Seeds of discontent

Cycad (Photo credit: Steve-SF)

Some dogs just don’t care what they chew on – bones, sticks, plants, rocks, the washing on the line, you name it.  The one thing the majority of dogs lack is a discriminative palate and for many, anything is fair game.  I’ve talked about Brunfelsia (yesterday, today, tomorrow plant) and the consequences to dogs of chewing on the plant or seeds.  One of the other plants we see a lot of problems with in emergency practice, here in Queensland at least, is the cycad group.  It was only recently that I realised just what a huge family they are.  And unfortunately, cycad toxicity can have a very bad outcome no matter how aggressive we are with treatment.  The case I am going to discuss does not have a happy outcome, and sadly we face this situation more often than we would like in emergency practice.

I saw a case recently of a young puppy who was found chewing on some seeds in his yard, thought to have been dropped in by the local crows.  The owners had never  seen these seeds before and they were unfamiliar to us as well.  Within a short time of chewing up one of the seeds, the pup began to vomit and was taken straight to its vet, then sent on to us later that day.  The pup was treated with aggressive fluid therapy to support her against a potentially nasty toxin (seeds are often the most toxic part of the plant) and given some medications to help her feel comfortable and control the vomiting.

This is the seed brought in with our patient.  I think it may be from a King Sago Palm (Cycas revoluta)

Through the night she remained fairly settled until the early hours of the morning (when everything tends to crash and die in emergency medicine – human and veterinary!).  She began to vomit repeatedly, vomiting up fluid that looked bloody, and her belly became more uncomfortable.  Given her propensity for eating things she shouldn’t, an x-ray was taken to make sure something was not stuck in her stomach or intestine.  The stomach was HUGE and full of fluid.  Some things will not show up on an x-ray because they have the same density as soft tissue, so there was a chance that there was an object blocking the movement of fluid from the stomach into the intestine that was not immediately identifiable.  We had an ultrasound performed and this confirmed that the stomach was not obstructed, it was just not moving and continuing to fill with fluid.

A blood test had been done earlier in the night which had shown an elevation of two of her liver enzymes, which can often be elevated by non-specific intoxications.  A blood clotting test was also performed which was normal.  But we were now thinking that the liver might have been more affected by the seed toxicity than realised, and when we expanded out search on what the seed might be, we began to consider that we might be dealing with a cycad seed, though not the type we normally see.

King Sago Palm seeds

Macrozamia sp seeds

Encephalartos sp seeds

Cycads are very common in Queensland and other tropical and subtropical parts of the world.  This pictures above show a little of the variation seen in seed structure.  The seed is the most toxic part of the plant, containing higher concentrations of “cycasin”, the toxic agent, which causes the gastrointestinal signs seen and the liver toxicity that results.  Neurological signs may also develop as a result of other toxins in the seed or secondary to the liver effects (hepatic encephalopathy – similar to that seen in the last post on shunts).  The toxicity is not always seen immediately and gastrointestinal signs may take 24 hours to develop while peak effects on the liver may not be seen for up to three days.  So our poor pup must have received a very hefty dose!

Treatment is as for general toxicities, including inducing vomiting (well she had done plenty of that!), giving activated charcoal (which her vet had provided earlier) and the gastric and liver support measures which we had also commenced.  The prognosis is good if the treatment is commenced soon after ingestion and before they have become unwell, however once they are vomiting and sick, the outlook is more guarded.  If liver failure develops, it is far more difficult to treat the disease and the mortality rate approaches 50-60% of animals.  Given that this poor little girl had started vomiting before seeing any vets, her chances were probably going to be a little worse than some other patients.

The pup was commenced on more aggressive liver support measures but unfortunately through the morning she deteriorated further and became quite dull and depressed.  Her blood clotting tests were repeated and were found to be excessively elevated and her liver enzymes had continued to rise.  At this point her outlook was becoming more grim and intensive management with blood products, repeated blood tests and further intensive care was required.  Her owners decided that it was not fair to put her through so much given that there was a high chance she may still die, and she was sadly but humanely put to sleep to end her suffering.

The lesson for us from this sad case, is that we have to keep an open mind about what our pets may have eaten, and what may be causing illness, as it is not always straight forward. It is also a VERY good lesson to pet owners to consider what they are growing in their yard and find out if any of their plants are toxic.  It is much harder if the local crows decide to garnish your yard, so trying to teach your pets about what is and what isn’t available to chew on is a good, albeit potentially difficult, step to take.