non-specific gastrointestinal signs. There is also a range of various neurological signs: convulsions, head pressing and central nervous system signs. (Head pressing is just what it sounds like: the cat goes up to a wall and presses his head against it. It's not known why cats do this.) The brain is affected by lead and so coordination and thinking is affected. There's a weight loss over the long haul, and blindness can occur.

The gastrointestinal symptoms of lead poisoning (vomiting and diarrhea) mimic other diseases, so it's an illness which is often mistaken for other illnesses, such as parasites, viruses, ingestion of foreign material or a change in diet. Twenty years ago, when many urban homes were being renovated and lead paint was very common, inner city veterinarians automatically suspected lead poisoning where gastrointestinal symptoms were involved.

Today, we don't think of lead, however, unless the veterinarian gets a good history. This would include such information as what neighborhood the cat lives in, and if the house is old. The astute clinician might suspect lead poisoning sooner rather than later and immediately take blood for testing. The unsuspecting veterinarian will just treat the GI signs. If there's no response in a day or two, then he may do a blood analysis.

While the main organs affected by lead poisoning are the central nervous system and GI tract, Gambardella notes "It's going to get into every organ in the body and cause a problem for every tissue." Eventually the kidneys will be affected, too.


The Birman Kittens. Photograph courtesy Paula and James Watson



There are no home remedies for lead poisoning. After the diagnosis made by a blood test, the cat must receive chelating agents from a veterinarian. Calcium EDTA is one such agent. Since lead is a heavy metal, Gambardella says, "You have to give them a substance that attaches to it or chelates it. This allows the lead to come out of solution in the blood and be excreted. Treatment can be expensive (five or six hundred dollars) and usually takes about five days in the hospital. The cat receives several injections of the Calcium EDTA a day.

Blood levels are repeated once the therapy is completed. Since the chelating agents are fairly effective, usually only one course of therapy is needed.

 

The medication used is "pretty much off-label, which means it's not legally approved for use in animals," according to Dr. Gambardella. There's an alternative treatment in the works, though. The Angell Memorial Animal Hospital in Boston is participating in the trial of a new oral medication. This new drug is much less expensive and doesn't require hospitalization of the cat. And, a bill going before Congress again this year would allow medication approved for human use to be used legally to treat animals. That would make the current treatment legal.

If your cat is exhibiting the symptoms we've described, you can suggest that your veterinarian check for lead poisoning. Said Gambardella, "Making a diagnosis is very much dependent not only on the clinical signs but also on the history, which leads one to suspect ingestion of lead. Once we suspect lead poisoning, then we can get into specific testing."

Remember that veterinarians serving recently-developed areas may not suspect lead poisoning. Today's construction and the environmental regulations have nearly eliminated the problems from newly-built areas. So it's possible for a veterinarian to treat a cat with G.I. signs for several days or more, and suspect lead poisoning only when that cat doesn't respond. Fortunately, if this occurs, the treatment is still effective in most cases.

As in Kreiter's case, where one cat got sick and not the other, only one cat in the household may be chewing something. Gambardella said, "Sometimes it has to do with dominance -- one animal doesn't let the other one do that," Of course, the crockery water bowl used by only one of the cats may have been the culprit. Crockery food dishes were a problem at one time because lead from the glaze was leaching out into the food and water. Lead-based glazes aren't used on pottery for people anymore.

To safeguard against lead poisoning, Dr. Gambardella recommends de-leading the house and not allowing pets to have materials that contain lead. Virtually all dishes and toys today are lead-free. "Bedding and scratching posts, cat litter, all of the things that you would buy for your pet don't have lead in them," said Gambardella. But it doesn't hurt to read labels and double-check everything.

If you live in a house built before 1960, check into the sources of lead to which you and your animals may be exposed. Lead was used in paints, wallpaper paste, and plumbing joints through the 1960s -- and in some cases, even later.

There's a lot of information available on lead poisoning and children. Awareness is keen now and your four-legged child can benefit from this information, too. Check with your local Building Inspector's office, health department, or library. Remember, it will take less of that lead to cause toxicity in your cat than in a child. Go unleaded and you'll keep your entire family healthy.