(METALDEHYDE TOXICITY)

In California, snail bait constitutes the most common poisoning agent in the dog. Not that malicious poisoning is the issue; most cases are inadvertent as many gardens have both dogs and snail problems.  Snail bait is commonly formulated in pellets (which can resemble dog food) and flavored with molasses or bran to attract snails (and unfortunately is attractive to dogs as well).  Snail baits are also available as liquids and powders which can get onto paws and be licked off in normal grooming. Very little snail bait is required to cause poisoning (less than a teaspoon per 10 lbs of body weight).

OBVIOUS TWITCHING

Signs of poisoning begin fairly quickly after the poison is consumed. The dog will begin anxious twitching at first only slightly and then uncontrollably. This progresses to seizures and potentially to death. The muscle contractions of the twitches raise body temperature so high that brain damage can result, leading to the colloquial emergency room term “shake and bake syndrome.”

Patients can also exhibit racing heart rates, vomiting, diarrhea, and rigidity, and respiratory failure.

There is a liver failure syndrome that occurs in some patients approximately 2-3 days after poisoning, so it is important for liver enzymes to be monitored by blood tests through out the recovery period.

MAKING THE DIAGNOSIS

Generally, the appearance of the twitching patient is very characteristic even if there is no known history of snail bait exposure. Testing of stomach contents or urine for the presence of metaldehyde can be done but is generally not necessary.

TREATMENT

There is no direct antidote for metaldehyde toxicity; treatment is aimed at controlling the clinical signs.  If less than one hour has passed since exposure, it may be possible to induce vomiting. If the patient is already twitching badly the stimulation involved in inducing vomiting may not be in the patient’s best interest. In this case, the patient can be anesthetized and stomach pumped.  Activated charcoal can be given to prevent absorption of metaldehyde into the body from the intestine. Cathartics (used to induce diarrhea) can also be used with the activated charcoal to assist in removing the metaldehyde from the intestinal tract promptly.

Twitching can be controlled with methocarbamol (a muscle relaxant) or injectable valium^® (diazepam). Fluid therapy and body temperature monitoring will be needed through the recovery period.

Chance of recovery depends on how much poison was ingested, how quickly therapy was initiated, and the general health of the patient. While this is a very serious type of poisoning most patients have a good chance at recovery if treated properly.

At home the yard should be hosed down with water to dissolve remaining metaldehyde and the dog should be restricted from the treated area for a two week period.

This page is dedicated to Justin, companion to Saeeda, who did not survive his exposure to metaldehyde. We promised to put up a web page in his honor to help educate dog owners and hopefully save the lives of some snail bait poisoned dogs around the world.

Page last updated: 9/22/03