Treatment odds for Martha's Vineyard pets
"What's wrong with Baby Buck?" I cried one day years ago when I spied my cat dragging one leg laboriously as she limped across the yard. Rushing out with vivid imaginings of broken bones and mangled flesh, I diagnosed something less dramatic. Buck had discovered one of those sticky-pad mouse traps, which was now firmly glued to her foot.
There's a reason for the old adage, "curiosity killed the cat." Felines love to explore. I have seen their explorations lead them to get covered in everything from candle wax to soot to pine sap to motor oil to Elmer's glue. So I wasn't surprised when Pal's mother called reporting that her kitty had gotten his underside thoroughly coated with latex paint.
"We've been cleaning it off," she said, "but what if he licked some?" My recollection was that latex paint was nontoxic, but I decided to confirm on-line.
"Let's see," I muttered, scanning the screen. "Mild gastrointestinal effects...vomiting or diarrhea. No worries, except — wait — what's this?" Here was a case of a cat who ingested "mildew-resistant" latex paint and subsequently went into acute kidney failure. "Is it labeled mildew-resistant?" I asked. The owner retrieved the can. It was, and the anti-mold additive was none other than ethylene glycol — that's antifreeze — a notoriously lethal substance for felines. Ethylene glycol tastes sweet. Cats like it. Ingestion of a single teaspoon can be fatal.
The paint can said it contained ethylene glycol, but not how much. The big question remained. How much might Pal have consumed? "Call Animal Poison Control," I advised. "The paint company, too. Find out the percentage of ethylene glycol in the paint." Pal's owners hesitated. He seemed fine, except for being mad about being bathed. Could they wait and see if he got sick? After all, we didn't know for sure he had licked the paint.
Ethylene glycol ingestion creates a particularly tricky set of circumstances. First, in order for treatment to be effective, current research indicates it should be started within three to four hours of exposure, although older sources give a window up to eight hours. Once symptoms occur, it's too late. Second, although there is a blood test to detect ethylene glycol in the blood, it's not always definitive.
False positives occur, particularly if the animal has ingested substances that cross-react, like propylene glycol which may be found in treats and medications. False negatives also occur, depending on brand of test, timing, and species involved. Finally, treatment ain't easy. There are two different antidotes. Both involve repeated intravenous injections or continuous infusions over several days, hospitalization, and close monitoring. Both have potential side effects and can be quite costly. "You make those calls," I said. "I'll gather everything to test and treat if needed. Call me back ASAP."
Fifteen minutes later we reconnoitered. The paint company could not say precisely how much ethylene glycol was in the product, nor did Animal Poison Control resolve our dilemma. It was unlikely the paint had enough ethylene glycol to be life-threatening, but they couldn't say for sure. We could run the blood test, but the high incidence of false positives and false negatives make results hard to interpret. They had to recommend treatment, but knew it might not be truly necessary. "If it were my cat," the toxicologist said, "I probably wouldn't be too worried or do treatment." But it wasn't her cat. And we were worried. We decided to run the test.
You can guess what happened next. Results are read by comparing the depth of purple color in the control tube with the sample tube. In some cases, it's obvious. One tube is deep purple, the other, pale lavender. No such luck for Pal. The control turned medium purple, the other reddish-mauve. What the heck does this mean? I wondered, dialing the test manufacturer. "The blood sample was hemolyzed," I explained to their technician. This means some of Pal's red blood cells had broken during drawing and processing, releasing red pigment into the serum.
"That's probably the source of the discoloration," the tech mused. We batted around the details, ultimately concluding the test was negative — maybe. I called other vets looking for another kit to repeat the test. No luck. Our three-hour window for starting treatment was rapidly closing. I showed the owners the tubes. We batted around the details. Seems Pal may have eaten treats that morning that contained propylene glycol. We concluded the test was negative — maybe — or a false positive from cross-reaction with nontoxic propylene glycol — maybe.
"I can start the antidote right now," I offered. "Then you head right to a 24-hour care facility to continue treatment. It will easily cost more than a thousand dollars." I knew money was not the main consideration. If we could pop Pal a quick and simple antidote, we would, regardless of cost, but several thousand dollars, days in ICU, and potential side effects? Did it make sense considering the scenario? "Or we can play the odds," I continued. Odds were the concentration of ethylene glycol in the paint was very small. Odds were he hadn't ingested a significant amount, if any. Odds were it was too late for treatment to be effective anyway. "If he's still healthy Monday, we'll have our answer."
Pal went home. As we waited anxiously for signs of illness, I pondered lessons learned. To always check the most current toxicology information. Otherwise, I would not have learned about the potential risk of ethylene glycol poisoning from usually nontoxic latex paint. That sometimes we don't have all the answers, and sometimes we're just lucky. Day by day Pal's family e-mailed. "So far, so good." "He seems fine." And finally, "We are greatly relieved." Me, too. Just like that long past day with my Baby Buck. We had to shave the gooey mousetrap off her leg and tail, which made for a few bad hair days, but she was otherwise unscathed. Sometimes our cats' nine lives trump that perilous curiosity.